Re: Widespread depositional systems (was re: inference)

Glenn Morton (
Mon, 17 Nov 1997 22:00:46 -0600

Hi Art,

At 09:46 PM 11/17/97 -0800, Arthur V. Chadwick wrote:
>At 07:16 PM 11/17/97 -0600, Glenn wrote:
>>Sigh. Karen, I can't emphasize strongly enough that what you get from the
>>young-earth apologists is not the correct view of geology. Yes we do find
>>widespread layers being deposited today. Lets look at the Morrison. First
>>it is NOT one single lithology. I quote:
>The Shinarump is supposed to be a fluvial deposit, in most places a few to
>a few tens of feet thick, spread over a vast area of the craton. It is
>uniform in composition and thickness, and extensive, and coarsely
>conglomeratic. Nothing like this is being formed today that I am aware of.
> Of course I could be wrong.

karen's point, I thought, was that there were no widespread deposits forming
today. I think that is demonstrably wrong. But is every type of lithology
being deposited today? No. I would agree that the shinarump type of
deposition is not occurring today. But then neither are banded iron
formations forming today yet they were fairly common long ago. Oolitic
ironstones are rather rare(to nonexistent) today. But I don't think one must
have every different lithology be present in every single age in order to
have widespread depositional systems.

Each age had a dominant to predominant type of deposition. There is the
widespread quartzites of the lowest Cambrian, the mottled, algal dolomites
of the lower Ordovician (Beekmantown, Red River etc), the red-beds and salt
of the Silurian, the black shales of the Devonian, the Crinoidal limestones
of the Mississipian, the coals and cyclicity of the Pennsylvanian, the
redbeds and salt of the Permian and Triassic, the oolites of the Jurassic,
the chalk and greensands of the Cretaceous, and the diatomites of the lower
Tertiary. Today we have widespread clastic deposition. This is merely a
continuation of what we have seen in previous geologic periods, only a
different lithology


Foundation, Fall and Flood