Scientific evidence against a global flood

The Ken-Cat
By Ken Gilmore
(Ken Gilmore is an in-fellowship Christadelphian, NOT an Ex-Christadelphian. He DOES NOT support or condone the Atheist position of this website.) 

Claims by YECs that there is considerable evidence for a global flood are completely without support.

Conversely, the scientific evidence against a global flood is considerable, a point that highlights both the poor research behind the YEC claims, and the lack of understanding of the scientific issues by those making such claims.

Geologists Gregg Davidson and Ken Wolgemuth, both of whom are Christians active in educating laypeople about geology and scientific shortcomings of YEC and flood geology have pointed out that when one examines the geological record in detail, features such as thick salt layers tens to hundreds of metres in depth between geological strata said to be deposited by the flood, the fossil sequences, and the lack of “fining upward” sequences consistent with flood deposition in the Grand Canyon are present. This is all consistent with mainstream geology, and inconsistent with claims that a giant flood deposited all the geological strata in a single year. Flood geology can only be maintained by ignoring the evidence and privileging a fundamentalist distortion of the Bible over reality. [1]

The presence of thick layers of salt, up to several hundred metres in depth, sandwiched between sedimentary layers is impossible to reconcile with the belief that these layers were deposited by a flood. Salt layers form by evaporation, which means that any salt layer that managed to form by evaporation (a dubious claim given that such evaporation would have to take place in conditions of high humidity and rain) would be dissolved by the flood waters. On this point alone, the claim that salt layers were deposited during a global flood is difficult to maintain. Once we factor in the presence of strata both below and above the salt layers, the flood geology claim becomes untenable:
One might argue that the waters from the Flood could have evaporated to leave behind the salt deposits we see today, but there is a serious problem. The thousands of feet of sediment on top of the salt is also said to be from the Flood, meaning the flood waters cannot have evaporated to produce the salt and still be present and violent enough to transport thousands of feet of sediment to the same location. In other words, a single flood cannot be called upon to explain both the salt and the overlying sediment. [2]
Quite often, when YECs are aware of such difficulties, they tend to invoke miracles as a ‘get out of jail free’ card. Davidson and Wolgemuth are justly critical of such moves:
For those who wish to argue that natural processes could have been vastly different during the Flood, there are at least two replies. First, under such a scenario, there is no point in Flood Geology studies any more than in normal studies, for nothing could be gained by the study of unknowable processes. A more important question, however, would be to ask why God would alter natural processes just to make Flood sediments look like they are not flood sediments.
The last point raises considerable theological questions – if a global flood did occur, why would God deliberately alter things to make it look like one did not occur? Such deceptive behaviour raises considerable theological problems which YECs have not credibly answered.

The Grand Canyon is frequently invoked by YEC as an example of a structure formed by a global flood. However, when critically examined, such a claim breaks down. For a start, the layers in the canyon need to be deposited, and as Davidson and Wolgemuth note, the layers are not the type that can be explained by a single process:
The Grand Canyon is made up of a sequence of layers that defies any reasonable attempt to explain by a single flood. The alternating layers of limestone, sandstone and shale each form in unique environments. If these deposits were formed at different times under various sea-level stages, it is quite simple to explain the different grain sizes and rock types as a function of depth and distance from the shore line. If explained with a single catastrophic flood that abided by God’s natural laws of physics and chemistry, logic must be stretched beyond the breaking point.
Apart from laying down the strata, an impossible task as explained above, a global flood is also claimed to have gouged out the canyon. What we see is however inconsistent with what a flood leaves behind:
As moving flood waters slow down, finer and finer grained sediment settles out resulting in a “fining upward” sequence. If most of the Grand Canyon layers were laid down by the Flood, then we should see the same thing – a “fining upward” sequence. Instead, we see a series of alternating layers of fine and coarse grained material, with smaller-scale alternating layers within the larger ones (Fig. 2). Increasing the violence of a flood does nothing to negate the standard order of deposition. Repeated surging of flood waters across the surface likewise offers little explanatory power; in this case we might expect successive layers, each with their own “fining upward” sequence, but such is not what is observed. Further, the Grand Canyon includes multiple layers of limestone, which are never found in flood deposits of any magnitude. Even in floods as massive as one thought to have catastrophically deluged the once dry Mediterranean Sea basin with thousands of feet of water – limestone beds are conspicuously absent.
Once we get to the ordering of fossils in the strata, the YEC position collapses. Floods have a habit of mixing things together, which means we’d expect to see all life mixed together, with humans, dinosaurs, and trilobites being found in the same layer. Given that YECs assert these animals coexisted, we’d be entitled to see this. Yet, we do not. Trilobites occur early in the geological record, followed by dinosaurs, and then humans.
What we actually observe is far different (Fig. 3b). There is an orderly sequence where trilobites only occur in very old rocks, dinosaurs in later beds, and mammoths in still later layers. Organisms like flowers and ferns are present together in more recent deposits, but only ferns with no flowers are found in older deposits. Some readers will recognize this as an example from the “geologic column” and be tempted to discount it as a fabrication. For those thinking this way, consider what Henry Morris had to say in both editions of Scientific Creationism:
“Creationists do not question the general validity of the geologic column, however, at least as an indicator of the usual order of deposition of the fossils…”
If we revisit the Grand Canyon for a moment, is it not striking that there is not a single dinosaur, mammoth or bird in the entire exposed sequence? Not one. To find these, you have to go to younger sediments found in deposits outside the canyon that have not been fully eroded away yet. How could such a lack of mixing be possible if the Flood was violent enough to move continents?

In a desperate attempt to rescue the global flood, YECs have invoked post-hoc explanations such as ecological zoning (walking from the sea bed to the land is a trip through ecological zones not time), differential mobility (fast animals at the top, slow at the bottom), and hydrological sorting (dense fossils at the bottom, light at the top). These arguments lack credibility:

If ecological sorting was true, then we’d expect to see ancient and modern fish in the same zone, along with creatures that share the same ecological niche such as sauropods and large herbivorous mammals. We don’t.
Old, infirm, frail organisms would not have time to escape the rising flood, so would be at the bottom. Likewise, ancient birds and pterosaurs would have been able to fly to the higher layers. Hydrological sorting does not explain why we see invertebrate fossils ordered by changes in shell morphology – as they are of similar density, we’d expect them to be ordered randomly. Likewise, ancient and modern animals of similar size and density should appear in the same strata. They do not.

Perhaps the most devastating object to a global flood is the correlation between varve layers and C14 content. Varves are sedimentary layers deposited annually. [3] If the varves were somehow deposited by the flood all in one year, then we would expect C14 dates for any organic material in each layer to have the same date, or (if a global flood altered C14 levels) to see a lack of correlation between C14 age and varve layer.

 What we see however is a remarkable correlation between C14 age and varve layer:
Figure 4 shows varve data from Steel Lake and Lake Suigetsu extended to the limit of carbon-14 detection. Serious consideration of this data should be sobering for the committed Young-Earther.

The high degree of linearity (straightness) of this data has two possible interpretations.

Option 1: 50,000 varves represent roughly 50,000 years, and the fact that the Suigetsu varves continue to about 100,000 means the earth’s history also must extend to at least 100,000 years.

Option 2: God started with a fast rate of carbon 14 decay and dozens of diatom blooms and die-offs each year, but then intentionally and precisely slowed down each independent and unrelated process in such a way as to make it falsely look as if the data confirms the accuracy of carbon-14 and varve counting as legitimate methods of determining age.

Option 2 should be unacceptable to all Christians, for it means God manipulated his creation so that a study of it would convincingly tell a story that was not in fact true.
Not only do we have evidence confirming that the Earth is much older than 6,000 years, we have zero evidence in the varve layers to show that any global flood occurred.


As shown in earlier posts, claims that scientific evidence supports a global flood do not withstand scrutiny. What we’ve seen here is evidence that not only refutes the claim that the geological strata were deposited in a single year a few thousand years ago, but that the Earth is considerably older than 6,000 years. Given these facts, the only credible option for YECs is to accept that they have badly misread both the Bible and the witness of the natural world, and reject flood geology.


1. This post is indebted to Davidson and Wolgemuth’s BioLogos series and is styled after it.

2. Davidson G, Wolgemuth K "
Biblical and Scientific Shortcomings of Flood Geology, Part 3" BioLogos Blog Sep 15 2012

3. Glacial lakes varves are formed by the alternation of fine clay sediment during winter, and coarse sediment delivered from the influx of meltwater in spring to the lake

4.  Davidson G, Wolgemuth K "
Biblical and Scientific Shortcomings of Flood Geology, Part 4" BioLogos Blog Sep 17 2012
Editor's Note:
The first paragraph of this article originally read:
"Claims by YECs such as the compiler of SEfaGF that there is considerable evidence for a global flood as my previous posts have demonstrated are completely without support."

I altered it slightly as I don't know what "SEfaGF" refers to and I don't suppose you do either. If anyone can enlighten us I would be grateful.

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