Dinosaur Tracks Found along Rio Grande Wild and Scenic River

Article by Don Corrick, Geologist, Big Bend National Park
for Park Paleontology Newsletter, Spring 2017

Two theropod dinosaur tracks discovered in Cretaceous rocks along the Rio Grande Wild and Scenic River.

(NPS Photo)

During a recent river patrol, Big Bend National Park staff confirmed the presence of a dinosaur trackway on the bank of the Rio Grande Wild and Scenic River, along Texas’s border with Mexico. Private river guides reported seeing possible tracks in the vicinity of the Upper Madison Falls rapids, which led to the investigation by Big Bend National Park staff (Rio Grande Wild and Scenic River is managed by Big Bend National Park). This portion of Rio Grande Wild and Scenic River is known as the Lower Canyons and is remarkably rugged and remote, with virtually no road access to the area.

The trackway consists of two clear, well-preserved tracks and about five faint or eroded tracks, leading in a straight line and apparently created by a single dinosaur. The tracks are three-toed, about 30 cm long, and have a stride length of about one meter. Ripple marks are present nearby, suggesting a shallow water depositional environment.

The trackway is exposed in a large bedrock outcrop that is interpreted to be Glen Rose Limestone, a formation that is well-known for its preservation of dinosaur tracks in Central Texas. Unfortunately, there are very few outcrops of Glen Rose Limestone in the Big Bend region.

The trackway is located on the Mexican bank of the Rio Grande, and Big Bend resource managers will share news of the trackway with our Mexican counterparts who manage several very large protected areas adjacent to Big Bend. Other future actions include making casts of the tracks and searching the Texas side of the river for more trackways. However, the trackway is difficult to visit as it requires a week-long, 83-mile wilderness river trip in order to access the location.

These are the first vertebrate tracks ever reported for either Big Bend National Park or the Rio Grande Wild and Scenic River.