FW: Ancient Times

Posted by Dennis Nettleton 09 Sen 1999 20:26:41

> -----Original Message-----
> From: Dennis Nettleton
> Sent: Thursday, September 09, 1999 10:11 AM
> To: 'Internet:paleosol@fadr.msu.ru'
> Cc: Carol Franks; Carolyn Olson; Deb Harms; Doug Wysocki; Ellis Benham;
> Jim Doolittle; John Kimble; Mike Wilson; Philip Schoeneberger; Rebecca
> Burt; Ron Paetzold; Susan Liebig; Warren Lynn
> Subject: Ancient Times
>
>
> Dear Paleosol Subscribers,
> I have followed the debate over the definition of paleosols and
> geosols with interest. It is a debate good for our science. Well, the
> software here failed to bring it all in during the time we were changing
> to another system. I have yet to fill in that loss of correspondence.
> One of the points that is in debate is the point in time that a soil
> becomes an ancient soil. Perhaps others have come up with a date, but my
> reference to one is that from F.F. Peterson, U. Nevada at Reno (Retired).
> He proposed it in correspondence to me in preparation for writing "Relict
> soils of the subtropical regions of the United States", by Nettleton,
> Gamble, Allen, Borst, and Peterson, p. 59-93, Catena Supplement 16,1989.
> In it we state that "We consider relict soils to be ancient, pedogenic
> soils that have persisted on land surfaces of Pleistocene or greater age".
> We elaborate further, but the point I want to make is that the Pleistocene
> - Holocene break is one that is commonly discernable on site. Of the many
> time breaks geologists describe this is one of the more definite. It may
> be supported by carbon dating. Landscapes tell the story to those that
> have experience. Yes there are climatic changes in the Holocene, but
> these are relatively small in comparison to those of Pleistocene or
> earlier times.
>
> Nettleton