[Rockhounds] Fallen Boulder at the Grand Canyon Exposes 300-Million-Year-Old Footprints

[Kreigh Tomaszewski]

The oldest fossilized vertebrate footprints ever discovered in the Grand
Canyon were found embedded in a recently fallen boulder located in plain
sight.

Around 314 million years ago—long before the first dinosaurs appeared on
Earth—a reptilian creature measuring around a foot long slowly angled its
way upward along a windswept sand dune. Shortly after, the same four-legged
animal, or possibly a similar one, took a more direct route, climbing
straight up the dune at a slighter faster pace. The resulting footprints
hardened after getting damp, then got covered in sand, which preserved them
for hundreds of millions of years.

Today, we know the location of these ancient treks as the Manakacha
Formation of the Grand Canyon. A boulder imprinted with these fossilized
trackways recently fell from a Manakacha cliff, landing near the Near
Bright Angel Trail. Norwegian geology professor Allan Krill noticed some
peculiar features on this reddish rock while hiking with students in the
area four years ago. Krill smartly sent photos of the boulder to Stephen
Rowland, a paleontologist at the University of Nevada Las Vegas and first
author of a new PLOS One study
<https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0237636>
describing
the trackways.

https://gizmodo.com/fallen-boulder-at-the-grand-canyon-exposes-300-million-1844830623