Biblical and Scientific Shortcomings of Flood Geology, Part 3

| By Gregg Davidson

This is the third in a four part series taken from Gregg Davidson and Ken Wolgemuth's scholarly essay "Christian Geologists on Noah’s Flood: Biblical and Scientific Shortcomings of Flood Geology".

In Part 2 of this series, we concluded by noting that, as Christian geologists willing to consider the possibility, we find no compelling evidence that the earth’s geological features can be explained by a global Flood. Here we consider three lines of evidence: global salt deposits, the order of deposition of sediment layers in the Grand Canyon, and the sequence of fossils in geological strata.

Salt Deposits

There are many places around the earth with layers of salt, some thousands of feet in thickness. Just off the southern coast of the United States in the Gulf of Mexico, thick salt deposits sit beneath thousands of feet of sediment (Fig. 1). These deposits lie within the layers that are said to have been deposited by the Flood.

We understand how salt beds form. At locations such as the Bonneville Salt Flats of Utah, or at the Dead Sea at the border of Israel and Jordan, salt is actively forming. Salt beds form when water is evaporated. During evaporation, the concentration of dissolved ions increases until the water cannot hold the salt in solution anymore and mineral salt begins to form. If a presently unknown or poorly understood process could produce salt without evaporation, as argued by young-earth advocates1, it would quickly dissolve as soon as it came into contact with flood water, just as the salt from your saltshaker rapidly dissolves when added to water or moist food.

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. 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. What would the purpose be? (We will revisit this thought later.)

Grand Canyon: Order of Deposition

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.

As a very simple observation, consider instructions given in virtually every gardening book. A good soil will have a mix of sand, silt and clay. To determine the quality of your soil, you take a handful or two, put it in a clear container, add water and shake it up. When you stop shaking, the coarse grained material will settle out first resulting in a sequence of layers: sand on the bottom, then silt, then clay. You can readily see how much of each you have by the thickness of each layer.

This is informative of what we see in flood deposits. 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.

Fossil Sequence

If a massive flood were responsible for the fossil record, what would we expect to see? If the Flood was violent enough to rip chunks of rock up from the earth and move entire continents (standard Young Earth claims)2, then it should be obvious that life forms from every imaginable niche would be tumbled and mixed together (Fig. 3a). We should find numerous examples of mammoths mixed with triceratops, and pterodactyls mixed with sparrows. Ferns and meadow flowers should be found in the same deposits, along with trilobites and whales. Further, we should find all major life forms still living today, for Genesis 7:8-9 is clear in stating that all terrestrial animals were preserved on the ark.

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…”5

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?


About the Author

Davidson Gregg

Dr. Gregg Davidson is chair of the Department of Geology and Geological Engineering at the University of Mississippi and conducts original research in geochemistry and hydrogeology, often employing radiometric dating methods to determine the age of groundwater and sediments. In 2009 he published a book about his keen interest in integrating a lifetime of studying geology with his firm conviction about the infallibility of God’s Word, When Faith & Science Collide – A Biblical Approach to Evaluating Evolution and the Age of the Earth.