March 2, 2015 | David F. Coppedge

Triassic Trackways Are Unique

Secular geologists claim that unique conditions prevailed when trackways were made by tetrapods in Triassic strata. Is this special pleading?

A press release from UC Riverside starts with a question: “How Were Fossil Tracks Made by Early Triassic Swimming Reptiles So Well Preserved?” Their hypothesis was published in Geology: “Swimming reptiles make their mark in the Early Triassic: Delayed ecologic recovery increased the preservation potential of vertebrate swim tracks.” The hypothesis reverberated as delivered truth on Science Daily and Live Science.

The trackways are widely known in Moenkopi strata in Utah and in Coconino sandstone in the Grand Canyon. Many show preferential orientations, as if the animals were swimming against a current and touching bottom as they went. The problem is that such transitory features are easily washed away, and the ones that remain are usually subject to bioturbation (scrambling by worms and other underground creatures). Why are so many trackways preserved? The Geology paper by Tracy Thomson and Mary Droser offers this explanation:

We suggest that the depauperate infauna characteristic of such environments was repressed due to delayed biotic recovery following the end-Permian mass extinction, resulting in extremely low intensities of bioturbation. Lack of biogenic mixing promoted semiconsolidation of dewatered mud substrates and the widespread production and persistence of firmgrounds capable of recording and maintaining swim tracks. Thus a combination of factors, unique to the Early Triassic, increased the preservation potential of detailed swim tracks: (1) depositional environments that promoted the production of firmground substrates, (2) delayed ecologic recovery resulting in the lack of well-bioturbated sediment, and (3) the swimming behavior of various Early Triassic tetrapods.

This is akin to magic, Droser told Live Science:

The researchers captured a “Goldilocks” window when they could see this behavior simply because they had “this magical time after this mass extinction,” said study co-author Mary Droser, a professor of geology at the University of California, Riverside.

It’s also magical because “something” happened, a selective catastrophe, that scientists can’t explain:

The start of the Triassic period was a desolate time in Earth’s history. Something — a bout of volcanic eruptions, climate change or even an asteroid impact — triggered the extinction of more than 90 percent of Earth’s marine species. However, it allowed giant reptiles, such as the dolphin-shaped ichthyosaurs and the long-necked plesiosaurs, to flourish well before the evolution of dinosaurs.

So with reptiles swimming about but no animals to disturb the fast-drying mud, trackways were preserved. Trackways are rare above and below this layer, but spike in the early Triassic, the geologists say. Creationists claim that the animals were running away from rising flood waters that covered the tracks.  One thing both sides agree on: currents caused the animals to slip-slide to the side as they ran:

The reptiles “are meaning to stay on the substrate, to stay on the ground,” Droser said. But the water’s current lifts them up, and “they get carried a little bit until they find their footing again,” she said. As such, the tracks rarely move in a straight line, Droser added.

Live Science posted a gallery of trackways studied by Droser and Thomson.

So both creationists and secular geologists invoke unique conditions in a special time, and both tell a story how it happened. Which one is scientific? Why are both sides not allowed to give their stories in the mainstream science sites? After all, nobody was in Utah with a video camera at the time.

Steven Austin discusses trackways in Grand Canyon: Monument to Catastrophe. The Coconino, classed as Permian, was long believed to be petrified sand dunes, but he shows how the trackways resemble those described by Droser for the Triassic Moenkopi trackways.  Worms were long present, even in the evolutionary scheme, because their burrows are found as low as the Bright Angel Shale (Cambrian). So Droser and Thomson are wrong to think that tetrapod trackways are unique, or that they were protected from bioturbation somehow. Austin says, “Vertebrate trackways have been studied for many years from the Supai, Hermit, and Coconino sandstones. Footprints were left as very distinct impressions in the mud or sand by clawed feet of wide-bodied, quadrupedal vertebrates,” most likely amphibians due to the presence of tail-drag impressions (p. 146). They show a strong trend of travel upslope, as if running up from rising waters. Austin also provides second-hand evidence of prints that contradict the evolutionary sequence.

When making inferences about the unobservable past from observable effects, one needs counter-arguments. Austin’s book examines the claims of the evolutionists, but the Geology paper completely ignores solid research by creation geologists. This creates a situation where the secularists are free to speculate unchallenged, even committing “special pleading” (introducing unique circumstances ad hoc) to support their story. The lapdog media doesn’t challenge their stories, either. So readers in the public never get to hear both sides unless they find creation literature independently. This is unhealthy for science. Science needs debate and criticism, especially from reputable scientists outside the consensus. That’s why we bring it to you here, so that you learn to think critically and evaluate all the evidence.




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