Friday, November 8, 2013

Question from a reader: Stratigraphically sorted swimmers?

Yesterday, a reader submitted this question about the sorting of fossils:
I was reading your section on the giant platypus this morning and wondered if the fossil record shows any division at all between animals we know to be swimmers and animals we think were unable to swim?  I think some of the ones that were purely water creatures survived the whole thing (I'm remembering something about a big dinosaur-like water creature found in the Pacific near Asia?  I'm kind of hazy on this).  But is there any layer difference for those that could swim for a while and those that would have drowned pretty much immediately?
In short, not particularly, at least not how you might be thinking.  Now for the longer answer.

Geologic Layers

Artist's depiction of the hypothetical geologic column, with associated
ages and fossils.  Credit: Ray Troll.  Image source.
First, let's do a brief overview of the geologic column.  The geologic column is a hypothetical construct.  Yes, we do find many layers upon layers in many places, but we never have the entire package in one place.  When geologists look at an package of rocks, they divide them up into "formations," which are thick, continuous, consistent layers that can be identified wherever the occur at the surface.  One formation might be a 10-foot layer of reddish limestone, another might be a quarter-mile-thick layer of black shale (yes, that does exist!), and another might be a series of alternating 3-inch layers of clay and sandstone.  Geologists make a few assumptions when interpreting these layers: (1) they were originally horizontal when deposited, (2) they were originally laterally continuous, and (3) newer layers were deposited on top of older layers.  So, if you find a shale formation on top of a limestone formation, then a few miles away you find a sandstone formation on top of the same shale formation, then you would draw all three in a vertical series when constructing your geologic column, because you assume that all three used to overlap.

Unfortunately, only the geologic column is shown in textbooks, so people have the idea that mammal bones are found directly above dinosaur bones, and dinosaur bones are found directly above primitive fish fossils, and so on.  That usually isn't the case, however.  Except for a few rare occasions, fossils are really only found at the surface, because that's the only place we can see.  Because of the way the geologic column is constructed, however, they are represented as being directly on top of another.

The Black Hills

Let's take an example from an area I'm familiar with in western South Dakota.  In the middle of the Black Hills, there is a bunch of granite, formed by a big blob of cooling magma.  As you move away from the center, towards Rapid City, you find several sandstone and limestone formations tipped up on their side.  If you could clear off the vegetation, the rocks around the Black Hills would make a giant bulls-eye pattern on the surface.  Cutting down into the rocks, however, reveals that the contacts between the formations are diagonal, leading to the interpretation that they were tipped up at some point by the uplift of the Hills.  These units are the Paleozoic ("ancient life") rocks, containing fossils that you'd find on a sea floor, like coral, trilobites, worm burrows, and the occasional fish.  Moving a little further out into Rapid City, you find Mesozoic ("middle life") rocks leaning against the Paleozoic ones.  These layers contain some water dwellers (fish, squid-like creatures, ammonites) along with the rare dinosaur bone.  Continue moving eastward and you'll run into a thick black shale unit stretching over a massive area.  In this layer you can find the big aquatic reptiles like mosasaurs, some fish, some flying pterosaurs, and even the occasional dinosaur bone.  At this point, something interesting happens.  If you go north from the Black Hills, you'll find another very complicated series of clay and sandstone layers that are extremely dinosaur-rich called the Hell Creek Formation.  On the other hand, if you keep going east, you run into the Badlands, which are made up of Cenozoic ("new life") rocks and contain fossils of many types of strange mammals.  Both the Hell Creek Formation and the Badlands formations have fossils of turtles and crocodiles, creatures that tend to live near water.

The Evolutionary Model

What is the evolutionary explanation of this area?  The "oldest" layers, the Paleozoic ones (about 540 to 250 million years old), are thought to have been deposited when sea levels rose and fell enough to form numerous shallow seas over the area, slowly depositing sand and lime with the bodies of primitive life forms.  In the Mesozoic (250-66 million years ago), the area tended to be along coastlines where rivers emptied into the sea, resulting in coarser sand and fossils of reef dwellers with the occasional dinosaur bone that was washed out.  Then, the Western Interior Seaway came through and split the continent in half, depositing the thick black shale seen in the middle of South Dakota, along with the remains of large seagoing creatures and smaller flying critters that fed on fish.  The Hell Creek Formation is basically interpreted as the "beach" of the sea, where dinosaurs were abundant and occasionally buried by river floods before their ultimate demise 66 million years ago.  At this time, the Black Hills lifted up along with the Rocky Mountains, causing much erosion and leading to exposure of the older rocks.  There was very little deposition after that until the Badlands were deposited around 30 million years ago in a savanna-like setting, preserving the mammals that met unfortunate ends in that region.

The Creationist Model

A display from the Creation Museum depicting the ecological
zonation model used to explain stratigraphic sorting.
Image source.
One would think that having the swimming animals buried under the non-swimming animals would cause a problem for creationists, but this is not necessarily the case.  According to the creationist view, the earth and its creatures were created about 6000 years ago.  At this time, the only rocks on earth were likely igneous rocks, formed from cooled magma.  Gradual erosion formed a few sedimentary layers that were later metamorphosed into the "basement" rocks we see today, attributed by evolutionists to a time before complex life evolved.  Around 2400 BC, the great Flood came upon the earth, as reported in Genesis.  Turbulent sea water picked up the sediment and creatures found on the ocean floor and carried them in a massive torrent of water and sediment.  As the water moved inland, it picked up new sediment and deposited the old, forming the Paleozoic layers.  The water moved in and out several times, probably from different directions, depositing many layers in such a fashion.  The beach and lowland sediments, with their dinosaurian occupants, were eventually flooded, picked up, and deposited across a wide area atop some of the Paleozoic ones.  It may be at this point that the Western Interior Seaway broke into the continent, carrying the great ocean life with it, or the sea may have been there to begin with and simply flooded its banks at this time.  The waters encroached and receded several times, leaving just enough time for the straggling dinosaurs to make their last attempts to find food and lay their eggs.  Eventually, the water covered the whole earth.  Numerous volcanic eruptions, earthquakes, and asteroid impacts likely happened during the entire time, possibly leading to the strange deposits that are associated with the dinosaur-killing meteorite in the evolutionary view.  The face of the earth was rearranged under the waters, with continents moving, sea floors reforming, mountains uplifting, and land disappearing.  As the waters retreated, much of the surface was eroded, exposing older rocks in some places.  The animals that were saved on the Ark dispersed quickly, finding any habitable area they could, likely reaching North America through a land bridge between Russia and Alaska.  Subsequent disasters, smaller than the Flood but catastrophic nonetheless, preserved the North American mammals in smaller areas, such as in the Badlands, and formed much of the topography we see today, such as the Grand Canyon.

The Swimmers

So what happened to the swimming animals during this time?  Obviously, they were not taken on the Ark. As we can see from the fossil record, not all of them survived.  The Flood was chaotic and catastrophic enough to bury marine creatures from underwater avalanches and influxes of sediment.  Water temperatures and salinity levels drastically changed, probably only leaving a small fraction of seagoing life alive.  The Bible does not specify whether all kinds of ocean life were preserved during the Flood.  All we know is that there were many forms that are now extinct.  


As we can see, neither the creationist nor the evolutionary model requires distinct separation of swimmers and non-swimmers, but they can both account for the interesting patterns that we see in the record.  We occasionally find land creatures in marine sediments, but it is quite rare for marine creatures to be found in terrestrial sediment, and this makes sense from both perspectives.  Whether the layers are indicative of chronological occurrence, as in the evolutionary model, or of geographic distribution, as in the creation model, we would expect to see a distinction of aquatic and terrestrial animals on a layer-by-layer basis.  The overall trend of marine fossils in the bottom layers and terrestrial fossils in the top layers is quite easily accounted for in the creation model as described.  Evolutionists, on the other hand, use this as evidence that life evolved in the oceans and eventually migrated to the land.  So, in summary, there is a general trend, and there is separation, but it is not what one would initially expect.  As usual, the evidence can be interpreted either way.

The Zuiyo-maru Carcass

The Zuiyo-maru carcass on board the Zuiyo Maru
fishing boat off the coast of New Zealand.
Image source.
As a bonus, I want to discuss the "big dinosaur-like water creature found in the Pacific near Asia" that the reader mentioned.  I believe she is referring to the Zuiyo-maru carcass, a large rotting body that was caught by a Japanese fishing boat.  The carcass resembled a plesiosaur, particularly in the widely-circulated photo shown here, with a small head, long neck, and large flippers.  When I first saw this photo as a child, I was amazed and believed that this would put the final nail in evolution's coffin.  Alas, it was too good to be true.  Just as a cloud can be seen from just the right angle to look like a fearsome dragon, this particular photo was taken at just the right angle to make it look "unmistakably" like a plesiosaur.  The carcass, as it turns out, was probably a basking shark.  Basking sharks have enormous mouths, and their eyes are placed very far forward on their head.  When their body decays, their lower jaw tends to fall away, making it appear as if the animal had a tiny head and long neck.  The few tissue samples that were kept from the specimen seem to confirm this.  Despite this, the carcass is still often displayed by creationists to support their ideas.  I strongly dislike misleading information being used to support someone's position, even one I agree with.  I created this site to put an end to that.  I caution you to take everything you hear with a healthy dose of skepticism.  Lies and deceit are tools of Satan, and only with the truth can we advance the Kingdom of God.

If you have a burning question you want answered in a post, submit it to!  If you just want a quick answer to a question about a particular post, leave it in the comments!


  1. First of all, I must say: Very well-written! Long-time reader, first-time commenter (the usual fan-mail stuff)...

    While this is a great overview of how there is no delineation in Flood deposits between (full-time) swimmers and non-swimmers, I'm curious about terrestrial animals that are better swimmers than others. This depends somewhat on the Flood/Post-Flood boundary (still in debate among creationists, as you know). Specifically, I'm wondering what your thoughts are about the apparent lack of mammals in Flood deposits (if the boundary is at the "K/T") or the apparent dinosaur/mammal change observed at the "K/T" (if the boundary is closer to the Pliocene/Pleistocene).

    I've heard some speculate that body density may have played a role in this distinction, with (supposedly) more dense dinosaurs being preserved, whereas less dense mammals would be carried away by flood waters. I've also heard speculations that this is why there are no human fossils found in human deposits - they would have sought high ground, swam, or floated on debris. I'm wondering if it's possible that mammals are generally better swimmers than dinosaurs, and that they (overall) had a similar fate to humans during the Flood. I can't help but think of the footage of elephants swimming - if an ELEPHANT can swim so well, I imagine most mammals could have kept up.

    I hope that's worded in an understandable way; if not I'd be happy to clarify. Thanks!

    1. As you say, there are numerous opinions about the Flood/Post-Flood boundary and mammals among creationists. As Dr. Todd Wood once pointed out to me, however, it is not just large mammals that are absent from Flood rocks. Angiosperms are largely absent below Upper Cretaceous rocks as well. There appears to be an entire ecosystem that was not recorded in Flood deposits. Personally, I believe this to be geographically-related. It may be that dinosaurs and gymnosperms dominated the lowland and shoreline areas of the pre-Flood world, whereas large mammals and angiosperms occupied higher inland regions. Dr. Wood suggested that perhaps mammals had their own continent at Creation, where the Garden of Eden was located, that was completely destroyed from intense tectonic activity. Or maybe it is buried under all the ice of Antarctica!

      Indeed, it is a perplexing question, but not a devastating one. We just don't have the information we need at the moment to produce a convincing and consistent answer.

      I hope that helps. Feel free to ask any follow-up questions. Thanks for your input!

  2. The real problem is when you consider several additional factors:

    1) Too well sorted-I am going to bet you will never find a marine mammal (cetacean) buried with a marine reptile (icthyosaurs and plesiosaurs), despite their similar morphologies and habitat environment, in shallow seas. Were cetaceans better swimmers too?

    2) the problem with giving dinosaurs surviving time to lay eggs means that its entirely possible that land mammals would survive alongside them. So why didnt they get preserved in the same burial sediment? What we see is exceptional preservation in situ-marine sediments (marked by sediments such as graywacke) preserving marine fossils, aeolian sand environments preserving land dinosaur fossils.(Google "Flaming Cliffs Mongolia" - a spectacular dinosaur preservation site). How does this work?

    3) A global Flood would in all likelihood erode and destroy continents, rather than deposit marine sediments right atop them. This is because the sea covers 70% of the entire Earth, and violent currents would erode places with higher altitude (land) rather than remove material from the seabed and carry on deposition above. In fact, most deposits would have ended up in the ocean.

    4) As you mention in your comment to David Lee-angiosperms are only found in upper Cretaceous sediment. Yet it is not only the plants themselves that fossilized in this order - even fossil pollen is remarkably sorted in this manner. You will never find angiosperms and their pollen in Paleozoic deposits - despite the fact that angiosperms are so ubiquitous in almost every forest you visit today.

    5) Meteor impacts - Some of the largest ever in existence that makes the famous Chicxulub crater look like a dwarf - google "Vredefort crater" or "Sudbury basin". Didnt Noah notice such massive meteorites striking the Earth?

    I made a post on fossil preservation and why a Global Flood has problems explaining it:

    Just trying to make sense of it.

    1. Thanks for your response, Daren! I will attempt to answer your questions here.

      1) Indeed, there is a lack of cetacean fossils in Paleozoic and Mesozoic rocks. Most, if not all, deposits containing large marine reptiles are interpreted as representing epicontinental seas rather than oceans. It appears that cetaceans were limited to the oceans, whereas marine reptiles thrived in the epicontinental seas such as the North American Interior Seaway.

      2) As with the separation between cetaceans and marine reptiles, dinosaurs and large mammals also appear to have been ecologically separated before the Flood. It is then quite possible that some large mammals survived until near the end of the Flood as the dinosaurs did, but we quite frankly don't know where that happened. Some creationists propose that many Tertiary deposits are actually Flood deposits and could be temporally (if not lithologically) correlated to Cretaceous formations. Others have suggested that the Flood remains of the large mammals are trapped under the Antarctic ice. As I mentioned in my response to David, still others think that the continent on which the mammals lived no longer exists.

      3) That really depends on the direction and motion of the waters. If sediment-rich waters rushed onto land and slowed, they would deposit their sediment on land. This is how beaches are formed, for example. Indeed, there was likely much erosion at the end of the Flood when the waters retreated. Some creationists hypothesize that most of the mammal fossils were lost in such a process. However, such erosion need not counteract the initial deposition.

      4) So it is apparent to the creationist that angiosperms were not so ubiquitous in the pre-Flood world. Admittedly, their extremely sudden and cosmopolitan appearance is a bit of a mystery to both creationists and evolutionists. However, I don't think it counters either view very well.

      5) I have no doubt that many meteors hit the earth during the Flood. Whether Noah saw them would depend on his exact location at the time they hit.

      Many aspects of dinosaur remains in the Mesozoic rocks have yet to be explained by creationists, but it is more an area of unknown than a problem. Keep in mind that there are very few actively-researching creationists compared to the rest of the scientific community, so our progress is relatively slow. Southwestern Adventist University currently has a large-scale taphonomic research project on Cretaceous dinosaur remains going on in Wyoming, which I have assisted with, but it will likely be several years before any results are published simply due to the sheer size of the project.

    2. "even fossil pollen is remarkably sorted in this manner."

      Fossil pollen has been found in rocks designated Precambrian. Google "Roraima Pollen Evolutionary Paradox". Plants weren't supposed to have existed for a billion years after Precambrian!

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  4. Not sure how this applys, but this video series needs to get out there.

    Stratification experiments DO NOT support evolution.

    1st of the 4 videos on this subject. I recommend them all.

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