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Stephen O. Moshier
Gregg Davidson
Joel Duff
Tim Helble
 on June 29, 2016

Flood Geology and the Grand Canyon: What Does the Evidence Really Say?

Five scientific evidences that show the impossibility of a single flood carving the Grand Canyon.


On July 7, Answers in Genesis (AiG) will open the Ark Encounter to the public. Built around a “full-size” wooden replica of Noah’s ark, this attraction is designed to promote the young-earth creationist (YEC) perspective on the Bible and science. AiG, led by popular creationist Ken Ham, has provided well-financed momentum to the YEC movement. The organization is also responsible for the successful Creation Museum in northern Kentucky, which has quickly become the most prominent symbol of the entire young-earth creationist cause. There is little doubt that the Ark Encounter will enjoy similar popularity.

Young-earth creationists today apply what they consider a literal understanding of the creation and flood accounts in Genesis to the interpretation of Earth’s geologic past.1 In doing so, they challenge the entire history of geological science in the modern era. Most of the pioneering natural scientists and geologists of the Renaissance and late modern era (1500 to 1815)—a group which included many pious Christians—expected that their field work would provide evidence of the biblical flood, reflecting a catastrophic event in earth’s history of only thousands of years. However, as they discovered the interrelated, dynamic processes of the rock cycle and pieced together earth’s history from the vertical sequence of rock layers around the world, they concluded that the earth must be far older than thousands of years. Furthermore, they couldn’t identify a single layer of rock or sediment that fit with a global flood occurring early in human history.2 By the early 20th century, most leading Christians accepted the great age of the planet earth. For example, notes in the popular Scofield Reference Bible published in 1909 provided an old-earth interpretation of Genesis 1.

In 1961, Henry Morris and John Whitcomb published The Genesis Flood, which laid out a radical rejection of modern geology and instead gave the biblical flood credit for almost all geological features and fossils in the world. The Grand Canyon emerged as “exhibit A” in their creation science apologetics. And, why not? Some five million tourists visit the national park every year! Continuing to this day, advocates of flood geology sell attractive books and offer bus, hiking, and raft tours to convince (or reassure) visitors that the Grand Canyon indeed provides breathtaking evidence of Noah’s flood and its aftermath.3 They invite seminary professors on free raft trips to ensure that the young earth view and flood geology is propagated to future pastors. However, the overwhelming majority of geologists, including Christian geologists who affirm the authority of the Bible, reject the flood geology narrative.

In a new book, The Grand Canyon, Monument to an Ancient Earth, eleven authors describe the geology of the canyon rocks and landforms and focus on the claims of flood geologists.4 The authors are a mix of Christian and non-Christian professional earth scientists who are concerned about the impact of flood geology on public science literacy and, especially for the Christian authors, the negative impact of a gospel message associated with faulty scientific explanations. The four authors of this article all contributed to the book.

Using explanations and illustrations found in our book, we will address five of the top evidences offered for a global flood that are supposedly revealed in the Grand Canyon. These evidences are summarized on a poster from AiG (find it here). We will consider them in a different order than on the poster, adding some additional compelling evidences that are inconsistent with the flood model and rarely mentioned in their literature.


Grand Canyon geology illustrated in a stratigraphic column. Flood geologists refer to the Paleozoic layers as “early flood.” (Fig. 4-1, The Grand Canyon, Monument to an Ancient Earth, illustration by Tim Helble)

1. Layers Over Entire Continents

Flood geologists believe that layers of sedimentary rock exposed across continents, such as observed at the Grand Canyon are evidence of deposition out of turbulent water during the Genesis flood. They observe that strata standing far above sea level contain marine (sea) fossils and therefore conclude that they must have been deposited by high levels of water that covered the continents during the deluge. Flood geologists have different opinions about how deep (or high) the floodwaters rose over the continents. Some imagine the water rising above the present heights of mountain ranges. Others suggest that during the late stages of the flood the continents were lifted up as water drained into the deepening ocean basins.

The character of the rock layers does not surprise old-earth geologists. In our chapter Plate Tectonics, Our Restless Earth, we explain how ocean and continental plates continuously move both laterally and vertically. We can actually measure this movement in real time by GPS today. Sometimes, internal forces of stress can stretch continental crust so that it thins and sinks below sea level, as evident at Death Valley and the Dead Sea. There are many places on earth today where very thick deposits of sediment and sedimentary rock are accumulating on continental crust below sea level. Examples include all of the wide continental shelves surrounding the Atlantic Ocean and Gulf of Mexico, the North Sea between the United Kingdom and Norway, the Gulf of Carpenteria between Australia and Papua/Papua New Guinea, and the South China Sea, to name a few. The weight of the sediments causes the crust to sink, giving more room for still more sediments, ultimately allowing miles of sediment to accumulate. As continents converge in the future, these sea deposits, containing abundant remains of sea creatures, may be lifted above sea level, just like they did in the layers of the Grand Canyon. The point is, many modern seas are on continental crust and none of the sedimentary rock layers in the Grand Canyon resemble deep ocean deposits.

While many sedimentary rock layers do cover vast areas of the continents, no single layer covers an entire continent from one end to the other as the flood geologists imply. Rather, the rock layers overlap one another like leaves piled up on a lawn. Rather than finding evidence of one massive deluge, geologists find abundant evidence of multiple periods of rising and falling sea level that varied by as much as 120 m higher or lower than at present.5 It’s the combination of low-standing continental crust and high-standing sea level that results in these sedimentary layers.

In our chapter Sedimentary Rock Types and How They Form, we describe how layers of sedimentary rock were deposited in the Grand Canyon region as sea level repeatedly rose and fell. With each rise in sea level, shorelines moved inland along with the deposits of sand, shale, and limestone that comprise the geological formations we see in the canyon. Geologists recognize that deposits at some locations accumulated by flows of sediment across the seafloor as flood geologists claim. But these are rare in the Grand Canyon! Most of the sedimentary rock layers there formed in very shallow water or just above sea level. Evidence of periods above sea level is evident from abundant sedimentary structures such as mudcracks, raindrop prints, ripple marks, cross bedding, and small animal tracks (we show many photos of these structures in our chapter Sedimentary Structures, Clues from the Scene of the Crime).

2. Billions of Dead Things (sea animals deposited rapidly on land)

Ken Ham frequently tells audiences that the worldwide flood resulted in “billions of dead things buried in the ground.” He describes the sea creatures being swept along by turbulent floodwaters and deposited, tsunami-style, along with the sediment forming the rock layers we see in the Grand Canyon. We devote three chapters to the story fossils tell us about Grand Canyon rocks. Rather than finding evidence of a single, global catastrophe, the fossils of the Grand Canyon provide one of the clearest pictures of a long history of changing environmental conditions and life forms. In the chapter Fossils of the Grand Canyon and Grand Staircase, we describe the fact that most fossil organisms are found in association with other fossils from coherent ecosystems – not violently transported and mixed with organisms from dissimilar environments. Discrete layers can be found in the Canyon where only terrestrial fossils are found, typical of a riverine environment, with no evidence of chaotic mixing with marine organisms. Most significantly, not a single mammal, bird, dinosaur, or flowering plant is found fossilized in any rocks of the Grand Canyon, yet they are abundant in the younger rocks of the Grand Staircase. Flood geologists call upon sediment particle sorting based on organism size and density to explain the order, yet the smaller mammals and birds and plants that should then be found in the lower layers are entirely absent.

The chapter also draws attention to inconsistent flood geology arguments, such as simultaneously arguing that exquisitely preserved delicate fossils are evidence of rapid burial by a catastrophic flood, and broken and strewn fossils are evidence of violent upheaval by a catastrophic flood. To say that both fine preservation and fragmented preservation are convincing evidence of the same phenomenon is no evidence at all. There are indeed variations in the preservation observed, but in each case, the character of the fossils is consistent with specific environmental conditions.

Rather than brief chaotic history, the fossils of the Grand Canyon tell us a story of a wonderfully diverse and deep history. For example, in our chapter Tiny Plants – Big Impact we describe the diversity of plant fossils in the Grand Canyon. It is significant that plant fossils are missing from most layers of rock in the Grand Canyon. This is consistent with the observation that much of the rock in the Grand Canyon is marine in origin and thus not expected – by geologists – to contain plants. Where plant fossils are found they show distinct patterns that are consistent with the preservation of local terrestrial communities.

The fossilized plants found in Grand Canyon rocks consist of only extinct ferns, lycopods, and conifers. No remains of flowering plants (e.g. sunflowers, grasses, oaks, etc.) or flowering-plant pollen grains are preserved in Grand Canyon rocks. However, pollen grains of conifers and spores from ferns have been found. Pollen and spores are incredibly small, and easily carried by wind and water great distances. How could a global flood with tsunamis sweeping across continents fail to deposit a single grain of flowering-plant pollen in the entire sequence of Grand Canyon layers? It makes far more sense if these layers were laid down during a time when flowering plants were not yet found on earth.

In addition to the stony remains of animals and plants, we also have preserved traces of their life. In our chapter Trace Fossils, Footprints and Imprints of Past Life, we describe trace fossils, which are records in rock of past activities of past animals when they were alive. For example, we find trilobite feeding marks indicative of a calm, shallow sea bottom.   There are preserved footprints and tail marks that vertebrates made while walking over wet sand dunes. How could these have formed and been preserved in the middle of a chaotic, worldwide flood? Likewise, there are preserved tracks and burrows of spiders, scorpions, millipedes, and more in Grand Canyon rocks.

So, yes, there are billions of fossils in many of the Grand Canyon rocks, but these fossils are not the jumbled mess that one would expect from a turbulent, global flood. Rather there is an amazing, predictable order in the succession of fossils that can be explained by changes in life forms over earth history.

3. Rapid Deposition of Sand Carried Across Continents

Flood geologists argue that sediments found in regional-scale rock formations, like the Coconino Sandstone in the Grand Canyon, must have been eroded from distant sources, carried long distances, and rapidly deposited by fast-moving water. The argument states: “no known sediment transport system is capable of carrying sand across the entire North American continent during the required millions of years.”6 But there is a well-understood sediment transport mechanism – rivers! A modern example is the Mississippi River, which carries sediment from the eastern Rockies and western Appalachians to the Gulf of Mexico.


Cross beds in the Coconino Sandstone. (Photo by Tim Helble)

In our chapter Sedimentary Rock Types and How They Form, we address the claim that the Coconino Sandstone could have been deposited by a global flood. This rock unit is distinguished by cross bedding, which are dipping, parallel layers within the formation that are seen in modern sand dunes. We point out how conventional geologists see the cross bedding in these sandstones, along with other features such as trace fossils (animal footprints), as strong evidence for wind-driven deposition in a giant dune sea, such as in Namibia, Africa today. Dry sand dunes don’t fit in the middle of a year-long global flood, so flood geologists argue that these cross beds were formed through underwater processes such as migrating sand waves.

One flood geologist estimated that only a 2 to 4 miles/hour (mph) current was needed to form migrating underwater sand waves as high as the Coconino cross beds.7 It is true that 4 mph currents over a sandy bed can eventually build up underwater dunes as high as the cross beds seen in the Coconino. However, flood geologists say that all the Paleozoic strata in the Grand Canyon and Mesozoic strata in the Grand Staircase were also deposited during the one year flood. This leaves only a matter of days to deposit each formation. To form the Coconino in a matter of days, it can be shown using simple math that we wouldn’t just need sand grains migrating over the tops of underwater sand dunes in a 4 mph current, we would need a wall of sand hundreds of feet high and hundreds of miles wide sliding laterally at this speed across thousands of square miles.8

Recently, flood geologists have turned to underwater gravity currents to explain how large, regional scale formations could have been rapidly deposited.9 These currents are said to have moved huge quantities of stockpiled sediment and fossils from higher areas, leaving behind deposits that happen to have all the features found in sedimentary rock, including complex cross beds, intact fossil communities, and even buried stream channels. This and other flood geology claims for rapid sediment transport would require a host of miracles. These include somehow maintaining the compositional purity of thousands of massive stockpiles of loose sediment in the face of fantastic turbulence and global currents until each stockpile was transported to form a particular formation somewhere on earth.

4. No Slow and Gradual Erosion

Flood geologists claim that rock layers in the Grand Canyon are flat and show little evidence of erosion. They refer to “knife edge” contacts between layers that do not reveal erosion between layers. They recognize at least one ancient surface of erosion at the base of the Grand Canyon strata, known as the Great Unconformity. This feature is a contact between underlying igneous and metamorphic rocks with some pockets of deformed sedimentary rocks exposed in the walls of the inner gorge and the overlying, mostly flat sedimentary rocks that we see along the upper walls of the canyon. But, it’s far from flat and “knife edge” in character. In many places along the canyon wall the contact projects several feet upward into the overlying Tapeats Sandstone like miniature islands. It’s clear that layer upon layer of sand covered this bumpy surface as the overlying unit was deposited. Gravel to boulder size fragments of the underlying rock are incorporated in the base of the Tapeats Sandstone along the Great Unconformity, providing evidence of erosion and exposure of the underlying bedrock.


Meandering stream channel, filled with the Temple Butte Formation, in the wall of Saddle Canyon, near River Mile 47.

But that’s only one of nineteen unconformities that we describe in our chapter Missing Time, Gaps In The Rock Record. Flood geologists must be aware of these unconformities because they are well documented in the geological literature and fairly easy to spot in the walls of the canyon. Two formations feature spectacular buried channels that formed after the units were deposited and their upper surfaces were eroded. During the next sea level rise, the channels were filled with sediment. The Temple Butte Formation fills channels scoured into the top of the Muav Limestone Formation. The Surprise Canyon Formation fills channels scoured into the top of the Redwall Limestone Formation. Not only was the top of the Redwall Formation eroded during a long period of exposure, but also sinkholes and caves formed within the limestone. Many of the ancient caves eventually collapsed or were filled with the younger Surprise Canyon Formation. Caves form in solid limestone. If the limestone was deposited rapidly and immediately buried by overlying sediments as flood geologists claim, how could caves have formed at all?


View of the Grand Canyon where the oldest Precambrian igneous and metamorphic rocks are exposed beneath the cover of tilted Late Precambrian layers (Supergroup) and flat-lying Paleozoic sedimentary strata. Compare with the geologic column. (Photo by Gregg Davidson)

5. Flat Layers Made in Rapid Succession

Most people have a mental image of the flat lying sedimentary rocks in the Grand Canyon because that’s what you see in most photographs and from many overlooks from the rim. In fact, there are many examples of tilted, folded, and faulted rock in the Grand Canyon. We describe them in the chapter Broken and Bent Rock, Fractures, Faults and Folds. Along the length of the canyon, the Colorado Plateau is broken by several prominent faults. The Kaibab Monocline is an immensely broad downward bend of the entire vertical stack of rocks. More severe and smaller scale folding is observed in the Tapeats Sandstone in the Carbon Creek area. Flood geologists say that such folding can only occur if the sedimentary layers are so recently deposited that they are still soft, not old, hard rock. As evidence they report that the folds lack fractures, which would be evidence of hard-rock breakage during folding. On the contrary, we show in our book that the folds are riddled with fractures and contain evidence of brittle and flexural slip within and between layers in the folds. These absolutely cannot form in recently deposited sediment, as claimed by flood geologists.

Twelve Thousand Feet of Strata Flood Geologists Can’t Explain!

The Grand Canyon Supergroup is a thick sequence of tilted layers that lies underneath the more familiar horizontal layers of the Grand Canyon. An erosional layer, or unconformity, separates the tilted layers below from the younger rocks above. Flood geologists claim the Supergroup layers were deposited before the great flood. Cataclysmic flooding and earthquakes faulted, tilted, and eroded the Supergroup, followed by thousands of feet of deposition of mud, sand, and lime, all during the first half of the flood. The chapter River to Rim, Putting all the Pieces Together explains why these layers should look vastly different from the overlying layers according to the flood geology scenario. The Supergroup is 12,000 ft thick, and sits on eroded metamorphic rock. We know it was eroded because igneous intrusions are truncated at the base of the Supergroup, and weathered fragments of the metamorphic rock are found in the lowermost Supergroup layer. Within the Supergroup, layers alternate between rock formed from mud, sand, lime, and lava, with evidence of many cycles of formation below and above water. Time above water is evident from the many layers with preserved mud cracks and raindrop impressions. Some layers are separated by erosional surfaces. Alternating layers of shale, sandstone, and limestone are consistent with changes in the depth of water and proximity to sources of sediment as the continents shifted in position and elevation.

The overlying Paleozoic rocks, said by flood geologists to represent early flood deposits, are 4,000 to 5,000 ft thick. They are deposited on an erosional surface, alternate between shale, sandstone, and limestone, and include many layers with preserved mudcracks and raindrop impressions. Multiple layers are separated by erosional surfaces, some with river channel networks carved into the surface – some up to 400 ft deep (described in 4, above)! On top of that are 5,000 to 10,000 ft of Mesozoic strata. In other words, the 15,000 ft of supposed flood deposits look nearly the same as the 12,000 ft of layers deposited before the flood. If it took a titanic flood to produce the Paleozoic and Mesozoic layers, why does it look so similar in thickness, character, and apparent history to the underlying Supergroup layers without one? In fact, the only substantive difference between the Supergroup and Paleozoic layers is fossils. In 12,000 ft of sedimentary rock, deposited during a time when flood geologists say all life as we know it was represented (at least in ancestral forms), not a single fossil is found that is more complex than algae. No clam shells, fish bones, twig fragments, or trilobites. Fossilization was clearly happening, but not even wind-blown pollen made it into the two-mile-thick sequence of sediments. The absence of complex life in the Supergroup only makes sense if complex life was not yet found on the earth.


The geology of the Grand Canyon is known fairly well after nearly one hundred and fifty years of careful field and laboratory studies of the rocks and landscape. In our chapter, Time Frame of Modern Geology, we describe multiple, sequential scenes in the history of the canyon with abundant illustrations and photographs. The geological evidence, only a fraction of it described here, is overwhelmingly inconsistent with flood geology – that strata were deposited in the span of less than one year during a global, diluvial catastrophe. Despite the claims of flood geologists, the rocks reveal multiple episodes of deposition and intervening periods of erosion. Every sedimentary formation can easily be explained by analogy to modern depositional environments, such as the open sea, coastlines, estuaries, and sand deserts. The condition and distribution of fossils in the strata do not reflect the rapid burial of sea animals and small land animals out of deep, turbulent water. Flood geologists have failed to conceive a physical model for catastrophic formation that is consistent with the real geology of the Grand Canyon.

Our goal for The Grand Canyon, Monument to an Ancient Earth is to provide a readable and well-illustrated overview of how modern geology succeeds in explaining its natural history. The grandeur of the Grand Canyon moves believers to worship the God who “laid the foundation of the earth” and who “causes the springs to gush into the valley.” It’s not our intention to settle the question of how to interpret the Genesis flood story (that is a matter for another book). However, as responsible earth scientists, we are motivated to give the public an honest accounting for the origins of a most glorious piece of creation!

About the authors

Stephen O. Moshier Headshot

Stephen O. Moshier

Stephen O. Moshier is a professor and chair of the Geology & Environmental Science Department at Wheaton College in Illinois. Moshier has practiced geology as a college professor and an oil company geologist. Much of his early research in geology involved describing and interpreting oil reservoir rocks. More recently, Dr. Moshier's research efforts are in the field of geoarchaeology, participating in expeditions to the Sinai, Egypt, and Israel. He has served as past president of the Geological Society of Kentucky and the Affiliation of Christian Geologists and currently serves on the Executive Council of the American Scientific Affiliation. He is a member of several professional geological societies.
Gregg Davidson

Gregg Davidson

Gregg Davidson has been a professor of Geology & Geological Engineering since 1996, specializing in hydrology and geochemistry, and serving for many years as the department chair. His professional writing is divided between the purely scientific, usually tied in some way to water, and the intersection of science and Christian faith. Gregg has a passion for understanding and communicating the harmony (or at least lack of conflict) that exists between the Bible and modern science.
Joel Duff

Joel Duff

Joel Duff is a professor of biology at The University of Akron. He earned his B.S. in biology from Calvin College, and a Ph.D. in botany from the University of Tennessee. He research focuses on understanding biological diversity by examining differences in DNA sequences and genome structure. He has worked on numerous plant and animals systems and has authored more than 40 research articles in science journals. He is an active writer and speaker exploring the intersection of science and Christian faith. He is a contributor to the book Grand Canyon: Monument to an Ancient Earth and blogger at Naturalis Historia ( He is an avid nature photographer and enjoys exploring God’s creation with his wife and five children.