Where is Noah’s Flood in the Geological Column?

Young-earth creationists have a geological column problem that 50 years of research has yet to solve: where is the boundary between Flood deposits and post-Flood deposits?

All young-earth creationists (YECs) are convinced that a large portion of the geological column and the fossils that it contains were deposited during a single cataclysmic global flood event that occurred no more than 4500 years ago. Creationists therefore expect that somewhere in the vertical column, represented by thousands of feet of rock and sediment that cover the earth, there lies a boundary or transition zone between those layers of sediment that were deposited during the global Flood and sediments that were deposited after that Flood. The layer deposited after the Flood, therefore, would be a record of the history of organisms that had existed from the end of the Flood to (potentially) the present day.

Put another way, somewhere in the geological column there must be layers of rock that contain fossils of mammals that perished in the Flood, above which are rocks which contain fossils of mammals that were descendants of mammals preserved through that flood, and repopulated the post-flood world. 

Identifying this dividing point in the geological record is essential to the success of any young-earth model of geological history.  In addition, I am going to argue here that any lack of consensus of young-earthers on where this boundary exists would also be a serious liability for creation biologists hoping to understand (and articulate) the origin and maintenance of biological diversity.

Given its importance, you will not be surprised that considerable effort over 50 years has been expended by young-earth creationists to elucidate which layers or rocks belong to these presumed major events in earth’s history.  What may be a surprise to the average young-earth follower is that, despite these efforts, there is no clear consensus about where this elusive Flood/post-Flood boundary is located.  Conflicting models and disagreements about the location of the boundary are prevalent in the creationist literature.   

What follows is a description of the two most popular young-earth models explaining the geological column followed by an illustration of how the existence of these two models places constraints on, and influences creationists conclusions about, the history of living things.

Let’s take a look at the two most popular YEC proposals.

On the furthest left side you see a simplified schematic of the geological column. This represents the general understanding of those at Answers in Genesis and, in particular, Dr. Andrew Snelling, their resident geologist.  Everything before the Cambrian period, conventionally dated to 541 million years ago, is considered to be the product of the pre-flood world from Creation 6000 years ago to the initiation of a global flood event about 1656 years after the creation week. How much of this portion of the fossil record occurred during the 7 day creation week is rarely discussed.  

The bulk of the rock layers of the geological column are found in the periods that conventional geologists refer to as the Cambrian through the Cretaceous periods. These layers are believed to be the product of a year-long global flood less than 4500 years ago. The top portion of the geological column, the entire Cenozoic era, conventionally dated 66 million year ago to present, is credited to events that occurred after the Flood – Ice ages, remnant tectonics, local floods, volcanism, etc.   

On the right side we see a schematic representing the hypothesis of ICR and Dr. Timothy Clarey, their resident geologist. They agree on the position of the pre-Flood/Flood boundary but radically break from AiG by placing the end of the Flood deposits near the end of the Cenozoic era right about the Neogene/Quaternary period divide. Conventional dating places this divide at just 2.6 million years ago.

There are other creationists who place the boundary lower or higher in the geological column, but these are the two most popular views today.  These views are not compatible with one another. They result from focusing on very different sets of observations leading to different conclusions.  Both of these views influence, or have the potential to influence, dozens of related creationists theories.

As an example, let’s look at how these contrasting views could influence these ministries’ understanding of the origins of biological diversity and their definitions of a biblical “Kind”(1) in particular.

Here we see an outline of the AIG and ICR hypotheses about the geological column. Let’s consider the fossil record of felines and how it would look projected onto these models.  First let’s consider how it would look on the  deeper AiG boundary.  Remember that AiG and most creationists consider all members of the “feline family” to be members of the same biblical kind. As such, Noah need only have brought two cats on to the Ark to preserve the feline “kind.” Those two cats are hypothesized to have diversified into all of the living and extinct species of felines that ever lived during the Post-flood era.

What story does the observed fossil record tell us?  Significantly, not a single feline fossil has been identified in any place on earth in the “pre-flood deposits. Furthermore, no fossils of felines have been identified in any “flood” deposits either. The first feline fossil appears well into what AiG considers to be post-flood deposits.  This means that all of the diversity of felines–extinct and living– are only found preserved in post-flood rocks.  

Superficially, this corresponds with the AiG hyperspeciation model of biological diversity in which most or all species of mammalian families find their origins in the post-flood world and, thus, find their common ancestor within the past 4500 years.  What is left unexplained is the complete absence of any evidence that felines existed prior to the Flood.

Now consider the ICR Flood deposit hypothesis.  We have a very different story. AIG and ICR agree on the facts of what is found in the geological column such as the location of fossils but given their differences in where they place the Flood boundary one would think that it should lead to very different interpretations of those fossils.  Notice that in the ICR model many of the feline fossils are preserved in rocks laid down by the Flood. These felines must have been alive prior to the Flood in order to have been fossilized in that event.  

Now the story gets very perplexing and this aspect has yet to be addressed by ICR – at least that I am aware.   Fossils identifiable as lion-like or leopard-like or cougar-like are found in Flood deposits right up to ICR’s proposed boundary, but also after that boundary in post-Flood deposits.  Furthermore, these fossils are found in similar geographical locations. – Hence it appears these feline lineages go right through the proposed Flood boundary.  What is going on here? Are we to understand that lions, panthers and leopards existed as separate species prior to the flood, and yet just one single pair from the entire “kind” walked on to the Ark, only to walk off less than a year later and hyper-evolve back into the very same species once again?  This is quite a convenient occurrence. 

Would it not make more sense (in terms of the ICR model) to view lions, tigers and leopards each as a separate kind, each having further diversified after the flood? When extinct lineages are considered that also straddle the Flood/post-Flood boundary, at least seven separate “kinds” of feline would need to have existed prior to the Flood with a pair of each having been preserved on Noah’s Ark. Other individuals of these kinds would have perished in the Flood with the Ark dweller pairs of each kind having repopulated the earth post-Flood. This would still leave unexplained the lack of fossils in pre-Flood and early Flood deposits and would leave the very perplexing observation that fossils of some lineages would be found in the same region geographically in Flood and post-Flood deposits.  For example, there are lynx fossils from the Neogene and the Quaternary Periods in North America. 

So here we see that the placement of the Flood boundary can and should have a significant influence on how these two groups understand the diversity of living things. 

Thus far ICR has not tackled this obvious obstacle to their model in any significant way. They still talk about “cats” as if they are all one kind, but as they continue to support this recent Flood boundary, maybe they will revisit their inclusive view of kinds (e.g. wolves, foxes and wild dogs are all the same kind or lynx, lions and house cats are the same kind) and the hyperevolution that this requires in favor of a more limited understanding of kinds that better fits their geological model (e.g. wolf-like species are a different kind than fox-like specie).

I am confident that we could apply this same analysis to all the families of mammals and nearly all would exhibit a similar pattern as this feline family.  Thus, AiG and ICR’s significant Flood boundary differences will result in increasing friction between the two organizations as they both will feel the need to show where the other is wrong.  If they double-down on their positions regarding geological history, it will certainly impact their views of biological history.

Let’s consider one more example, the great apes! I have written about AiG’s going all-in on a post-Flood hyperspeciation thesis that all the great apes (except humans of course) belong to a single kind. Chimps, gorillas and orangutans all have evolved from a common ancestral pair that walked off the ark just 4350 years ago.  As we can see, this model is not impacted directly by their deep Flood boundary placement. In fact, I would argue that their confidence in this broad interpretation of what a biblical kind is, is influenced by their view of where the Flood boundary is found. They observe that every fossil of great apes is found solely in post-Flood rocks and that allows them to reduce the apes to just one kind, making a lighter load for Noah. They still have a serious problem, though, but one that is shared by all creationists: the lack of any observed fossils of these animals in most of the geological column.

Now consider the ICR model and the great ape fossil record. You will quickly see that ICR’s position conflicts with AiG’s thesis that all great apes are a single created kind. In their model, chimps, gorillas and orangutans all have identifiable fossils from each of their “kinds’ in the upper Flood deposits. This testifies  to the existence of these “kinds” being present in those forms prior to the Flood. I have yet to see ICR make any direct statements about whether they believe chimpanzees are a different kind than gorillas, but I believe that they conclude that there are at least three different kinds of apes. This is in direct contrast to the very public display at AiG’s Creation Museum, which declares them to be but a single kind.

Let’s return to our first slide to make a few additional observations.

First, I am aware that the boundary we are talking about does not necessarily have to be a sharp boundary. There would be considerable fuzziness in that boundary because of remixing of flood deposits with post-flood deposits.   As a result fossils laid down late in the Flood could have been eroded in the post-Flood world and redeposited with new fossils from that post-Flood world.   The AiG boundary is fairly well defined in the geological column and there are places where what is below is clearly different from what is above.  It also represents a significant “extinction” boundary in that many organisms found below that boundary never appear again above it, most notably hundreds of lines of dinosaurs.  

Secondly, there are many additional hypotheses among YEC about where the boundary is located.  Some push the pre-Flood/Flood boundary much lower, nearly eliminating any record of the pre-Flood world.  Others push the Flood/post-Flood boundary much lower than even AiG, leaving half or more of the geological column to have formed in the time since the Flood.  AiG and ICR as organizations appear to have settled on a preferred Flood boundary which reflects the beliefs of their primary geologists (Snelling and Clarey). CMI as an organization doesn’t seem to be committed strongly to either of these views. In general, AiG’s deeper Flood boundary is the most popular, not necessarily for its merits, but just by virtue of that organization’s influence on the Christian community who aligns itself with young-earth creationism.  

At every large creation conference, creation scientists present what they are working on. When discussions ensue on how to assign the Flood to the geological column, these are of the most vigorously debated.  The fact that this is still a big unanswered question raises the question: Is there no answer because there was no global Flood?  This is the only question that is not asked at these gatherings. But just maybe the answer to that question is the key to understanding the geological column.  

Below is a link to my YouTube version of the content of this post.    

(1) A “kind” refers to the biblical mention of God creating “kinds” of organisms. What organisms are included in a “kind” has been difficult to determine from scriptures as it is used variously of groups of organisms and of particular species. Likewise a common scientific definition of “kind” has also eluded Young-earth creationists though they are committed to the reality of created “kinds” as distinct and separate creations of organisms and thus share no common ancestry. Does a wolf and a fox share a common ancestor and thus the same “kind” or are they distinct creations and therefore not share a common ancestor. This is one of the most important unanswered questions in creationism.

Editing provided by MC


  1. So the Snellings and Clareys of this world, at least when talking to each other, are completely sincere, and unaware that they are asking a question that is of its nature unanswerable because of the falsity of its preassumptions

    Liked by 1 person

  2. robert byers says:

    Glad you asked! Organized creationism is giving great research to this stuff. I understand most YEC think its the k-pg/k-t line. Theyt are right. this simply based on the biology fossilized. below its weird and above common. Then the great sedimentary deposits that cover all the earth, on the dry land save volcanic areas, could only of been deposied by the great flood event. What is above is more sparing and often volcanic only. chump change. the issue YEC has is not yet imagining a great post flood event also created , within days, great fossils/sedimentary strata. This leading within a few more days to the ice age. Seeing the flood strata as opposed to other just by looking at it seeems likely only the degreeof deposition would be the clue.
    By the way the creatures above/below need only be seen as members in kinds. so before the flood a KIND diversifued, rebboted to a single pair on the ark, and then after diversified. So there was no cats before the flood in that way.


    • Taking the k-pg boundary as the line between flood and post-flood deposits means an awful lot of geology has to happen post-flood, including volcanic activity in the UK, deposition of ‘low energy’ clay deposits and formation of the Alps and Himalayas! It stretches credulity, to put it mildly.

      Liked by 1 person

      • Indeed. At the Giants Causeway, Palaeocene, there is a baked laterite layer in between lava flows, implying 1s of thousands of years of weathering. And that’s just one detail in one event sequence

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  3. Great post. The problem of finding the flood is huge geologically. I want to point out a couple of my posts that provided more geological problems for YEC that arise because of the boundary.
    First shows a large selection of views: https://jesusinhistoryandscience.com/?p=2505
    Second shows problems when we think about comparing the last 4000 years to the short period that the YEC model predicts: https://jesusinhistoryandscience.com/?p=2850

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