From: skroger@zeus.calpoly.edu (Seth L. Kroger)
Newsgroups: talk.origins
Subject: Re: Help needed to debunk creationism
Date: 25 Aug 92 18:09:36 GMT
Organization: California Polytechnic State University, San Luis Obispo

eftv03@castle.ed.ac.uk (L R Watt) writes:
>4. I need a debunking of the hydrodynamic sorting theory
>   of stratification.

In Flood geology, fossils are sorted by two main factors.  They are
differential habitat/mobility and differential settling rates (due to
fulid mechanics).  Organisms along the sea bottom will get swept into
the sediments first (mostly marine invertebrates).  Then the rest of
the ocean dwelling creatures got caught up next.  After that, the
amphibians and reptiles living along the coasts as the Flood waters
rise.  The larger reptiles, better able to escape the rising waters,
would be above them, followed by the "superiorly mobile" mammals at
the top layers.  They are also sorted by size.  The smaller,
"primitive" creatures settle faster than the larger "advanced"
creatures.  Thus smaller invertebrates are normal found lower than
large vertebrates.

There are a number of problems with the habitat/mobility process.

One is that modern fish (Teleosts) aren't found below Mesozoic strata
(the Age of Reptiles/Dinosaurs)  This is well above the layers where
the amphibians and early land reptiles are found.  Teleosts should be
found all through out the early strata from the flood, since there are
many species that are bottom dwellers, as well as free swimmers.

Another problem is flowering plants.  They aren't found until the
Cretaceous (the latest of the three periods in the Mesozoic), well
above the fossils of other land plants.  Since they aren't very
mobile, and many species inhabit coastal areas, how did they all end
up where they are?

The hydrodynamic sorting by size is even more bogus, and requires one
to suspend the principles of fluid mechanics.  

While smaller objects will have a smaller drag than larger ones, the
important factor is the velocity at which the objects fall or settle.
The important parameter is the balistic coefficient, or the area/mass
ratio.  If you drop a feather and a steel ball of the same area, the
steel ball will fall much faster than the feather.  The feather has a
much slower velocity with its high area/mass ratio.

  [Falling objects will come to a speed called their terminal
   velocity.  At this velocity, the object's drag is equal to 
   the force due to gravity.  Using good ol'e F=ma, we get the 
   equation D=mg. (D - drag, g - acceleration due to gravity.)
   Drag is D=Cd*1/2*den*v^2*A (Cd - coefficient of drag, den -
   density of the fluid, v - velocity, A - area).  Solving both
   equations for velocity get us v = 1/sqrt((1/2g)*Cd*(A/m)*den)]

Generally, as the size of an object increases, the area increases by
size^2, and mass increases by size^3.  This gives us the relationship
that the balistic coefficient is proportional to 1/size.  The smaller
the object, the higher the balistic coefficient, and the slower the
velocity.  This indicates that smaller objects should settle *above*
larger ones, not the other way around as Flood Creationists claim.

Large streamlined fish are found only in upper levels.  Jellyfish, with both
lousy Cd's and balistic coefficients, are found in the lower Cambrian
strata.  The Precambrian (the entire section before you find virtually all
multicellular fossils) have vast numbers of single-cell protists and
bacteria fossils.  These are small enough to actually stay afloat in water
without falling (like dust floats in air).  If hydralic sorting was
responsible for fossil distribution, we'd have a radically different picture
of the fossil record.

>    If anyone has FAQ's on any of the above topics, I'd
>really like to see them.
>
>Many thanks in advance.
|======================================================================|
| Seth Kroger                       "If God made us in His image we    |
| skroger@pan.calpoly.edu               have certianly returned the    |
| Cal Poly, San Luis Obispo             compliment."  -Voltaire        |
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