Widespread depositional systems (was re: inference)

Glenn Morton (grmorton@waymark.net)
Mon, 17 Nov 1997 19:16:13 -0600

At 09:33 PM 11/16/97 -0600, Karen G. Jensen wrote:

>Do we see any processes depositing coarse sand and conglomerates over
>100,000 sq.mi. like the Shinarump Conglomerate (requiring high energy
>water), on top of over 5000 ft of similarly widespread strata (the entire
>Grand Canyon series), and overlain by many more widespread layers including
>the Morrison Formation (400,000 sq.mi.) with few places showing erosion
>between layers?

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 Upper Morrison in central to western Montana is characterized by dark
coal-bearing shale or mudstone beds of probable paludal-lacustrine origin.
Coal beds attain maximum thickness along a rather well-defined, east-west
trend in the Great Falls-Lewiston coal filed of Montana
"Elsewhere in the region Morrison beds consistently maintain a
lithology dominated by varicolored red, gree, gray and tan mudstone, with
interbedded siltstone, sandstone, and thin lacustrine beds." James A.
Peterson, "Jurassic System," Geologic Atlas of the Rocky Mountain Region,
Denver: Rocky Mountain Association of Geologists, 1972), p. 187

With this in mind, lets look at the northern half of the Gulf of Mexico,
west of Pensacola's longitude, where I work. This region consists of around
230,000 square miles and only sands and shales are being deposited. If we go
south along the Mexican coast another 80,000 square miles could be added
before you run into an area of significant limestone deposition. The Gulf of
Mexico basin is is a similarly widespread system as the Morrison.

Take the Sahara Desert with 3,320,000 square miles. 20% of that is covered
by desert sand which is being deposited today. This is a nearly single
lithology being deposited today. 20% of 3.3 million square miles equals
664,000 square miles. Hmmm. Bigger as the Morrison as you measure it.
About equal to the Morrison as I measured it in the Geologic Atlas above.
Encyclopedia Britannica 1982, vol 16, p. 147,148.

Look at Antarctica. It is surrounded by band 500 miles wide in which
conglomerates (technically diamictites) are being deposited and that is
surrounded by a 600 mile wide band of diatomite deposition. The approximate
circumference of Antarctica is (using a diameter of around 2000 miles)
12500. Thus a 500 mile wide band in each of these depositional systems is
approximately 6 million square miles each! (See the map on page 64 of Karl
K. Turekian, Oceans, Prentice Hall, 1976)

Karen, I would strongly suggest that you not only check out for yourself,
what I say, but also what any apologist says. I was forced to conclude that
too many people don't do the hard work of really understanding a field
before they criticise it.


Foundation, Fall and Flood