Dinosaur Tracks in Sand Dunes … Under the Sea?

There are many reasons to go to Las Vegas, Nevada.  One reason is to see some spectacular ancient sand dune deposits. Young Earth Creationists (YEC), who try to explain much of the geologic record as deposits from Noah’s flood, interpret these to have been deposited underwater during a global catastrophic flood. An interesting complication for this interpretation is the fact that dinosaur tracks are found in these ancient dune fields.

First, I need to describe the rock formation that we are looking at. The formation is the Aztec Sandstone. It is Jurassic in age regardless of how long ago that was or how it formed. Here is a description of the unit from the website for the Red Rock Canyon State Park in Nevada:

“The great sandstone cliffs at Red Rock, thousands of feet high, are made up of the Aztec Sandstone.  This formation, about 180 – 190 million years old, is comprised of lithified sand dunes that formed in a vast desert that covered a large part of the southwestern United States during the Jurassic time.  Lithification is the process of changing unconsolidated sediment into sedimentary rock.  Massive cross-bedding, typical of aeolian (wind) deposits, is a result of the shifting wind direction across the Jurassic dune field and is seen in the Aztec Sandstone rock outcrops.” (Southern Nevada Conservancy 2024)

This contrasts with YEC explanations in several ways. YEC authors interpret these Jurassic sandstones to have been deposited by the flood and if this were true, a number of observed features would need to be explained, including those dinosaur tracks right in what were ancient sand dunes. Maybe those ancient dunes were not formed by wind. This article will compare conventional models with the flood geology proposal. Before looking at the dinosaur tracks, we need to understand a bit about the sandstones and compare them using other characteristics.

Figure 2. Aztec Sandstone, Red Rock Canyon, Nevada

Visiting Red Rock Canyon                                                              

Let’s look at the Aztec formation in Red Rock Canyon, near Las Vegas, Nevada. I spent a great afternoon there in 2020 guided by my nephew, Paul Dunsworth. This was just before the covid-19 pandemic shut the country down. Here is what happened. In January of 2020, my wife and I decided to meet Paul in Las Vegas where he lives and then go down together to visit my brother who lives in Yuma, Arizona. January is a much better time of year to visit both of these places than say, August. We flew in on a Sunday morning, rented a car and drove to Paul’s apartment. I suspect that many of the people on the plane with us hurried to the never stopping excitement of the Las Vegas Strip.   Paul knew that was really not our scene. Instead, he took us to see rocks. That was exciting.  Thankfully, my wife is quite patient with my passion for geology and rocks and she also loves natural beauty. It was a gorgeous sunny afternoon and many people were out to experience the Red Rock Canyon. We stopped at the visitor center and then drove up to the beautiful red rocks. Walking up to them, I was amazed by the number of small figures moving all over them. This is a spectacular place for rock climbing for those who are younger, more agile and perhaps a bit braver than I. You will see climbers in some of the images that I am including. Geologists like to include people in their slides to provide approximate scales to appreciate the sizes of the features. In many cases, it is difficult to find someone willing to put in the hiking and effort to be a scale in many areas, but these climbers provided great scales without even knowing that was their purpose.

Figure 1, taken from the visitor center, shows the spectacular red and yellow sandstones of the Aztec faulted down below the much older Cambrian limestones in the background. The sandstones are not just horizontal parallel bedded such as form in many settings. When laminations and beds formed in non-parallel fashion they are referred to as cross-bedded and the cross-bedding in the Aztec is spectacular.  (Figure 2, 3 and 4). 

Figure 4. Cross-bedding in Aztec Sandstone with various sized humans for scale.  Notice that in addition to depositional cross-beds, there are other bands that were formed by ground water, known as Liesegang bands.  These are common in this unit.

Figure 5.  Map of preserved distribution of Jurassic sandstone units deposited at approximately the same time.

Figure 6.  Great Sand Dunes National Park, Colorado (photo by National Park Service)

Figure 7  Comparison of the outcrops of the exposures of the Jurassic sandstones.  The Aztec, Navajo and Nugget Sandstones (ANN) were contemporaneous.  Here you can compare their extent with the modern Sahara and Arabian Deserts using a Google Earth image.

1. Extensive mica and dolomite.

               I have not found any note of mica from the ANN sands but they may contain trace amounts such as are found in the Coconino. Calcareous beds including dolomite are found in the ANN and typically interpreted as lacustrine deposits such as one would expect in interdune areas.  Interdune areas in modern ergs often have ponds and oases and carbonates such as limestone and dolomite would have be deposited in such settings.

Mica can be transported a long distance. Eolian mica is reported in soils in Hawaii (Dymond, Biscave, and Rex 1974) and Japan (Mizota and Takahashi 1982). Such micas are clearly not locally derived and eolian transport seems the only logical mechanism. One would not expect mica to remain in more than very low percentages in eolian sands, but they are reported in modern eolian sands in some cases, such as in the Hexi Corridor in China (Zhu, Zhang, and Sun 2021).  Helbe (2024) showed that the mica in the Coconino Sandstone fits well with the results of YEC testing with modern sands (Helble 2024; Anderson et al. 2013). 

2. Large parabolic folds

               Folded beds are not uncommon in the ANN. One example is shown in Figure 8. Many soft-sediment deformation features are documented by Dr. Gerald Bryant in his doctoral dissertation: “Outcrop Studies of Soft-sediment Deformation Features in the Navajo Sandstone” (Bryant 2011).   He shows many complex features of various sizes and shows that they are often associated with sand injections.  While Bryant notes that similar scaled modern analogs are difficult to find, the model proposed by Colby Ford for such folding in the Navajo Sandstone in Zion National Park seems to explain how dune collapse could account for such features (Ford 2015). Whitmore and Garner give no reason that such could not be associated with eolian sedimentation so perhaps this objection collapses.

Figure 8.  Folded dune sands, zoom in on portion of Figure 4.

3.   Extensive current lineation:

I did not observe surfaces such as are reported in the Coconino.

4,    Planar beds:

It is not clear what Whitmore and Garner are describing in this objection. Planar beds are common in the Coconino Sandstone, ANN formations and modern dunes (McKee 1979).  Horizontal planar beds also occur. This should be expected given the variety of different depositional settings that would have existed across an erg.

5. Poor Sorting and roundness of grains:

I did not sample the Aztec in the state park but the reports that I have seen do not show any issue here.  Figure 9 shows that at least published examples of Aztec sand are similar to published examples of dune sand from the Sahara Desert (Eichhubl et al. 2004; Pastore et al. 2021).  While I do not have quantitative data from the Aztec Formation, the sorting and rounding seem similar.  An image of a slide from the Navajo Sandstone in Utah was published in a MS Thesis and it appears similar but less magnification was used (Hansen 2007).

Figure 9. Comparison of sands from the Navajo SS from the Valley of Fire, Nevada published by Eichhubl, et al., 2004 with uncemented sands from the Sahara Desert published by Pastore et al, 2021.  (I am assuming fair use to post these.)

Figure 10. Cross-bed sets in the Aztec SS in Red Rock Canyon. White lines show angle of 30 degrees.  Many beds exceed this and if they were corrected for the regional dip, the depositional dip along the leeward slipface or foreset would be higher.  The red circled area is the folded area shown in Figure 8.

Figure 11. Cross-bed sets in the Aztec SS in Red Rock Canyon.  Again, white lines show 30 degrees of dip.  The leeward foresets shown have dips approximately this.

Figure 12 . Cross-bed sets in the Aztec SS in Red Rock Canyon.  Here three of the sets have had the uppermost and steepest parts of the beds truncated by the boundary of the next sets.

Figure 14  Tracings of cross-beds made from trenching a barchan dune in White Sands National Park, New Mexico

6. Similarity of vertebrate trackways to those made underwater

YEC biologist, Dr Leonard R. Brand  has published experiments to examine tracks formed by lizards and salamanders under various conditions. (L. R. Brand 1978; L. Brand and Tang 1991). He examined tracks on 1) dry sand, 2) moist sand, 3. wet sand, 4. underwater sand and included different slopes.  He concluded that the tracks from the Coconino were most like those from underwater sand. Brand and Tang (1991) argued that these trackways were made by animals that were partially buoyant in water and drifting with currents.  I don’t know the settings for the tracks in the Coconino Sandstone.  It is not difficult to believe that at times portions of an erg would have had small streams. Recognize that paleontologists studying tracks often recognize tracks that actually were made in shallow water (references).

It is evident however that the conditions that Dr. Brand tested are very different than the proposed conditions for Noah’s flood.  He tested small animals in 4 cm of slow moving water. (~8 cm/s).  The rates of water movement demanded by the proposals for flood waters were often over an order of magnitude faster (Snelling 2021). The limited time of Noah’s flood (1 year) with the amount of sediment deposited demands that rates have been very high with very, very little time for pauses or slow moving water. (Mitchell 2018; Mitchell and Tilman 2024). It takes some strong faith to believe that the ancient small animals that left tracks in the Coconino Sandstone would have left such tracks during a catastrophic flood. It is also important that Brand’s testing is not likely to be valid for dinosaurs.  More on this later. 

7. Sand injectites – discussed with parabolic folds and not repeated here.

 The concerns that Whitmore and Garner (2018) raised for the Permian Coconino Sandstone don’t seem to be relevant for the Jurassic ANN formations regardless of their validity in the Coconino.  We have a series of dune deposits in units where all of the fossils are consistent with terrestrial environments.  The high angle cross-beds are consistent with subaerial dunes. Sand grain information available is consistent with subaerial dunes. Published slides of the sand grains are similar to modern dune sands.  If we stopped there, subaerial dunes would be a logical conclusion, but there is much more.

Dinosaur Tracks in the Sands

As the title of this post suggests, there is another important type of data to reconcile. Any explanation for the units must account for the dinosaur tracks.  Were the dinosaurs living and hunting through an ancient desert region or were they dealing with a global catastrophic flood? 

Many dinosaur tracks have been found and studied in the ANN (Bonde et al. 2008; 2012; D. B. Loope 2006; David B. Loope and Rowe 2003; Minter, n.d.; Rowland and Mercadante 2014; Rowland et al. 2014; Stoller 2011; Wilkens 2008; Reynolds 2006).  Many types are found along with the tracks and trails of many other types of animals. At one time, it seemed that dinosaur tracks in southern Nevada were anomalously scarce.  That changed when Dr. Stephen Rowland, professor emeritus from the University of Nevada at Las Vegas and others in 2014 published this report: “First Report of Dinosaur, Synapsid, and Arthropod Tracks in the Aztec Sandstone (Lower-Middle Jurassic) of Red Rock Canyon National Conservation Area, Southern Nevada”   Here are a few points from this report:

He documents “tridactyl, grallatoroid dinosaur tracks up to 14 cm long” at 3 sites in the Red Rock Canyon National Conservation Area.  One of the tracks is particularly well preserved, (Figure 15) (Rowland et al. 2014).  Other sites have more tracks but not as well preserved (Figure 16) (Rowland et al. 2014).   The authors also make a significant interpretation of the state of the dunes at the time the dinosaurs traversed it.  Here I quote: 

“We can also say something about the moisture content of the sand. Neoichnological experiments with dry, moist, and saturated sand have shown that recognizable tracks can form only when the moisture content of the sand is in the range of 2-24% by weight (Manning, 2004). Below 2% moisture, the sand is not sufficiently cohesive for distinct tracks to form, and above 24% the sand flows under its own weight, also preventing the development of tracks. In the case of the track at Tracksite UNLV-AZ-005, the moisture content was probably toward the upper end of that range. Clearly, the sand was cohesive enough to preserve the track and also for brittle failure to occur. Moreover, it contained sufficient moisture that the increase in pore pressure, caused by the penetration of the dinosaur’s foot into the sand, permitted the sand to flow, thus creating the 7-mm displacement bulge.” (Rowland et al. 2014).

Neoichnology is the study of the tracks of animals from today and Dr. Brand is not the only one to have investigated tracks using living animals.[1]  Several important studies have been published including some in the Navajo Sandstone. (D. B. Loope 2006; Manning 2004; Falkingham and Gatesy 2014). Notice that Rowland and his co-authors believe that they can not only determine that the tracks were made under subaerial conditions but recognize the moisture content of the sands.  That is cool. 

One thing that is true in the ANN Sandstones, as in many other units with dinosaur tracks, is that the fossils go in many directions, as you can see in Figure 16. Some YEC in the past hypothesized that dinosaur tracks formed as the dinosaurs were running away from the flood. If so, they couldn’t agree which way to go. It is interesting that many of the tracks found in the ANN formations are found on the steeper side of the dunes. I observed similar tracks in the sand dunes of the White Sands National Park (Figure 17). I am not sure what made them, but I am pretty sure that it wasn’t dinosaurs.  At White Sands, we saw many types of tracks, including those from mammals, birds and insects.  In the Aztec Sandstone, there also were a variety of animals ranging from dinosaurs to spiders to scorpion like creatures and even mammal-like animals (Reynolds 2006; Rowland et al. 2014). Many levels were bioturbated, that is chewed up by animals below the surface, probably including worms. One trace fossil has been recognized that has been attributed as possibly formed by “burrowing colonial insects” (Stoller 2011)  (Fig. 6). “These consist of a network of variously oriented, tubular, sand-filled burrows, round in cross-section, and about 8 mm in diameter”. Today that would probably mean ants.

[1] Concerning the Coconino Sandstone, this quote reflects

“The DeChelly study indicates an erg environment in which the foresets of dunes provided a substrate for the passage of numerous presumed synapsids (Laoporus trackmaker), rare diapsids/areaoscelids (Dromopus sp.), spiders (Octopodichnus trackmaker), scorpionoids (Paleohelcura trackmaker) and other arthropods. These surfaces were also swept by winds that produced eddies and wind ripples on the lee or avalanche slopes. Such evidence provides definitive proof of a sub-aerial depositional environment, not a subaqueous setting as proposed by Brand and Tang (1992). For this reason we are dubious about the interpretation of tracks made by animals with “aquatic adaptations” in similar facies (Cornberger Sandstone) of Europe (Fichter, 1994).

In addition to straight-line Laoporus trackways with normal alternating gait, these surfaces reveal various oblique and zig-zag trackway configurations, of the type noted and attributed to swimming by Brand and Tang (1991). Such evidence provides definitive evidence that such trackways can be produced in sub-aerial settings (cf. McKee, 1944, 1979), and that explanations for such unusual configurations must be sought through an analysis of terrestrial locomotion on sloping substrates.” (M. G. Lockley et al. 1995)  The trace fossils strongly support subaerial deposition of the Coconino Sandstone. 

Figure 16. Map generated by photogrammetric data of tracks from one bed in the Red Rock Canyon area. The authors note that more than 50 tracks are found with various states of preservation.  The data suggest that the animals were walking diagonally up a slope.

Figure 18. Multiple layers of mudcracks in cross-section view, Moenkopi Formation, Red Canyon, Glen Canyon National Recreation Area. At least 5 levels are visible. Photo from  the National Park Service.

Figure 19. Dinosaur tracks and mudcracks in the Moenkopi Formation, which is estimated to be early to middle Triassic in age (252 to 235 million years ago).  This formation is older than the ANN units, but they serve to demonstrate that ancient mudcracks developed by exposure in the rock record just as they do today.

Figure 20.  Map showing locations of published accounts of dinosaur tracks associated with mudcracks.

Trace fossils such as dinosaur tracks are not the only type of fossils found in the ANN.  In the Valley of Fire State Park in Nevada, occasionally petrified logs are found.  These logs are not in growth position and so could have been transported there, though they are associated with rocks that would be interpreted as interdune, not on the sand dunes. There are exceptions to this in the Navajo Sandstone.  Parrish and Falcon-Lang (2007) describe trees in growth position in the ANN (Parrish and Falcon-Lang 2007). They studied interdune areas that, just as we find today apparently developed lakes. Carbonate mounds are found that they propose developed as ancient springs fed into the area. In a few cases, they found where the carbonate developed around trees trunks. They describe the trees as coniferous.  They report:

 “A few stumps preserved in growth position are rooted in eolian sandstone immediately below the lake deposits, and evidently established on interdune soils in response to a rising water table. Following at least several decades of growth, trees were killed as the water table continued to rise forming shallow lakes containing ostracods.”  

Clearly this would be impossible in a flood deposit. A deposit made in a few days would not  have given the opportunity for trees to grow.          

I want to show one more example of a Jurassic feature that is difficult to imagine in anything but an eolian setting. The crescent shaped marks shown in  Figure 21 ((Kirkland and Milner 2006) developed as wind blew a plant around.  Both pictured examples reflect this.  The left example shows that during the Jurassic in what is now Utah, depositional processes stopped long enough for a small plant to grow.  Wind then blew it around, leaving us evidence to find.

Figure 21. Examples of near circular and crescent shaped marks left by plants blown by wind.  The left photo is from White Sands National Park in New Mexico.  The right photo is of a smaller feature that formed the same way from the Upper Jurassic Moenave Formation in southwest Utah.

Discussion and Implications

The ANN formations have been interpreted to be from eolian settings for very good reasons. We have seen that the complex sets of cross-beds are consistent with dune sands that covered areas similar to large deserts of today.  We saw a number of features that fit that general depositional environment including: high angle cross-beds that are at times “gigantic scale” (McKee 1979), cycles within the cross-beds consistent with annual climate variations (D. B. Loope 2006), often well rounded and well sorted sand grains, sediments consistent with interdune deposition, paleosols, dinosaur tracks that are indicative of moist to dry sand tracks, other trace fossils consistent with an arid or semi-arid setting, petrified wood even occasionally in growth position and mudcracks that indicate desiccation over some period of time. 

Next, let’s consider the observations that suggest an aquatic or submarine dune setting. The main arguments presented seem dominantly to be providing possible alternative explanations for the features above. In terms of features that are directly indicative of a subaqueous setting, I have not identified any. It has been suggested that we might expect to find more ripple marks (McKee 1979), though they are not uncommon. Helbe, (2024 92) showed that rippled beds in the Coconino Sandstone fit well with eolian characteristics.  This would be good data to collect in the ANN Perhaps the strongest argument for deposition by moving water is that it fits the YEC model, while a non-aquatic model would not.  Perhaps the comment on the Coconino would need to be applied for the ANN units: “It is likely the Coconino was deposited during the Flood by depositional processes operating at rates that we have not yet been able to model in the laboratory or with the computer.” (Whitmore and Garner 2018, 618). 

Dinosaur tracks add a real complication for the moving water interpretation. If the dunes were deposited in moving water, then we should be able to tell some things about the water by knowing the sand size. Larger sand grains require more energy and hence faster moving water to move. Figure 22 (Lewis 1984) is one version of a commonly used summary chart used to characterize the bedforms or sedimentary structures that develop with moving water of different velocities vs. sediment grain sizes. It has been cited many times and one version was used by YEC flood geologist, Dr. Andrew Snelling (Snelling 2022, 241). Dunes require relatively high velocity moving water down at the sediment-water interface where actual deposition takes place. Above this interface, water would have been moving more rapidly.  This tells us something about what had to be happening when footprints were made if the ANN dunes were deposited underwater.

We have modern examples of underwater dunes, termed “aqueous dunes” They can even involve gravels moved by catastrophic floods apparently due to glacial outflows. (Carling 1996). They also form with up to medium sands (Reeder 2011). Most are in fairly deep water. As Brian Romans observed, “Sand dunes observed in water are typically smaller than their eolian cousins (some wind-blown dunes are hundreds of feet tall) because the height of dunes scale to the height of the current that creates them. The taller the current, the taller the dunes”(Romans 2018). If the ANN dunes were as tall as they apparently were, the currents would have needed to be thick. Modern subaqueous dunes are reported with heights of 1.5 to 20 m (5-90 ft) in water depths of 100-830 m 2700 ft) (Geng et al. 2024; Romans 2018; Reeder 2011; Carling 1996; Flemming 2000).  It seems clear that the ANN dunes were larger and thus by implication in at least similar water depths.

Now picture dinosaurs walking up the slipface of a subaqueous dune in hundreds of feet of water. Figure 24 shows my poor attempt to draw a picture of what this would have looked like.  Despite the artist’s obvious limitations in the drawing, you can see that it takes a determined faith to believe that dinosaurs were climbing submarine dunes.  In an underwater setting with a strong current flowing, picture several types of dinosaurs, small mammals or mammal-like animals walking on the dunes.  It is not even as if the tracks were just on one bed at each site, but they are preserved on many different beds, sometimes at the same site. Picture trees growing under the water.  Remember that the trees that grew in-place are not setting on pre-flood sediments in the YEC models. There are thousands of feet of flood sediment below and above them.

Figure 24. Illustration intended to show an underwater setting subaqueous dune with track forming animals walking around and conifer trees growing in the interdune area.   Remember that the current must have been flowing rapidly.

One other ancient animal is represented in the Jurassic in the same area: pterosaurs – winged reptiles (Bilbey et al. 2004).  Pterosaur tracks are also reported in the Navajo and Aztec formations, but these are too poorly preserved to be verified (M. Lockley, Harris, and Mitchell 2008). Why would they not have flown away instead of walking around under the sea?  In the FG explanation, these bird-like creatures were walking underwater.

It all is too difficult to reconcile for me. The YEC models actually limit God.  God, as we see Him revealed in nature, works on a larger scale than we ever would have imagined before the discoveries in astronomy over the last century.  He also works at a much finer scale than we would have considered before the discoveries of subatomic particles.  We also have discovered that his time scale for creation was much longer than we are used to in our human lives.  He created wonders such as dinosaurs, perhaps in part just because He gets joy from creating.  He even shares them with us through their bones and footprints.

References:

Allen, Jessica, Si-Yong Lee, and Sally Potter-McIntyre. 2013. “Three Dimensional Geologic Model of the Eolian Jurassic Navajo Sandstone in Central Utah for the Evaluation of C02 Sequestration.” UGA Publication 42 (2013)—The San Rafael Swell and Henry Mountains Basin: Geologic Centerpiece of Utah, October.

Anderson, Calvin J, Alexander Struble, John H Whitmore, and Matthew Cheney. 2013. “Micas in Cross-Bedded Sandstones and Their Abrasional Trends.” In . https://gsa.confex.com/gsa/2013AM/webprogram/Paper230552.html.

Avanzini, Marco, Silvia Frisia, Koenraad Van den Driessche, and Eddy Keppens. 1997. “A Dinosaur Tracksite in an Early Liassic Tidal Flat in Northern Italy: Paleoenvironmental Reconstruction from Sedimentology and Geochemistry.” PALAIOS 12 (December):538. https://doi.org/10.2307/3515410.

Balsley, John. 1980. Cretaceous Wave-Dominated Delta Systems: Book Cliffs, East Central Utah: A Field Guide. Vol. Available in most university geology libraries. Denver: Amoco Production Company.

Beakawi Al-Hashemi, Hamzah M., and Omar S. Baghabra Al-Amoudi. 2018. “A Review on the Angle of Repose of Granular Materials.” Powder Technology 330 (May):397–417. https://doi.org/10.1016/j.powtec.2018.02.003.

Bilbey, Sue, Debra Mickelson, Evan Hall, Scott Madsen, Chaunice Todd, and James Kirkland. 2004. “Vertibrate Ichnofossils from the Upper Jurassic Stump to Morrison Formation Transition Flaming George Reservoir, Utah.” Journal of Vertebrate Paleontology 24 (September):39A-39A.

Bonde, Joshua, David Varricchio, Gerald Bryant, and Frankie Jackson. 2012. “Mesozoic Vertebrate Paleontology of Valley of Fire State Park, Southern Nevada.” In , 108–26.

Bonde, Joshua, David Varricchio, Frankie Jackson, David Loope, and Aubrey Shirk. 2008. Dinosaurs and Dunes! Sedimentology and Paleontology of the Mesozoic in the Valley of Fire State Park. Geological Society of America Field Guide. Vol. 11. https://doi.org/10.1130/2008.fl.

Brand, Leonard R. 1978. “Footprints in the Grand Canyon.” Origins 5 (2).

Brand, Leonard, and Thu Tang. 1991. “Fossil Vertebrate Footprints in the Coconino Sandstone (Permian) of Northern Arizona: Evidence for Underwater Origin.” Geology 19 (January):1201–4. https://doi.org/10.1130/0091-7613(1991)019<1201:FVFITC>2.3.CO.

Bryant, Gerald C. 2011. “Outcrop Studies of Soft-Sediment Deformation Features in the Navajo Sandstone.” University of Toronto. https://tspace.library.utoronto.ca/bitstream/1807/31699/1/Bryant_Gerald_201111_PhD_thesis.pdf.

Carling, Paul A. 1996. “Morphology, Sedimentology and Palaeohydraulic Significance of Large Gravel Dunes, Altai Mountains, Siberia.” Sedirnentology, 647–64.

Collins, Lorence G. 2022. “Eolian or Water Deposition of the Coconino Sandstone,” September. Eolian or Water Deposition of the Coconino Sandstone.

Dymond, Jack, Pierre Biscave, and Robert W. Rex. 1974. “Eolian Origin of Mica in Hawaiian Soils.” Geological Society of America Bulletin 85 (January). https://doi.org/10.1130/0016-7606(1974)85<37:EOOMIH>2.0.CO;2.

Eichhubl, Peter, W. Lansing Taylor, David D. Pollard, and Atilla Aydin. 2004. “Paleo-Fluid Flow and Deformation in the Aztec Sandstone at the Valley of Fire, Nevada—Evidence for the Coupling of Hydrogeologic, Diagenetic, and Tectonic Processes.” Geological Society of America Bulletin 116 (9): 1120. https://doi.org/10.1130/B25446.1.

Evans, J.R. 1971. “Geology and Mineral Deposits of the Mescal Range Quadrangle, San Bernadino County, California.” National Geologic Map Database. https://ngmdb.usgs.gov/Prodesc/proddesc_269.htm.

Falkingham, Peter L., and Stephen M. Gatesy. 2014. “The Birth of a Dinosaur Footprint: Subsurface 3D Motion Reconstruction and Discrete Element Simulation Reveal Track Ontogeny.” PNAS, December, 18279–84. https://doi.org/10.1073/pnas.1416252111.

Fischer, Tobias, Patrick Chellouche, Martin Lockley, and Christian Meyer. 2021. “The Dinosaur Tracks of Bad Essen-Barkhausen in the UNESCO Global Geopark TERRA.Vita (NW Germany): 100 Years of Development from an Industrial Quarry to an Open-Air Museum Article Information Geoconservation Research Volume 4 / Issue 2 2021 / Pages(***) 2” 4 (October).

Flemming, Burghard. 2000. “On the Dimensional Adjustment of Subaqueous Dunes in Response to Changing Flow Conditions: A Conceptual Model.” In .

Ford, Colby. 2015. “Soft-Sediment Deformation and Dune Collapse in the Navajo Sandstone.” MS Thesis, Loma Linda University. https://scholarsrepository.llu.edu/etd/334.

“Fossil Trackway, Moenkopi Formation – Flagstaff, Arizona | e-Magazine of the AZ Geological Survey.” 2021. Arizona Geology E-Magazine. April 13, 2021. https://blog.azgs.arizona.edu/blog/2021-04/fossil-trackway-moenkopi-formation-flagstaff-arizona.

Froede, Carl R, Jr. 2004. “Eroded Appalachian Mountain Siliciclastics as a Source for the Navajo Sandstone.” Perspectives. https://creation.com/images/pdfs/tj/j18_2/j18_2_3-5.pdf.

Geng, Minghui, Haibin Song, Shengxuan Liu, Yaoming Zhang, Linghan Meng, Bing Yang, Lijie Wang, Yuan Gu, Junzhao Rong, and Baojin Zhang. 2024. “Characteristics and Migration of Subaqueous Sand Dunes Influenced by Internal Solitary Waves in the Dongsha Region, Northern South China Sea.” Geomorphology 461 (September):109325. https://doi.org/10.1016/j.geomorph.2024.109325.

Getty, Patrick R., Christopher Aucoin, Nathaniel Fox, Aaron Judge, Laurel Hardy, and Andrew M. Bush. 2017. “Perennial Lakes as an Environmental Control on Theropod Movement in the Jurassic of the Hartford Basin.” Geosciences 7 (1): 13. https://doi.org/10.3390/geosciences7010013.

Graham, John P. 2016. Glen Canyon National Recreation Area Geologic Resources Inventory Report. National Park Service. https://npshistory.com/publications/glca/nrr-2016-1264.pdf.

Hansen, Ashley D. 2007. “Reservoir Characterization and Outcrop Analogs to the Navajo Sandstone in the Central Utah Thrust Belt Exploration Play.” MS Thesis, Brigham Young University. https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=1953&context=etd.

Hassan, Muhammad Sadeed. 2015. “Outcrop Based Facies and Architecture Analysis of the Regional Intertonguing of Early Jurassic Kayenta Formation with the Navajo Sandstone, Kanab Canyon, Utah.” Thesis. https://tspace.library.utoronto.ca/handle/1807/79801.

Helble, Timothy. 2024. “Flood Geology and Conventional Geology Face Off Over the Coconino Sandstone.” Perspectives on Science and Christian Faith 76 (2): 86–106. https://doi.org/10.56315/PSCF9-24Helble.

Henriques, Maria, and Miguel Ramalho. 2005. Jurassic Heritage of Cabo Mondego (Central Portugal). Vol. Jurassic Heritage and Geoconservation in Portugal: Selected Sites.

Kirkland, James, and Andrew Milner. 2006. “The Moenave Formation at the St. George Dinosaur Discovery Site at Johnson Farm, St. George, Southwestern Utah” 37 (January).

Lallensack, Jens, P. Martin Sander, Nils Knötschke, and Oliver Wings. 2015. “Dinosaur Tracks from the Langenberg Quarry (Late Jurassic, Germany) Reconstructed with Historical Photogrammetry: Evidence for Large Theropods Soon after Insular Dwarfism.” Palaeontologia Electronica 18 (June):1–34. https://doi.org/10.26879/529.

Le Loeuff, Jean, Christian Gourrat, Patrice Landry, Lionel Hautier, Romain Liard, Christel Souillat, Eric Buffetaut, and Raymond Enay. 2006. “A Late Jurassic Sauropod Tracksite from Southern Jura (France).” Comptes Rendus Palevol 5 (July):705–9. https://doi.org/10.1016/j.crpv.2006.01.007.

Lewis, D.W. 1984. Practical Sedimentology. Stroudsburg, Penn: Hutchison Ross  Publications.

Lockley, M. G., A. P. Hunt, H. Haubold, and S. G. Lucas. 1995. “Fossil Footprints in the DeChelly Sandstone of Arizona; with Paleoecological Observations on the Ichnology of Dune Facies.” Bulletin – New Mexico Museum of Natural History and Science 6 (January):225–33.

Lockley, Martin, Jerald D Harris, and Laura Mitchell. 2008. “A Global Overview of Pterosaur Ichnology: Tracksite Distribution in Space and Time.” Zitteliana Reihe B: Abhandlungen, December, 185–98.

Loope, D. B. 2006. “Dry-Season Tracks in Dinosaur-Triggered Grainflows.” PALAIOS 21 (2): 132–42. https://doi.org/10.2110/palo.2005.p05-55.

Loope, David B., and Clinton M. Rowe. 2003. “Long‐Lived Pluvial Episodes during Deposition of the Navajo Sandstone.” The Journal of Geology 111 (2): 223–32. https://doi.org/10.1086/345843.

López-Martı́nez, N., J.J. Moratalla, and J.L. Sanz. 2000. “Dinosaur Nesting in Tidal Flats.” Palaeogeography, Palaeoclimatology, Palaeoecology 160 (July):153–63. https://doi.org/10.1016/S0031-0182(00)00063-8.

Manning, Phillip L. 2004. “A New Approach to the Analysis and Interpretation of Tracks: Examples from the Dinosauria.” Geological Society, London, Special Publications 228 (1): 93–123. https://doi.org/10.1144/GSL.SP.2004.228.01.06.

Marzolf, J. E. 1976. “Sand-Grain Frosting and Quartz Overgrowth Examined by Scanning Electron Microscopy; the Navajo Sandstone (Jurassic (?)), Utah.” Journal of Sedimentary Research 46 (4): 906–12. https://doi.org/10.1306/212F708B-2B24-11D7-8648000102C1865D.

McKee, Edwin D. 1979. A Study of Global Sand Seas. Vol. Geological Survey Professional Paper 1052. US Government Printing Office. https://pubs.usgs.gov/pp/1052/report.pdf.

Minter, Nicholas. n.d. “Footprints and Invertebrate Traces from a New Site in the Nugget Sandstone (Lower Jurassic) of Idaho: Implications for Life in the Northern Reaches of the Great Navajo-Nugget Erg System in the Western USA.” Accessed August 11, 2024. https://www.academia.edu/1237334/Footprints_and_invertebrate_traces_from_a_new_site_in_the_Nugget_Sandstone_Lower_Jurassic_of_Idaho_implications_for_life_in_the_northern_reaches_of_the_Great_Navajo_Nugget_Erg_System_in_the_western_USA.

Mitchell, Stephen. 2018. A Texas- Sized Challenge to Young Earth Creation and Flood Geology: A Christian Geologist Looks for Answers. Christian Faith Publishing, Inc.

Mitchell, Stephen, and Kennen Tilman. 2024. “Tonto Depositional Processes and Rates.” Peaceful Science, August. https://doi.org/10.54739/giu8.

Mizota, Chitoshi, and Yuko Takahashi. 1982. “Eolian Origin of Quartz and Mica in Solls Developed on Basalts in Northwestern Kyushu and San-In, Japan.” Soil Science and Plant Nutrition 28 (3): 369–78. https://doi.org/10.1080/00380768.1982.10433652.

Monolithic Dome Institute. 2023. “Monolithic Dome Gypsum Storages.” Monolithic Dome Institute. April 12, 2023. https://monolithicdome.com/gypsum-storages.

Noffke, Nora, James Hagadorn, and Sam Bartlett. 2019. “Microbial Structures and Dinosaur Trackways from a Cretaceous Coastal Environment (Dakota Group, Colorado, U.S.A.).” Journal of Sedimentary Research 89 (November):1096–1108. https://doi.org/10.2110/jsr.2019.57.

Oard, Michael J. 2008. “Dancing Dinosaurs?” October 28, 2008. https://creation.com/dancing-dinosaurs.

Paik, In Sung, Min Huh, Kye-Hun Park, Koo-Geun Hwang, Kyung Kim, and Hyun Kim. 2006. “Yeosu Dinosaur Track Sites of Korea: The Youngest Dinosaur Track Records in Asia.” Journal of Asian Earth Sciences 28 (December):457–68. https://doi.org/10.1016/j.jseaes.2005.11.007.

Parrish, Judith, and Howard Falcon-Lang. 2007. “Coniferous Trees Associated with Interdune Deposits in the Jurassic Navajo Sandstone Formation, Utah, USA.” Palaeontology 50 (July):829–43. https://doi.org/10.1111/j.1475-4983.2007.00689.x.

Pastore, Guido, Thomas Baird, Pieter Vermeesch, Alberto Resentini, and Eduardo Garzanti. 2021. “Provenance and Recycling of Sahara Desert Sand.” Earth-Science Reviews 216 (March):103606. https://doi.org/10.1016/j.earscirev.2021.103606.

Prothero, Donald, and Fred Schwab. 2013. Sedimentary Geology. Third edition. New York: W. H. Freeman.

Reeder, D. Benjamin. 2011. “Very Large Subaqueous Sand Dunes on the Upper Continental Slope in the South China Sea Generated by Episodic, Shoaling Deep-Water Internal Solitary Waves – ScienceDirect.” Marine Geology, 12–18.

Reynolds, Robert E. 2006. “Jurassic Tracks in California.” In Making Tracks Across the Southwest: The 2006 Desert Symposium.

Romans, Brian. 2018. “Deep-Water Sand Dunes in the South China Sea | WIRED.” WIRED. November 23, 2018. https://www.wired.com/2010/11/deep-water-sand-dunes-in-the-south-china-sea/.

Rowland, Stephen, and Jennifer Mercadante. 2014. “Trackways of a Gregarious, Dunefield-Dwelling, Early Jurassic Therapsid in the Aztec Sandstone of Southern Nevada.” PALAIOS 29 (December):539–52. https://doi.org/10.2110/palo.2013.067.

Rowland, Stephen, Heather Stoller, Neffra Matthews, and Marvin Saines. 2014. “First Report of Dinosaur, Synapsid, and Arthropod Tracks in the Aztec Sandstone (Lower-Middle Jurassic) of Red Rock Canyon National Conservation Area, Southern Nevada.” In , 249–59.

Sciscio, Lara, Emese M. Bordy, Mhairi Reid, and Miengah Abrahams. 2016. “Sedimentology and Ichnology of the Mafube Dinosaur Track Site (Lower Jurassic, Eastern Free State, South Africa): A Report on Footprint Preservation and Palaeoenvironment.” PeerJ 4 (August):e2285. https://doi.org/10.7717/peerj.2285.

Snelling, Andrew A. 2021. “The Petrology of the Tapeats Sandstone, Tonto Group, Grand Canyon, Arizona.” Answers Research Journal 14. https://assets.answersingenesis.org/doc/articles/pdf-versions/arj/v14/petrology_tapeats_sandstone.pdf.

———. 2022. “The Petrology of the Muav Formation, Tonto Group, Grand Canyon, Arizona.” Answers Research Journal 15:139–262.

Southern Nevada Conservancy. 2024. “Red Rock Canyon: Geology Highlights.” Red Rock Canyon Las Vegas (blog). March 1, 2024. https://www.redrockcanyonlv.org/geology-highlights/.

Stoller, Heather Marie. 2011. “Ichnology and Paleoecology of the Jurassic Aztec Sandstone.” University of Nevada, Las Vegas. https://digitalscholarship.unlv.edu/thesesdissertations/2032.

Wagensommer, Alexander, Marianna Latiano, Géraud Leroux, Gianluca Cassano, and Simone D’Orazi Porchetti. 2012. “New Dinosaur Tracksites from the Middle Jurassic of Madagascar: Ichnotaxonomical, Behavioural and Palaeoenvironmental Implications.” Palaeontology 55 (January). https://doi.org/10.1111/j.1475-4983.2011.01121.x.

Walker, Tas. n.d. “Valley of Fire, Nevada.” Creation.Com. Accessed March 7, 2024. https://creation.com/valley-of-fire-nevada.

Whitmore, John, and Paul Garner. 2018. “The Coconino Sandstone (Permian, Arizona, USA): Implications for the Origin of Ancient Cross-Bedded Sandstones.” The Proceedings of the International Conference on Creationism 8 (1): 581–627. https://doi.org/10.15385/jpicc.2018.8.1.42.

Whyte, M., and M. Romano. 2008. “Dinosaur Footprints Associated with an Ephemeral Pool in the Middle Jurassic of Yorkshire, Uk.” In . https://www.semanticscholar.org/paper/Dinosaur-footprints-associated-with-an-ephemeral-in-Whyte-Romano/effd18b03cda0d8dc821d922b6149477c9cbb721.

Wilkens, Nathan D. 2008. “Paleoecology of Early Jurassic Navajo Sandstone Interdune Deposits.” Arizona State University. https://www.academia.edu/10552103/Paleoecology_of_Early_Jurassic_Navajo_Sandstone_Interdune_Deposits.

Zhu, Bing-Qi, Jia-Xing Zhang, and Chun Sun. 2021. “Physiochemical Characteristics, Provenance, and Dynamics of Sand Dunes in the Arid Hexi Corridor.” Frontiers in Earth Science 9 (August). https://doi.org/10.3389/feart.2021.728202.