CONCEPTUAL BACKGROUND. Paleopedology in the simplest terms is the study of old soils. In technical terms it is not so clear, because it is an interdisciplinary science with diverse applications and blurred academic boundaries. It is a field of study that principally draws from soil science, geology, geography and biology, but also overlaps with other sciences concerned with the earth's surface. In fact, all who study the "biologically active" zone that underlies the land surface of the earth have reason to study soils, including paleosols.

The principal object of study in paleopedology is the "paleosol". However, there is no agreement among practitioners about what constitutes a paleosol, or how to best define one. The principal motivating interest for the Second International Symposium on Paleopedology was to seek a common understanding of the terminology used in the study of paleosols. Ironically, one of the goals of the Symposium was to try to reach a consensus on a definition of "paleosol" to serve the broad interest, but no ratified agreement was reached. Philosophical and theoretical differences still separate opinions on paleosols in different areas of research and applications. The main problem centers on the concept of soil itself, and how we conceptualize the genetic pathways that produce a soil profile and the process involved that preserve it as a paleosol. There seems to be no disagreement within the earth science community about conferring paleosol status to buried soils, if they are deeply buried and retain sufficient pedogenic characteristics. The most common problem, and perhaps the most vexing one that has generated conceptual confusion for decades, is whether "old" soils on the present land surface should be recognized as paleosols. The inions seem to depend on three circumstances:

1) the conceptual framework used to explain soil genesis;

2) how one defines a paleosol; and 3) how adept one is at interpreting

"old" morphologic signatures.

Dokuchaev's "five factors" model of soil formation has traditionally been employed to explain soil genesis by most pedologists and paleopedologists, though in the last 20 years, the tradition has been challenged with more advanced and sophisticated alternative models. The popular Dokuchaev concept reduces the complexities of soil genesis to four environmental

factors -- climate, organisms, relief, and parent material. This has led to overly simplistic definitions of paleosols, such as, paleosols are soils that formed in the geologic past; soils that formed under different geologic or environmental conditions than today; soils that have gone through more than one climatic or "soil forming cycle" or episode; old polygenetic soils, and so on. But these definitions sidestep the fact that soil genesis involves far more than the four generalized environmental variables. Over the last 100 years, we have learned that soil genesis involves many specific and complex processes and conditions that can produce properties and morphologic imprints that can themselves significantly influence pedogenic pathways. These intrinsic factors add great complexity to the study of soils and paleosols. In some cases they may be difficult if not impossible to distinguish from extrinsic ones.

Popular or useful models are not immutable truths, they are merely conceptual contrivances to explain things. A logical alternative to the Dokuchaevan philosophy of soil genesis is to posit that all soils are polygenetic, and thus that all soils are paleosols because the environment is always changing and soils are constantly evolving. But pronouncing all soils as paleosols would make the term redundant and unnecessary, an unsatisfying fate for the most fundamental and sacrosanct term of paleopedology. A resolution to this problem, discussed in this volume, is that the term paleosol be applied to buried soils -- in keeping with the convention of early workers -- and that the concept of polygenesis be applied to all soils. In this view the genesis of the soil or paleosol becomes a matter of the degree of polygenesis. Then, stages could be differentiated in terms of time, morphology or genesis. This, however, raises the question on how to recognize the "mono" elements of polygenesis. This volume deals with aspects and applications of this genetic theory and related issues. Historically, the main issue derives from the experience that the terms "soil" and "paleosol" have been used in different ways to serve different needs in agriculture, geology and other areas of natural science. We do not reach a synthesis of the main issues of paleopedology in this volume, but have made progress in defining some of the important problems.

SYMPOSIUM BACKGROUND. The first attempt to examine the state-of-the-art of paleopedology with an international audience was the Symposium on the Age of Parent Materials and Soils, which came to be known as "the First International Symposium on Paleopedology". It was held in Amsterdam in 1970 under joint sponsorship of two societies, the International Union for Quaternary Research (INQUA) and the International Society of Soil Science (ISSS). The Paleopedology Commission was formed in l965 as Commission 6 of INQUA and as Working Group PP of the ISSS to bridge two organizational centers with a mutual interest in paleosols. Selected papers from the Amsterdam Symposium were published in a book entitled "Paleopedology: Origin, Nature and Dating of Paleosols", edited by Dan H. Yaalon (1971). This symposium brought attention to paleopedology as a discipline and stimulated a rapid growth in the study of paleosols including the application paleopedology in other areas of science. The growth in interest occurred mainly within agricultural-based soil science, stratigraphically oriented glacial or Quaternary geology and soil-oriented geomorphology/geography.

These centers of interest and the "islands" of interest that have been spawned within other disciplines have not been sufficiently connected in practice to have developed a common set of terminology for paleosol work. In the different areas of paleosol studies, the needs and goals were different. Therefore, different applications of the terms have developed, which have caused overlap and confusion among terms and definitions used in paleosol studies.

To address the problems stemming from the growth of conflicting terminology, multiple definitions and related classification issues, the Paleopedology Commission organized the Second International Symposium on Paleopedology at the University of Illinois (USA) in 1993. In general the goals were to address the different genetic views of paleosols, the guiding philosophies and related practices to seek consensus on the conflicting terminology, definitions and classifications in current use. It was envisaged that a "quorum of experts" could set standards for all to use in the study of paleosols. This built on the work of an earlier Working Group that led to the Paleopedology Manual edited by John Catt (l990, Quaternary International, V.6). The Manual covered the essential subject areas for the study of paleosols -- methods and interpretation, but did not examine all the options and conflicts which have arisen over the last 23 years.

The Symposium conveners, L. R. Follmer and D.L. Johnson, sought response from all interested parties to address viable options and propose solutions to conflicts regarding terminology, definitions, classification and genetic interpretations. Participants were encouraged to submit contributions in any form including PROPOSITIONS, position statements advocating attention or action on an issue; ESSAYS, free style discussion of a subject deemed important; ABSTRACTS, the essence of a proposed paper; SHORT PAPERS and standard PAPERS.

A free choice of style was chosen to encourage contributions that would allow the mainstreams of interest or concerns to emerge. Over 100 people promised to deliver a contribution in one style or another. That number declined to 47 by Symposium registration day, 8 August 1993. The submissions were organized into four Paleopedology Commission Newsletters (Follmer, 1993) and circulated for comment.

Overall, 90 people participated during the four day Symposium held August 8 to 12, 1993. The total included 14 people from outside the USA, 17 graduate students and 12 local people. The 7-day excursion after the Symposium was attended by 24 people plus 11 participant-leaders who joined us along the way. The first two days and evenings were devoted to the presentations of all contributors. It was a stimulating experience to hear the advocates and critics debate the current issues in paleopedology.

The written record of these transactions compose the first four Parts/Chapters of this volume. The breadth of subjects and concerns go beyond any simple summary. The ABSTRACTS are included because they show important dimensions of interest that did not mature as papers for this volume. The third day was a break to go into the field to see the classic Sangamon Geosol (formerly named "Soil" -- an example of a dual and confusing use of popular terminology, i.e. it confuses a pedostratigraphic name with what may appear to some people as a name for a soil type).

During the fourth day of the Symposium, six working groups were formed to consider (1) Definitions, (2) Classification, (3) Analytical Methods, (4) Field Descriptions, (5) Pedostratigraphy and (6) Diagenesis. The groups had two sessions in the morning so that participants could attend two of their choice. Enthusiasm was enormous, which made it difficult to draw each session to a close. In the afternoon volunteer leaders presented summaries to a general session. It appeared at the time that all groups generated a momentum and should carry on. Also, the discussions developed a hurried character that indicated a need for "one more day".

After the Symposium the interest in Working Groups grew and is described in the Paleopedology Commission Newsletter 11 Part 2. More Working Groups were proposed and 75 people indicated an interest in participating; most indicated interest in more than one Working Group, some up to five. The added groups were (7) Alluvial Pedogenesis, (8) Paleoclimate and

Interpretation of Paleosols and (9) Dating of Paleosols. Reports from four Working Groups, (1) Definitions, (2) Paleosol classification, (5) Pedostratigraphy, and (7) Alluvial Pedogenesis, are included in this volume (Part 5). Eventually the enthusiasm for participating in a Working Group waned because of communication difficulties. Hopefully, this may be less of a problem in the future as electronic mail becomes more available to the membership.

One of the primary reasons for the Second International Symposium on Paleopedology was to follow up on many of the important issues discussed in the First Symposium in 1970. There was also much interest in trying to gauge the progress of paleopedology as a discipline over the 23 years. This volume clearly indicates this interest, though it is difficult to draw

any specific conclusions beyond the fact that interest has greatly expanded to more people in more areas of application. Perhaps the area of greatest expanding paleopedological interest is in pre-Quaternary studies, particularly in conjunction with paleoclimatology and paleobotany for developing a broader base for the interpretation of ancient environments.

Within the primary reason to reexamine the state-of-the-art in paleopedology was a desire on the part of many long time members of the Paleopedology Commission to recognize the efforts of Dan Yaalon, who organized the First Symposium. This volume is dedicated to Dan Yaalon for his life long contributions to the development of the science of paleopedology. To many people of our generation Dan is our "Paleopedologist Man of the Century".

ACKNOWLEDGEMENTS: The efforts of many individuals and agencies are necessary for the success of a symposium. We want to be reasonably explicit about credits because they are deserved and because examining what we did and how it was done will be useful for planning future activities. Corresponding members of the Commission contributed essential elements to the planning and development of the Symposium. Participants at the Symposium gave their time and talents. The many authors who were motivated to put their case in writing and the peer reviewers who were willing to critique the authors came forth spontaneously. Most papers dealing with issues received from three to five reviews; four received over 20, and the most popular paper received 36. This made evaluations and responses slow and cumbersome, but this certainly added to the "depth" of the issues.

The preliminary business and hosting the Symposium required much time from local staff. Principal people handling correspondence and word processing were Barbara Bonnell, Geography Department, University of Illinois and Pam Cookus, Illinois State Geological Survey (ISGS); and Symposium host was Lisa Smith of the ISGS. The four newsletters printed by the ISGS served as premeeting agenda materials. The Allerton House staff (University of Illinois) provided special services for the ideal meeting environment for the Symposium. The ISGS covered most of the local transportation and incidental costs of the Symposium.

Planning for the 7-day Post-Symposium excursion evolved over several years with input from many people. Our goal was to visit the most significant sites in a five state area from western Illinois to southern Nebraska. Don Johnson arranged the excursion logistics and the final plans with 13 co-leaders, who prepared chapters for a guidebook. Bill Johnson (University of Kansas) with the aid of many volunteers organized the excursion in Kansas, absorbed part of the costs and prepared the guidebook for the entire excursion (Johnson, 1993). Many of the stops on the tour were at new sites of recent or on-going studies. Principal co-leaders who were willing to discuss their work on site were Larry Abbott, Cindy Balek, John Tandarich, Peggy Guccione, Alan Arbogast, Tom McCahon, Donna Porter, Rolfe Mandel, Charles Martin, David May, Mat Joekel, Art Bettis, and Kathy Woida.

The organizers sought grant funds to subsidize costs for graduate students and foreign travelers. The Soil Science Society of America granted $2000 in support of special functions to promote the science of pedology. The International Science Foundation/Soros Foundation gave travel support for two scientists from Russia. The subsidy commitments under the uncertain conditions led to a cost overrun of about $2000, which was covered by a grant from INQUA.

Overall, the Symposium activities took a large commitment from many people and agencies. Their efforts and support are greatly appreciated. During times of minor crisis, the costs seemed almost too great, but now, reflecting on the out-come, they seem incidental.

REFERENCES

Catt, J. A., editor. (1990). Paleopedology Manual. Quaternary International 6, 95 pp.

Follmer, L. R., editor. Paleopedology Commission Newsletter series:

No. 8. May 1993 Symposium Part A) 25 pp.

No. 9. July 1993 Symposium Part B) 39 pp.

No. 10. August 1993 Symposium Part C) 36 pp.

No. 11.

Part 1. July 1993 (Addendum to No.10). Pedostratigraphic Issues. 12 pp.

Part 2. August 1993 (Addendum to No. 10) Symposium Part D Revised and reprinted October 1995, 38 pp.

Newsletters were printed and distributed by the Illinois State Geological Survey,

615 East Peabody Drive, Champaign, IL 61820.

Newsletters are available in electronic form from: Paleopedology Commission Secretary Alexander Makeev

E-mail <makeev@fadr.msu.ru>

Internet <http://www.fadr.msu.ru/inqua>

Johnson, W.C. (1993). Field Excursion for the Second International Paleopedology Symposium, August 13-20, 1993. Kansas Geological Survey Open-file Report 93-30. 200 pp.

Yaalon, D. H., editor (1971). Paleopedology: Orgin, Nature and Dating of Paleosols. International Society of Soil Science and The Israel University Press, Jerusalem. 350 pp.

PREFACE

PART I -- PROPOSITIONS

Summary Outline and Recommendations on Paleopedological Issues

A Universal Definition of Soil.

Paleosols are Buried Soils.

Paleosol Classification

Root Traces and the Identification of Paleosols

International Consensus on Calcareous Paleosol Classification

A Scale for Judging Degree of Soil and Paleosol Development

Klumpen—a Mesoscale Level of Classification for Soil Structure: Rationale

PART II -- ESSAYS

Classification of Paleosols

Origins of Soil-Stratigraphic and Soil-Geomorphic Research

Classification and Stratigraphic Terminology of Paleosols

Stratigraphy of Quaternary Paleosols in Louisiana

A Comment on the Issue of Disciplinary Status

Paleopedology Evidence of Past Climatic Changes in Nigeria

Problems and Concepts of Paleopedology in Argentina

How Can The Treatment of Pedostratigraphic Units in the North American Stratigraphic Code be Improved?

PART III -- ABSTRACTS

Differentiating Pedogenic and Diagenetic Properties

Holocene Floodplain Soils of the Mississippi River

Using Alluvial Paleosols to Interpret Floodplain Processes

Diagenesis and Vertic Paleosols

Complexity of Soil Development in Loess

Establishment of a Buried Soil Chronosequence with a Feldspar Index

Paleosols as Indicators of Paleoclimatic Conditions

Modified Mack-James-Monger Classification of Paleosols

Complexities in the Parent Materials of the Sangamon Soil

Natric Soil Genesis on the Loess-covered Till Plain

Olivine Weathering and Iron Activity of Andisols

Pedological Response to Vegetation and Climate Changes

Paleosols and Their Relation to Sea Level Changes

Distribution of Pedogenic and Geologic Calcic Concentrations

Tertiary Bauxites and Associated Laterite-derived Sediments

Greenhouse Climate During Ordovician and Miocene?

Genesis of `Lateritic' Duricrusts in Western Australia

Classification of Paleosols—A Comment to the System of Mack et al.

Classifying Paleosols—Possibilities of the FAO System

Recognition and Interpretation of Aggradational and Multisequal Soils from different Depositional Environments: Some New Zealand Examples

Field Description of Paleosols and Paleosol Sequences

Buried Loessal Soil in Kansas and Nebraska

Conventional 14C Ages From Late-Quaternary Soils

Pedogenic Influences on Magnetic Susceptibility Patterns in Loess-Paleosol Sequences of southwestern Illinois

Pedostratigraphic Units from the Chinese Loess Plateau

Climatic Trend and Habitat Variation Based on Oxygen and Carbon Isotopes in Paleosols from Liujiapo, Shaanxi, China.

PART IV -- SHORT PAPERS

Adapting Soil Taxonomy for use with Paleosols

Reconstructing Paleoenvironments from Ancient Soils

Origin of Carbonate Glaebules in Pliocene Paleosols

How the Absence of a Paleosol can be a Useful Geological Tool

Clay Illuviation and Mechanical Clay Infiltration

Basic Research on Laterites in Tropical Countries

Subsolum Weathering Profile Characteristics as Indicators of the Relative Rank of Stratigraphic Breaks in Till Sequence

Origin of Stone Concentrations in Loess-derived Interfluve Soils Troy Cox. A Paleopedological Examination of the Sediments in Tabun Cave, Mount Carmel, Israel

Analyzing Ground-Water Gley and Surface-Water Gley (Pseudogley) Effects in Paleosols

PART V -- WORKING GROUP REPORTS

Report from Working Group on Pedostratigraphy

Report from Working Group on Paleosol Classification and Horizon Designation

Report from Working Group on Definitions used in Paleopedology

Report from Working Group on Alluvial Pedogenesis

PART VI -- PAPERS

The position of paleopedology in geosciences and agricultural sciences

Deep soils on stable or slowly aggrading surfaces: time versus climate as soil-forming factors

Reconstructing ancient soil-forming environments: a critical review

Parent materials, buried soils and fragipans in northwestern Buenos Aires Province, Argentina

A lithosequence of buried Sangamon soils along the older drift margin in south-central Indiana

Role of Micromorphology in Paleopedological Research

Paleopedology—One of the Primary Tools in Stratigraphic and paleoclimatic Investigations, Middle Mississippi River Valley, USA

Loess Accumulation Rate and Diagenesis as factors in the Apparent Lack of Syndepositional Pedogenesis in the Peoria Loess

A Classification System for Buried Paleosols

Post-Burial Changes and Paleosols

Paleopedological studies on age, properties and genesis of illuvial bands on an archaeological site

Core concepts of paleopedology

Paleopedologic Interpretations of Soils Buried Directly Beneath Tertiary and Pleistocence-age Volcanic Ashes: Southcentral Kansas, Western Oklahoma, and Northwestern, Texas, U.S.A.