Flood scenarios (was Precambrian Geology (1))

David Campbell (bivalve@mailserv0.isis.unc.edu)
Mon, 26 Apr 1999 12:09:07 -0400

For clarity, ME is put in front of my replies:

ME: In reply to one question, the reason why oil does not turn up in every
well despite the accuracy of biostratigraphy is that biostratigraphy tells
how old the deposit is. Other lines of evidence are needed to tell what
age to expect the oil-bearing deposits to be. Paleontologists also tend to
think that the oil companies do not pay enough attention to biostratigraphy
or at least do not pay enough biostratigraphers.

>>> the latest thinking in Flood catastrophism involves a series of asteroid
>>>impacts which set up mega-tsunami (impanami?) which sweep ashore with high
>>>erosion near the
impact site and wide deposition as the wave energy depletes. Thus the
depositions contain what was near the impact sites and do not represent
what was setteling out of a single large mass of homogenously mixed water

ME: This does not account for the presence of the same sequence of fossils
worldwide, especially microfossils. For that matter, such continuous high
energy does not allow the microfossils and fine-grained sediment to settle
at all. Flood deposits should all be coarse, with finer and finer grained
deposits as things settle back down again.

>>>Since flooding mega-tsunami could only occure by impacts in large bodies of
water, one would expect that the first depositions would contain primarily
marine life. As the mega-tsuanmi sweep inland (several waves would
generate from a single impact and each would follow the previous one ashore
before the first had time to drain back off) more and more land would be
innundated. Following impacts on continental areas now covered by
mega-tsunami distributed waters would start making depositions of land
based plants and animals. The more moble animals (and birds) would be
fleeing the mega-tunami for higher ground thus being (in general) the later
ones to begin to be deposited. Body boyancy would also play a part, but
not likely a major part. At this time, more detailed explanations that may
account for the apparent ordering are lacking. But time will tell.

ME: This scenario also runs into trouble with regard to preservation of
delicate structures such as whole skeletons, soft parts, footprints, etc.

>>> Just how this model can explain the deposition of forams, nannoplankton and
>>> diatoms as described, I don't know at this time. But, in my optimism for
>>> the model, I expect an explanation can be found.
>>YOu are an unusually(unreasonably/blindly) optimistic fellow. You are
>>suggesting that NO explanation is a reason to believe your view.
>That's _not_ what Allen said, Glenn. He said, "I expect an explanation
>_can_ be found. In the meantime, he is looking for an explanation to
>explain the data within his model.
>I tend to agree with Glenn that hydrodynamic sorting is not the answer,
>and that the widespread horizontal/narrow vertical distribution of index
>fossils reflects what was alive at the time. Glenn and I would disagree
>only in the length of time required to modify the morphologies. I would
>say that under unusually high stress conditions, shell variations
>occurred quickly, were spread around the world by currents, and then
>changed again as deposition continued with still different types.

ME: To fit any young-earth scenario, those had to be big currents. It
takes hundreds of years, under modern-day conditions, for currents to
spread things throughout the oceans. Even with ridiculosly faster
currents, it will take a while for something to get halfway around the
earth, plus enough time for the organisms to grow, live, and die and form a
layer. Additionally, it is necessary to do some sorting of kinds of
organism by location on the globe (cooler and warmer water regions, low
versus high nutrient regions). This distribution and sorting must work for
organisms ranging in size from about ten microns to ten meters.

>Within the last few months, there was a post supporting rapid change
>under high stress; unfortunately, I can't find it now.

ME: Probably one of mine, with regard to evolutionary mechanisms. The
minimum amount of time for rapid change in a population would be determined
by the reproductive rate, which in turn roughly (and with exceptions)
corresponds to body size. This would assume that viable mutations were
occurring rapidly and immediately replacing the old form.

David C.