Some Basic Problems with Flood Geology

 (Hill Roberts, 2003 )


It is very understandable why so many people think the flood of Noah is responsible for the geological features observed in the earth’s surface layers. (1) Such features are global, so a global flood could well be the cause; (2) the surface layers are usually sedimentary rock (sediments that settled out of water and hardened into rock as a layer), and floods are known to leave big sediment deposits; (3) many of the sedimentary layers also contain fossils (the remains of dead plants and animals buried in sediments and eventually mineralized), and Noah’s flood was intended to kill both mankind and the animals in a relatively quick flood event; and (4) many fossils are found in areas now well above sea-level, including mountains, which seems consistent with a flood deep enough to cover the mountains. So “flood geology” argues that the major geological features are better explained as simply the result of the biggest flood that ever occurred within human history, rather than naturalistic explanations of slow processes operating over the eons of time geologists now posit for the pre-human history of the earth.


The fact of Noah’s flood is taken as a given by this writer. However, the view that “flood geology is credible as a valid geological explanation” is at issue. The main problem with a global flood causing all (or even a significant part) of the geological features of the earth's surface is that Flood Geologists (FGs) want it to be “just a flood doing what floods do” without invoking miracles. For example, once God miraculously causes the flood to occur, it doesn’t take a further miracle for the animals to drown. That is just the natural consequence of being caught in the rising flood waters. So FGs understand the bulk of the fossil record to be a rapid flood effect caused within the timescale of human history. Similarly, FGs claim many of the other geological features observed today were just the natural results of this huge flood once it happened, instead of the slow work of time as understood in geology.[1] This writer understands the appeal of such arguments. If the geological features are simply the observable consequences of the flood, then the rocks become physical validation for the flood, so that faith in the whole Genesis account has a firmer footing on empirical evidence. Arguments for the origin of the universe are appealing for the same reason. The difference is that there is standard scientific evidence for a beginning of the universe.


The FG approach has a huge problem with the matter of evidence because we know what floods do, and floods do not cause the type of geological features requiring explanation. It doesn’t take complicated science to understand these problems, just common experience and common sense. Four basic problems will be addressed herein, but problem areas could easily be multiplied a hundred-fold.


1) Sediment

The average depth of fossil bearing sediment layers on the continental crust is one mile, such as seen at the Grand Canyon. (Sediment layers are much deeper than one mile in some places.


This is how deep the sedimentary rock is today. When it was still wet muck, the deposited sediments would have been even thicker.) It must be assumed by FGs that this sediment material came from the erosion of non-sedimentary rock during the flood: i.e., from erosion of igneous rock like granite and basalt. Otherwise, the flood didn't produce the sediments, and then its existence must be explained without the flood doing it. But the sediments themselves are the primary feature that must be explained by any geological explanation, be it FG or standard geology. FG cannot make the sediment; it must already exist before a flood can move it around.

So why couldn't the flood make that much sediment, since it was such a big flood?


For the most part floods do not make new sediment material from rock at all, they simply redistribute existing soils. A large volume of water directed at hard rock will not erode it at any appreciable rate unless the water is moving at hyper-velocity pressures from precision water-jet cutting nozzles (20,000 to 60,000 psi required to cut rock). This is much more powerful than pressure washers produce ( ~ 5000 psi). There is no natural physical process to accelerate water even close to such velocities/pressures during the flood. Ergo, no large scale massive erosion to speak of, and hence no appreciable volumes of sediments produced, and hence no sedimentary rock formations can be accounted for by the flood because there isn’t enough loose sediment on the earth to form all the sedimentary rock.[2] Just doesn't work.


Erosion of rock into sediment is primarily a surface weathering effect, as every grade school kid knows, caused by freeze-thaw cycles, wind erosion, chemical reactions in ground layers eating away the rocks, and wave action at seashores. Very fast moving water, as in mountain streams, causes some erosion by banging large rocks together, slowly producing sand particles which are carried downstream. Primarily this is the work of gravity, not water; more water actually impedes this process. Similarly wind driven waves at the seashore produce sand, but once the water gets a few meters deep that process halts. As water gets deeper, it moves more slowly, so less erosion occurs. Since the flood waters rose very rapidly (~40 days) to cover the whole earth, most of the land was under deep water very quickly, all of it in just over a month. A fast, deep inundation actually PREVENTS large scale erosion of the area under water, rather than causing it. Hence little erosion at all is going on during most of the flood period. The area under the water is where sediments can get deposited by flood waters, but not manufactured.


If such an amount of unhardened sediment already existed prior to the flood, the surface of the earth would be uninhabitable. The average thickness of soil above continental rock is about 10m now. Even that thickness of soil can become very unstable with just a little bit of moisture content. That is why buildings etc. have to be footed on bedrock, not surface soil. That is why mudslides happen so easily with just normal rain cycles: even thin soils are very unstable on slopes. Soil over a mile thick would be so unstable that it could not support its own weight. This is why sediment layers are always flat when formed (see layers in above Grand Canyon photo) – they cannot support their own weight, as is true for any liquid or slurry. A mile thick layer of sediment would be as if the earth were coated all over in quick sand. So FGs must explain how the flood made all the sediment that is found today in the average one mile thickness of sedimentary rock, because before the flood a mature earth suitable for habitation can have very little unhardened sediment, and even a really big flood cannot make new sediment materials in any appreciable amount.


Remember, the Bible does not say or imply that the flood made all the world’s sediments.



2) Stratigraphic Sequences


Now assume the sediment was produced by the flood – somehow.


Then it has to settle out into the observed layering as the flood recedes. What would happen (what does happen in a flood) is that two factors control the deposition of sediment from a moving water suspension: (1) the velocity of the water carrying the sediment load; and (2), the mass of the sediment particulates. Sediment settles out into strata as a function of mass for any given water velocity. Faster flow rates will hold heavier particulates in suspension. As the flow rate slows, the heaviest particulates settle out first, then the next heaviest, etc., as the flow slows down. What this means is that water-borne sediments will be sorted bottom to top, as a function of size at any given locale, and also laterally sorted. For example, at the mouth of rivers, deltas form in a very predicable, observable manner in this way. Upstream, where water is moving fastest, only heavy rock loads drop out. As water spreads out at the mouth, hence slowing, lighter materials drop out, like gravels, then sands, then silts, etc. So the order from bottom to top and moving out from the mouth are overlapping layers of rocks, gravel, sands, muds. These then harden into conglomerates, sandstones, mudstones (shales, etc) by a chemical cementing process that occurs as the layers dewater under pressure over time.


Why is such stratigraphy a problem for the "flood did it" explanation?


Well, simply put, such size sorting is simply not a characteristic of the actual sediment layers in general. As often as not, gravel and sandstone layers will be on top of muds and limestones, instead of underneath where water deposition would put it . A single flood can't produce the type of distinct layer sequencing actually found worldwide in the sedimentary layers. Fine grained particulates (like lime, chalk, clay) will never settle out of water until the water completely stops moving, allowing the CaCO3 particles that form lime mud layers (forming limestone and chalks) to settle out. Such layers can only form under completely still water conditions, not flood conditions, nor during flood water runoffs.  In general the more turbulent a water stream, the more it mixes all the suspended elements together, so that if the water suddenly stopped, it would just deposit a continuous mess with heaviest stuff on the bottom graduating smoothly to the most finely divided particulates on the top, not in distinct layers. This does not remotely resemble the observed diverse and distinct layers such as seen in the Grand Canyon. Notice that the Coconino Sandstone lies directly on top of the Hermit shale. That’s not the correct sequence. Those layers must have been deposited by separate events separated in time, not from a single flood. Furthermore, the Coconino sandstone was not even deposited underwater, it is a remnant of desert sands  that were later buried by the overlying marine sediments now forming the Toroweap formation and Kaibab limestone. (Sand deposited underwater is distinctly different from desert sands. Desert sand particles are wind blown and have rounded off surfaces from the “sand blasting” effect. Underwater sand deposits do not move fast enough to smooth the grains, and hence are very rough surfaced particles.) Not seen in the Grand Canyon photo are several thin volcanic ash layers in between some of the layers. How did airborne layers of volcanic ash find their way intact in between sediments while it’s all being deposited under water during a flood? Also, the top of the Redwall limestone layer looks all weather worn, exactly like the eroded limestone karst in my backyard on Weatherly Mtn in Huntsville. But the Redwall is buried under the Hermit shale, and several other layers. How did it get so weather-worn on the top while being deposited as lime muds underwater during a flood? Those types of features soundly contradict the deposition of all the layers happening during a single flood event for the whole thing! Caused by long durations of regional inundations separated by long times? Yes. Caused by a single, global, brief flood? No.


Now, assume the flood did produce the sediments – somehow.


Then, the fossil sequences found in the sediments must be accounted for. Some FG attempts have been made, but all fail even cursory inspection. The main FG attempt to explain the fossil sequences is that the animals fled the rising waters so the fastest, smartest were killed and buried last. So fish are in the bottom layers, other animals in between, and humans on top.  Of course the problem is that often marine sediment layers with marine fossils are found on top of mountains! And since that is the case, there should be cases of human fossils, or whales, being intermingled with marine fossils such as trilobites. Why? Well not all humans are fast or smart. Ditto for all the other animals. So different types of fossil environments should routinely be co-mingled in the FG fossil record, but they never are in the real fossil layers. Whales, bass and clams are never found with trilobites, but in FG they should all be mixed together, since all are in the marine environment first buried according to the FG model. The FG model simply doesn’t match the facts.


Finally assume the sediments with the fossil sequences in them resulted from the flood a few thousand years ago – somehow.


Any guess as to how long it would take a mile thickness of wet sediment to turn into rock? Answer: there would still be nothing but a world-wide layer of wet muck covering the world. And last but not least, explain the presence in some locales of up to seven miles thickness of delta sediment layers, such as under the Mississippi river basin. If it had been deposited all at once relatively recently, a seven mile high pile of spreading wet sediment would still be there today. Instead, the seven miles of sediment have all hardened and sunk into the earth’s igneous rock crust underlying those sediment layers (like an inverted mountain), so that now it is a plain, instead of the world’s tallest mountain. Sinking and bending igneous rock is a process that can only happen slowly due to gradual build up of sediment material, not rapidly.


Remember, the Bible does not say or imply that the flood deposited any of the strata.


3) Uplifted Strata


Floods don't cause mountain uplift, but many sediment layers (strata) are found on top of mountains. For example the Appalachians are mostly uplifted limestone, shale, and sandstone strata. Many are fossil-bearing sediment layers. They have being uplifted to very oblique angles in general, so the deposition couldn't have occurred during the flood, or else the sediment layers there would be level, not oblique. So the uplift must have happened AFTER the sediment deposition. But if the limestone sediments have already settled out, then the waters have already receded, so there is nothing left of the flood to cause any uplift of the sediment layers into the mountainous forms. The top of Mt. Everest is an obliquely uplifted limestone layer!!! (On top of a whole series of uplifted sediment layers.)


Remember, the Bible does not say or imply that the flood uplifted the mountains.


4) Plate Tectonics

Geological evidence indicates the continents spread apart very slowly over time due to the convective processes of plate tectonics. FGs must offer an alternative.


One such FG idea is that when the flood started, a crack opened up all around the circumference of the earth releasing a torrent of subterranean water, and flipping the edges of the rock layers up extremely high at the crack regions. So high that they slide “downhill” at the crack driving the whole rock layer (not just the flipped up part) away from the crack at high speeds. Then the rock layers slowed down and, voilá, spread continents.  (In this idea the mid-Atlantic ridge is taken as a remnant of that crack.)


Rapid separation of the continental crusts during the flood would be silly, if some folks didn’t take it so seriously. Continental-sized masses moving that fast (1000s km/yr) liberate so much heat due to the kinetic energy (1/2mv^2) and potential energy (mgh) being converted to heat as the continents slow down and settle, that the rocks would melt, the water boil away, and the atmosphere would be saturated with superheated steam. Wouldn’t one wonder how even Noah survived that?


If all this happened only a few thousand years ago, the earth's surface would still be reverberating with devastating world-wide earthquakes, and the seas and atmosphere would still be boiling cauldrons. This idea is just silly at even a superficial level of inspection. Flood geologist Walt Brown[3], with a PhD in physics, came up with this “hydroplate” idea[4]. Another FG, John Baumgartner - who does computer simulations for Los Alamos Labs -  once showed that if completely non-physical properties for geological materials were used in the professional geological simulations he developed, he could get what he calls "runaway subduction" where the continents move rapidly due to some of the crust being rapidly swallowed down into the earth’s mantle.[5] But if he uses REAL values for the physical properties (mantle viscosity[6], temperatures, thermal capacity, material strengths, densities, etc.) then nothing unusual happens at all. No fast continental motions. No runaway subduction. No hydroplate motion.


But there is a simple problem with Brown’s idea much bigger than all the aforementioned. In Brown’s idea the whole pre-flood planet is covered by a single integrated crust supported by a large layer of trapped subterranean water. He has to have the crust completely connected to sustain the internal water pressure he needs to hold the heavier crust up before the flood. He maintains that all the crust was suspended on top of that water sort of like a water bed. If there were any fractures, it would deflate like a water bed with a hole in it. He believes the subterranean trapped water was the primary source of flood water.  According to Brown only after the flood did that released water fill the current ocean basins, and only in regions where the crust sank when it slowed down.


So one can envision Brown’s model as two hemispherical bowls representing the two halves of the ruptured planet crust. All around the circumference where the bowls meet, the crust ruptures and gets flipped up. He supposes that then the crust slides downhill all along the ruptured region. But as can be easily seen from the bowl picture, there is nowhere for the continuous crust to slide. For it to slide “down” on one side of the bowl, it must slide up on the other side. But that doesn’t produce the requisite continent separation. As can be easily seen, in Brown’s model the earth’s crust wouldn’t go anywhere at all. It would just settle back down along the cracks, but now be covered by all the released water. Big flood maybe, but no continents, no separations.


It is interesting that Brown never draws a 3D world-view perspective of his idea. His only illustrations of the rupture and sliding show his rupturing crust as flat, never spherical. A spherical illustration completely destroys his concept. I’m sure Brown doesn’t believe in a flat earth, but his model would require a flat earth to work the way he illustrates it.


Remember, the Bible does not say or imply that the flood spread the continents apart.





Flood Geologists are "Nice enough folks, they just hadn't thought it through."[7]


1) Unless one accepts FG as an article of Biblical Christian faith, one’s faith will be immediately suspect by FGs. It will be suggested that you do not really believe the Bible, nor in God’s creation, and probably have no depth to your faith whatsoever. You are just a closet evolutionist, or at the very best a theistic evolutionist. Such erroneous reports are likely to spread like wildfire.


Answer: The Bible account of the flood contains none of the basic elements of flood geology.


2) As soon as one points out that a single flood doesn't naturally produce the required effects at all, the answer will be "Well THIS flood could have done it somehow, since it was so big. And if you just had more faith in God’s word you would see that.”


Answer: “Bigger” still doesn't cause the required effects naturally. Water still behaves like water, sediments still behave like sediments.  (And it isn’t a matter of faith in God’s word, see #1 above.)


3) "Well this was a miracle flood, so how do you know it was like other natural little floods? God could have miraculously caused a flood in which all these problems didn’t happen." 


“Okay, now we’re getting some help here. Now they’re getting it!”


I agree entirely! The flood was a miracle performed by God. That is exactly my point always: any global flood must have been a miracle just as much in the going as it was in the coming. If it was a miracle, it is not legitimate to claim the miraculous flood must have caused all the geological features as a rapid consequence of natural flood processes. Being a miracle, it could have; but also by being a miracle, it could just as easily not have done much permanent geological damage at all. Why did God choose to eliminate mankind with a flood, instead of just causing them all to die? I don’t know. I would suppose because that best served His purposes for reasons that are inscrutable to us. Once we step into the realm of miraculous interventions, we really have very little basis for the naturalistic cause and effect analysis that underpins all of Flood Geology. (Whereas, natural explanations are entirely appropriate for standard geology’s interpretations of post-creation pre-flood natural events.)


There is no indication in the Bible that the world Noah stepped back onto from the ark was much different than the world he lived in before the flood, other than the missing people and animals. Whereas, the FG world would have been NOTHING like the world Noah previously knew. Huge layers of wet sediment are completely covering everything previously familiar, everywhere the denuded landscape is wiped slick, mountains have been uplifted, sliding continents are still quivering and steaming in the aftermath. Noah might as well have gotten off on a different planet. Strange for him to say nothing about such cataclysmic geological changes which the FGs say must have occurred to produce the observed features resulting from this catastrophe. Instead he builds an altar. In the FG scenario there wouldn’t be any rocks on the surface for him to build an altar with.


Nor is it credible to claim that properly conducted science supports the ideas of FG. Not even common sense supports FG, much less science. Indeed, the natural physical properties of water and sediments are easily understood to see that a single flood does not cause such effects. And since it was a miracle, don’t expect to find the physical evidence, as if it were just a natural result of cause and effects. One can’t have it both ways. If someone wants to believe that God miraculously created the sediment, the strata, the fossils, the continents, and the mountains at the time of the flood, so be it. But once again the Bible says nothing about it. And science certainly says nothing for it, and everything against it.  So three strikes – FG is out! The large-scale geological features must be explained by some other processes than a single global flood. Such pre-flood geological processes are not a matter the Bible addresses in connection with Noah’s flood.[8]


“I, Hill Roberts, by faith in God’s word believe in a miraculous world flood in the days of Noah which killed everyone in that world except Noah, his three sons, and their four wives.”

The Bible does say that.

[1] FGs generally do not initially appeal to “appearance of age” arguments. Instead, they argue that any appearance of geological age is mostly due to the rapid results of the flood, if the evidence were only correctly interpreted by scientists. However, FGs will also usually affirm that the earth was initially created in a fully functional, mature form ready for human habitation, which is used by FGs to explain some geological features outside the scope of FG.

[2] Similar arguments can be presented regarding coal and the fossils. There could not have been enough plant material alive when the flood occurred to have been formed into all the coal that exists. That much plant material simply cannot live at once on the surface of the earth.  But since most coal is contained between sedimentary layers, it would have had to have been alive at the time of the flood. Similarly, all the animals and plants represented as fossils in the sedimentary rocks could not have all lived at one time on the earth: too many animals and plants, not enough space for them all to live here.

[3] Walt Brown, “In the Beginning: Compelling Evidence for Creation and the Flood, 7th ed.,”

     Center for Scientific Creation, 2001 (ISBN: 1878026089)

[4] Martin Selbrede “Dr. Walt Brown’s Hydroplate Theory”

[5] John Baumgartner, “Runaway subduction as the driving mechanism for the genesis flood” 1994. ICR monograph, (For a mathematical rebuttal to Baumgartner go to  by Joe Merts)

[6] Mantle viscosity is about 10^22 poise. (Honey is about 10^1) Baumgartner uses 10^13: off by 9 orders of magnitude from reality! So, he needs to melt the mantle, thus he increases radiogenic heating by a factor 10^6. That much heat released then would still be prevalent today keeping surface temperatures above boiling!

[7] Classic one-liner from the movie “Wag the Dog”  (Same for the upcoming  “… Now they’re getting it” line.)

[8] For further reading, there is a really good analysis of flood arguments by Tom Couchman. His article will probably tell you more than you ever wanted to know or even have to think about on this topic. It’s on the LIB-CD in the /Articles/Couchman folder, and also on the Time  page of the LIB website: “The Lord Will Send Rain Upon the Earth.”             ( )