Re: Widespread depositional systems (was re: inference)

Glenn Morton (
Thu, 20 Nov 1997 06:05:59 -0600

Hi Karen,

Out of curiosity are you using my CRSQ article as a source?
Morton, G. R. (1984). Global, Continental, and Regional Sedimentation
Systems and Their Implications Creation Research Society Quarterly. 21:23-33.

At 12:32 PM 11/19/97 -0600, Karen G. Jensen wrote:

>If there is not much erosion and deposition of sand and shale, how did the
>vast sand and shale beds of the Lower Paleozic get deposited? I'm thinking
>particularly of the Ordovician St. Peter Sandstone, which is a pure quartz
>sand, very well sorted, that extends over much of the continental United
>States. Dott & Batten mention it briefly in their 1976 edition, p. 221 &
>224; other texts show pictures of the grains and especially look for a map
>of its extent. It is only about 300 ft. thick in the eastern US, thinning
>westward, yet is recognizable over all those thousands of square miles,
>very well sorted and unfossiliferous. Not a calm seaside scene....

Go look at AAPG Memoir 26 p. 84. On that page is the Vail sea curve for the
Phanerozoic. You will see that at the end of the Cambrian, the sealevel
dropped before gradually rising again toward the end of the Ordovician
again. As I said the sea level oscillates. But also the amount of exposed
land oscillates. As young-earth creationists are often quick to point out,
erosion of the land can occur very rapidly and reduce the land to near sea
level if there are no uplifting forces. What this means is that you two
competing things, the sea level and the speed of erosion. And by the way,
the St. Peter is believed to be a marine deposit because of its very well
sorted nature. its average thickness is 85 feet and it covers 325,000 square
miles (see Dapples, "General Lithofacies Relationships of St. Peter and
Simpson groups AAPG Bulletin 39:4(1955), p. 454

Obviously during St. Peter deposition there was a large volume of land as a
source for the deposit, but if it was eroded as quickly as youngearthers
say, then after only 14 million years, you are back to a case where there is
little land to be eroded and back to carbonate deposition. By the way,
carbonates lie above and below the St. Peter.


Foundation, Fall and Flood