"Best evidences for a young Earth": Snelling and the ocean-sediment flux

In September, 2012, Answers in Genesis featured a review article of what they deemed the 10 Best Evidences that Confirm a Young Earth. From this list, I have already addressed #2 (Bent Rock Layers), #6 (Helium in Radioactive Rocks), and #7 (Carbon-14 in Fossils, Coal, and Diamonds) in previous articles:

• "Rock layers folded, not fractured" — or are they?
• Clearest evidence that the Earth is 6,000 years old: helium diffusion in zircons
• Radiocarbon evidence for the antiquity of the Earth

So today, I want to discuss one of Andrew Snelling's arguments from the content of our oceans that the Earth cannot be hundreds of millions of years old. Snelling presents us with two claims on his list: #1, that too little sediment is accumulated on the ocean floor, and #9, that the oceans contain too little salt. Let's begin with #1.

Evidence #1: Very Little Sediment on the Seafloor

The argument here is rather simple. Snelling cites an article by Milliman and Syvitski (1992) to claim that every year, rivers discharge 20 billion tons of sediment into the world's oceans. He further cites Hay et al. (1988) to claim that only 1 billion tons of sediment are removed by subduction of oceanic plates (and with them, marine sediments). At this rate, Snelling claims, the whole of the marine sediments on the ocean floor would accumulate in only 12 million years.

Snelling's claims and calculations are riddled with errors and what I can only deem very dishonest research. First, Milliman and Syvitski (1992) note up front in their abstract that their estimate of sediment discharge applies only to the modern period prior to human damming of rivers. Dams tend to reduce the sediment output of rivers to the ocean by mitigating floods that carry substantially more sediment. Secondly, and most important, the authors suggest that "prior to widespread farming and deforestation... sediment discharge probably was less than half the present level." In their discussion, Milliman and Syvitski (1992) estimate the total sediment discharge to the oceans was "considerably less" than 10 billion tons per year.

So already, Snelling's calculation is off by a factor of 2 or more, due to his unwillingness to read the entire article that he cited (or even the entire abstract!). Correcting the misquotation already shifts the age estimate of ocean sediments to more than ~30 million years. Granted, this number is less than 3 billion years (the estimated mean age of our oceans), but if Snelling is willing to deceive his audience by misquoting a publicly available abstract, his methods are already suspect. One should also note that of the dozens of studies regarding sediment flux to the oceans, Snelling cites only one. Why? Since Snelling published his article in 2012, estimates of sediment flux to the ocean have multiplied and improved. One of the most recent publications places a long-term estimate at 5.5 billion tons per year (Willenbring et al., 2014), which is far less than the 20 Gt/yr used by Snelling.

Uniformitarian extrapolation

Anticipating criticism, Snelling writes that "those who advocate an old earth insist that the seafloor sediments must have accumulated at a much slower rate in the past." He provides no citation for this response, presumably because his readers would never ask for one. Thus he sets up a strawman to persuade his readers that us 'old-earthers' are desperate dogmatists. In truth, the main errors (below) in Snelling's article have less to do with the actual rate of sediment flux to the oceans. Nonetheless, we should consider the way that Snelling twists uniformitarianism in his approach to persuading readers of a young Earth.

There is nothing scientific about extrapolating rates of any natural process blindly into the past. Either one should establish good physical reason for these rates never to change (as with the speed of light or radioactive decay), or one should make predictions about past rates that can be tested by historical evidence (like the kind preserved in rocks). Thus Snelling's age estimate of the oceans, based on sediment flux, remains only conjecture and is as weak as his poorly derived assumptions.

First, why should we expect the rate of sediment delivery to the oceans to have remained constant over time? Apart from human influence, natural variations in climate affect sediment delivery, because the temperature and precipitation affect rates of chemical/physical weathering. Glaciations significantly increase the sediment flux by grinding millions of tons of rock into dust and gravel, but widespread glaciation is far more common today than even 2 million years ago, and is absent from the vast majority of Earth history. Glacially and tectonically driven changes in sea level also affect sediment flux to the deep ocean, since higher sea levels reduce the area of exposed land that can be eroded into the oceans. On longer time scales, plate tectonics greatly affect the sediment flux by raising mountain ranges and deforming brittle rock formations. Today, massive mountain ranges span the whole western coasts of the Americas, and the Himalayas constitute the single largest source of sediment to the oceans. These mountain ranges are relatively young, however, so it's reasonable to conclude that sediment flux is far greater today than for much of Earth history.

Ocean sediments in the dividend: Snelling's big error

To estimate a maximum age of 12 million years for the oceans, Snelling used his sediment flux of 19 billion tons per year to determine how long it would take to accumulate 1,300 ft (400 m) of sediment, which Hay et al. (1988) take to be the average thickness of ocean sediments. However, this average thickness includes only deep ocean pelagic sediments, of which ~74% is biogenic calcite that formed in surface waters (i.e. was not carried in by rivers). Since most riverine sediments accumulate on the continental shelves, deltas, and other nearshore basins, Snelling is comparing apples and oranges to make his case. In fact, he does not even include continental shelves, deltas, and other nearshore basins in the calculation, despite that he depicts the continental shelf in his Figure 1, titled "Where is all the sediment?".

Snelling also cites Hay et al. (1988) when he claims that only 1 billion tons of sediment are removed from the oceans via subduction, but this amount only accounts for deep ocean sediments removed via subduction, so it is incomplete. Total subduction is sufficient to recycle the entire crust in 1.8 billion years (Clift et al., 2009). Snelling's calculation thus falls to pieces with very little examination.

Most of the sediment carried to the ocean by rivers accumulates in deltas and along the continental shelves. In fact, the Ganges-Brahmaputra delta accumulated up to 70 m during the Holocene alone (i.e. in 11,700 years), according to Khan and Islam (2008). Prior to dam construction, this river system also carried nearly 1/10 of the global sediment flux. The sedimentary layers in delta sequences tend to be hundreds of meters to miles in thickness, so if we are to ask "Where is all the sediment?", the first answer should be: deltas. Fjords constitute another significant catchment, and provide ~25% of recent riverine sediments (Syvitski et al., 1987), due to the efficiency of glacial ice (particularly when it melts) in discharging sediment to the oceans.

Ocean sediments in the rocks: Snelling's really big error

A bulk of sedimentary rocks in the Earth's crust have been interpreted to be marine sediment sequences. If this interpretation is correct, then nearly all of the sediment load from rivers since the beginning of Earth history is bound up in the rocks beneath your feet. Strangely, Snelling omits this massive reservoir of riverine sand, silt, and clay while determining that our Earth's oceans cannot be older than 12 million years. The sheer volume of sedimentary rock is astounding, but is consistent with the estimate by Willenbring et al. (2014) that approximately 5.5 billion tons of sediment were discharged each year into the oceans.

We can visualize this process from a cross section of just one record of nearshore deposition, which begins with the Marcellus Shale (a major source of petroleum today). Notice that the sedimentary layers thicken to the east, where the sediment source (now the Appalachian Mountains) was once located. More than a mile of sediment accumulated in this region in a few millions of years:

Image from Wikipedia commons.

Yet Dr. Snelling omits this volume of sediment from his calculation, asking us rhetorically to account for its fate. How long will YEC's continue to trust Andrew Snelling to do their research?

"A Matter of Faith": Fear Factor - 1, Academia - 0

"Which came first: the chicken or the egg? Today we'll learn that evolution has the answer!" In the upcoming film A Matter of Faith, Harry Anderson plays Professor Kaman, a popular biology professor teaching college freshman about the origin and diversity of life through something called science. In other words, he's the villain.

It happens once a year. Waves of college freshmen pour into the lecture halls of introductory courses to fulfill their 'general ed' requirements and get their first taste of university life. Back home, many a worried parent speculates about the potential dangers of releasing their grown-up children into the wild world of academia. With what will they experiment? Sex? Drugs? Majoring in theater? And to what kind of bad influences will they be exposed? Friends with poor study habits? Political liberalism? Campus dining plans?

Now, I don't mean to belittle the ubiquitous and legitimate concern that parents have for their children first entering college and/or moving out on their own. College often is a mishmash of poor decisions and moral bankruptcy—by anyone's standard—that results in a series of life lessons and nostalgic regret for the best and worst of times. Bad behavior aside, most parents (religious or not) would also prefer to see their children grow in the worldview in which they were raised, rather than abandon it for what they learned at school. Entrusting one's higher education to professors with far more academic freedom than public school teachers, therefore, is a trial of trust for any parent hoping to confirm they have 'raised their children right'.

For many families, choosing a Christian college can mitigate these concerns. The pressure to "let go of one's moral conscious" is minimized, and every professor ascribes to a statement of faith, made public by the university. While students are still exposed to all sorts of non-Christian paradigms, it is done by academics who have reasoned through the paradigms and come out the other side with faith intact. This can be a comfortable transition for students of faith into a world where critical thinking and intellectual independence are in high demand.

So the otherwise anxious parent might think, "It's a Christian college; what could my child possibly encounter that would challenge his/her faith?"

Well, for Answers in Genesis, choosing a Christian college is only the first step. Some time ago, I wrote a 3-part review of Already Compromised by Ken Ham and Greg Hall, a book that warned parents which colleges were staffed by 'evolution-friendly' faculty that rejected a young-Earth, creation science, and overly literal readings of Genesis. (In fact, some biblical professors in the sample group even rejected that Moses alone wrote the Pentateuch!) Three years later, with the upcoming theatrical release of A Matter of Faith, it appears the YEC's fear tactic for worried parents has changed very little:

In short, a father is surprised to learn that in a university biology class, his daughter is being taught the the most elegant and commonly accepted explanation for the origin and diversity of life on this planet. Who would have known? In response, a man shocked to find that real science conflicts with his oversimplified faith decides to do his own homework and, armed with strawman objections to an established scientific theory, seeks to defeat the 'already compromised' biology professor on his own turf. We'll have to wait until September 26 to find out who wins, but my money is on the guy without the Ph.D. in biology. If I'm right, the moral of the story will be that with a few hours in his personal library, any concerned father can discover what faithless academics failed to learn through 6+ years of graduate school.

So how will this story benefit Christians with children in college/high school? Does it teach them intellectual independence and critical thinking? I want to echo here the sentiments raised by John Dunne (author of the brilliant Esther and Her Elusive God) in his review of the trailer earlier this month. John writes:

"The problem that I have... is the silly appropriation of the same trope: Christians versus educators. The attitude is Christians contra mundum. Christians versus the philosophers and Christians versus the scientists. If debates are what you want, watch a real debate. Don’t watch a scripted exchange where Christians defeat fictional foes. There is nothing about this trope that is helpful; Christians should be ashamed of the anti-intellectualism on display."

As a Christian research scientist hoping to find a permanent position in academia one day, the fact that Answers in Genesis and the filmmaker are encouraging future students to immunize themselves against mainstream science is troubling to me. This sort of attitude, once hardened in the minds of zealous young Christians, is extremely difficult to crack, and it tends to leave a long-lasting imprint on the brain. Some will struggle for years trying to recover from the young-Earth molding; others will rather leave the faith altogether. In either case, the detrimental impact of Answers in Genesis on our college generations will only continue to grow so long as they're willing to resort to anti-intellectual fear tactics to preserve a failed paradigm.

Andrew Snelling concedes, radiometric dating of meteorites is solid

Figure 18 from Snelling (2014), illustrating the frequency of isochron ages obtained from the Allende CV3 carbonaceous chondrite meteorite via six independent radioisotope systems (color coded, in legend). Note the strong peak at 4.56 Ga, the conventional age of our solar system and Earth.

After years of sorting through the results of radiometric dates, all placing the age of our Earth and Solar System at ~4.56 billion years, Andrew Snelling has essentially conceded that he cannot twist isochron ages of meteorites and bulk-Earth materials into supporting his already disproven conjectures regarding accelerated nuclear decay. If you're not familiar with this claim already, Andrew Snelling and colleagues in the RATE team have decided to brush away the overwhelming evidence of an old Earth from geochronology by suggesting that at several points in Earth's 6,000-year history, rates of nuclear decay increased by a million times or more, leaving us with the false impression that geological history spans millions to billions of years instead.

Despite the obvious scientific deficiencies behind Snelling's claim (namely, that accelerated nuclear decay would obliterate all life/water/atmosphere on Earth), we should give Snelling credit for being the master of ad hoc, deus ex machina explanations so intricate, that they are rarely found outside popular science fiction writing. But since Snelling presents his claims within the cosmic fabric of this reality, you should be shocked by the level of deception that Snelling employs through propagating his message, and the level of deception that he ascribes to God, who must have tinkered arbitrarily with natural laws like a skilled, cosmic hacker, laying a trap for inquisitive scientists that dare reconstruct Earth history through natural evidence or deviate from oversimplified readings of Genesis. Regarding accelerated nuclear decay, Snelling writes:

"...changes [to physical laws governing atomic binding forces] would thus have to have affected every atom making up the earth, and by logical extension every atom of the universe at the same time, because God appears to have created the physical laws governing the universe to operate consistently through time and space, though of course He Himself is not bound by those physical laws which He can change at any time anywhere or everywhere."

 For Snelling, the philosophical possibility that God can arbitrarily change characteristics of how the universe functions has become an axiomatic point of departure to explain why both scientists and biblical scholars must be wrong about history. Snelling (2014) further writes in his concluding remarks about why meteorites may represent the 'primordial' creation material:

"Faulkner (2013) pointed out that the Hebrew word ‘āśâ meaning “to do” and “to make” is used specifically of the creation of the astronomical bodies in Genesis 1:16, rather than the Hebrew word bārā’ meaning “to create” as used in Genesis 1:1 in reference to the creation of the universe generally... Therefore, it seems entirely possible to read Genesis 1:16 as saying God used already-existing “primordial material” which He had created out of nothing at the beginning of Day One of the Creation Week (Genesis 1:1) to then fashion it into the other planets, their satellites and the stars. Most meteorites are believed have been derived from asteroids via collisions between them breaking off fragments that then hurtled towards the earth. So to be consistent, if the asteroids were also made on Day Four from this Day One primordial material left over from the making of the planets and their satellites in the solar system, then this would imply the meteorites could represent samples of this same “primordial material.”"

The implication here is that the Genesis author chose his verbs (or received them divinely) as a function of the material origins of different parts of the cosmos, rather than something of interest to the original, Israelite audience. This line of reasoning imports a rigid—and entirely modern—distinction between the Hebrew verbs in a manner that is fine-tuned to address the concerns of a 21st-century American audience. Thus Snelling's ad hoc approach to scripture resides in a symbiotic relationship with his ad hoc approach to science, each gaining traction from the other. Snelling reads what he wants to read in scripture so that he may see what he wants to see in nature. In short, he has traded truth for certainty.

Radioisotope Dating of Meteorites: I. The Allende CV3 Carbonaceous Chrondrite

Snelling's summary of radiometric dates obtained from this particular meteorite is messy, to say the least, and illustrates well why he will never be published in an influential, peer-reviewed journal. A bulk of the Answers Research Journal article consists of unnecessary background information and tedious petrological descriptions of the meteorite samples. These sections are inconsequential to Snelling's main thesis, that despite the overwhelming consistency and precision of radiometric dates (all pointing to an age of 4.56 Ga), he still won't accept that this one meteorite, let alone the universe, is much older than 6,000 years.

To preclude the most parsimonious interpretation of the data, accepted universally by research geologists, Snelling attempts to argue that the 4.56-billion-year age of the meteorite merely reflects the geochemistry of the primordial creation material. Essentially, he claims that both meteorites and the planets were derived from this primordial creation material, which consisted of all elements and isotopes created by God on Day 1. Both parent (radioactive) and daughter (radiogenic) isotopes were incorporated into the new material, according to Snelling. Then, accelerated nuclear decay affected all atoms in the universe at several stages in Earth history (defined arbitrarily by Snelling and other creationists). As a result, both meteorites and the bulk Earth contain a common distribution of isotopes from the Uranium-Lead, Lead-Lead, Potassium-Argon, Rubidium-Strontium, Lutetium-Hafnium, and Samarium-Neodymium systems, yielding a common isochron age for both meteorites and the bulk Earth. Since these model ages do not account for isotopes/elements inherited from the primordial creation material, they are not true ages, so Snelling is free to maintain his 'biblical age' of 6,000 years as an axiomatic reference.

In case you didn't follow all of that (it took me several attempts), don't worry. You need only reference Occam's Razor to understand why Snelling's conjecture is and will remain ad hoc conjecture. It is predictive of nothing, and his starting assumption regarding the age of the universe guides his interpretation of the data. This approach stands in stark opposition to conventional geochronology, which makes precise predictions that are confirmed/disconfirmed by real data.

Snelling's conclusions are scientifically meaningless, because he cannot account for the fact that these six radiometric systems yield the same age, based on decay rates measured in the present. Despite his attempt to plead otherwise (see below), the age of meteorites and the bulk Earth are obtained through independently verifiable results.

Why should all six isotope systems yield the same age if it is not real? That is the pressing question, which Snelling cannot answer, so he glosses over it with filler descriptions of the samples and discussions of Hebrew verbs.

If we apply Snelling's model to explain the radiochemistry of meteorites, then we must assume that the primordial creation material from which God made the meteorites/planets contained just the right proportion of isotopes so that after x amount of accelerated nuclear decay, all systems appeared to have aged precisely 4.56 billion years. But this is not science, and it barely qualifies as pseudoscience (which at least has the appearance of being scientific). We need a new category to account for the level of deception employed by Andrew Snelling's latest 'research' report. Can you think of an appropriate term?

Why are there isotopes?

Assumed by Snelling and all other creationists is the notion that a recently created universe should contain a wide assortment of both stable and radioactive isotopes. But why? What exactly in the young-Earth creationist paradigm would predict the existence of isotopes at all? Isotopes are not necessary to maintain life, either of plants/animals or the solar system itself. On the contrary, radioactive isotopes produce destructive heat and energy, which is the single most prominent cause of cancer, among other disorders.

In conventional science, the existence and relative abundances of isotopes are readily predicted by models of solar evolution, because stars produce elements with varying numbers of protons and neutrons by combining lighter elements of varying masses. It makes sense within this paradigm that isotopes exist in the first place, and by using isotopes as tracers for natural processes, we've made sense of the history of the universe. But I want to suggest that in the young-Earth creationist paradigm, the mere existence of isotopes (radioactive or stable) makes absolutely no sense. Did God make isotopes just to give scientists an additional tool by which to understand physical processes 6,000 years in the future? Any answer to this question by YECs will be entirely arbitrary, rendering Snelling's model of meteorite isotope systematics even more absurd.

Meteorite isochron ages using the Al-Mg, Hf-W, Mn-Cr, and I-Xe systems

Snelling makes an odd statement amid his discussion regarding the calibration of isochron ages to the Pb-Pb system (forgive the long citation):

"The other “successful” radioisotope methods are not really independent and thus objective, because they are calibrated against the Pb-Pb method (see table 1) and therefore are automatically guaranteed to give ages identical to those obtained by the Pb-Pb isochron method. Specifically, the Al-Mg method is calibrated against the Pb-Pb isochron age for the D’Orbigny achondrite meteorite (Bouvier, Vervoort, and Patchett 2008), the Hf-W method is calibrated against the Pb-Pb isochron age for the St. Marguerite chondrite meteorite (Kleine et al. 2005) and the D’Orbigny achondrite meteorite (Burkhardt et al. 2008), the Mn-Cr method is calibrated against the Pb-Pb isochron age for the St. Marguerite chondrite meteorite (Trinquier et al. 2008), and the D’Orbigny and LEW 86010 achondrite meteorites (Yin et al. 2009), and the I-Xe method is calibrated against the I-Xe age of the Shallowater achondrite meteorite (Hohenberg et al. 2001), which is calibrated against the Pb-Pb isochron age for the St. Marguerite chondrite meteorite (Brazzle et al. 1999). Thus, as to be expected, all the dates obtained by these methods which are calibrated against these Pb-Pb isochron ages all plot in the 4.56–4.57 Ga mode with the clustered Pb-Pb dates (figs 18 and 20)."

Note that missing from the list of supposedly 'calibrated' radioisotope systems are the ones I cited in the previous section to confirm that meteorite ages are independently verifiable (U-Pb, Sm-Nd, Rb-Sr, Lu-Hf, and K-Ar/Ar-Ar). The reason is that Andrew Snelling has misunderstood the application of short-lived isotope systems, such as the Al-Mg chronometer. Al-Mg chronometry cannot give you an age of 4.56 billion years, because it depends on a short lived isotope set (i.e. radioactive isotopes that decay very rapidly, and have disappeared since the early days of the solar system). Instead, Al-Mg isotopes tell us about how long it took for the cores of chrondritic meteorites (and their various minerals) to solidify after the accumulation of raw material. Of course, the Al-Mg ages must use the formation age of the meteorite, based on Pb-Pb isochrons, as their 'starting point'. Therefore, Snelling's claim that these systems are somehow calibrated to the Pb-Pb system to yield artificially consistent results is not only bogus, but completely ignorant of the basic science behind these various applications in geochronology.

Snelling showcases his stellar research in Table 1, which reports, for example, that some of the meteorite ages in his histogram were calculated through an Al-Mg isochron. He cites one paper by Bouvier et al. (2008), where he claims that Al-Mg isochron ages were calibrated to Pb-Pb ages. However, not only does the reference cited provide no isochron ages of any kind, it also makes absolutely no mention of the Al-Mg system, period.

Exhortation

Rather than wade through Snelling's repeated attempts to rationalize the success of geochronology in constraining the age of our solar system and geological history, I strongly encourage readers to recognize that Snelling has now subtly conceded the conclusion already reached by tens of thousands of his colleagues: we can pin down the age of the Earth with great precision, and it's far older than 6,000 years. Snelling's persistent trail of misguided arguments has long lead enthusiastic readers off the path of logic and evidence, perhaps to the point that these attributes of science are no longer recognizable. For this, I cannot help but to lament the loss of millions to the dark forest where Snelling has built his pseudoscientific palace. In case the loss is only temporary, however, I will continue to toss morsels of evidence from the lonely path.

Set your eyes to Zion, as a million generations before you

Figure 1: View south down Zion Canyon (National Park), near the base of the Emerald Pools trail. Sandstone cliff walls are comprised primarily of the Jurassic Navajo Sandstone. The Virgin River is seen cutting through the more fragile Kayenta Formation.

Easter weekend for me involved another return trip to one of the most popular hiking destinations in the American southwest: Zion National Park, Utah. Located just north of the humble valley town of Springdale, the canyon is full of visitors throughout the warm season, who include outdoor enthusiasts and office hermits alike, hailing from both faraway places like Europe and Asia and the local cities of Utah, Arizona, and Nevada. Many families make the rather convenient, ~3-hour trek to Zion National Park from the Las Vegas airport, before continuing a few hours south to the famed north rim of the Grand Canyon.

Figure 2: A tranquil valley setting, showing
the homogenous/pure mixture of sand that
comprises the sandstone cliffs of Zion.

The proximity of these parks is no coincidence. The sedimentary rock layers of Zion National Park are essentially the Early Mesozoic continuation of those found in Grand Canyon, in a long sequence of what's been termed the Grand Staircase (the uppermost layer of the Grand Canyon is Permian, the last period of the Paleozoic). This stratigraphic sequence continues into Bryce Canyon, where the later Mesozoic and early Cenozoic layers of the Colorado Plateau outcrop with astounding beauty. Now, despite the ongoing debate over exactly when and how these canyons were carved out, it is universally agreed that all three monuments to the power of erosion were formed sometime in the past 70 million years in response to substantial uplift of the Colorado Plateau.

While young-Earth creationists have commonly touted the Grand Canyon as a 'monument to catastrophe', somehow in favor of their position, this region's geology remains a testament to deep time and long, drawn-out geological processes. The 'Flood Geology' position requires a dishonest telescoping of data, fitted into an extremely oversimplified model, but a wider regional perspective as much as a detailed look at these rock formations provides ample evidence that this model is flat out wrong. I want to provide you with some basic observations, which demonstrate that the Flood Geology model fails to account for the 1) time required for deposition of sediments; 2) characteristics of the rocks prior to erosion; and 3) time required for erosion/removal of the bulk of sedimentary strata from the region.

1. Sedimentary Strata of the Colorado Plateau — all in a year's work?

Between the rim of the Grand Canyon and the peaks of Zion National Park lie more than 1,000 meters of sedimentary rock. Even if we allow the entire flood year to deposit this small fraction of the geologic column, this amounts to ~2.78 meters of sediment per day. While modern catastrophic floods have been known to deposit 2–3 meters of sediment in a single day (e.g. Thompson and Croke, 2013), the deposition is very localized (confined to flood banks) and offset by more intense erosion elsewhere in the channel. In other words, the sediment is simply moved downstream, but deposition is accompanied by distinct erosional features and does not result in flat, horizontal layers. More importantly, floods that are sufficiently powerful to deposit upward of 2–3 meters in a day are also sufficiently powerful to move large chunks of rock and debris, so that catastrophic flood deposits invariably consist of a mixture of sediment sizes, ranging from sand/mud to large boulders and gravel.

Triassic and Jurassic sediments of southern Utah are well known for their heterogeneity between layers and homogeneity within. Some layers are thin and contain only silt and clay, while others are thick, cross-bedded, and contain only medium-sized sand. Localized deposits of fine sediment or evaporites provide evidence of temporary lakes across the landscape. Shallow erosional features are common in the form of stream-sized sandstone channels, similar to modern floodplains in semi-arid regions (Martin, 2000). Perhaps the best known formation of this sequence is the red-stained Navajo Sandstone, a remnant of a massive desert dune-scape that rivaled the modern Sahara. To many a geologist, the portrait of a slowly evolving desert landscape over tens of millions of years could not be more clear.

Subtle clues to the paleoenvironment recorded by these rocks come in the form of sedimentary structures and fossils. Relatively thin sandstone beds contain planar bedding (horizontal) or epsilon cross bedding, much like modern river channels that now cross the American southwest. Massive sandstone beds of the Navajo Formation, on the other hand, are rather typical of wind-blown sand dunes, whose angle of repose (30–34°) matches that of the preserved sandstone. Experimental setups today (e.g. Fielding, 2006) have allowed geologists to distinguish clearly what kind of bedding structures (e.g. cross bedding) develop under various water depths, flow rates, etc., so that we can be confident that the Navajo Sandstone was deposited by air—not water. Other features like mudcracks or even dune collapse (e.g. Bryan et al., 2013) could not possibly form during catastrophic deposition.

Finally, fossils ranging from footprints (Lockley et al., 1998) to mammalian burrows (Riese et al., 2011) to body fossils of dinosaurs and other desert-dwelling terrestrial fauna (Rowe et al., 2010) preclude the catastrophic deposition rates required by the flood geology model, but corroborate well the conventional interpretation of these rock layers. Are we to believe that dinosaurs and small mammals were leaving footprints and making burrows while the sediment-choked flood waters raged at several meters per second? Are we further to believe that such powerful water masses imported millions of tons of sand/silt, but not an ounce of marine shells, bones, or lime mud, as is the case today when strong hurricanes/tsunamis make landfall? That is precisely what the folks at Answers in Genesis would have you believe, but this line of reasoning requires a staggering level of geological ignorance.

So the Flood Geologist is presented with a theoretical dilemma. The flood model might predict either a thick sequence of sediments, produced by a powerful slurry of sediment-choked water, or a relatively thin sequence of sediments, in which sedimentary structures and fossil features might be preserved through relatively mild, oscillating flow patterns. But they cannot have it both ways. If the entire 1,000-meter section of sediment from Grand Canyon to the Zion peaks were laid down within one year, it could not possibly contain such a diverse mixture of thin and thick, planar and cross bedded layers of sand, silt, clay, and evaporite, let alone footprints and burrows of small animals, who could never have walked amid such torrential waters. Besides, footprints and burrows in soft sediment are destroyed instantly under catastrophic flow conditions.

Along the highways of southern Utah, these massive cliffs of sedimentary rock stand testament against any rapid process of formation. So if this 1-kilometer sequence—only a fraction of the miles of sediment beneath the Colorado Plateau—cannot be explained by a year-long flood, why would Answers in Genesis go on pretending that it's even plausible for the entire geologic column (give or take) to have been laid down in a year? This is not a contrast between two worldviews examining one set of data, but a contrast between those who are willing to examine the data and those who are willing to misrepresent them unreservedly.

2. Post-flood transformation—between a soft rock and a hard place

Let us grant, for the sake of discussion, that all the Mesozoic sediments of Zion National Park were deposited within the flood year. Now how do these sediments become rocks? Under the weight of overlying sand and silt, water should begin moving of the sediments toward the surface—a process called dewatering and compaction. If accompanied by strong earthquakes, as young-Earth geologists tell us should have been the case, we would expect to find massive dewatering structures throughout the sedimentary layers.

Figure 3: Sandstone cliff exhibiting brittle
fracture zones, which somewhat resemble
conchoidal breaks in glass.

But we don't. All the layers and their bedding are intact (Fig. 3).

So how long did it take for these sediments to compact and lose enough water to begin precipitating iron-oxide cement between the sand grains (responsible for the red color of the cliffs)? By standard models of groundwater flow, this process could take thousands to millions of years, since the water is forced to flow through tiny pore spaces between grains. By no means do fresh laid sandstone bodies, hundreds of meters thick, go from sandcastle material to solid rock in a matter of days or even decades. This fact alone falsifies the young-Earth timeline, so young-Earth geologists strain at credulity in suggesting otherwise.

Flood geologists frequently make the claim that large-scale erosive processes were aided by the fact that sedimentary layers were not yet solid, meanwhile ignoring the fact that to this day, these rocks should not be solid. Even granting them this impossible scenario, however, we must note that erosion and weathering of Zion National Park exhibits features consistent only with the deformation of solid rock—not soft sediment. How old is Zion Canyon according to the young-Earth creationist? We cannot be sure exactly, and never would they offer an answer with much precision, but previous workers (like Austin and Snelling) cite retreat of the flood waters and/or residual inland seas as one mechanism to erode massive canyons in little time.

Figure 4: A side canyon, which has retreated
along a vertical fault (see right).

Figure 5: Waterfall along the main fault res-
ponsible for the side canyon. These falls are
the source of the Emerald Pools.

But if that were the case, then the erosional features of Zion Canyon make absolutely no sense. The sedimentary strata are filled with brittle fractures, joints, and faults, indicating the sediments were already solidified before the canyon eroded (Figs. 4-5). Furthermore, the canyon walls have been retreating for millennia by losing large, planar slabs of solid rock through a combination of freeze/thaw weathering and the pull of gravity. The result are pseudo-conchoidal pits on the vertical walls, as seen in the photo above (Fig. 3). Therefore, we can conclude confidently that Zion National Park was not eroded within days, centuries, or even millennia after deposition of the raw sedimentary materials. This process took far, far longer.

3. Post-flood erosion: we're gonna need a lot more dynamite...

Figure 6: Base of the uppermost Emerald Pool,
where the results of gravity and wintertime
weathering are most clearly seen. It will be
centuries before these boulders are ground
to fine sand again.

The Mesozoic strata outcropping in Zion and Bryce Canyon National Parks are not present in the Grand Canyon region, or even across much of the southern Colorado Plateau. Where did all the sediment go? We know that much of it was recycled into other formations across the western US, while the rest was carried off to the Baja region of western Mexico, where it now comprises much of the Cenozoic delta deposits of the modern Colorado River. As seen in Figure 2, rivers are extremely efficient at grinding rock slabs and boulders (see Fig. 6) down to fine sediment.

So once again, the Flood Geologist has put us into a strange dilemma regarding the Mesozoic sediments of Zion National Park. To be eroded quickly, these sediments must have been still soft, but to produce the deformational/erosional features found today, they must have been solid and well cemented. At the same time, these sediments were eroded and transported to form other fine-grained sedimentary deposits in the region, such as the sedimentary layers of the Cretaceous Interior Seaway, which extend from eastern Utah into Kansas. This could only happen rapidly if the Mesozoic sediments were still soft. But still other sedimentary deposits contain gravel and boulders of Mesozoic sandstone layers (e.g. the Iron Springs Formation of southern Utah), indicating unequivocally that the Mesozoic sediments were solid and well cemented at the time they were eroded and recycled into other sedimentary formations.

Conclusions
So which of these mutually exclusive scenarios should the young-Earth geologist choose? Were the sediments still soft or already lithified at the time that they were weathered and carried off of the Colorado Plateau? If we choose the latter scenario, we are left with one final problem: how were millions of tons of solid sand and silt stone ground to individual grains and then removed from the whole of the southern Colorado Plateau? Given the timeline offered by the Flood Geologist, it is abundantly clear that no option even begins to explain the most basic geological observations of the Zion National Park region.

I highly recommend a trip to Zion National Park, if you've not made the trip so far. It is truly a testament to deep time and the gradual evolution of landscapes in history and provides some of the most unique hikes available in the U.S. Only a few hours drive from Grand Canyon, Bryce Canyon, Red Rock Canyon, Lake Powell, Valley of Fire, San Rafael Swell (among others), one is able to trace more than ~800 million years of sedimentary strata in a single trip. Where else on Earth is that possible?