Exploring the wonders of geology in response to young-Earth claims...

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Friday, May 16, 2014

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.

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?


  1. Here in the UK I recently saw (on the freeview channel named Quest) a Discovery Channel programme entitled 'Fearless Planet' which discussed the formation (in several stages) of the Grand Canyon.

    1. I haven't seen that yet, but I've tried to keep up on the main research regarding the formation of the Grand Canyon. It's a very complex problem, since it occurs, as you note, in several stages that are extremely difficult to constrain. I've been to the canyon a few times, though, and am always astounded that folks like Tom Vale can still lead groups down the canyon trying to convince people that its history can be reduced to a few centuries. The evidence against him is so overwhelming that I can't help but to pity a little those willing to cast him so much credibility (and a good-sized check).

  2. I just found your blog and I love it. The problem with YECism is that they compress all of Earth's beautiful prehistory into this narrow 2,000 year timeframe. Its an over-simplistic, almost childish worldview that seems so counter-intuitive to what the tens of thousands of feet of sedimentary rock, buried with fossils of animals utterly bizzare and alien to our world. Keep up the great work!!

    1. Thanks, Daren, I appreciate your thoughts. Always good to hear from someone that recognizes the oversimplicity of YEC and how it distorts the beauty of Earth's history.

  3. Am visiting Zion and am amazed at the geology. Your challenges to the young earth/flood model are interesting. One feature I noticed around were two bands I would guess some 20 feet wide. They are a level plane on both sides of the canyon perhaps 100 to 200 feet up the wall and carved in perhaps some 6 to 10 feet deep. (Dont quote me on the numbers as they are only guesses. ) Your thoughts?

  4. Am visiting Zion and am amazed at the geology. Your challenges to the young earth/flood model are interesting. One feature I noticed around were two bands I would guess some 20 feet wide. They are a level plane on both sides of the canyon perhaps 100 to 200 feet up the wall and carved in perhaps some 6 to 10 feet deep. (Dont quote me on the numbers as they are only guesses. ) Your thoughts?