Re: coal again!

Keith B Miller (
Thu, 15 Apr 1999 23:29:57 -0500

Bill Payne wrote:

>>Rooting is not
>>the basis for recognizing soils. Saturated or gleyed soils can be
>>recognized by diagnostic microstructural features which you refuse to
>>consider. Many (most?) underclays are soils.
>Could you please list the diagnostic microstructural features for me, or
>provide a reference?

I have already provided references! You specifically stated that you had
not read them. You can find my references by accessing the archives.
Exchanging e-mail posts does not substitute for reading the literature.

>Bob Gastaldo (personal communication) told me, when I had said that I
>didn't see roots beneath coals, that he could show me roots every time.
>Now I have learned to recognize the roots he was talking about, which are
>actually fine rootlets, not the larger Stigmarian axial systems I was
>looking for. Are you suggesting that the larger axial root is destroyed
>but the fine rootlets are preserved? Or, are you suggesting that the
>axial roots from the in situ coal swamp trees never penetrated the
>underlying soil?

The _traces_ of fine rootlets often are better preserved because of the
chemical alteration that occurs around the them. The actual root organic
material is not easily preserved.

>The base of the coal is essentially an unconformity? Are you then saying
>that the coal swamp had essentially no connection with the underlying
>soil? If so, can you offer a modern analog where trees with stumps 2
>feet in diameter and trunks in excess of 50 feet tall have no roots in
>the underlying soil? If not, then the swamp flora rooted deeply into the
>saturated soils (as we observe with trees growing in swamps today), and
>we are back to the question of what happened to the roots.

You seem to want all coals and all soils to have the same characteristics.
In some major widespread Pennsylvanian coal seams the paleosol immediately
underlying the coal is genetically unrealted to the coal. Thsee paleosols
represent the land surface that preceeded peat formation and record
different environmental and climatic conditions. Several widespread coals
appear to be associated with rising groundwater tables during sealevel
rises. My previous list of references include papers documenting these

If the stumps and trunks extend from the top of the coal seam into the
sediments overlying the coal, then I would not expect to see any rooting
_from those trees_ in the underclay. The trees growing in many peat
forming environments today have very shallow roots. The roots of trees in
the peat-forming marshes of Louisiana do not penetrate through the
vegetation mat.

If they did
>in fact at one time intensely penetrate the soil, then they would have
>destroyed the microsturcture of the soil. Destroying the roots would not
>restore the microstructure (your "diagnostic microstructural features"
>and "well-developed soil structure") into continuous, fine interbeds
>which I have observed, would it? Is there a way to create these
>continuous, fine interbeds, which look like sedimentary features, from a
>homogenous soil as roots are destroyed?

Rooting is one of the processes that _creates_ soil microstructure! The
laminations and bedding _are_ original sedimentary features! They are
preserved in poorly developed saturated soils. Sedimentary fabric is
destroyed by physical and chemical processes and biological activity which
is not very active in saturated soils. Rooting alone (which is not
"intense" in saturated soils anyway) will not quickly destroy sedimentary
fabric. There are paleosols I have studied in which root traces and molds
are abundant but the macroscopic sedimentary fabric is still depositional.


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