Re: Fossil Scenario

Arthur V. Chadwick (
Wed, 03 Dec 1997 21:34:55 -0800

At 09:09 PM 12/3/97 -0600, Glenn wrote:
>You left out the real liklihood that the delta will shift somewhere else.
>The Mississippi River has not always emptied where it does today. 5000
>years ago it was depositing sediment far to the west of its present location
>and at one time it deposited its sediment eastward in the Chandeleur Sound.
>Spreading the sediment out, allows for subsidence to accomodate the space.
>I also did a calculation a few days ago in which I calculated that the
>Mississippi spread its sediments over around 115,000 square miles and given
>the rate of sediment influx observed today it would take 49 million years to
>deposit the 40,000 + feet of sediment we see out there.

Most of these figures are for sedimentary basins and are average figures
for the basin, so this has already been taken into account.

>But since the Eustatic sealevel was higher, there was less land to erode and
>less clastic input to the ocean. To me, the eustatic sealevel curve
>explains this problem. It also explains why there was so much carbonate in
>the Paleozoic.

Maybe, for some parts but the stuff I study in early Paleozoic is mostly
clastics, and then this was (supposedly) a transgressive situation, so lots
of shallow water, and lots of clastic input from lots of exposed craton.