E.I. Alexandrovskaya,1) A.L. Alexandrovskiy2)
In the central part of Moscow, above the surface of the initial soddy-podzolic soil (Podzoluvisol), one can observe the cultural layer that was formed here in the 12-20th centuries. The thickness of this layer reaches 3 m on the elevated watersheds and up to 15 m in the depressions. This layer is markedly different from the background zonal soddy-podzolic soils by the elevated content of organic matter, carbonates, and phosphorus compounds. Organic matter is represented by detritus and humic substances; the overmoistened horizons preserve considerable amounts of wooden remains of house constructions and wooden chips. The main sources of carbonates in the cultural layer are the limestone, which was used as building material, and, mainly, the constructional lime, which has been widely applied after the transition from the wooden construction to the stone one in the 17-18th centuries. In result of migration of carbonates into the lower lying layers, including the buried podzoluvisols, the reaction in these layers has changed from acid to alkaline. The input of municipal phosphorus-containing wastes resulted in the increase in the phosphorus content by 100-200 times as compared with the initial soils (from 1-5 to 200-550 mg/100g).
The studies within the Red Square evidence that the buried podzolic soils, which were cultivated in the 11-12th centuries, contain insignificant quantities of metals and other elements owing to the initially impoverished composition and acid reaction, and the absence of industrial pollution in those times. In the cultural layers of the 12-13th centuries, the accumulation of organic matter, predominantly in the form of wooden chips is traced as well as the accumulation of carbonates, phosphorus, metals (Zn, Cu), and arsenic; arsenic-bearing minerals were used for tanning.
The above-lying thickness is represented by predominantly organic cultural layer of the time of wooden construction (14-17th centuries) and lime-brick layer of the 17-19th centuries with inclusions of the horizons of garden, park, and waste-land soils, which could form during the pauses (or slow rates) in accumulation of the cultural layer. This thickness is enriched in Ca, C, Pb, As, Cu, Zn, and other elements, whose concentration is 40- to 150- times greater than that in the background soils. All these elements were widely applied in construction and various industries; they were used for paints and, also, were applied for pest control in orchards and gardens.
The cultural layer of the
city is an accumulator and reservoir of a huge amount of substances
withdrawn by human activity from the adjacent areas. For example,
within the limits of the boulevard circle, the amount of organic
matter accumulated in the cultural layer reaches 7.5x105
t against 2.5x104 t in the initial soils, i.e., increased
by 30 times. Taking into account the total urban area (more than
1%), one can calculate that the sink of organic carbon into the
cultural layer constitutes more than 3% of the total reserves
of organic carbon in the pedosphere. Accumulation of CaCO3 in
the cultural layer within the boulevard circle and within the
whole city is assessed at 1.5x106 and 1.5-2x107
t, respectively. The amount of mobile phosphates (by the Kirsanov
method) increased from less than 2x103 t in the initial soils
of Moscow to 4x104 t. The content of lead within the
limits of the boulevard circle increased from 2x101
to 2x103 t; for the whole city these values constitute
1-2x103 and 3x104 t, respectively.Soils
and Paleosols of Burial Mounds Near the Novosvobodnaya Settlement
(North Caucasus): Trends and Rates of Pedogenesis
A.L. Alexandrovskiy
Institute of Geography, Russian Academy of Sciences,
Staromonetnyi 29, Moscow, 109017 Russia
The studies of modern and buried soils on the dated surfaces of different age are of great importance for solving the problem of soil development in time. We studied the series of burial mounds (5500-1000 years BP) near the Novosvobodnaya settlement on the foothills of the Northwest Caucasus (500-600 m a.s.l.; oak-beech forest zone): (1) Burial mounds (up to 5-7 m in height and up to 60 m in diameter) with the age of about 5500 years. These mounds are composed of chernozem, loess, eluvial horizons of soils, and alluvial deposits of various lithological composition. Mature Luvisols have formed on these mounds; (2) Burial mounds composed of loess sediments with limestone paving on which rendzinas have formed; (3) Chernozems buried under the mounds of the Bronze and Neolithic age; the 14C age of humus substances from these Chernozems varies from 6450+100 to 9780+580 years; (4) Degraded Chernozems and Luvisols buried under the mounds of younger age; (5) Interglacial (Mikulinskaya epoch) soils buried within the loess deposits; (6) Background Luvisols with the second humus horizons inherited from the chernozemic stage of soil development (7130+40 years) and with krotovinas and carbonate concretions; (7) Luvisols of truncated surfaces from which the material for the burial mounds construction was taken; (8) Background soils (leached Chernozems) buried under limestone pavements. Paleopedological data testify that during the Holocene this territory experienced strong environmental changes. Thus, in the Early and Middle Holocene steppe landscapes propagated up to 700-m height. The expansion of broad-leaved forests from the mountains to the footslopes took place 3500 years ago.
Within the last 3000 years, mature Luvisols have developed on the chernozem- and loess-composed burial mounds and on the truncated surfaces around the mounds. The leaching of soil carbonates took place at the beginning of the first stage of forest pedogenesis, within tens-the first hundreds of years. Afterwards, the lessivage process started. The rates of lessivage were the same for the chernozem-composed and loess-composed mounds (0.3-0.5 t/ha annually). The transformation of clay minerals in soils is less evident (Alexandrovskiy and Birina, 1986). Rendzinas have developed on the mounds composed of calcareous material, because the release of bases from the weathering limestone fragments prevents the destruction of clay-humus complexes and substantially retards the development of lessivage. The buried soil of Mikulinskaya interglacial epoch had a different evolution (as compared to the Holocene soils). In this soil, the stage of textural differentiation preceded to the stage of humus horizon formation. The features of textural differentiation are well preserved in the profile.
Our investigations prove that
the soils of the Holocene (which is an analogue of interglacial
stages) have experienced a complex evolution; the features of
modern soils reflect just the latest stage of this evolution;
the soil profile that had formed by the Holocence optimum has
completely destroyed or strongly transformed during the second
half of the Holocene.
W. Andres, J.Wunderlich, H. Rittweger, S. Nolte, P. Houben, C. Berger
Institut für Phyicalische
Geographie, J.-W. Goethe Universität, Frankfurt a. M.,
Germany
The research presented here is carried out within the DFG (German Research Organization) priority programme "Changes of the Geo-Biosphere during the past 15,000 years - Continental Sediments as Evidence for Changing Environmental Conditions".
The working group of Prof.
W. Andres concentrates on the reconstruction of the late Glacial
and Holocene environmental changes documented by sedimentary and
pedogenetical features in two study areas within the Hessian Depression.
Fluvial sedimentsas well as lacustrine and colluvial deposits
in small restricted catchments are investigated in order to distinguish
between natural and man-made changes. Therefore, we make use of
litho-,bio-, chronostratigraphical, tephrochronological and pedostratigraphical
methods. These methods comprise the field survey and laboratory
analysis of sediments and colluvia, palynology, microfossil and
macrofossil analysis, radiocarbon dating, heavy mineral analysis,
magneto-stratigraphy (magnetic susceptibility), and chemistry
of isotopes.
Late-Glacial palaeosols
The late Quaternary stratigraphical
record of a reach of theWetter river reveals stable stream channels
and the dominant depositionof overbank fines during the Late-Glacial.
Several palaeosols consisting of weak A- horizons developed. Organic
muds at the base of the overbank fines (OF 2) were submitted to
pollen analyses. Plant macrofossil survey and pollen-analyses
indicate an abandoned channel fill surrounded by a tundra environment.
Radiocarbon measurements of selected organic fragments give early
Late-glacial dates of 13,000 1 190 yr B.P. and 12,250 1 90 yr
B.P. Although pollen analysis from the buried soils of the overlying
overbank fines (OF 3 and 4) produced pollen at concentrations
too low to count routinely, the pollen content indicates environmental
conditions of a cold climate. In contrast to the other gleyed
overbank fines, in OF 3 iron-oxide concretions and a number of
undisturbed tubelike iron-oxid bodies occur. They may have developed
because of intense gleying above an impeding layer, possibly a
permafrost table Therefore, from sedimentary and palaeopedological
properties we extract palaeoenvironmental information as follows:
After the deposition of the Late-Wurmian Lower Terrace the flood
deposition of overbank fines represents a change from a braided
precursor to the Late-Glacial fluvial environment. The fluvial
system concentrated on one channel mainly caused by a more continuous
runoff. As the deposition fines is due to dominant suspended load
supplied by the loess-mantled terrain, marked periods of soil
erosion occurred probably under cold climatic conditions
Boreal-Subatlantic Black Floodplain Soil
In numerous central European floodplains a dark brown to blackclayey horizon developed between Late-Glacial and middle or late Holocene deposits. Although this so-called Black Floodplain Soil (BFS) is a very common phenomenon of German valley floors (e.g Becker 1982, Händel 1967, Mäckel 1969), detailed investigations were only carried out at a few sites. Due to the scarcity of well preserved organic matter like pollen or macro remains the formation of the BFS is still uncertain. histosol, which was later on affected by a nearly total disintegration of organic matter. Only stable organo-mineral complexes persisted.
Analysis of the distribution
of certain stable isotopes (d13 C org, d34 S tot) is currently
being conducted to reconstruct the palaeoecological conditions
(e.g. sulphur cycle) during the formation of the BFS. Preliminary
results indicate a formation under anaerobic conditions. Numerous
pollen analyses (Rittweger 1997) support this interpretation,
as the results are indicative of a swampy area underneath a canopy.
Extremely high clay contents are attributed to a low-energy deposition,
caused by a dense vegetation cover. Pollen analytical results
and radiocarbon datings accord with other authors, which give
age ranges of the formation period of the BFS starting in the
Preboreal/early Boreal period and lasting until Atlantic or even
Subboreal (cf. Mdckel 1969, Stobbe 1994). At present, we discuss
the hypothesis that the ensuing disintegration may correspond
to a lowering of the groundwater table caused by the more dry
climate of the Subboreal. The ongoing research will focus on
the chronostratigraphic significance of the BFS within the early
or mid-Holocene palaeoenvironmental and archaeological framework.
References
BECKER, B. (1982): Dendrochronologie und Paläoökologie subfossiler Baumstämme aus Flurablagerungen. Ein Beitrag zur nacheiszeitlichen Auenentwicklung im südlichen Mitteleuropa. - Mitt. Komm. Quartärforsch. Österreichischen Akad. d. Wiss., 5: 1-120.
HÄDNDEL, D. (1967): Das Holozän in den nordwesstdeutsche Flurauen. - Hercynia N. F., 4: 152-198.
MÄCKEL, R. (1969): Untersuchungen zur jungquartären Flurgeschichte der Lahn in der Gießener Talweitung.
Eiszeitalter u. Gegenwart, 20: 138-174.
RITTWEGER, H. (1997): Spätquartäre Sedimente im Amöneburger Becken. Archive der Umweltgeschichte einer mittelhessischen Altsiedellandschaft. - Mat. Vor- und Frühgesch. Hessen, 20 (in press).
STOBBE, A. (1994): Die holozäne Vegetationsgeschichte
der nördlichen Wetterau - paläoökologische Untersuchungen
unter besonderer Berücksichtigung anthropogener Einflüsse.
- Dissertationes Botanicae, 260: 216 pp.
R. Bäumler and W. Zech
Institute of Soil Science and Soil Geography,
University of Bayreuth, D-95440 Bayreuth,
In South Kamchatka soils developed from Quaternary glacial and glaciofluvial deposits were studied with special regard on pedogenesis and the reconstruction of the history of the landscape. Study sites are located in the Plotnikova valley near Natschiki, at the western foothills of the Balaganchik range (1117 m asl) close to the edge of the depression of Apacha, and at the modern sea coast of the Okhotsk Sea near Ust-Bolsheretsk. In the mountains and close to the mountains, two moraine complexes could be identified at the valley bottoms 400-500 m below a series of Lateglacial and/or Holocene terminal moraines. Both complexes are correlated with glaciofluvial terraces and descend to 260-300 m asl and 280-350 m asl, respectively. The relief of the lower one is smooth- and vague-shaped without kettles, wheras the younger one is characterized by a well formed relief showing a lot of kettles and ridges.
The soils developed from this glacial or glaciofluvial deposits are covered by multiple layers of tephra resulting from explosive volcanic eruptions throughout the Holocene. Intensive studies on tephrochronology were carried out by the Institute of Volcanic Geology and Geochemistry in Petropavlovsk-Kamchatskiy. Due to their results, the deepest, resp. oldest tephra was derived from one of the most explosive caldera eruptions of Kuril Lake and Il'Inskaya 7.600-7.700 yr BP.
The intensity of soil development and the relative dating of the buried soils was carried out using weathering indices and pedogenic iron oxides. The analytical results show slight differences between both complexes. In addition, the soils of the older deposits reveal stronger cryogenic disturbances. The boulders and gravels are characterized by more pronounced weathering crusts in comparison to the younger drift and terraces.
The results indicate that both complexes are of Late Pleistocene origin. The older drift was probably deposited during an early phase of the Late Pleistocene and more pronounced than the younger one. The younger complex characterizes a second phase of the Late Pleistocene glaciation probably equivalent to the last glacial maximum in Western Europe. According to the differences in soil development, both phases are separated by an interstadial and not by an interglacial.
In addition, we found glacial deposits at the modern coast of the Okhotsk Sea resting on fluvial conglomeratic gravels of more than 5 m. The glacial deposits are characterized by thick weathering crusts around the boulders (1-3 cm) and by numerous pronounced and deep fossil ice wedges and cryoturbatic features in comparison to the glacial deposits at the foothills and in the valley bottoms of the mountains. The glacial drift is covered by compact limnic sediments (100-150 cm) followed by soil horizons developed from eolian deposits of fine sandy-silty texture (200-220 cm), and by the multiple layers of Holocene tephra (80-100 cm) which we also found at the soils of the Late Pleistocene deposits. Between the buried moraine soil and the limnic sediments we found remains of white tephra extremely rich in potassium. The volcanic deposits belong to a large caldera eruption of the Opala volcanoe about 40.000 yr ago.
J. Berenyi Üveges1), P. Stefanovits1), E. Micheli1), W.W. McFee2)
Hungary belonged to the periglacial belt in the Pleistocene Epoch. Soils influenced by periglacial processes are observed in several locations as burried soils or on the surface due to erosion[3]. Examples located on the Pediment of Mátra mountains were chosen for studying macro and micromorphology of relic periglacial soil formations. Some of them are common forms like ice wedges[1], [4] and involutions[1], [4] others show unique characteristics that are the result of several different periglacial processes and biological activity.
A red clayey paleosol[2] and calcium-carbonate accumulations in different forms occur on most of the locations. The difference in the stratigraphy (occurrence or lack of layers with special characteristics) and paleotopographic position caused the difference in morphology of the different sites.
The selected sites are:
Visonta: ice wedges in the wall of an open lignithe mine
Kerecsend: ice wedges and involutions
Hered: contorted forms in a layer consists of red clayey soil and lime
Atkar: unusual pattern in a layer consists of different materials (red clayey, yellowish gray clay and lime) triggered by biological activity, cryoturbation and other types of frost action[5].
REFERENCES
[1] F. A. COOK, L. HAMELIN (1967): Illustrated Glossary of Periglacial Phenomena
[2] PECSI M. (1985): The Neogene Red Clays of the Carpathian Basin In: Studies in Geography in Hungary, Akademiai kiadó, Budapest pp89-98
[3] STEFANOVITS, P.(1971) Soils of Hungary, Akademiai Kiado, Budapest
[4] WASHBURN, A. L. (1969): Periglacial Processes and Environments, Edward Arnold, USA p172
[5] VAN VLIET-LANOE, B. (1985): Frost Effects in
Soils In: Soils and Quaternary Landscape Evaluation, John and
Wiley and Sons Ltd. Pp117-156
A. Bronger1) and S.N. Sedov2)
1) Department of Geography, University of Kiel, D-24098 Kiel, Germany
2) Department of Soil Science, Moscow Lomonosov
University, 119899 Moscow, Russia
Selected surface Terrae rossae or Rhodoxeralfs from calcarenites of Mid-Quaternary age along the Atlantic coast of Morocco in the more moist Rabat - Casablanca area show a considerable formation of clay minerals including kaolinites. The main sources of the pedogenically formed kaolinites, mostly of disordered structure and poor crystallinity, are primary feldspars >2µm and smectites (2-0.2 and <0.2 µm) inherited from calcarenites as parent material, though some eolian input is not excluded. The resource of weatherable minerals in the C horizon, however, is not sufficient enough to explain quantitatively the rate of clay increase in the Bt horizons by weathering in situ only. An explanation of the differences in clay content partly by clay illuviation meets some difficulties: first, almost no well developed or aged illuviation argillans are visible in the Bt horizons of the majority of Terrae rossae. However they occur in several BCk horizons covering carbonates as unstable surfaces. With deepening of the leaching front former illuviation argillans might be destroyed by argillipedoturbation and bioturbation. Both processes are documented micromorphologically; only the „youngest" generation of illuviation argillans in present BCk horizons is visible. Second, an eluvial horizon is mostly absent. For this soil erosion seems to be responsible, as well as for the patchy distribution of Terrae rossae as a result of human activity which is still grossly underestimated in comparison with Quaternary climatic variations in this area. Thus combination of weathering and „masked" clay illuviation allows to explain mostly the high ammount of clay mineral formation including kaolinites in this „typic xeric" soil moisture regime with still some water surplus in the first three months of the year in the northern part of this area. On younger calcarenites (< 100.000 years) only rendzinas to weakly developed Terrae rossae with small clay mineral formation are found. According to literature mediterranean climatic conditions with minor fluctuations persisted in the Rabat - Casablanca area throughout the Quaternary: the mean annual temperature in the „glacial" cycles was only about 2-30 C below today or in the mesic at the border to the thermic soil temperature regime; the water budget tendencies according to field observations and models for the last „glacial" period suggest conditions somewhat moister than at present. Therefore we conclude that the Terrae rossae with high ammount of clay mineral formation including kaolinites are formed in a period of several 100 000 years in a similar climate with only minor fluctuations and therefore should be named vetusols according to an earlier proposal of M. Cremaschi.
In the southwestern part between
El-Jadida and Agadir with a „dry xeric" if not „aridic"
soil moisture regime Terrae rossae occupy much smaller areas mostly
in depressions. They show still moderate partly higher rate of
clay mineral formation but with only small amounts of kaolinites
if any. Former decalcification as a precondition of the higher
silicate weathering occured in all probability during periods
of distinctly more moist climate in the past. Micromorphological
features of recent recalcification are frequent in these Terrae
rossae, indicating that they are no longer in equilibrium with
present day climate. Therefore these soils are regarded as non-buried
paleosols (relict soils)
Bronger1), N. Bruhn-Lobin1), P. Wichmann1), L. Zoller2)
In a climatic sequence from ten to one humid months per year nine surface derived soils from saprolite of weathered granitic gneiss in South India were examined for recent and relict soil features. Besides soil chemical properties the studies were focussed on the mineralogy of sand, silt and clay fractions as well as on micromorphological features of the soils and its parent material. Above a threshold of 2000 mm (6 humid month) in an Udic Rhodustalf deep weathering is a recent process leading to the formation of kaolinites. Above 2500 mm in 900 m a.s.l. (10 humid months) in a Typic Rhodudult and a Typic Hapludox it leads also to the formation of gibbsite. These soils are considered to be Vetusols, old non buried soils which unterwent the same or very similar processes of soil formation over at least several 100 ka under a similar constellation of the soil forming factors. Under (now) drier conditions in Typic and especially Aridic Rhodustalfs earlier soil-forming processes such as deep weathering and strong kaolinite formation have almost ceased; instead secondary carbonate is accumulating in the saprolite (Cr) and lower part of the Rhodustalf (Lixisol) Bt horizons. We conclude that most Alfisols (not only Ultisols) or Lixisols in now seasonal semiarid India are relict soils or non buried paleosols formed in an earlier period of much more moist climate than the present.
For a confirmation of these conclusions six selected "Red Soils" in two intramontane basis of hyperthermic SW-Nepal with 1600-1800 mm rainfall/year (5-6 humid months) were investigated by the same methods for comparison. In some of these soils resp. the underlying parent material traces of late paleolithic cultures have been found; first TL-dates give an age between 10-30 ka. Main results are that the yellowish silty parent material of the "Red Soils" is a fluvial redeposited (partly aeolian?) already preweathered soil sediment. The primary mineral composition contains only few easy weatherable minerals: around 5 % feldspars and 10-15 % phyllosilicates which are mostly muscovites. Only surprising little pedogenic clay mineral formation could be identified. The illites in the soils are predominantly of detritic origin and are inherited as well als the kaolinites. The few non-regular mixed - layered minerals in the fine clay fraction (< 0,2 um) are regarded as a possible initial stage of the silicate weathering. In contrast the hematites are proved to be of pedogenic origin. Therefore the rubefication is an autochthonous and recent process; rubefication of soils alone is not a reliable indicator for strong pedogenic weathering.
To summarize an important
result is that the efficiency of weathering in the seasonal tropics
has been overestimated by far in many cases especially in the
geomorphologic literature, in which the weathering is assumed
to be as fast or even father than the surface erosion. However,
in today semiarid India the soil development processes have changed
and the rate of compensatory regeneration of soil is in effect
(almost) zero. The soil erosion there is consequently a permanent
loss of the country's most important natural resources, but it
has not been recognized as such because the soils were not identified
as paleosols.
N. J. Conrad, T. Schneidermeier
Institut für Ur- und
Frühgeschichte und Archäologie des Mittelalters, Abteilung
Ältere Urgeschichte und Quartärökologie, Universität
Tübingen, Im Schloß - Burgsteige 11, 72070 Tübingen
The objective of the project is to reconstruct climatic and ecological changes in Southern Germany during the late Middle and Upper Pleistocene and to assess how these changes impacted Middle Paleolithic subsistence, technology and settlement. The project adresses the following questions:
These questions cannot be answered using the current database of knowledge available for the Middle Paleolithic in Southern Germany. Therefore we conducted prospections to locate new, potential, open-air sites which offer a clear stratigraphic context. The ideal stratigraphic situation for an open-air, archaeological site contains loess deposits with visible paleosols from previous interglacial and interstadial periods. In our prospection strategy, localities with preserved paleosols situated near known archaeological sites, such as excavated cave sites and surface collections, have been chosen. Through borings, geophysical measurements and geochemical analysis, information about paleorelief and chemical composition of soil horizons have been gained. In a well stratified sequence, archaeologically significant layers and other marker horizons may be identified and extrapolated over the landscape.
Since its beginning in June,
1996, our project has logged approximately 100 cores with a total
depth of 450m, performed 19 hand-augered borings and recorded
eight soil profiles in Southern Germany (Upper Rhine, Middle Neckar,
Ingolstadt and Straubing Basins, Schwabian and Franconian Alb).
Through the cooperative efforts of several research teams within
the SFB, the initial results about paleorelief in the researched
areas are now complete. The next step will be to identify archeological
horizons using chemical variables. To this end, we have recently
initiated chemical analysis of different parameters, such as phosphate,
polyaromatic hydrocarbons and lipids.
G. Durn1), F. Ottner2), A. Mindszenty 3), D. Aljinovic1)
Red soil known as terra rossa is the most extensive soil type in Istria. It is recognised as polygenetic paleosol but also constitutes pedo-sedimentary colluvial complexes. The intent of the present study is to determine the origin and composition of terra rossa in Istria by mineralogical, geochemical, and micromorphological methods.
The coexistence of hematite and goethite, and typical average value of Fed (dithionite soluble iron) in terra rossa from Istria support specific pedoenvironment of terra rossa formation (Boero and Schwertmann, 1989). Kaolinite which does not form intercalation compounds with DMSO (highly disordered kaolinite), hematite and goethite represent authigenic mineral phases in terra rossa. The differences in REE observed in terra rossa can primarily be attributed to the different REE content in parent rocks and less to fractionation during the weathering processes.
External material contributions
have strongly diminished the influence of insoluble residue of
limestones and dolomites as the primary parent material of terra
rossa in Istria. This polygenetic material is mainly composed
of strongly weathered and reworked loess of the Lower and, more
probably, Middle Pleistocene age. It also contains (1) reworked
relicts of old terra rossa-type soils which might have formed
from limestones, dolomites and flysch, and (2) remains of eroded
bauxites of Jurassic and Paleogene age. Due to processes of erosion
and redeposition they are more or less incorporated in terra rossa.
The external material observed in the upper part of some terra
rossa profiles represents Upper Pleistocene loess.
X-M. Fang1-4) Y. Ono2), S. Nagatsuka3), D.-H. Guan1), B-T. Pan1),
J-J. Li1), H. Fukusawa4), M. Torii5)
The 24 m Shajinping loess section on the second terrace of Huang He (the Yellow River) in the City of Lanzhou has been found to have developed 22-layers of paleosols each 30-50 cm in thickness occurring at similar intervals of about 1 m (ca. 2,500 years) during the past 60,000 years BP, in which four paleosols are Holocene in age (equivalent to marine oxygen isotopic stage MIS-1) and five in the late last glacial (MIS-2) and thirteen in the last mega-interstadial (MIS-3). Field observations and laboratory analyses including soil micromorphology have indicated that Holocene paleosols are weekly-moderately developed luvic calcisols in type characterized by a thin massive-channel Ah horizon, a thick distinct dull brown (7.5YR 5/3) medium angular blocky ped Bw horizon relatively rich in organic matter and clay content and low in carbonates (round 9 wt %), and a clear massive Bk horizon with carbonates up to 16 wt % as fine nodules and channel coatings and infillings. Paleosols in the last glacial and last mega-interstadial are mainly weekly developed manifested merely as a thin dull yellowish brown (10YR 5/4 - 4/3) massive-medium blocky ped ochric A horizon or mollic A horizon slightly rich in organic matter and clay content and low in carbonates (round 9-10 wt %) as fine nodules and thin coatings. However, there are six relatively strongly developed paleosols are pedogenetically similar to those in Holocene with their organic matter and clay contents in Bw horizon and carbonate enrichments in Bk horizon being only slightly lower than those of Holocene soils respectively. Emphasis should be placed to that these six relatively stronger paleosols occur also at similar intervals of 3-4 m.
Continuous sampling of the
section at 2.5-5 cm intervals for measur of contents of carbonates
and organic matter and magnetic susceptibility have yielded decadal-
to century-scale climatic records. These records have demonstrated
that the Asian summer monsoon experienced rapid episodic warm
pulses lasting only about several hundreds to two thousands of
years in the last mega-interstadial and late last glacial. These
warm pulses can be well correlated to warm peaks or periods of
the oxygen isotopic climatic record from the GRIP ice core in
Greenland. Most of these warm pules occur in non- or quasi-orbital
forcing cycles and have pedogenic responses as described above.
This phenomenon in one hand may indicate that pedogenesis is a
continuous process in response to climatic changes and only needs
less than few hundreds of years in equilibrium to a climate in
semiarid and arid areas. The so called "monogenetic or polygenetic
soil and mature or unmature soil" are meaningless concepts
in high resolution soil climatic research and in area such as
the Chinese Loess Plateau where soil parent materials (dusts)
accumulate continuously. Thus those soil concepts should be aborted
or just limited to use as very loose concepts in relation to timescales.
In other hand, warm pulses of the Asian monsoon may suggest that
there are other alternative mechanisms and driving forces to drive
Asian monsoon changes, besides recognized Milankovitch and Northern
Atlantic Ocean climate-driving forces.
D. Faust1), F. Diaz del Olmo2)
1) Lehrstuhl Phys. Georaphie, Kath. Universität, 85071 Eichstaett
2) Sevilla, Spain
During Holocene climatic influence
on morphodynamics becomes insignificant. Morphodynamic is mainly
influenced and reigned by human activity. Environmental changes
and changes in morphodynamics (activity and stability) can be
observed in silty flood plain sediments. In our opinion the conditions
for morphodynamic processes are related to social and cultural
conditions (soziokulturelle und soziooekonomische Bedingungen
bzw. Zustaende) during the past. We like to present some first
results of paleomagnetic analysis in the sediments of the Rio
Fraja allowing to identify phases of morphodynamical activity
and stability in the region. The research is accompanied by geoarcheologigal
analysis (dating of ceramics). In Holocene floodplain sediments
of the rio Fraja valley (Prov. Cçdiz) one can observe humic
dark grey horizons which indicatein situ soil forming processes.
Geoarcheological research (ceramics), C14AMS
analysis as well as paleomagnetic examinations in the hole exposure
allow exact stratigrafic classification of the sediments. It is
possible to distinguish in situ soil forming processes from removed
soils (ex situ). In addition the paleomagnetic examinations indicate
a short time event of reverse polarity.
P. Felix-Henningsen
Institut für Bodenkunde
und Bodenerhaltung, Wiesenstraße 3-5, D-35390 Gießen
Paleosoils of humid periods are farly spread on ancient dunes of the Sahara in eastern Niger. They were investigated along a SW-NE traverse across the TJnJrJ desert and the southern Tchigai mountainous region with respect to theit stratigraphical and paleoclimatical indication. On all sites only one generation of ancient dunes was found, overlain by recent, active eolian sand sheets and dunes. Terrestrial paleosoils display an up to 100 cm thick red brown to yellow brown Bw horizon and can be classified as Chromi-Cambic Arenosols and Cambic Arenosols respectively. The structure of the soil horizons is stabilized by pedogenic cementation and losened by bioturbation. Characteristics of clay migration are alo micromorphologically not detectable. Fine substance from clay and silt fractions form birefringent coatings around quartz grains of the sand fractions. Therefore the Bw horizons display a marked hue, althoug the contents of fine substance < 63 :m are less than 10 %.
Since the neolithic humid period the denudation of the paleosoil in flat areas amounted only to some centimetres to decimetres. Towards the shore region of extended paleolakes the terrestrial paleosoils transform into Gleyic Arenosols. The former shore lines are marked by fringes of stem-like to massive oxide accumulations ("bog iron ores"), which were formed in the upper part of Go horizons by accumulation of iron oxides around roots and stems of the shallow water vegetation. Within the paleolake depressions white bleached ancient dunes due to gleying are coverd by lacustrine sediments rich in silt. Neolithic artefacts strewed on top of the lacustrine sediments indicate, that the paleolakes did not exist in their original extension during the neolithic humid period. Therefore they give evidence of older wet periods with enhanced humidity. The thickness as well as the characteristics of the paleosoils gives evidence for a development during the Early Holocene humid period. Because characteristic of lessivation are completely missed, as they are typical for paleosoils of Pleistocene humid periods, a higher age seems not to be probable.
Due to the decrease of humidity
during the humid periods from SW to NE, the degree of rubefication
as well as several physical, chemical and mineralogical properties
of the paleosoils display a more or less narrow correlation to
the geographical location of the sites along the traverse. A gradient
of decreasing weathering intensity of the terrestrial paleosoils
in the same direction is superimposed by local variations of
mineralogical properties of the parent materials and dust yields.
Introduction to Excursion C
P. Felix-Henningsen
Institute of Soil Science
and Soil Conservation, Wiesenstr. 3 - 5, 35390 Giessen, Germany
Weathering of Paleozoic slates and sandstones of the Rhenish Massif in western Germany, which occurred during the Upper Mesozoic and Tertiary under warm, humid tropical to subtropical climatic conditions, led to the formation of a regolith up to 150 metres thick. In flat upland areas of the Hunsrück and Eifel, where the tectonic uplift was relatively weak, remnants of this weathering mantle, more or less truncated by Upper Tertiary and Pleistocene erosion, are still preserved. On overlapping sections and drill cores of an autochthonous paleosoil and the saprolite underneath, the morphological, geochemical and mineralogical zonation of a complete profile of the weathering mantle has been reconstructed.
A fossil pre-Oligocene Plinthitic Acrisol, covered by Oligocene fluvial sediments, displays characteristics formed under a high groundwater table. On the other hand the underlying saprolite can be subdivided into a lower reduction horizon and an upper oxidation horizon, each of them more than 40 meters thick. This indicates a polygenesis of the weathering mantle during the Tertiary, due to descending groundwater tables caused by the beginning tectonic uplift of the Rhenish Massif and drier climatic periods during the Middle Tertiary. During the Upper Oligocene the deposition of kaolinitic clays derived from removed horizons of the kaolinitic soils started in fault-block depressions. Periglacial processes during the Pleistocene led to a further removal of the weathering mantle and to the deposition of superficial layers on top of the autochthonous remnants of the saprolite. Presently the kaolinitic sediments as well as the saprolite are exploited as kaolin deposits.
In the Vogelsberg area near
Lich Miocene basalt which weathered in Middle Miocene saprolite
is exposed. Deep weathering caused the neoformation of kaolinite
and gibbsite. Due to periglacial redistribution the saprolite
is covered by a red kaolinitic-gibbsitic soil sediment, which
derived from Miocene Ferralsols.
P. Felix-Henningsen, T. Scholten & M. Schotte
Institut für Bodenkunde
und Bodenerhaltung, Justus-Liebig-Universität, Wiesenstr.
3-5, 35390 Gießen, Germany
Introduction
Remnants of autochthonous kaolinitic weathering mantles, which can be subdivided into the two genetic sections "solum" and "saprolite", are farly spread in old land areas outside the recent humid tropics, e.g. in Middle Europe or South Africa. They developed under warm and humid (tropical) climatic conditions, mainly during Cretaceous and Tertiary. Kaolinites are the typical mineral neo-formation and, according to their structural properties, several ordered and disordered types can be subdivided. The latter are typical for soils and saprolites. Intercalation of kaolinites with Dimethyl-Sulfoxide (DMSO) allows a distinction between different types of kaolinites by x-ray diffraction. While well ordered as well as b-axis-disordered kaolinites (s. BRINDLEY 1961, BAILY 1963, RANGE et al. 1969) change their basal spacing from 0,72 nm to 1,2 nm due to intercalation of DMSO, "fireclay minerals" show no reaction and therefore an "intercalation disorder" (RANGE et al. 1969).
Systematic investigations
of the type and quantity of disordered kaolinites in soil-saprolite
complexes from slates of the Rhenish Massif (Germany) and from
crystalline rocks in Swaziland (Southern Africa) were carried
out. The results are discussed with respect to the genesis of
the weathering mantles and stratigraphically correlated sediments.
Methodology
The mineral composition of
silt and clay sub-fractions was detected with orientated, Mg and
Glycerol treated samples by XRD. Primary Fe-Mg chlorite, occurring
in samples of lower saprolite horizons from slates, was eleminated
by treatment wit Hcl in order to identify a kaolinite peak at
0,72 nm. A maximum of DMSO intercalation of orientated kaolinite
samples was reached by DMSO vaporation at 70° C after 72
hours.
Results and Discussion
In the up to 100 m thick saprolites from Lower Devonian slates of the Rhenish Massif kaolinite derived from weathering of the primary Fe-Mg chlorite and illite, which occur in fresh slates beside muscovite and quartz. As an intermediate stage in lower saprolite zones smectites may occur with small amounts (< 10 %). In upper saprolite zones (10-20 % clay) the maximum content of kaolinite in the total fraction amounts to 20 - 30 % and increases up to 95 % in the soil horizons (65 % clay) of an Lower Tertiary ferralitic Paleo-Gleysol. The kaolinites of all soil horizons and saprolite zones are of b-axis disordered type with Hinckley indices < 0,3 in soils horizons and 0,5 - 0,3 in saprolite zones.
With regard to intercalation of DMSO there are distinct differences between kaolinites of soil horizons and of saprolite zones. About 90 - 100 % of the amount of kaolinites from all saprolite zones show a shift of the basal spacing from 0,72 to 1,1 nm, due to the intercalation of DMSO, while only up to 10 % of the kaolinites are characterized by intercalation disorder.
Kaolinites of the Tertiary paleosoil display an increasing proportion of "fireclay-minerals" with intercalation disorder from the bottom horizon (about 10 % ) to the uppermost horizon (about 80 %). Within the silt and clay subfractions there is an increasing amount of "fireclay minerals " with decreasing grain size. The maximum amount of "fireclay minerals" is to be found within the fraction < 0,02 nm of the soil horizons.
These differences in kaolinite disorder between saprolites and ferrallitic soils seem to be typical and independent from the type of parent material, since kaolinites of soil-saprolite complexes from crystalline plutonic rocks (granite, diorite) in Swaziland (Southern Africa) show the same differences and quantities of disorder.
According to RANGE et al (1969),
intercalation disorder of kaolinites results from irregular isomorphic
tetrahedral substitution of Si by Al. Additional positive charges
are gained from K+ or H+ ions in the neighbourhood
of those tetraherdal sites, leading to distortions and partial
strengthening of bonding energies between the silicate layers,
which the polarizing forces of the DMSO molecules cannot overcome.
Furthermore an octahedral isomorphic substitution of Al by Fe+++
ions (HERBILLON et al. 1976) may enhance the bonding energy between
tetrahedral and octahedral layers, due to the bigger ion radius
of the Fe+++ ions.
Conclusions
The preferential neo-formation of "fireclay minerals" in horizons of ferrallitic soils indicates diffent chemical conditions compared to those in the saprolite. The ferrallitic soils, rich in hematitic iron oxides, are characterized by relatively strong acidity, desilication and congruent dissolution of kaolinite. SiO2:Al2O3 molar-rations < 2 of the NaOH-soluble soil fractions prove, that secondary kaolinite, which predominantly occurs in the fine clay fraction, obviously crystallized under conditions of Si deficiency in the soil solution. Additional Fe+++ ions were present, due to oxidizing conditions in the soil horizons with consequence of ferrihydrite formation as a precursor of hematite. Therefore tetrahedral and octahedral isomorphic substitution in primary and secondary kaolinites of the soil horizons was probable. On the other hand kaolinites in saprolite zones developed under moderate acid conditions and a relatively high Si activity of the pore soulutions, with consequence of a lesser extent of isomorphic substitution.
Beside the pedogenetic aspects,
the type and quantity of kaolinite disorder enables to subdivide
between ferrallitic soil horizons and saprolites as sources for
kaolin sediments and periglacial superficial layers in Middle
Europe. Because the formation of "fireclay minerals"
is a characteristic of soil horizons, also the sedimentary kaolins
of the Rhenish Massif, which derived from erosion of the Tertiary
soil cover since Upper Oligocene, are rich in kaolinites with
intercalation disorder.
References
All citations are documented as references in:
FELIX-HENNINGSEN, P. (1990):
Die mesozoisch-tertiäre Verwitteriungsdecke (MTV) im Rheinischen
Schiefergebirge. - Relief, Boden, Paläoklima, Band 6, 192
S., Borntraeger Berlin, Stuttgart.
U. Hardenbicker
Dep. of Geography, Martin-Luther-University
Halle-Wittenberg,, Domstr. 5, 06108 Halle (Saale), FRG
In the eastern Harz Foreland buried Quaternary loess
paleosoils are of great importance for the recent landscape development,
esp. role for erosion processes. Subsurface erosion is preferentially
located in areas where paleosoils or saprolite bedrock are underlying
loess. The shallow groundwater that flows in the valley deposits
upslope of the gully head appears to follow the subsurface paleotopography
marked by paleosoils. In the eastern Harz Foreland 20 km west
of Halle (Saale) -near the village Langenbogen- patterns of recent
subsurface erosion processes which are mainly caused by subsurface
paleosoils are investigated. In this studies the initiation and
evolution of forms by subsurface erosion above the nearly impermeable
paleosoils is examined. The subsurface erosion processes occur
in a Pleistocene depression filled by up to 15 m thick layers
of fossil paleosoils, esp. humic zones, solifluction material
(reworked loess) and loess. The paleosoils are an Eemian
interglacial soil complex
with a lessive and one or two humic horizons (early Weichselian)
at the upper border of loess deposits. They could be found by
borehole drilling on an area of 100 m x 500 m in a depth up to
8 m. (7°). Subsurface erosion i.e. results from a second
drainage network, that is connected to the first network on the
surface influenced
by relatively impermeable
layers. Because of
their low permeability the zone above the fossil humic zone with
underlying paleosoils is the main zone of subsurface erosion.
However, thin humic and clay layers in the 1 to 2 m thick reworked
loess can cause subsurface erosion, too. The roofs of hollow spaces
and pipes consist mainly of wuermian loess. The first visual signs
which are built up by subsurface erosion are little sinkholes.
Sometimes collapses of the pipe roofs take place in segments resulting
in a line of holes and gullies on the upper surface. They reach
a maximum depth of 2 m. Next a few pipes in a depth of 3 to 5
m where the paleosoils are situated merge and initiate wide badlandlike
forms by collapsing. Anthropogenetic factors like deforestation
and agriculturing and esp. the loss of the A-horizon by soil erosion
increase the infiltration into the subsurface layers. Linear hollows,
induced by men since the Middle Ages have intensified the hydraulic
gradient of subsurface waterflow above the buried paleosoils.
In the study area initiation and evolution of subsurface erosion
result from a combination of natural and anthropogenetic factors.
During the passed 50 years the intensification and mechanisation
of agricultural production -which went together with a marked
enlargement of the plots of land- accelerated the subsurface erosion.
The relevance of the buried paleosoils for young quaternary morphological
processes and interrelation to the human impact are investigatet.
A.V. Ivanov1), V.F. Babanin1), S.A. Shoba2)
1) Yaroslavl' State Technical University, Yaroslavl', Russia
2) Moscow State Lomonosov University,
Moscow, Russia
Magnetic susceptibility of buried and non-buried paleosols is considered to be of high value for paleoclimatic deductions. This opinion is based mainly on very good correlation between curve of magnetic susceptibility in loess-paleosol sequences of Central and Eastern Asia and d 18O record in marine sediments. However for correct paleoclimatic interpretation we must know the origin of increase of magnetic susceptibility in upper soil horizons compared to parent material (which is observed in majority of paleosols and modern soils).
Magnetite and maghemite are regarded as paramount agents responsible for the average magnetic susceptibility of the soil profile. In a big variety of modern soils (well developed as well as primitive) we found, separated and studied with scanning electron microscopy specific silt-size spheric particles of these minerals (iron spherules) concentrated mainly in the uppermost horizon. These particles are at least partly responsible for the increase of magnetic susceptibility in these horizons. We do not exclude also that biogenic synthesis of magnetite and maghemite contribute to this increase, this hypothesis being supported by resent observations on bacterial synthesis of magnetite. Pedogenic synthesis of this minerals from solutions could be very limited and located only in areas with reductive conditions and oxygen deficite.
Iron spherules proved to be of cosmogenic, technogenic and volcanogenic origin. Both technogenic and volcanogenic input is strongly dependent on the distance from local source whereas cosmogenic fallout is more or less uniform over Earth surface. Cosmogenic fallout is assumed to occur constantly over Earth history ; volcanic deposition is clearly periodical and technogenic input started approximately two centuries ago.
The accumulation of cosmogenic
iron spherules (and increase of magnetic susceptibility) in humus
horizons of soils is dependent upon soil environment the conservation
of spherules being facilitated in automorphic "zonal"
soils. In humus horizons of buried soils the prerequisites for
magnetic minerals synthesis and decomposition change. Conservation
of magnetic spherules and partially of profile variations of magnetic
susceptibility is possible only in stable oxidizing conditions.
Anyhow the weakening of magnetic susceptibility maximum in buried
humus horisons is found to be dependent upon duration of burial.
P. Kallis, Klaus E. Bleich , K. Stahr
Institute for Soil Science
and Site Ecology (310), University of Hohenheim, D-70593 Stuttgart,
Germany
There had been reports from occurrences of concentric carbonate concretions (fresh-water carbonates, lepolites, pisolites) on the Swabian Alb northern of the miocene sea shore since the turn of the century. Since then the genesis of these carbonates is discussed controversely.
Gile et al. (1966) and Wright & Tucker (1991) introduced models for terrestric carbonates based on morphological characteristics. The described characteristics are also formed in palustrine (Platt & Wright, 1992) or lacustrine systems and Sanz et al. (1995) see them as typical for distal areas of floodplains. Verrecchia (1994) interpreted this conformity of characteristics between different environments as a polygenetic genesis.
The investigated object, miocene 'fresh-water carbonates' in a deposit of Upper Fresh-Water Molasse located in Heidenheim-Mergelstetten, Germany (Reiff & Müller, 1993; Kallis & Bleich, 1994) was analysed geochemically and micromorphologically. The supposed fresh-water character (only fossil terrestrial snails have been determined) could be confirmed by analysis of stable carbon- and oxygen-isotopes. The mean values of d13C =-7.2‰ and d18O = -4.5‰ (PDB) are comparable to the results from cretaceous and tertiary lacustrine carbonates (Cameros Basin, Spain: Platt, 1989; Steinheimer Becken, Germany: Reiff, 1992).
Analysis of the micro-facies revealed the characteristics described for terrestric carbonates. Also identified features of reworking (intraclasts), grey/black pebbles and a carbonatization restricted to the depression area cannot be explained by using a pedogenic model and are indications for an allochthonic genesis. Cathodoluminescence-microscopy confirms the meteoric character of the sparitic cements and allows a differentiation into three phases of formation according to different luminescence behavior (Baker & Kopp, 1991). The arrangement of zones suggests a chronological variation of the environment from oxidizing conditions at the beginning of cementation to reducing conditions (last event of pore filling). These two extreme conditions are linked by a phase of rapid cristall growth and a subsequent phase of frequent changes between oxidizing and reducing conditions. According to Platt (1989) this cemente sequence corresponds to the meteoric/phreatic conditions during lake regression and subsequent transgressions.
The results suggest that the
formation of these miocene carbonates has to be based on a polygenetic
model, whereas the formation of the primary compounds took place
under a palustrine/lacustrine environment. Subsequently they were
superimposed by pedogenetic processes.
Literature:
BAKER, C. E. & KOPP, O. C. (1991): Luminescence microscopy and spectroscopy. Qualitative and quanitative applications. - SEPM Short course: 25, Dallas/Texas.
GILE, L. H., PETERSON, F. F. & GROSSMAN, R. B. (1966): Morphological and genetic sequences of carbonate accumulation in desert soils. - Soil Science, 101: 347-360, Baltimore.
KALLIS, P. & BLEICH, K. E. (1994): Bodenentwicklung im Jungtertiär am Rande des Molassebeckens (Heidenheim-Mergelstetten/Ostalb). - Mitteilgn. Dtsch. Bodenkundl. Gesellsch., 74: 379-382, Oldenburg.
PLATT, N. H. (1989): Lacustrine carbonates and pedogenesis: sedimentology and origin of palustrine deposits from Early Cretaceous Rupelo Formation, W Cameros Basin, N Spain. - Sedimentology, 63: 665-684.
PLATT, N. H. & WRIGHT, V. P. (1992): Palustrine carbonates and the Florida Everglades: Towards an exposure index for freshwater environment? - J. sed. Petrol., 62: 1058-1071, Tulsa/Oklahoma.
REIFF, W. (1992): Zur Entwicklung des Steinheimer Beckens. - Jh. geol. Landesamt Baden-Württemberg, 34: 305-318, Freiburg.
REIFF, W. & M&UUML;LLER, S. (1993): Ein Vorkommen von Oberer Süßwassermolasse bei Heidenheim und seine Bedeutung für die Landschaftsgeschichte. - N. Jb. Geol. Paläont. Abh., 189: 255-274, Stuttgart.
SANZ, M. E., ALONSO ZARAZA,
A. M. & CALVO, C. P. (1995): Carbonate pond deposits related
to semiarid alluvial systems: examples from the Tertiary Madrid
Basin, Spain. - Sedimentology, 42: 437-452.
R. A. Kemp1), A. J. Busacca2), P. A. McDaniel3)
3) Department of Plant,
Soil & Entomological Sciences, University of Idaho, Moscow,
USA
The loess-paleosol sequence of the western Palouse in northwestern USA represents one of the best terrestrial records of climatic change in North America. A sound dating control is provided by the interbedded tephra layers, which can be correlated on the basis of elemental analysis of volcanic glass and volcanogenic ilmenite to specific eruptions from adjacent volcanic centres. The loess and tephra units thin and the climate becomes moister towards the eastern margin of the Palouse, resulting in welding of paleosols and bioturbative mixing of tephra within the paleosol complexes. Tracing of the individual loess and paleosol units across the whole of the Palouse region is therefore difficult due to the low stratigraphic resolution of the sequence in the east.
Detailed micromorphological
analysis of five (non-buried) welded paleosol profiles within
this eastern zone has allowed
the constituent
pedosedimentary processes to be reconstructed on the basis of
depth trends and superimposition of associated pedological and
sedimentary features. The elemental composition of individual
glass shards within some of the faunal excrements and illuvial
clay coatings comprising the microstratigraphic associations have
been determined and correlated to tephras from specific volcanic
eruptions. The microstratigraphic positions of these dated glass
shards provide not only clues to the timing of initiation of fragipan
development, but also unequivocal evidence of Holocene clay illuviation
within these welded paleosols. Furthermore, they highlight a potential
means of correlating different stages within pedosedimentary reconstructions
to the high resolution sequence in the west.
A. Kleber
Chair of Geomorphology,
University of Bayreuth, 95440 Bayreuth, Germany
In deep soil profiles of semiarid areas, argillic and calcic properties are often associated within the same horizon. Both properties cannot have formed simultaneously, because carbonate enrichment and clay translocation are mutually exclusive in one horizon at one time since clay translocation is only possible while carbonate is being depleted (natric properties were not observed in the soils under study). Thus, such horizons indicate carbonate enrichment subsequent to clay translocation. Argillic horizons enriched with pedogenetically translocated carbonate are therefore considered older than their carbonate overprint.
There are four main sources of the carbonate enriched in soils, and two of them may be excluded for most studied soils. (1) Ascending or lateral enrichment is impossible due to the lack of nearby ground water in most soils. (2) Weathering of Ca2+ ions from bedrock cannot apply to certain bedrock types, which contain no significant amounts of Ca-bearing silicate minerals. The remaining possibilities are (3) parent material carbonate leached from the upper profile down into lower parts and (4) the influx of airborne calcium as dust fall and/or Ca2+ ions in rainwater.
Loess is admixed to many parent
materials, as indicated by the abundance of coarse silt in many
profiles compared to C horizons, and by the heavy mineral suites;
it may have been a source of carbonate. However, the carbonate
enrichment must have succeeded the formation of the argillic horizons
as outlined above; since the clay translocation needed essentially
carbonate-free material, there would not have been sufficient
carbonate to form the Bk horizons after the formation of the argillic
horizons. Thus, the carbonate could stem from more or less steady
eolian influx onto the soils. Several Bk horizons at various depths,
as occurring in many profiles, could then be explained by several
climate-driven episodes of varying leaching intensities, each
leading to an horizon of carbonate enrichment. Any intense leaching
event would dissolute older calcic horizons higher in the profiles;
this implies a decreasing trend of leaching intensity with time-i. e.
during the Pleistocene because comparable soils are absent on
Holocene surfaces. However, in the lake history of nearby Tuz
Gölü and Great Salt Lake, comparable climatic trends
are not displayed for instance by the lake levels. Another problem
with this hypothesis is that calcic horizons occur to depths of
4 m. According to models, a thermic soil temperature regime
is needed to form calcic horizons as deep as 3 m. It is unlikely
that the areas have experienced such a climate since the Tertiary.
Another complication comes from buried soils, which often bifurcate
without changing their properties, so that several composite horizons
are separated by fresh, largely unaltered material, indicating
distinct phases of pedogenesis. Apparently, neither alternative
(3) nor (4) is alone sufficient to explain all phenomena. The
phenomena may rather be explained by multi-phase models: several
phases of deposition and synchronous loess enrichment were each
followed by major pedogenic phases, leading to sequences of buried
soils in areas of predominant deposition, and to multi-storied
polygenetic soils in other areas, each being formed during approximately
A.O. Makeev, T.E. Yakusheva
Dokuchaev Soil Institute, Moscow, Russia
Soils of the Russian Plain are mostly formed on glacial and periglacial sediments and are so deeply influenced by postglacial lithogenesis combined with paleocryogenesis and paleopedogenesis that should be regarded as surface paleosols. To study their genesis and geography combined pedological and geological approach is needed.
A prominent feature of glacial sediments is their vertical stratification, that is the result of a polifunctional and polichronous character of postglacial sedimentation. Such a stratification increased during the final stages, resulting in a microstratigraphy of an upper part of parent rock strata withing the profile of surface soils. Cryogenic and slope processes could influence microstratigraphy especially in this final stages. Each genetic type of glacial and periglacial sediments is characterised by specific type of microstratigraphy, that is very constant regardless of where and when it was formed, because similar mechanism of deposition was succesively reproduced in different areas following the retreat of an ice shield. This steady sequence of layers and features in parent rock strata within surface soil profile we call lithomorphotype of soils. Lithomorphotypes serve as a lithological matrix, that have determined constitution of soil profile and soil geographic pattern.
In contrast with other Great Plains of the Northern hemisphere the areas of different glacial shields do not coinside with each other. Differences in glaciodinamics of glacial shields superimposed on specific latitudinal type of Russian Plain macrotopography produced extensive belts with the predominance of different combinations of lithomorphotypes. Lithomorphotypes on limnoglacial sediments are abundant in an area of Valdai/Wurm age. A complex of lithomorphotypes on mantle loams, ground moraines and paragenetic fluvioglacial sediments predominates in an area of Moscow/Riss II age. Lithomorphotypes on loess mantles are widely spread in an area south of Moscow glaciation. Modern soil geography of Russian Plain is a result both of a bioclimatic and lithogenic zonality. To study the real bioclimatic impact we need to trace soil sequence in different environmental conditions but with similar lithomorphotypes. As an example we traced soil lithomorphotypes on typical loesses and mantle loams.
The main feature of soils
on mantle loams is texture-differentiated profile formed by two
phases of eolian accumulation of material from different sources:
the heavy part (B and C horizons) - ground morain material; light
textured layer (A2 horizon) - loessic dust of fluvioglacial deposits.
In a wide area from tundra to steppe the constitution of this
lithomorphotype principally similar and does not correlate with
bioclimatic conditions. Universal features of soils with loess
lithomorphotypes studied in an wide area from middle part of taiga
zone to central part of steppe zone are: 1) absense of textural
differentiation, even under taiga vegetation, with slight variability
of texture in soil horizons; 2) differentiation of loessic material
on brownish and whitish microstripes even on gentle slopes produced
by mud flow and solifluction. Paleocryomorphic features are present
mainly in southern and western parts of main loess area. They
confirm sequential sedimentation of loess strata. Cryomorphic
features include "swell and swale" microtopography with
microstriping on the slopes, paleohydromorphic humus horizons
in the bottoms of depressions and differentiation of secondary
carbonates with their leaching in soils of depressions and accumulation
in soils on the interfluves. In both soil lithomorphotypes bioclimatic
impact may be seen in gradual increase in depth of humus layer
and humus content. Studies of lithological matrix in different
soil lithomorphotypes, allow to define more accurately the possibilities
of modern soil formation.
S. Miara
Geologisches Landesamt
NRW, 47710 Krefeld
In the years 1991-1995 the Middle and Upper Pleistocene sediments in the area of Baltringen (north of Biberach a.d.Riá), which is the stratotype area of the Riss-glaciation after Penck und Brückner (1901-09), were reinvestigated. The focal point of the investigations were the sandy and silty loess loam sediments covering the Lower ("untere Hochterrasse") and the Upper high terrace ("obere Hochterrasse").
The results of pedochemical, pedophysical and micromorphological investigations of the aeolian cover sediments show different interstadial and interglacial palaeosoils within the loess profiles.
The development of various palaeosoils within the profiles requires different stratigraphic ages for the Lower and the Upper high terrace. The different stratigraphic age of the high terraces results from the different position of the last interglacial (Riss/Wurm-(=Eem-) Interglacial) palaeosoil within the profiles of the Upper and Lower high terrace.
On the Upper high terrace the last interglacial soil is developed in the lower part of the loess profile in a sandy loess covering the weathered gravel ("Schotterlehm"). The results from the heavy mineral analysis express that the sandy loess originates for the most part from the sediments of the Upper Marine Molasse ("Obere Meeresmolasse"), which is deposited east of the Upper high terrace.
On the Lower high terrace however, the Riss/Wurm-interglacial soil is represented by brown weathered gravel. TL-dating of aeolian cover sediments from the Upper high terrace confirm the pedostratigraphic interpretation.
The weathered gravel on top of the Upper high terrace, situated below the Riss/Wurm-interglacial soil derived from sandy loess, suggests another warm period (intra-Riss interglacial) between the aggregation of the gravel from the Lower and Upper high terrace. The question that an even older glacial-interglacial cycle is to be included into the Riss-glaciation complex (suggested e.g. by SCHREINER 1989) is not concerned by these results.
The molluscs collected from
the calcareous loess on top of the aeolian cover sediment on the
Upper high terrace indicate moist pleniglacial conditions at the
time of its deposition. The TL-datings place this calcareous loess
into the younger part of the upper pleniglacial, not younger than
about 16,000 calendar years.
References:
MIARA, S. (1995): Gliederung der riáeiszeitlichen Schotter und ihrer Deckschichten beiderseits der unteren Iller nördlich der Wurmendmoränen.- Münchener geogr. Abh., Bd. B 22, 33 Abb., 18 Tab., 185 S., München.
MIARA, S. (1997): Schwermineraluntersuchungen an quartären und tertiären Sedimenten im Riátal bei Baltringen (Iller-Riá-Schotterplatte, Baden-Württemberg, SW-Deutschland).- Jber. Mitt. oberrhein. geol. Ver., N.F. 79: 53-78, 10 Abb., 1 Tab., Stuttgart.
MIARA, S., Zoller, L., Rögner, K. & Rousseau, D.-D.(1996): Quartäraufschlüsse bei Baltringen/Riá und Gliederung des Riá-Komplexes - neue stratigraphische, pedologische und geochronologische Aspekte.- Z .f. Geomorph. N.F., 40, 2: 209-226, Berlin, Stuttgart.
PENCK, A. & BR&UUML;CKNER, E. (1901-09): Die Alpen im Eiszeitalter.- 3 Bd., 1199 S. Tauchnitz-Verlag, Leipzig.
SCHREINER, A. (1989): Zur
Stratigraphie der Riáeiszeit im östlichen Rheingletschergebiet
(Baden-Württemberg).- Jh. Geol. Landesamt Baden-Württemberg,
31: 183-196, Freiburg i. Breisgau.
E. Micheli 1), W.W. McFee 2), J. Berenyi 1), P. Stefanovits 1)
Hungary was not covered by icesheets however evidences of the changing climate and the climatically controlled features of the Quaternary period can be observed. The periglacial environment of Pleistocene Epoch had an important effect on the formation of Hungary's current surface [3],[4]. The terrain developed in earlier geological periods was significantly modified by periglacial processes and the development of the loess cover which is the most common parent material of Hungarian soils was deposited during this epoch also [3], [5].
In addition to the most common periglacial processes such as loess deposition, solifluction, formation of ice-wedges [2],[6], at some locations of Hungary unusual evidences of frost induced calcium carbonate accumulation and cryturbation can be observed [4]. Since most of the studied formations are at or close to the surface their characteristics are influencing the current environment and the agricultural potential of cultivated soils. This paper will discuss the characteristics, the supposed genesis and classification problems of typical periglacial soil formations in Hungary.
In the Hungarian soil classification system there is no category for frost-affected soils. The two systems widely used internationally, US Soil Taxonomy and the FAO classification, also lack categories for such soils, however there are new proposals to fit these soils. The International Committee on Permafrost-Affected Soils (ICOMPAS) proposed the addition of the order of "Gelisols" with cryopedogenetic properties [1].
The proposed "World Reference Base for Soil Resources" (WRBSR) includes the category of "Cryosols" for permafrost affected soils, those developed under the environmental conditions of thawing and freezing [7].
The authours of the paper
suggest that several of the studied soils show the properties
of past cryogenic processes and satisfy the requirement of the
suborder of relic "Turbels" or relic "Statels"
of Gelisols and the category of relic Cryosols in WRBSR.
REFERENCES
[1] Circular Letter No. 3, June 8 1995 of the International Committee on Permafrost-Affected Soils pp7-11
[2] LOZINSKY, W. (1909): Uber the mechanische Vervitterung der Wandsteine im germassigten Klima. Bulletin International De l' Academie Polonaise des Sciences et des letters. 1:1-25
[3] PECSI, M. (1985): The Neogene Red Clays of the Carpathian Basin In: Studies in Geography in Hungary, Akademiai Kiado, Budapest pp89-98
[4] STEFANOVITS, P (1971): Soils of Hungary, Akademiai Kiado, Budapest
[5] SZEKELY A (1983): The Pleistocene periglacial geomorphology of the Matra mountain. Proceedings of Geography pp99-216
[6] WASHBURN, A. L. (1969): Periglacial Processes and Environments. E. Arnold, USA p172
[7] Word Reference Base for Soil Resources (1994) ISRIC, Wageningen, FAO, Rome pp3, 48-51
A. Mindszenty,1 )B. Varga,1)Z. Horvath,1)L. Fodor,1)R. Zeese2)
Paleosols developed within and above sediments of the Kerri Kerri alluvial complex were studied in order to see the eventual response of a rather peculiar intertropical pedogenetic environment to climate change during and partly also after Kerri Kerri times.
Two profiles (of 60 and 75 meters total length) were measured and studied in details.The Takur profile is situated at the southernmost tip of the Kerri Kerri Plateau, close to the contact of Kerri Kerri sediments with the underlying Late Cretaceous Gombe sandstone. The other profile Kadi was logged at one of the classical outcrops, described earlier by Adegoke et al. (1986). It is a spectacular outcrop close to the periphery of the Mega Chad Basin, where Kerri Kerri sediments gradually pass into the lacustrine environment of the Chad Formation. The rest of the Kerri Kerri area was checked at several points at reconnaissance scale along the Yuli river, Yankari and Gombe.
Field observations proved that weakly to moderately developed, single to composite and cumulate, intraformational paleosols mainly associated with overbank sediments of the alluvial system are frequent all over the Kerri Kerri area. They are characterized by abundant gleying and profuse clay illuviation. Their clay mineralogy (predominant kaolinite) is in apparent contradiction with their weak to moderate profile development. The anomaly is easily explained, however, by the highly preweathered nature of the parent sediment, major constituents of which are quartz, inherited kaolinite and particulate ironoxide..
Intraformational alterations are partly overprinted by the effects of deep weathering associated with an episode of lateritization which has affected the area of the former alluvial basin after the alluvial system was shut down. Subsequently, an obvious period of rhexistasy resulted in large scale soil erosion, ferricrete and ferriband formation. It is suggested that landform evolution related to the above outlined sequence of events involved also major (repeated) rearrangement of the the groundwater hydrological regime as a result of which many of the ferricretes, now capping the hilltops, could have been formed at places of regional groundwater discharge. Some of the ferribands encountered in the alluvial sequence may also be related to the same paleohydrological processes inasmuch as they seem to occur in the vicinity of sharp permeability gradients provided by the intraformational paleosols mentioned above.
The poster will present particularities of both the intraformational paleosol suite
and the capping ferricretes.
On conclusion it is suggested
that intraformational paleosols described from the Takur profile
were formed on top of fining upward alluvial cycles, they are
regularly stacked one above the other, and reflect rather stable
autocyclic control, whereas in Kadi the "paleosols cum sediment"
complex records an episode of extremely high rate of sanddeposition
following a preceeding episode of lower rate, fluviolacustrine
sedimentation. After the deposition of the thick tabular sandstone
complex a period of aggradation and cumulate soilformation commences
then, coarser grained sedimentation resulting in more or less
irregular alluvial cycles resumes again. The record points to
a much less equilibrated system than the one reflected by the
Takur profile.
The capping laterites and
ferricretes are considered as witnesses of a major environmental
change reflecting considerable drying following a long lasting
period of rainforest coverage. Since stratigraphic control is
inadequate we can but speculate whether this major environmental
change was related to the Oligocene or the Mid Miocene climate
deterioration recorded world wide.
References
ADEGOKE,O.S.AGUMANU,A.E.BENKHELIL,M.J.AJAYI,P.O.(1986): New stratigraphic, seidmentologic and
structural data on the KerriKerri Formation, Bauchi and Borno States, Nigeria. Journ.African Earth Sci.
5. 3 249277
LANG,J.KOGBE,C.ALIDU,S.ALZOUMA,K.DUBOIS,D.HOUESSOU A.TRICHET,J.(1986): Le Sideroloithique du tertiaire ouestafricain et le concept de continental terminale. Bull.Soc.Geol.France 2. 4. 605622
Morozova T.D., Dlussky K.G.
Institute of Geography,
Russian Academy of Sciences, Moscow, Russia.
The aim of the present work
is to revise the structure of long-term climatic fluctuations
during the interval between Elster (Oka) and Saale III (Moscow)
glaciations based on paleosols and their diagenesis analysis in
the Oka river drainage basin (53-55°N, 36-44°E). The
region under study is located in recent zones of broad-leaved
forests and forest-steppe. It is the northernmost region of middle
Pleistocene soils preservation on the East European Plain. The
specific feature of region is the widespread erosion in the past.
The results of micro- and macromorphological studying and humus components properties investigation have allowed to reach conclusion, that 2 independent interglacial soils were formed in this region in the considered time interval. The loess-like silt accumulation took place between soil formation epochs.
Polygenetic soil with textural
differentiated profile A1-A2-Bt1-Bt2 was
formed during the first (more ancient) soil forming epoch. It
is characterised by two maxima of C(org) content and domination
of fulvic acids and humin in humus composition. Silt-clay cutans
are present from top to bottom of the soil profile. Plasma has
skelsepic orientation throughout the whole soil profile too. Thus,
the immature polygenetic soil was formed under more cool and humid
climate, than the modern one on the given area. We believe that
the soil corresponds to the Kamenka paleosol by soil forming time.
The erosion-sedimentation
stage began after this warm soil forming epoch. A non-stratified
loess like silt about 1.5 m thick was accumulated during this
epoch. Then, this silt was wholly involved in soil forming. Cryogenic
deformations of underlying paleosol have not been recorded.
The second (more young) warm
middle Pleistocene epoch was also complicated. Corresponding paleosol
has very distinct illuvial horizon and thick humus horizon with
domination of structured humic acids in humus composition. The
soil is heavily disturbed by cryogenic deformations. The humus-clay
cutans are abundant. We consider this paleosol to be poligenetic,
since the position of eluvial part of soil is 0.5 m below the
paleosurface. The micro- and macroagregation is excellent. Probably
at first paleoenvironmental conditions were more humid and after
some sedimentation got drier and probably warmer. We believe the
soil corresponds to the Romny paleosol.
The short interval of initial
soil forming was during a transition to maximum of Moskovian glaciation.
This interval is marked by cryogenic gley paleosol, which was
strongly transformed by solifluction.
C. Muggler 1,2), P. Buurman 1)
The centre south part of the
state of Minas Gerais, Brazil has an undulated topography with
large tops at the same altitude, which are remains of a former
planated landscape. The landscape is dominated by Oxisols, that
are deep and redder at the tops, and yellow and shallower downslope.
Aiming to unravel the link between landscape evolution and phases
of soil formation, topographic and weathering soil sequences were
sampled. Careful field examination coupled with micromorphology
and detailed mineralogy of the soil and saprolite materials allowed
the identification of various evolution phases and related relict
properties. In the field they are recognized by the presence of
buried rooted and burrowed horizons and distinct coloured layers.
Micromorphological observations show distinct clay and iron nodules,
clay formation features and iron oxides ocurrence, and SSXRD,
SEM and TEM studies of selected micromorphological features show
differences in crystallinity and morphology of kaolinite and iron
oxides. They show that the former stable landscape was affected
by various phases of gully formation and filling-up by sediments
alternated with soil formation phases, eventually overprinted
by a phase of Oxisol development. The last landscape incision
removed most of the red Oxisol cover and was followed by the
present soil formation giving origin to yellow soils in the slopes.
W.D. Nettleton, C.G. Olson, and D. Wysocki
USDA-NRCS, NSSC, 100 Centennial Mall North, Lincoln,
NE, USA 68508
F. Ottner1), G. Durn2), J. Tisljar2), B. Schwaighofer1) and H.W. Müller1)
During Early Cretaceous time the Adriatic Carbonate platform was built up by the rhythmical alternation of various shallow water related carbonate sediments, which are interrupted by several local and regional subaerial unconformities. They are particularly well expressed in West Istria where, from Hauterivian to the upper part of Late Albian, at least 8 subaerial exposure phases of different duration occur. These unconformities are accompanied by greenish, grey pelitic layers with high clay content, whose thickness is paleorelief related and laterally changes from several centimetres up to one meter. They occur as either emersion breccias with clayey matrices or, more often, as clays.
The intent of the present study is to investigate these pelitic sediments by geochemical, mineralogical, and micromorphological methods, to clear up the origin of the material they are composed of, and to see whether or not they are paleosols.
These materials have a very high clay content up to 95%. Most samples are composed only of clay minerals with small amounts of quartz and pyrite. The clay fraction (<2µm) consists mainly of smectitic and illitic material, in some samples small amounts of kaolinite and chlorite were detected. According to infrared studies the smectites are aluminum-rich montmorillonites without iron substitution in the octahedral position; the amount of magnesium is also very low. The 10 peak of the illitic material is very broad which indicates a very small particle size.
REE patterns in clays from
the Late Aptian regional emersion may indicate that their main
source rocks are not the underlying limestones (e. i. insoluble
residue) but probably aeolian derived material.
Paleosol
studies of archaeological monuments in Priazov'e
L. Pesochina1), S. Zaitsev2)
One of the important task in complex soil-archaeological studies is reconstruction of the habitat of ancient man. Paleosoils buried under archaeological monuments (kurgans, banks, necropolises and etc.) are the unique research matherial reflecting paleoenvironmental conditions for periods of its burial. Paleopedologists can examine soil chronosequences comprising paleosoils, buried during the second half of Holocene at intervals from 100 to 500 years due to archaeological monuments widely extended all over the forest-steppe and especially steppe zones of Russia. Dating of the monuments and, consequently, time of soil buried can be usually established in accordance with the archaeological chronology up to 50-100 years for the Early Iron and the Middle Ages and up to 200-300 years for the Bronze Age.
The emphasis in the present work is given to both theoretical and practical aspects of the usage of paleosoils in reconstructing of paleoenvironment for the second half of Holocene in Priazov'e.
The main theoretical problem is: what soil diagnostic features should involve as the basis for reconstructing of paleoclimatic conditions? We suggest to select the number of elementary soil-forming processes which are the most susceptible to hydrothermal changes of paleoclimates and are characterized by minimum sufficient complex of soil properties formed in each process.
The object under study was the soil chronosequence, comprising paleosoils buried about 4000, 3700, 2400, 2000, 1900, 1200 years ago and modern soils, situated on the territory of Rostov region.
The morphological-chemical complex analyses were carried out by methods usually used in pedology.
Considerable changes of soils for some Holocene chronocuts were observed. Among all soil-forming processes effected on soils of this chronosequence the two groups of processes such as humus formation and the substance migration (salt migration: salinization-desalinization; solonetzization- desolonetzization; calcium migration: leaching, gypsum and calcite accumulation) were the most dynamic and were closely connected with climatic conditions.
It has been established that
periods of the Bronze Age ( about 4 -3,7 thou. years ago) and
of the Earlier Middle Ages (VIII-XII centuries A.D.) were characterized
by climatic aridization caused soil salinity. The Early Iron Age
was the period of an alternation of microarids and micropluvials.
About 2400 years ago the climate was cooler and specified by
higher humidity the evidence of which was absence of easily soluble
salt and gypsum accumulations, lack of actual solonetzic features
and decreasing of humus acid content, but about 2000 years
ago it was interrupted by shot microarid periods. This work was
carried out under support of Russian Foundation of Basic Researc
N. Proti1), N. Kosti2)
Loess is the most important parent rock for the development of the variety of soils in Serbia. It also comprises many paleosoils within the profile and because of this it gives an opportunity for chronosequential investigations of paleopedogenesis as well as physicochemical, mineralogical, paleonthological and other relevant investigations. In this domain works of V. Laskarev (1922, 1926, 1938) around Belgrade ,J.Markovi} Marjanovi} (1950a, 1950b, 1954, 1972) and M. Raki} (1985) in Vojvodina as well as D.Aleksandrivi} (1954, 1956, 1957, 1974) and M. Zeremski et al. (1991) in Vojvodina, Pomoravlje and Podunavlje, are considered as crucial for that matter. Also works of A. Bronger (1969, 1970, 1971, 1975, 1976, 1979) are important for the chronology of paleosoils in the Pannonnian valley in Hungary, Romania, Slovakia and Serbia, where he had determined eleven pedocomplexes( Stari Slankamen).
The paper would deal with pedomineralogical, some chemical and physical analyses of the paleosoils investigated, which were used to elucidate some of paleoclimatic conditions during Pleistocene. Selected profiles at KapelaBatajnica, near Belgrade and Stala}, were developed in loess and loesslike materials on a approximately north to south transversal with distance of about 210 km.
The samples were collected along the profile from each horizon or lithological unit, at the 0,5 m intervals or smaller depending on the horizon thickness. Particle size analysis was carried out according to the internationally recognised method of Atterberg, subsamples were dispersed by boiling and shaking with 0.4M Na4P2O7. The calcium carbonate (CaCO3) content was determined by means of Scheibler calcimeter.
Mineral composition of bulk samples and their clay fractions were analysed by using PHILIPS and SIMENS XRD diffractometers. Quantitative phase analysis was carried out by using Chung F.H. (1974) adijabatic method, and Thorez J. (1985, 1989) tables for mineral identification and determination of
This preliminary investigation along the northsouth trasfersal of the loess occurences and paleosoils within has shown regularity in seqential distribution, sinchronicity and cyclic nature in the changes of sedimentary and pedogenetic processes.
Similaritites in the morphogenetic
properties of the paleosoils in the loess profiles investigated
had pointed out to synchronological paleoclimatic conditions
in the origin of the paleosoils examined. The existing differences
could be attributed to rather local than global erosion processes.
K. E. Pustovoytov 1) , M. M. Pakhomov 2) , A. A. Nikonov 3) T. Nakamura 4)
The problem of paleoenvironmental interpretation of modern and buried soils is of special interest for the regions where another sources of information on the past natural conditions are few or unavailable. The object of this study is to infer the landscape development during the Late Pleistocene and Holocene for the Western Crimea from soils buried due to seismic phenomena and present soils. Seismically faulted Late Quaternary loams with buried soil profiles on local watershed in a reference cross-section within a great quarry near Sevastopol town were investigated by technics of paleopedology, palinology and paleoseismology. To develop chronology of soil formation and sedimentation 2 radiocarbon datings for humic acids and 6 ones for carbonate material have been obtained.
Three main intervals of soil formation have been found.
1. The Late Pleistocene soil development from a brown loam layer took place before about 20 000 BP. There is no strongly developed soil horizons and the duration of soil development as a whole was presumably not longer than the first several thousands years. A coniferous forest vegetation was characteristic for the region immediately before the burial of the soil surface and testifies to relatively cool and wet climatic conditions. Due to a violent earthquake about 20 000 BP the loam layer with the overlying soil had been ruptured and partially settled down. The soil on the sunk loam blocks was buried. On the relatively uplifted ones the soil formation was continuing.
2. The Late Pleistocene (after about 20 000 BP) - Middle Holocene soil development was recognised in the upper layers of the blocks uplifted by the Late Pleistocene earthquake. Throughout this period morphologically definit soil horizons (A-Bk-Cox-C) have formed. Accordingly to soil properties and palinological spectra the general climatic trend for this period was a progressing drying. The carbonate accumulation zone had been elevated and coniferous forests gave way to open vegetation. Another strong earthquake in the Middle Holocene induced the burial of this soil surface, too.
3. The modern soil development
has begun on stabilized sediment surface after the Middle Holocene
earthquake. The soil profiles are more leached, than at the previous
stage and demonstrate signs of clay illuviation (profile type
A-Bt-C). The general tendency in environmental changes for this
time span was climate wetting and broad-leaf forests propagation
over the area.
G. Reuter
Institut für Bodenkunde, Unversität
Rostock, 18051 Rostock
Paleopedology as a developing branch of soil science needs specific terms in order to describe and explain particular soil characteristics, and to them into a system of classification. Most of the terms in use were adopted from classical sciences, other have newly been introduced and/or are under discussion.
Within the first group some terms were modified in there sense and their usage is not clearly standardized in an international frame. The author takes up some examples:
paleo-, fossil, recent, relic, buried.
After discussion regarding the origin as well as the partly non-uniform usage of these terms some proposals are presented in order to improve their logical definition and to care for consequent usage.
The term paleo- coming from the Greek palaios = old, raises the question „What is old?" Answers are very different if you look at stratigraphy (paleozoic), prehistory (paleolithic), or paleopedology (bevore holocene?).
The traditional term fossil coming from Latin fossilis = buried, in natural science is used, as adjective and as a noun, for relics of extinct plants and animals which mostly have been preserved by a covering with sedimentary materials. Fossil soils are not extinct natural bodies, but they were covered with other materials. They are the typical paleosols, not corresponding with the present-day environmental conditions (climate, hydrologic), in other words, they show signs of relic character. We should not use the term „buried" in connection with fossil soils, because we better use this term in another, specific way.
All soils as well as soil characteristics (esp. horiozons) which been formed under former climatic and/or hydrologic conditions should be called relic, in contrast to the recent ones which correspond with the present-day conditions.
As buried soil/horizons we should name such ones having got a sedimentary cover under recent conditions. Normally, they do not show other characteristics than the uncovered soils in the related environment. Under genetic aspects it seems necessary to set them apart from the fossil soils.
Soil horizon designations. fA = fossil, rGo = relic, bA = buried
Facing surface soils it seems necessary top distinguish between soil genesis development under constant climatic and/or hydrologic conditions on the one hand, and under changing of these environmental conditions on the other hand. The terms harmonic and disharmonic are useful for this. They have been overtaken from usage in geomorphology.
In the course of soil development changes in profile
characteristics are common, even in a way that requires change
of the type name. During this process asoil profile shows horizon
characteristics of two or even more different soil types. We name
such a state type interference. As type interferences may
develop under constant climatic and/or hydrologic conditions as
well as under their changing we distinguish between harmonic and
disharmonic soil type interferences.
Institut für Bodenkunde
und Bodenerhaltung, Wiesenstraße 3-5, D-35390 Gießen
Introduction. The prevailing parts of the weathering mantle in the Middleveld and Highveld of Swaziland, affected by severe soil erosion, consist of thick soil-saprolite complexes formed by intensive chemical weathering of crystalline rocks (Granodorite - Gabbro), mainly during Cretatious and Lower Tertiary. The dimension of surface cutting by gully erosion in Swaziland accounts for the annual loss of about 2.000-3.000 ha of land. Therefore, these erosion processes are important not only as a limiting factor in crop production and livestock but also in recent geomorphogenesis and landscape development at the Great Escarpment of Swaziland and comparable subtropical regions. This paper summarizes first results of the genesis and erodibility of soil-saprolite-complexes from plutonic rocks in the Middleveld of Swaziland.
Materials and Methods. Four represetative soil toposequences on grano-diorite, diorite, gabbro-diorite, gabbro were characterized by mapping of soils and vegetation cover as well as detailed investigation of up to 20 m thick sections of soil-saprolite complexes exposed in large erosion gullies. Field measurements of infiltration capacity, unsaturated hydraulic conductivity, shear strength and penetration resistance were carried out on autochthonous horizons of soils and saprolites. Samples from each horizon were investigated in the laboratory in order to determine the soil physical (bulk density, saturated hydraulic conductivity, pore size distribution), chemical (pH, Corg, Nt, CEC, pedogenic oxides, total major and minor elements), mineralogical (bulk samples, clay minerals, oxides) and micromorphological characteristics. From the results isovolumetric mass balances and K-factors were calculated.
Results and Discussion. Geomorphologically the study sites belong to the Great Escarpment predominantly formed by erosion. The geological structure is characterised by high diversity of Archaic intrusive rocks with average ages between 2.500 and 3.500 mio. years. The underlying parent materials of the study sites are micro-granites, granodiorites, diorites and gabbros. Thick saprolites developed already during Cretaceous and Lower Tertiary (FRÄNZLE 1984)) under a tropical humid climate. The regolith was cut by several erosion phases during Upper Tertiary and Quarternary. Therefore the truncated landscape displays an association of soils of different ages and environments. The common soil types in the study area are Ferralsols associated with Acrisols and Cambisols in undulated and plain areas of the mountainous region. They are accompanied by Fluvisols from alluvial sediments at flood planes and river terraces, as well as Leptosols at the summit and steep backslope positions.
The saprolites developed by chemical weathering in an oxidizing environment, characterised by leaching of silica and bases. The weathered rock is very friable and can be easily crushed by hand. The texture of the dispersed material is a sandy silt, rather poor in clay (about 10 %). Clay minerals predominantly consist of kaolinite and small amounts of gibbsite. On gabbro smectite and illite are also present. According to an average bulk density of fresh rock of 2,70 g/cm3 the maximum mass loss during saprolite formation until today is for gabbro 54 %, diorite 53 %, quartz-diorite 41 % and granodiorite 55% in the Cw1 horizon (uppermost saprolite horizon).
A 1 to 1,5 m thick red brown Ferralic Acrisol on saprolite from grano-diorite displays an up to 25 cm thick Ah horizon (6 % COM) and a clay content up to 60 percent in the Bw horizon. Al ions dominate the CEC. The occurrence of gibbsite in the topsoil as well as micromorphological characteristics of reworked clay cutans in the lower part of the profile and a coherent microstructure in the upper Bw horizon indicate the transition of an older Acrisol stage into a younger Ferralsol stage. Due to the higher clay content and the formation of soil structure the bulk density and shear strength of the subsoil horizons are markedly higher than those of the underlying saprolite.
For evaluation of erodibility
the K-factors were determined for topsoils, subsoils, transition
zones and saprolites. The results show that the transition zones
between soil and saprolite as well as the saprolites are highly
exposed to erosion. With average K-factors of 0,5 to 0,7 the erodibility
of the saprolites is at least twice as high as for the solum with
values from 0,1 to 0,3 on the study sites. This explains that
saprolite layers are the essential precondition for development
of deep incised gullies. At the study sites gullies are 15-20
m deep and up to 500 m long, lineary dissecting the regolith by
regressive erosion. A further beneficial agricultural use of these
areas is no longer possible and pathways as well as farm sites
are cut off. In valleys the erosion deposits destroy fields and
a high sediment load in the rivers leads to sanding-up of water
reservoirs. Because of lack of recultivation measurements on eroded
areas erosion increases rapidly.
Literature
FRÄNZLE, O. (1984): Bodenkunde
- Südafrika. - Afrika-Kartenwerk, Beiheft S 4, Borntraeger,
Berlin,Stuttgart.
B. Terhorst
Geographisches Institut , 72074 Tübingen
The research area is located in an agricultural loess region in the south of Heilbronn (Baden-Württemberg).
Geomorphological investigations were made with respect to holocene evolution of landscape forms.
On the basis of drilling and field mapping it was possible to reconstruct a former, periglacial relief, different phases of development and the degree of enviromental changes caused by human activities.
Originally periglacial loess depressions were much deeper and their slopes were steeper than present relief forms lead one to assume. It could be shown, that accelerated erosional processes lead to levelling of former topography. As a result of human exploitation, soil erosion and sedimentation processes took place. Therefore, the little loess-valleys (dells) were buried with colluvial sediments, while slopes were eroded. Chernozems were found as an relict of the early holocene pedogenesis in the "loess dells" near by Heilbronn. These fossil soils were graduell degraded to luvisols (Parabraunerden) during the atlanticum. Hydrological conditions and superposition by colluvial layers due to preservation of chernozems and their special degradation forms. Additionly, these relictic buried soils and their influence on distribution and pedogentic development of recent soil were considered.
With respect to pedogenesis and colluvial processes a number of typical cross sections through loess dells were chosen for representation.
An attempt to show the approximate conditions, before human acitivities took place will be done as well.
Furthermore we tried a subdivision for colluvial soil sediments. In this context, I'm going to refer shortly about the experiment to detect the extension of heavy metal contamination caused by human activities in the accumulation zones.
Recent
and relic soils of the Friedberg-Bruchenbrücken early Neolithic
archaeological site
H. Thiemeyer
Institut für Geographie,
Friedrich-Schiller-Universität, 07740 Jena
When the "Neolithic Revolution" took place approximately 7,500 years ago, soils have become an important factor of the economic system. However, the landscape at which we look today has changed during the last 8 millenia. On the one hand, climatic influences and the time factor caused natural changes, on the other hand the landscape has been transformed by human impact since thousands of years.
At the archaeological site of Friedberg-Bruchenbrücken, where a settlement of the Earliest Linear Pottery Culture had been excavated, pedological investigations were carried out to answer the following questions:
- How did the landscape look like when the early farmers arrived?
- Which soils had developed at this time?
- How and in which period have the soils been transformed since that time?
The archaeological site is situated on the lower slope of the Wetter valley, which is covered with loess, mainly of young Wuermian age. The loess dives beneath the holocene alluvial sediments. Investigations have been done in a ditch which were opened from near the river up to the excavation site.
The soil pattern of the immediate surroundings of the excavation site show Luvic Chernozems and - due to post-neolithic erosion - sections, which are more or less cut. The former topsoil horizon (Al) beneath the plough horizon (Ap) is already absent in nearly the whole area. In the lower parts of the slopes transitional to the flood plain colluvial sediments have therefore been accumulated which form Cumulic Anthrosols. The intensity of the soil erosion led to Calcaric Regosols (Pararendzinas) in heavily affected areas where the whole soil profiles had been eroded.
Pedologically, it is for the Wetterau region of special interest, at which time the transformation from Chernozems to Luvic Chernozems and Luvisols had taken place. Insofar, situations are highly welcome where it is possible to connect stratified archaeological finds with pedological diagnosis.
When the early farmers arrived in Bruchenbrücken, they found Chernozems which had not yet been transformed into Luvic soils. Degradation started only after the abandonment of the settlement: All traces of human impact (pits, postholes etc.) have been subject to pedogenesis into Luvisols after abandonment and refilling, except the deepest of the former pits, where the lower parts of the filling still have a carbonate content. Here it can be shown that the infilled soil material derived from Chernozems, which at that time had not yet been degraded.
The Chernozems generally should
have had a soil depth of approximately 60 cm as non eroded fossil
soils under a cover of alluvial sediments show. These parts of
the recent flood plain belong to the lower terrace and were in
former times unaffected by high waters. After the raising deposition
of alluvial loamy sediments deriving mainly from accellerated
soil erosion in the catchment area, high waters were able to overflood
this areas and the Chernozems became fossilized under a sediment
cover.
B. Urban,
University of Applied Studies
and Research, Nordostniedersachsen, Suderburg
In the Schöningen open lignite mine (Northeastern Lower Saxony, Germany), Tertiary strata are unconformably overlain by Quaternary sediments and soils of Middle and Younger Pleistocene and Holocene age. The complex Pleistocene sequence contains a number of interglacial and interstadial deposits and soils and is of significans for the subdivision of the Younger Middle Pleistocene in NW Europe and for archeological evidence of early human occupation by Homo erectus. Recent studies reveal evidence for three interglacial periods between the Elsterian and the Saalian ice advances. One of those, named the Reinsdorf interglacial is the some of great deal of debate as it has no palynostratigraphic equivalent elsewhere in NW Europe. Despite of pollen, the deposits are also rich in small and large mammal remains, and contain a variety of invertebrates and plant macrofossils including wooden artifacts (spears). Their dating is critical for determination of the time arrival of people as the interglacial layers and soils contain two lower paleolithic horizons. The peaty horizon of the Schöningen interglacial is supposed to be the youngest of those three interglacial periods. Based on Uranium/Thorium dating of peat of the Holsteinian, Reinsdorf , Schöningen and Eemian interglacials tentative correlation is made with oxygene isotope stages 11 (Holsteinian > 350 ka), 9 (Reinsdorf about 320 ka), 7 (Schöningen about 200 ka) and 5 (Eemian 115-149 ka).
There is evidence of a soil complex developed in glacial sediments of the Drenthe Stadial (Saale). Those two Stagno-(Calcaric) Gleysols are overlain by reworked loesslike material with cryoturbations and eolian loess contributed to the Warthe Stadial. The hydromorphic duplex soils are not yet finally studied in detail.
The Early and Late Weichselian
and Late Glacial can be subdivided by soil sequences deriving
mainly from loess (Chernozems) or showing organic (peat) features
(Alleröd). The Holocene sediment and soil genesis has been
studied in detail at various exposures.
M.-R. Usai, J.D. Dalrymple
University of York, E.A.U.,
Walled Garden, Heslington, York YO15DD
Reddened weathering belts outcrop in Sardinia along unconformities between Miocenic sediments and the products of a series of volcanic events during Tertiary. In order to assess whether the MioPliocenic weathering belts were, or contained, paleosols, and to establish the most suitable methods for paleosol diagnosis, pedological investigations were carried out on two representative outcrops (Serri and Siddi). Morphological measurements of ped types, voids, colour, consistence, at the 1:1 scale (in the field and in the laboratory) displayed spatial anisotropic patterns correlatable to soil pedons at Serri, but not at Siddi. Spatial distribution of groundmasses and pedofeatures at microscopic scale were diagnostic for the identification of a paleosol formed during alternating dry and wet seasons at Serri, whilst they confirmed only rock weathering at Siddi. Xray diffraction, fluorescence and scanning electron microscopy showed a) heating of the upper part of the paleosol by the basaltic materials burying it; b) silica impregnating the Serri paleosol matrix or occurring as an illuviated pedofeature, during alternating wet and dry seasons; and confirmed the micromorphological recognition of c) a volcanic fall event (different from the basaltic flow materials burying the Serri paleosol during PlioQuaternary) synchronous with the formation of the Serri paleosol. This study has showed that these paleosols could be interrelationships between different features. Stratigraphic correlations showed that only the existence of paleosols formed insitu on Miocenic materials is a stratigraphic marker of MioPliocenic continentality, whilst reddened weathered layers are not.
This approach is currently
being used to investigate catenary sequences in archaeological
sites of importance in Northern England, including Low Hauxley,
Northumberland, where a paleocatena was found buried in the vicinity
of Bronze Age Cairns and Mesolithic remains. Investigations on
paleocatenary sequences are also being carried out on paleocatenas
with plough marks buried below Roman remains near the Hadrian's
wall in Cumbria and Northumberland.
A. A. Velichko 1), P. Haesaerts 2) , H. Mestdagh 2) , T.D. Morozova 1) , V.P. Nechaev 1) ,
K.G. Dlussky 1) , V.V. Semenov 1) , S.N. Timireva 1) .
1) - Institute of Geography, Russian Academy of Sciences, Moscow, Russia
2) - Royal Institute of
Natural Sciences of Belgium, Brussels, Belgium
The aims of the presented paper are 1) to find a chronostratigraphical correlation between Upper Pleistocene loess-soil deposits in continental and preatlantic regions of Europe, and 2) to compare analytic data, obtained by Russian and Belgian specialists using different techniques.
The presented Upper Pleistocene Loess-Paleosol Sequence is situated near the town of Zheleznogorsk (52°12`N, 35°25`E, Kursk district, Russia) in an iron ore quarry. The quarry of the Mikhailovsky Ore-Mining Enterprise is located at the watershed plain between Svapa and Nerussa river valleys, at a densely dissected interfluve. The section itself was studied at the location of a small Eemian paleodepression fixed by polygenetic Mezin soil complex; later the depression was gradually filled up by Valday (Vistulian) loess deposition containing Bryansk fossil soil. The complex of analyses (including micromorphological investigations in thin sections (29 samples), chemical and granulometrical analyses (79 samples), study of sand grains morphoscopy and magnetic susceptibility measurement) reveal a complicated sequence of stages of soil forming, erosion and sedimentation under periglacial conditions. Particularly thorough investigations were carried out for Mezin soil complex and Bryansk paleosol as polygenetic phenomena. Several micromorphological features related to 1) loess accumulation, 2) erosion-sedimentation, 3) freezing and thawing in a periglacial environment and 4) pedogenesis were analysed and consequently put in chronological order of pedological events
As a result, in total, 11 pedolithostratigraphical layers were identified in the Zheleznogorsk profile, which embrace the end of Middle Pleistocene up to the Holocene.
|
|
| ||
| 1.Brown forest soil formation | Salyn phase of Mezin soil complex developed on middle Pleistocene loess |
| ||
| 2.Erosion-deposition by
gelifluction | Turbations and erosion of soil of Salyn phase | Mikulino
interglacial | ||
| 3.Weak grey forest
soil formation | Immature grey forest soil in humiferous sediments | |||
| 4.Continuation of erosion- deposition by gelifluction | Turbations and erosion of soils | 1st Smolensk cryogenic phase | ||
| 5.Accumulation of a humiferous soil-sediment under
cold conditions | Probably subphase of Mezin soil complex | |||
| 6.Chernozem-like
soil formation | Krutitsy phase of Mezin soil complex formed in humiferous sediments | Early Valdai Krutitsy interstadial |
| |
| 7.Erosion, sedimentation and cryogeneisis | Inverted soil profile with cryogenic deformations | 2nd Smolensk cryogenic phase | ||
| 8.Loess accumulation and filling of the depression | Khotylevo loess | Early Valdai glaciation stage | ||
| 9.Gley cryogenic
soil formation | Bryansk soil | Bryansk interstadial | ||
| 10.Loess accumulation interrupted by initial soil formation | Desna loess
Trubchevsk gley level Suponevo loess | Late Valdai glaciation stage | ||
| 11.Chernozem soil formation | Holocene soil | Holocene | Holocene | |
M. Watanabe1), K. Aoki1), K. Sakagami2)
Yokohamashi 226, Japan, fax:+81-45-924-5532
The development of Andisol
profiles are basically regulated by the rate of volcanic ash supply.
Sequences of buried soils of late Pleistocene and Holocene are
able to be recognized as paleosols formed under a high-rate ash
supply in many parts of Japan (Watanabe et.al,1996a;1996b). While,
loess deposits derived from continental eolian dusts and local
tephric materials, which are the materials supplied in a relatively
low rate, influence the formation of Andisol profile during the
period of volcanic inactivity. Soil forming process of this period
is closely associated with humus supply and climatic condition.
We may expect to trace the successive change of the terrestrial
environment conserved in surface soils as well as in buried soils
by subdividing the thick A horizons into soil layer units of
5-10 cm. Carbon content, C/N ratio, clay content, humus composition,
mineral composition, pH, and concentration of chemical elements
are studied through profiles located in volcanic areas in Japan.
From the vertical behavior of organic and inorganic components
in surface A or buried A horizons, we discuss the paleopedological
significance of studying the chronological sequences of Andisol
profiles and the limitation for applying the provided data to
the moving average of the past environmental change.
REFERENCES
M.WATANABE, K.SAKAGAMI AND K. AOKI (1996a): Environmental Changes Inferred from Inorganic and Organic Components of Holocene Volcanic Paleosols in Japan;
T.MIKAMI, E.MATSUMOTO, S.OHTA &T.SWEDA (eds):Paleoclimate and Environmental Variability in Austral-Asian Transect during the Past 2000 years. Proc. of the 1995 Nagoya IGBP-PAGES/ PEP-II Symposium, 152-157.
M.WATANABE, H.TANAKA, K.SAKAGAMI, K. AOKI AND S.SUGIYAMA
(1996b): Evaluation of Pg Absorption Strength of Humic Acids as
a Paleoenvironment Indicator in Buried Paleosols on Volcanic
Ash Beds, Japan; Quaternary International, 34-36, 197-203.
E.Y. Yakimenko
Institute of Geography, Russian Academy of Sciences,
Moscow, Russia
At the area of the Russian Plain Quaternary paleosols are better preserved and understood to the South of the boundary of Late Pleistocene (Valdai) glaciation, where Quaternary sediments show the most complete sequence of glacial-periglacial deposits.
Eemian paleosols are wide spread and relatively well preserved in the loess and loess-like sediments at the Russian Plain. Mostly they are known to be included in the so-called Mezin paleosol polygenetic complex. Part of it (pseudopodzolic A2 and Bt horizons) was formed during Eemian interglacial, but the upper horizon (A1) was developed during later interstadial (Stillfried A). These polygenetic paleosols are better preserved in lower positions , and consequently studied there in more detail. However initial order , thicknesses and peculiarities of genetic horizons have been forming under forest vegetation within Eemian interglacial at this area is not quite clear. Furthermore, it is a controversial question what was the real time of pedogenesis there during Eem.
Pleistocene paleosols were described in the loess and loess-like sediments , on the plateau, at the right bank of Oka-river. They have preserved two distinguishable genetic horizons A1 and B(t), which demonstrated typical features of soil organisation. Both of them showed the same age (100-110 Ka), determined by the method of Optical Stimulated Luminescence, that means Mikulino (Eem) and suggests no reworking affects of later pedogenesis in the upper part of the profile as it was described for this area (Morozova, 1981).
The average thickness of buried
soil humic horizons (30-40 cm) studied is rather thick and more
that is typical of the modern zonal Grey forest soils there. Particle
size distribution and total amounts of chemical elements do not
reveal any clear differences within the soil body and also between
fossil paleosols and enclosing them sediments, excluding some
iron accumulation at the upper soil boundary. These similarities
in the composition likely result from the secondary processes,
bringing about profile homogeneity. Mineral compositions of clay
fraction (<0,001 mm) from paleosol layers and loess and loess-like
sediments are very similar and represented by smektites, mika,
kaolinite and quartz. Small amounts or even traces of chlorites
occur both in soils and loams. Samples of clay fractions containing
X-ray amorphous minerals never revealed any traces of chlorites.
In general, buried Eemian soil layers studied did not show any
specific composition or character of distribution for mentioned
minerals of clay fraction in the comparison with Quaternary sediments
above and below.
T.E. Yakusheva,
Dokuchaev Soil Institute, Moscow, Russia
Soils with texture-differentiated profile (Sod-Podzolic and Grey Forest soils) could be found as a small areas in river valley complexes in the Centre of Russian Plain. Their differentiation is usually explained by deep evolution of alluvial soils under forest vegetation during the first half of sub-atlantic period. Our field studies of Oka river valley complexes and it's tributaries proofed that texture-differentiated soils have been formed on the sediments quite different from alluvial ones - on periglacial loess loams, being a part of extensive loess mantles, that covers adjacent interflues and valley slopes. Within the floodplain loess cover remained on the most ancient remnants of socle areas and directly border younger alluvial sediments with abrupt contact and signs of erosion.Texture-differentiated soils on the floodplains are similar to soils on the interflues and completely different from adjacent alluvial soils, where texture-differentiation is absent even in the most ancient (few thousands years) varieties.
In contrast to soils on the interflues and valley slopes, floodplain soils are characterized by well developed complex of paleocryogenic features, including relic soil cover pattern, following paleocryogenic microtopography; buried cryohydromorphic humus and organic horizons; pseudomorphs on former ice-wedges and fissures; lithogenic inclusions, structural deformations of soil profile, etc. The most common types of microrelief include swell-and-swale, polygonal and gully paleothermokarst, depending on ancient surface level. Buried humus and organic horizons are situated in the depressions, forming thick lenses, that separates A2 and B horizons. Within the deep gullies, that is a result of thermokarst transformation of polygonal network of ice-wedges, thick ground wedges (up to 4 meters) are filled with heavy loam, enriched in organic matter.
Studies of unique remnants
of ancient socle floodplains, being now destroyed by river activity,
broaden our knowledge on postglacial environment. It also allows
to evaluate the degree and trend of the Holocene soil evolution.
Better development (comparing to watersheds) of paleocryogenic
features in floodplain soils corresponds with better moistening
of bottom lands in a cold and arid environment of periglacial
period. Within the socle floodplains the most developed paleocryogenic
features occur in the lowest positions. Comparison between soils
on loesses and adjacent alluvial soils confirm an ancient age
and lithogenic nature of texture-differentiation. Dependence on
paleocryogenic microtopography confirms pre-Holocene age of buried
humus horizons.
A.A. Yamskikh
Dept. of Biology, Krasnoyarsk State University,Svobodny
79, 660041 Krasnoyarsk, Russia
Organic matter is traditional and very good source of information for paleopedological researches. Nevertheless, investigations of the Early Holocene vertical sequences of the alluvial sod soils located in the valley of the Middle Yenisei, allowed us to reveal some new properties of the organic matter. These sequences locate in the upper 2-3 - meter thick stratum of 9-th meter high terrace. Each sequence consists of several (up to 9) elementary soil profiles. Humic and fulvic acids of II fraction prevail. Organic matter has humic and fulvic-humic composition.
Statistical interpretation revealed existence of typical fraction. Acids of this fraction prevail over other fractions. Besides typical fraction is characterized with statistical difference in different age elementary soil profiles. Acids of this fraction determine dynamics of group composition of organic matter. Humic acids of II fraction is typical fraction in section
Yazaevka, fulvic acids of II fraction is typical fraction in section Zimoveynoe. Typical fraction is unstable from thermodynamics point of view. Therefore it reflects paleoecological changes.
For the fraction composition studying there has been calculated of the C of humic acids to C of fulvic acids (Cha/Cfa ratio) and III fractions. Relatively high values of Cha/Cfa ratio are typical for the fractions I (up to 9.5) and III (up to 16.7 and more) ofthe Zimoveynoe section organic matter. Relatively low values of the Cha/Cfa ratio are typical for the I (up to 0.8) and III (up to 1.5) fractions of the Yazaevka section organic matter. One can state that acid (humic or fulvic) formed typical fraction have relatively low content in the other fractions: humic acids in section Yazaevka, fulvic acids in section Zimoveynoe.
In conclusion we can hypothesize
that peculiarities of the typical fraction are forming mainly
under the influence of global scale environmental changes,
properties of other fractions - under the predominance of local
conditions of soil formation It can be used for revealing
difference in organic matter behaviour of soils of one and
the same type.
R. Zeese1), L. Fodor2)
The Nigerian Shield in Central
Nigeria, almost totally surrounded by Mesozoic to Cenozoic sedimentary
basins, is fringed to the Southeast by a prominent Cretaceous
shear basin, the Benue rift. Its history is well investigated
(Benkhelil et al. 1988). Much less is known about Neogene crustal
deformations in the shield itself. Informations as landforms,
fractures, dykes etc. can be recognized in the landscape, but
are difficult to be dated. Ferricretes from Central Nigeria have
been investigated recently (Zeese et al. 1994). They intercalate
or cover the so-called fluviovolcanic series of the uplifted Jos
plateau, but also the sediment fills in the surrounding basins.
Flat-topped hills, protected against erosion by ferricretes on
top of deep weathering profiles, are prominent landmarks on planation
surfaces of the basement. All investigated ferricretes are of
Tertiary age, they postdate the breakup of Gondwana. On the other
hand their concentration of iron and alumina oxides predates the
semiarid to subhumid Quaternary (and probably also the Pliocene).
Therefore dislocated ferricretes are used as indicators of Neogene
crustal movement provided that mass movement can be excluded.
In the paper two areas will be represented: 1. The passage from
the Tertiary Kerri-Kerri sediments to the basement north of the
Benue plains, where fault scarps were detected by air photo interpretation.
From the orientation of the faults and from field investigations
of stress fields in ferricretes tensional stress can be assumed.
Between the Bauchi plains in the uplifted basement and the basin
fringe with at least three ferricretes or ferribands (in the sediments
and on top of them), the landscape is tilted to ESE along a prominent
SSW-NNE running line 2. The middle part of the Jos plateau, where
more complex structures can be observed. In the granites and metamorphics
a WNW-ESE compression and perpendicular tension stress may be
related to the early phase of opening of the Atlantic ocean. This
stress field is not documented in the weathering profiles and
ferricretes on Tertiary sediments and volcanics. In the area
of study two main types of stress field could be identified in
these sequences. One is a NE-SW to ENE-WSW tension, sometimes
combined with horizontal compression (strike-slip type stress
state), the other one is an E-W to ESE-WNW tension, again sometimes
with strike-slip events. At several outcrops clear examples of
mesoscale normal faulting could be demonstrated. The faults belong
to different stress fields, indicating that structural history
was not homogenous after the deposition of fluviovolcanics and
the formation of at least some of the ferricretes. The interpretation
of both the stress field and the mesoscale faulted tilted block
pattern may have two alternatives. One is that the two stress
fields and related structures followed each other, ESE-WNW tension
being somewhat younger. The other alternative is that the stress
field was not homogenous and local deviations occured, mainly
along larger fracture zones. The tilted blocks of the Jos plateau
may support this latter idea.
References
BENKHELIL, J., P. DAINELLI, J.F.PONSARD, J.F.POPOFF & L. SAUGY (1988): The Benue Trough: Wrench fault related basin on the border of the Equatorial
Atlantic.- In: MANSPEIZER,
W. (Ed.): Triassic-Jurassic Rifting and the opening of the Atlantic
Ocean.- Amsterdam (Elsevier). ZEESE, R., U. SCHWERTMANN, G.F.
TIETZ & U. JUX (1994): Mineralogy and stratigraphy of three
deep lateritic profiles of the Jos plateau (Central Nigeria),
Catena 21, 195-214.
The project was sponsored
by Volkswagen Foundation and logistically supported by J.Berger/Nigeria.
L.P. Zhou
The Godwin Laboratory,
Department of Earth SciencesUniversity of Cambridge, Free School
Lane, CambridgeCB2 3RS, UK
Enhancement of magnetic susceptibility in surface soils was observed and investigated in the 1950s and 1960s. Later studies on geological sequences containing buried soils have revealed large differences in magnetic susceptibility between the buried soils and the intervening sediments. These have been interpreted as evidence of climatic change through time, and magnetic susceptibility is increasingly used as a proxy for paleoclimate during soil formation. Before this approach is applied more widely, two questions of particular interest to paleopedologists should be considered: 1. What is the basis for the quantitative reconstruction of past climatic variables from magnetic susceptibility measurements? 2. How do susceptibilitybased reconstructions compare with those inferred from other paleopedological work?
Discussion will be focussed on one of the most complete and accessible of Quaternary terrestrial sequences, namely the loess of northern midlatitudes. The following aspects will be considered:
L. Zoller
Max-Planck Institut, 69126Heidelberg
In the Heidelberg Laboratory, thermoluminescence (TL) dating of loess has been tested and applied to loess-palaeosol sequences since 1984. World-wide our laboratory belongs to the most experienced ones in this field. Infrared stimulated luminescence (IRSL) dating of loess and colluvial sediments has been tested since 1992 and has been applied mainly to Late Glacial and Holocene sediments.
The enthusiasm of the early years was severely cut down since the mid-eighties when TL and, later, also IRSL age underestimates were reported from all over the world. The estimates of the upper dating limit, however, differed by more than one order of magnitude. It has been a long-standing debate if and how far the apparent upper dating limit is controlled by different laboratory techniques. Although the reasons for luminescence age underestimates are still not well understood, considerable progress has been achieved during the past years from both, physical and empirical approaches.
It has been proved by spectral resolution of the luminescence from natural minerals, e.g., that the stability of the latent luminescence signal strongly depends on the emission wavelength. Consequently, not only filtering of thermally stable signals, but also optical filtering of suitable luminescence wavelengths is required in order to obtain reliable ages. Much fundamental research has been devoted to better understanding of luminescence sensitivity changes due to optical bleaching. It is now evident that sensitivity change can significantly contribute to age underestimates if the so-called "regeneration method" is used to obtain the samples radiation dose absorbed since deposition (AD). In particular for loess older than ca 60 kyrs the regeneration method is now often found to yield younger apparent ages than the "additive dose (total bleach) method". Last not least it has been demonstrated more clearly that secular disequilibrium of the 238U decay chain may cause considerable age underestimates.
Laboratory techniques always need to be refined according to progress in the understanding of the complexity in both, the luminescence process and radiation dosimetry. Testing of advanced laboratory techniques by application to luminescence dating of loess-palaeosol sequences with independent age control yields the following conclusions at the present state of the art:
Some examples supporting these
conclusions will be presented. The sites mentioned include those
visited by the field trip.
Geologisches Landesamt Sachsen-Anhalt, 06035 Halle
Paleosoils are known from several places in the Eastern forelands of the Harz mountains.
By correlation with neighbouring areas, they are dated mostly as Eemian. No age determinations were made.
By geological mapping, a new locality of paleosoils was found in an opencast sand mine near Hedersleben, about 8 km ENE of Eisleben, district-capital.
The opencast mining is situated on the southern slope of the Laweke-valley leading to the Salza- and Saale-meadows. Within the slope, the opencast mining is located in a flat hollow of about 300 m in diameter wich is penetrated by two joining erosion channels.
On the surface, calcaric regosols are developed in sand loess. They are associated with chernozems. The climate is dry and warm. Annual temperature amount to 8.5 Celsius degrees in average, annual percipitation is about 450 mm.
From top to bottom, the Quaternary sequence consists of sand loess, solifluction and water displaced loess covering Saalian till, solifluction till and glaciofluviatile sand wich are underlayed by presaalian glaciolacustrine sand. Thickness of the singel beds is quite varying. The whole thickness of the Quaternary deposits in the outcrop is unknown. It reaches 22 m in a drilling 350 m to the North.
In the mentioned well section the Quaternary sediments overlay sandstones and siltstones of the Upper Buntsandstein deposits wich contain four gypsum beds. The Upper Buntsandstein beds dip gently to the Northeast. They are cutted by the slope surface.
Morphological position and increasing thickness of solifluction and water displaced loess as well as of glaciolacustrine sand in direction to the central part of the hollow make subrosion origin probable. Subrosion could be caused by solution of the gypsum beds.
The subrosion depression led to the conservation of the paleosoil sequence.
The investigated paleosoil sequence is located on the eastern wall of the opencast sand mine. The wall shows a complete section through the Weichselian deposits of the subrosion depression. The paleosoil sequence is complex by means of erosion, deposition, soil development and solifluction. It is superimposed by calcareous impregnation.
A cyclic succession within the loess sequence was observed. A complete cycle contains the following sediments and phenomena from bottom to top:
The observed paleosoil sequence is situated in the late Saalian to Weichselian periglacial region. That's why it is supposed that sediment cycles are caused by climate changes. This assumption corresponds with observations in lacustrine environments. The soil represents the most optimal climate conditions within each cycle. So the soil development reached stages from luvisol and podzoluvisol to chernozem.
A first age determination (14C, made by GEYH, Niedersächsisches Landesamt für Bodenforschung Hannover) results in 27400 years b.p. for redeposited humous sediments at the top of a thick luvisol/podzoluvisol sequence.
Institute of Geography, 109027, Moscow, Staromonetny, 29,Russia
As a complex open bio-abiotic system soil consists of many components and structural-functional facets. Such systems have an ability to change in many different ways due to different behavior in time of its various components and facets.
The problem is if we can develop one holistic model describing the soil change, i.e. time behavior of the whole soil system including all components and facets, or it is easier and more realistic to build up the different «partial» models for the changes of different facets and components of soil systems depending on our objectives.
The holistic understanding of complex soil system includes three facets of the system interacting in time and space: a) soil as a multicomponent functioning system, reactor of the gas, solutions, biota, solid phase interactions in belowground tier of the ecosystem; b) soil as an exogenic solid-phase body and structure, pedomatrix for the whole multiphase soil system, result and memory of its long-term functioning; c) soil as a regulator and transformer of the external fluxes of matter and energy passing through soil system.
Soil system time-behavior for monogenetic soil is described by the following time-sequence: «crossing» of soil-forming factors within the initial lithomatrix -> multiphase functioning of soil system -> pedogenesis as a formation of solid-phase pedomatrix within the lithomatrix -> transformation and/or regulation of external and internal fluxes and cycles by new developed pedomatrix. For the polygenetic surface soils this sequence is complicated by the addition of one or more other superimposed time-sequences (factors->functioning->pedogenesis->regulation). For the fossil soils the mono- or polygenetic sequences have to be prolonged by additional events: ->burial of soil body->diagenetic transformation of soil after burial.
The term «soil change» has many different meanings: natural and human-induced, monogenetic self-development and polygenetic evolution, sustainable and catastrophic changes, «normal», denudational and sedimentary soil changes, etc. The impacts generating soil change are also very divers: direct and indirect, vertical and lateral, aboveground and belowground, biotic and abiotic, mechanical, chemical, etc. Each case of this diversity can be the subject of modeling. Taking into account the complexity of multifaceted soil system we have to try to discriminate the change in time and depth (space) of the main different facets and components of soil system: change of soil functioning processes that control short-term behavior of gases, solutions, soil biota, heat and mass balance; change of-pedogenic, weathering and diagenetic processes that control long-term behavior of stable solid organic and mineral components of soil system (pedomatrix or pedomemory); change of soil systems geoecological functions in regulation and/or transformation of external biotic/abiotic fluxes and cycles. In various cases of soil change we need to recognize change of which facet and/or component of soil system do we want and really can model and in what time-and space scale?
The other aspect of soil system complexity that leads to diversity of soil change models is the hierarchical organization of the system: from the level of crystals to the levels of peds, soil horizons, pedons, patterns, etc. Many of soil change models mentioned above can be applied to the distinct levels of soil organization. The real diversity and multiplicity of soil change models can be displayed as a combination (or multiplication) of the different types of models of soil system behavior in time.