Tough Questions about the Flood

by Dr. Andrew Snelling on March 26, 2010

Dr. Andrew Snelling, AiG–U.S., helps a fellow Aussie understand some of the tough aspects of the Flood and how science works from a biblical point of view.

I believe in the global Flood of Noah. I am wondering how to explain the frequency of large fragments of sedimentary rock ( e.g. the size of a house or car) which include strata yet are broken from a parent rock, also cliff faces bearing horizontal strata which also have vertical fissures where two different slabs of sedimentary rock meet. Obviously the strata was laid by the flood but for large pieces to be broken and repositioned during the flood would require that sedimentary rock can harden whilst under water within less than a year.
The existence of folded strata shows that hardening had begun underwater and that uplifting processes happened during the flood, but is there sufficient evidence to conclude that 100% hardening can be achieved underwater or is a drying out process also required?
If a drying process is required then the fragments could best be explained by a post flood uplifting catastrophe, but of course the scriptural evidence for this is wanting.
—B.F., Australia

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Thanks for your questions about the hardening of rock layers during the Flood. I am delighted to hear from a fellow Aussie who lives not far from where I was born and grew up!

I am very pleased to see that you are committed to believing in the global Flood of Noah, and within that biblical worldview you are just struggling with understanding some of the scientific specifics. I commend you for that. Too many Christians look at the evidence of specific geological processes, for example, and if they have difficulties or doubts they then, unfortunately, question the biblical worldview.

Instead, like you, they should simply be admitting that they don’t yet fully understand the geological processes in question. When one does that and starts asking good questions, like you have, then often the Lord supplies us with the answers that remind us that ultimately the evidence in God’s world will always agree with what we read in God’s Word.

Thus, the objective in this instance is to understand how rocks may have hardened during the Flood year, sometimes sufficiently to then be eroded and broken up for pieces of rock laid down earlier in the Flood to be included in later rock layers. I agree with you that in many such instances it would be all too easy to explain the erosion of the fragments and their inclusion in another later rock unit to be the result of a post-Flood catastrophe, but I agree with you that there is no scriptural evidence for such, and, therefore, there has to be a viable valid explanation within the Flood catastrophe itself.

In answering your questions, which are all good questions to ask, we should begin with the issue of the cementing process in rocks. As with man-made Portland cement, water is often an important ingredient in the natural cementing process in rocks. In the case of man-made cement, the water actually triggers the reaction in the mixture of dry cement and sand so that the cementing process not only relies on water, but can take place underwater. Many natural cements are somewhat similar in that they can achieve sufficient hardening under water without needing to dry out.

However, a further issue needs to be explored here. Most people can’t conceive of the drying out process in rocks occurring until the Flood waters receded late in the Flood year, but that is not entirely true. Even when the Flood waters were still rising in the early part of the Flood, the water levels would have fluctuated widely due to two processes at work at the same time.

First, there would be the normal global tidal rises and falls. Today in many places, that can be as little as one meter, but in others it can be as much as ten or twenty meters. We need to remember, though, that during the Flood there eventually was a global ocean, which means that because of the tidal surges being almost in phase with one another, there could have been a resonance process as well that meant some of the tidal surges were even greater in the rises and falls of the water levels.

Then, the second process at work would have been giant tsunamis generated by the many destructive earthquakes that were repeatedly occurring during the Flood due to catastrophic earth movements. We have seen lots of evidence of what tsunamis can do in the past decade. As a tsunami approaches the land, the sea retreats from the coastline as the water level drops, and then as the tsunami rolls in onto the land, there is an incredible rise in the water level as the water surges many kilometers inland.

So, if we put these two processes together during the Flood, there would have been periods when the water levels may have dropped hundreds of meters and exposed recently deposited sediment layers. If this exposure was for several hours between high and low tides, then there could have been sufficient time for these rocks that had already begun to harden as a result of the cementing process to now begin to dry out.

We can’t simply assume that after deposition, rock layers were always underwater during much of the Flood.
It would have been during such periods of exposure that dinosaurs, for example, walked across such exposed surfaces and left behind their footprints, which were then buried and fossilised when the water levels rose and brought new sediments in. So, we can’t simply assume that after deposition, rock layers were always underwater during much of the Flood.

Now, with these considerations dealt with, we come to your question about how earlier deposited rock layers could harden in the time during the Flood, to later be eroded and broken up so fragments up to the sizes of houses and cars could be included in subsequently deposited sediment layers. I think you can now see that due to the processes I have already outlined, it would be possible for sediments laid down early in the Flood to have hardened sufficiently to then be eroded and broken up, with fragments of them being then included in subsequently deposited sediment layers later in the Flood year.

And I might add that any drying out process while sediment surfaces were temporarily exposed would involve contraction within the sediment layers, which would open up vertical fractures in them. In any case, we know from experimentation that it is possible for even wet sediment layers that are hardened due to the cementation process to also contract even underwater. So, with these considerations, it is possible to later obtain, after the new landscape was eroded as the Flood waters retreated, cliff faces bearing horizontal strata which also had vertical fissures within them, even where two different slabs of sedimentary rocks meet.

I hope I have answered all your questions satisfactorily. I commend you again for asking such good questions, and I encourage you to go on asking them. The main thing is that you maintain your biblical worldview and ask questions. It is our understanding of geological processes that is deficient as we try to piece together the puzzle in understanding what happened during the Flood. As I said before, when we begin with the Scriptures and ask the right questions, then we are in a position to find satisfactory answers.

Best wishes,
Dr. Andrew Snelling.

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Answers in Genesis is an apologetics ministry, dedicated to helping Christians defend their faith and proclaim the gospel of Jesus Christ effectively. We focus on providing answers to questions about the Bible—particularly the book of Genesis—regarding key issues such as creation, evolution, science, and the age of the earth.