Young-earth creationists consider Noah’s Flood to have been global in its extent and left behind a catastrophic impact on the earth’s geologic record. However, determining where the Flood strata start (the pre-Flood/Flood boundary) and end (the Flood/post-Flood boundary) is perhaps the most widely discussed and debated topic of young-earth geology.
The purpose of this article is to summarize the main views so that you can investigate the claims of each one for yourself. It should be noted that there are many variants of the models listed below, and thus this summary does not reflect all ranges of opinions.
Due to the nature of this subject matter, this article is subject to changes/updates in the future and may only represent the current literature on the topic.
Where Do We Start?
It should be clear from this summary that there are a diverse array of opinions regarding which geologic strata are pre-Flood, post-Flood, or from the Flood itself. There even lie disagreements within these Flood models, as their adherents are not always in agreement in the more specific details. What is the best way to progress from here?
First, we should remember that the debate over where the Flood is in the geologic record is an “in-house” debate. All of the models discussed below reject any notion that the earth is billions, millions, or even hundreds of thousands of years old.
- Understand Flood Chronology
The first and most important place to start with any scientific investigation is the Word of the One who was there at the times the events in question occurred. God has provided us with the cliffnote rendition of early earth history in Genesis 1-11 (with helpful tidbits scattered throughout the rest of Scripture). We can glean it for an overarching sequence of events that would have left a mark upon the geologic record.
The Flood certainly would have left geologic evidence behind in its wake. Not just the Flood, but we should be able to delimit specific systems of the geologic record to specific phases of the Flood. Currently, Hebraist and Bible scholar Dr. Steve Boyd is heading up the Cataclysm Chronology Research Group (CCRG) with the goal of assembling a consistent, cohesive chronology of the Flood year. Before we can understand how Biblical history and geological history correlate, there are several chronology-related questions we must answer. Were all pre-Flood land animals “blotted out” in 150 days or just 40 days? When did the torrential rain and fountains of the great deep cease? When did the mountains appear as the waters began to recede? The answers to questions such as these have major implications for how we might interpret the geologic record.
Once complete, a cohesive Flood chronology will provide Flood geologists with the necessary framework for the construction of a biblically-consistent Flood model. Check out the articles below for some of the CCRG’s recent breakthroughs.
- Anderson, L., Jr. (2014, April 1). A Deeper Understanding of the Flood—Details Matter. Answers Magazine. doi:https://answersingenesis.org/the-flood/details-matter/
- Boyd, Steve W. “The Last Week before the Flood: Noah on Vacation or Working Harder than Ever?” Answers Research Journal, vol. 9, 17 Aug. 2016, pp. 197–208., doi:https://answersingenesis.org/the-flood/last-week-before-the-flood/
- Boyd, S. W. (2020). It’s for the Birds: Avian Fine-Tuning of Flood Chronology. Answers Research Journal, 13, 135-152. doi:https://answersingenesis.org/bible-timeline/avian-flood-chronology-noah-window/
- Correlate Biblical History with Geological History
Once we have assembled a sound Flood chronology, the next step will be to correlate the events recorded in the Bible to specific signatures in the geologic record. Can we identify at what point in geologic history sea levels were at an all time high, à la Genesis 7:20? What can we expect of the fossil record formed during the inundation phase versus the recession phase? Where are the ‘fountains of the great deep’ referenced in Genesis 7:11 located today?
Also necessary is the correlation of pre-Flood and post-Flood history with the geologic record. Can we identify signatures in the Precambrian geologic record that point us to the existence of a worldwide ocean (Genesis 1:2-3) that preceded the uplift of dry land (Genesis 1:9)? How soon after the Flood did the Ice Age occur? Was it contemporaneous with early patriarchs like Abraham and Job?
- Determine Which Flood Model is the Most Parsimonious
When we say that a scientific theory or model is parsimonious, we mean that it is the simplest scientific explanation that best fits the data we currently have at hand. So we must figure out which Flood model is the best fit based on what we know about the geologic record. This involves identifying what criteria and potential flaws characterize certain aspects of the various Flood models and comparing them against observed geological patterns in the rocks. In many cases, this may require reassessments of rock and fossil deposit interpretations produced by secular geologists. This has proven very useful in understanding the Coconino Sandstone of the Grand Canyon. Though often cited as an aeolian (wind-blown sand) deposit, research by creation geologists such as John Whitmore suggests that it was actually subaqueous (deposited underwater) in nature. This is something we would not have known if we did not investigate the data for ourselves and come to our own conclusion.
Neogene/Quaternary Boundary Model
This is the second most widely-accepted Flood model and posits that the Paleozoic, Mesozoic and all of the Cenozoic (up to the Ice Age) were the result of the Flood. Some, like geologist Tim Clarey, argue that most of the Precambrian was formed during Creation Week, while others, like Michael Oard and Tas Walker, place the Precambrian in the Flood as well. There is also considerable debate among this model’s advocates on the existence of the geologic column. Regardless, all agree that there is a general order to the geologic record.
Many proponents of the Neogene/Quaternary boundary model explain the fossil record as the result of Ecological Zonation Theory; the order of burial reflects the order in which their native ecosystems were buried during the Flood. Lifeforms on the deep ocean floors were the first to be buried due to their low elevation. Next to be swept away, transported, and buried were ecological communities along the coast, in the lowlands, and finally those in the uplands. Differential escape and hydrodynamic sorting may also have played a role in the order of fossils. This model suggests that the last air-breathing land animals perished by the 150th day of the Flood. The Cenozoic animals and plants buried near the top of the geologic record were likely living in the upland regions of the pre-Flood world. Since these were the last to be taken out by the Flood, many were likely buried in depositional basins around the world as the floodwaters receded.
A brief ice age lasting for centuries occurred in the immediate wake of the Flood, during which the woolly mammoth, woolly rhinoceros, and other animals commonly associated with the glaciation period lived.
In Support of this Position:
Clarey, T.L., and D.J. Werner. 2018. Use of sedimentary megasequences to re-create pre-Flood geography. In Proceedings of the Eighth International Conference on Creationism, ed. J.H. Whitmore, pp. 351–372. Pittsburgh, Pennsylvania: Creation Science Fellowship.
Holt, R. D., 1996. Evidence for a Late Cainozoic Flood/post-Flood boundary. CEN Tech. J., 10(1): 128-167.
Against this Position:
Arment, C. (2020). Implications of Creation Biology for a Neogene-Quaternary Flood/Post-Flood Boundary. Answers Research Journal, 13, 241-256. doi:https://answersingenesis.org/the-flood/implication-creation-biology-neogene-quaternary-flood-post-flood-boundary/
Johnston, Richard H. THE FLOOD/POST-FLOOD BOUNDARY. Creation Ex Nihilo Technical Journal, vol. 11, no. 2, 1997, pp. 162–165.
Cretaceous/Paleogene (K/PG) Boundary Model
The general consensus among creation geologists and paleontologists is that the Flood is responsible for much or all of the Paleozoic and Mesozoic strata, regardless of their Flood model. According to this specific model, the majority of Precambrian strata was formed via Supernatural Formative Processes during Creation Week. On the other hand, much or all of the Cenozoic strata is the result of localized or regional natural disasters occurring as the earth settled down from the Flood itself. This Flood model was popularized in 1994 by geologists Steve Austin and Andrew Snelling, paleontologist Kurt Wise, and others. 
As with the Neogene/Quaternary model, ecological zonation plays a role in explaining the order of fossils. Another factor is that of biogeographic zonation, in which ecological communities are segregated and/or spatially adjacent to each other. Both models also agree that the air-breathing land animals were extinguished by day 150.
Unlike the previous model, the Cretaceous/Paleogene model argues that the Cenozoic represents successive snapshots of post-Flood recovery ending about the time of Abraham. In this framework, some residual catastrophic processes were still at play in the years or even centuries after the Flood. So, there may still be widespread features in post-Flood deposits, albeit dwarfed by the ones from the Flood itself.
Some advocates of this model think that certain features, like microbialite “reefs” in the Paleozoic, require longer time to form than that allotted in the year-long Flood. They suggest that extensive geologic activity may have been occurring in the ocean basins of the pre-Flood world during the centuries leading up to the Flood. In this case, the first true terrigenous sediments (that is, those washed from off the land) marks the beginning of the Flood in the geologic record. This would put the pre-Flood/Flood boundary somewhere in the upper Paleozoic or lower Mesozoic. Interestingly, this view was held by many scriptural geologists of the 19th century. 
In Support of this Position:
Whitmore, J. and Garner, P., Using suites of criteria to recognize pre-Flood, Flood, and post-Flood strata in the rock record with application to Wyoming (USA); in: Snelling, A.A. (Ed.), Proceedings of the Sixth International Conference on Creationism, Creation Science Fellowship, Pittsburgh, PA, and Institute for Creation Research, Dallas, TX, pp. 425–448, 2008.
Against this Position:
Oard, M.J., Geology indicates the terrestrial Flood/post-Flood boundary is mostly in the Late Cenozoic, J. Creation 27(1):119–127, 2013.
Late Paleozoic Boundary Model
In 1988, paleontologist Joachim Scheven proposed a new Flood model in his book, Megasuccessions and Climax in the Tertiary: Catastrophes between Flood and Ice Age. Other European creationists got on board, including Michael Garten, Paul Garner, David Tyler, Bernard Northrop, and Steven Robinson. This model is known as the Late Paleozoic Boundary model and was greatly expounded upon by Robinson in 1996.
According to its supporters, the Flood begins in the upper Precambrian and ends in the lower Carboniferous (Mississippian) strata. The raging waters from the “fountains of the great deep” and the torrential rain (Genesis 7:11-12) swept away the pre-Flood land surface, “blotting out” all remains of air-breathing terrestrial life not aboard Noah’s Ark, within the first 40 days. Left in the floodwaters’ wake was the massive, worldwide erosion surface known today as the Great Unconformity.
The geologic record from the Great Unconformity onward to the upper Ordovician represents the global rise in sea level, during which successions of marine organisms, one ecological community after another, were washed onto and over the continents, many buried and later becoming fossils. Fish and other more powerful swimmers largely avoided this fate because of their mobility and ability to escape to open water. The upper Silurian-Mississippian represents the ebb and flow of the receding floodwaters during the latter half of the Flood year. Advocates of this model point out that just as the Flood account does not address the survival of fish, it also does not tell us of the fate of creatures that resided upon pre-Flood floating forests, like pelycosaurs, dragonflies, and petrolacosaurs. Since these creatures were not residents of “dry land,” and since their biome was, by its very nature, already afloat, the animals that lived on it could survive through much of the Flood, drifting across the submerged continents. As the waters receded, the floating forests were broken apart, beached, and buried in layers on top of each other (later to become coal). Their surviving inhabitants scrambled onto newly-exposed land surfaces, ready to colonize a post-Flood world.
According to this model, the Flood/post-Flood boundary lies in the mid-Carboniferous, specifically at the Mississipian/Pennsylvanian boundary. The fossil record of terrestrial vertebrates found in Permian to the Tertiary strata demonstrate how the animals that left the Ark multiplied, diversified and repopulated the world.
This is the third most widely held young-earth history model. Steven Robinson no longer accepts an upper Paleozoic Flood boundary, now favoring Recolonization Theory instead because he does not feel certain geologic and fossil features could be explained in the context of the year-long Flood. Paul Garner has also left this position, but for the opposite reason. He currently adheres to the K/Pg model, arguing that it best fits the overwhelming geologic patterns in the rock record. Meanwhile, David Tyler advocates for a unique model that combines elements of the Late Paleozoic Boundary Model with those of Recolonization Theory.
In Support of this Position:
Robinson S, 1996, Can Flood Geology Explain the Fossil Record?, CEN Tech. J, vol. 10 nr 1: p. 32–69.
Tyler, D.J. 2006. Recolonisation and the Mabbul. In Reed, J.K., and M.J. Oard (editors), The Geologic Column: Perspectives within Diluvial Geology, pp. 73–86
Against this Position:
Starting in the late 1990’s and early 2000’s, some creationists began to argue that the fossil record is not the result from the Flood, but rather the product of different phases of Earth’s recovery after the Flood. This model has been called Recolonization Theory. One of its most vocal advocates has been geologist Steven Robinson. Those who accept this model often posit that the genealogies of Genesis 5 and 11 may contain gaps, making the earth between 8,000 and 20,000 years old. Earthhistory.org.uk, which promotes Recolonization Theory, states that, “We take no position on the age of the Earth, except to point out that its claimed age of 4.6 billion years old rests on the assumption that rates of radioactive decay have always been constant. That is a fundamental tenet that science is currently unprepared to question. In our opinion, the primary evidence (some of which we discuss) indicates much shorter timescales.” 
Recolonization Theory correlates the Noahic cataclysm to the Late Heavy Bombardment, a hypothesis which posits that the early earth was pummeled by failed planets and huge chunks of rock left behind from the formation of the solar system. In this scenario, the “rain” of Genesis 7:4 was not water, but actually a rain of asteroids. It was also at this time that the entire world was submerged by subterranean water bursting forth from below the earth’s surface. Between the flooding and pummeling from extraterrestrial bodies, the pre-Flood earth’s crust was destroyed and anything upon it “blotted out.”
Seeing as no evidence of the Late Heavy Bombardment exists on Earth, the Flood/post-Flood boundary lies at the base of the Archean, the oldest rocks on the planet. Recolonization Theory posits that the fossil record represents the hundreds and/or thousands of years after the Flood, during which successions of the surviving organisms’ descendants (be they from the Ark or from subaqueous refugia) repopulated the empty earth.
In Support of this Position:
A record of earth’s recolonisation. (n.d.). Retrieved March 10, 2021, from https://www.earthhistory.org.uk/recolonisation
Against this Position:
White, D., & Taylor, P. (2017, October 23). The ‘recolonisation theory’-the latest compromise. Retrieved March 24, 2021 from https://answersingenesis.org/bible-timeline/genealogy/the-recolonisation-theory-the-latest-compromise/
It is our hope that you can use this as a guide on your own quest to unravel the enthralling history of our planet as it relates to the historical record given in God’s Word.
 Austin, Steven A.; Baumgardner, John R.; Humphreys, D. Russell; Snelling, Andrew A.; Vardiman, Larry; and Wise, Kurt P. (1994) Catastrophic Plate Tectonics: A Global Flood Model of Earth History, Proceedings of the International Conference on Creationism: Vol. 3 , Article 56.
 Johns, W. H. (2016). Scriptural Geology, Then and Now. Answers Research Journal, 9, 317-337.
 About us. (n.d.). Retrieved from https://www.earthhistory.org.uk/about