The Talk.Origins Archive: Exploring the Creation/Evolution Controversy

Floods & Fossils
Post of the Month: October 1996
Tim Thompson

A University of Ediacara Flood & Fossil Lecture by Professor Timothy J. Thompson, Ginenthal Professor of Planetary Physics

S o, is the fossil record compatible, or not compatible, with the idea that the fossils were laid down in the/a "genesis flood"? The 'Grand Canyon' threads started to hash that out, and now the 'trilobites, clams and jellyfish' thread is into it as well.

I cannot imagine how any sane and reasonable person could ever think that the fossil record is compatible with the genesis flood. Indeed, quite the opposite, the fossil record is quite sufficient to refute the global flood hypothesis all by itself.

Notice that the creation-science proponents of the global flood theory never address the detailed vertical fossil sequence, they speak only in broad generalities (as one might expect when one is limited to nebulous discussions of 'kinds'). When they do try to get detailed, as the stalwart 'Ksjj' has done, they just get it wrong. One cannot discuss the fossil record reasonably if one does not know what the fossil record is, and one cannot discuss the fossil sequence reasonably until one knows what the fossil sequence is either.

My news-server has been very slow, and I feared that the appropriate points were not getting air-time when I didn't see them. However, now I have seen some very pointed comments, from MacRae and Hershey just for example. MacRae gave us a good schematic [repeated here for your edification ... ]

In article <53jbk3$>, (Andrew MacRae) writes:

[ ... ]
>E == early,  M == middle, L == late
>"Karl's Reality"		  Actual reality
>From some unknown source	  (greatly summarized!)
>				  Silurian
>				  ----------------
>				  L. Ord.  (Vertebrates, Fish)
>				  M. Ord.  (different trilobites)
>				  E. Ordovician (different trilobites)
>----------------		  ----------------
> Cambrian			  L.Camb.  (different trilobites)
>  (Invertabrates)			   (euconodonts (chordates))
>  Trilobites,Clams		  M.Camb.  (different trilobites)
> Jellyfish.				   (non-"sea urchin" echinoderms)
>  (Vertabrates)			   (plenty of other invertebrates)
>					   (halkierids, soft-bodied
>					   "transitional" chordates)
>      Fish			  E.Camb   (first trilobites)
>					   (small shellies, including
>					    armoured bits of lobopods)
>					   (trace fossils)
>----------------		  ------
>worms (upper pre-cambrian)	  "worms" (upper pre-cambrian)
>				  probable "flatworms", cnidarians
>				  (i.e. jellyfish relatives), "segmented
>				   worms", possible ancient deuterostomes
>				  of the Ediacara fauna
>alge, bacteria			  (transitional fossils?)
>				  -----
>				  a few small "blobby" multicellular
>				  remains (e.g., see Hofmann, 1985)
>				  -- hard to tell if animal or plant
>Granite earth crust		  more single and multicellular "algae"
>------------------		  and bacteria in mid Precambrian
>				  sediments, including stromatolites
>				  -----
>				  more metamorphic and igneous rocks
>				  eventually unfossiliferous

I feel less compelled to worry that the real points aren't being made, but I want to make one more anyway. The fossil record is sorted vertically with an incredible amount of global fine structure. One might argue that variations in horizontal distribution are habitat related (the flood buried them where they live), and feel good about one's self, even if it may be a less than wholly satisfying idea. However, there is no such leeway allowed for the vertical structure. We are forced to ask how the flood was able to sort the fossils with 100% precision, by species. The only answer I can come up with is that there was no flood.

Arthur Strahler talks about this in his book Science and Earth History (Prometheus Books, 1987, ISBN 0-87975-414-1, BS653.S77), notably in chapter 39, "Fossils and Flood Strata - A Hydraulic Stratigraphy", pp 371-382. This is worth reading for anyone interested in pursing the matter in more detail. Strahler's approach is rather general, but should be adequate. He notes, for instance (page 377) that the settling velocity through non-turblent water, of a falling sphere, is proportional to the square root of the diameter (this is because smaller objects have a larger surface to volume [mass] ratio, and drag is related to surface area, so smaller things actually have a larger proportonal drag, and larger things will fall faster under a smaller proportional drag). Although this applies technically only to falling spheres, and most dead things falling through the water are not spheres, the rule can still be applied as a comparison. In other words, big things usually still fall faster, even if they aren't spheres.

So, of course, one can start asking general questions, like why aren't all of the big, fat, and fast-falling dinosaurs at the bottom? How did all that little stuff get under them (remember, dinosaurs went extinct only about 65 million years ago, and the 'cambrian explosion' is dated around 545 million years ago). Dinosaurs, all of them, are near the top. Not even one lone dinosaur made it to the bottom. Yet, in a flood geology, the bottom of the bottom should be carpeted with fat dinosaur carcasses. Where are they?

But the real death of the flood comes not with these 'large scale' arguments, but rather with the fine-structure, the small scale sorting of the fossils. Different species of trilobite, for instance, are found rigidly segregated into seperate vertical layers, not a single one out of place, even when it takes a careful examination by an expert to tell one from the other; a typical difference might be the number of elements in the trilobite compound eye. Can a flood sort them that perfectly?

Now, take a break and consider this ...

Article (Refs:8)
by Lask-PB (*R)
Univ Cincinnati,Dept Geol/Cincinnati//OH/45220
PALAIOS v8 (3) : pp219-225 (1993 Jun)

Artificial trilobite sclerites may be used as surrogates in flow tank and field experiments to reveal the settling and transport characteristics which affected the deposition of fossil trilobite remains. In this study, epoxy casts were produced of molds taken directly from a fossilized cephalon, several pygidia, and a complete enrolled specimen of the Ordovician trilobite Flexicalymene meeki. The models were cast in a range of densities estimated to subsume that of fresh trilobite exoskeleton. Settling velocity and behavior were determined as the sclerites fell through a column of still water. The cephalon and pygidium always settled in a concave-up orientation. The threshold velocity of transport was tested in a hard-floored flow tank for each sclerite model in both concave-up and concave-down attitudes, in three orientations to the current. For both sclerite types, the concave-down attitude was most stable when either the anterior or side margins faced the current. Enrolled specimens were transported readily at current speeds much lower than those required to move the more stable configurations of either sclerite type. When placed on a fine sand substrate in the stable positions stated above, both types of sclerites were buried by moving sediment without being dislodged by currents of up to 0.5 m/sec. If further work confirms these preliminary findings, trilobite sclerites will be useful as paleocurrent indicators. The hydrodynamic properties of sclerites control their transport and burial; understanding these properties should help clarify related aspects of trilobite taphonomy.

The implication is interesting - we may well be able to use the orientation of trilobite fossils to determine details of their aquatic burial, especially if they died in a flood and settled, as opposed to passing away quitely on the bottom. There isn't much material out there on how animals fall through water, but this is a start.

But let me add one more nail to the flood coffin before I put my 'tirade' to rest for the evening. Not much has been said about microfossils yet. Fossilized bacteria, and other tiny one-celled or few-celled things are all over the place. Top to bottom of the fossil record. Yet in a flood scenario these tiny things should have remained suspended in the water for a very long time, whether it was turbulent or not; there should be virtually none at the bottom. Yet, despite this, the big fat dinosaurs are on top, and hordes of tiny things are on the bottom, and that's about as un-flood as you can get. But, even more un-floody is the fact that the bacteria, the tiny things, are also sorted by species in vertical layers. Now you might make up some corny argument about trilobite eyes making all the difference in falling velocity, but that won't work for really tiny things where Brownian motion becomes important. No flood imaginable, save one that includes copious divine intervention to circumvent physics, can ever explain the strong vertical segregation of microfossils by species.

So now it's quiz time.
Are there pre-cambrian fossils? ........................... Yo
Are the fossils in sequence? .............................. Yo
Can any real flood explain that sequence ................ No

Class dismissed, and you all get extra credit for reading this far.

Article originally posted October 11, 1996

Home Page | Browse | Search | Feedback | Links