Re: Coal - Gastaldo III

Keith B Miller (
Tue, 26 May 1998 13:23:14 -0600

Bill Payne wrote:

I visited with Steve Austin
>and four of his students when he was leading them through his thesis
>area in west Kentucky. I made the statement that I had never seen roots
>in underclays, and Steve corrected me. He said, "You will find root
>*fragments* in the underclay, just not intact root systems." This is
>what I meant to say, that the underclays that I have observed have never
>displayed intact stigmarian axial root systems (with rootlets). I do
>commonly see plant fragments, which other geologists have pointed out to
>me and said, "There are the roots." These fragments are normally an
>inch or two long, and may be leaves instead of roots. I cannot believe
>that these fragments represent the entire root structure of arborescent
>lycopods exceeding 38 meters in height.
>As I mentioned in the critique, I could even accept axial root systems
>in the underclay and still maintain an allochthonous origin, I just have
>never seen any (most of my observations are limited to north Alabama).

You seem to be willing to identify a paleosol based on only one single
criteria - that of intact root systems. Interestingly, this is not even a
critieria used by soil science in recognizing or defining modern soils.
Rooting alone is not considered an adequate critieria to recognize soil
profiles. In the buried Holocene and Pleistocene soils that I have briefly
examined, I have yet to see any intact root systems. Intact root systems
have very poor preservation potential in soils (although they are sometimes
preserved), the microstructure and chemical/mineralogical zonation is what
is commonly preserved. Soils are fundamentally zones of chemical and
physical alteration resulting from surface weathering processes subject to
vegetation type, topography (ground water levels), climate, nature of
parent material, and length of subaerial exposure. The chemical and
physical alterations and their characteristic vertical and spatial
variation can be recognized in ancient paleosols. The macroscopic and
microscopic features of these paleosols are virtually identical to those
observed in modern soils - even sometimes including the associated soil
biota. I have previously sent a list of basic references on soil
description and identification which you seem to consider irrelevant. As
long as you will not consider the criteria used by soil science as relevant
evidence I don't see how any productive dialog on this question is

Interestingly, in the comment above, you will not accept axial root systems
as evidence of soil formation, yet you disregard the evidence that does
confirm soil processes (ie. chemical and structural alteration).


Keith B. Miller
Department of Geology
Kansas State University
Manhattan, KS 66506