It is the only place in the world where nearly all of the Triassic is represented in an undisturbed sequence of rock deposits. This allows for the study of the transition between dinosaurs and ancient mammals; research is ongoing.
Badlands of the Valle de la Luna
The arid badlands around the formation are known as Valle de la Luna ("Valley of the Moon") due to their rugged, otherworldly appearance. In the Carnian this area was a volcanically active floodplain dominated by rivers and had a strongly seasonal rainfall.
Petrified tree trunks of Protojuniperoxylon ischigualastianus more than 40 m (131 ft) tall attest to a rich vegetation at that time. Fossil ferns and horsetails have also been found.
Rhynchosaurs and cynodonts are by far the predominant findings among the tetrapod fossils in the park. Dinosaurs comprise only 6% of the findings, but these include early samples of the two major lineages of dinosaurs (ornithischians and saurischians).
The carnivorous archosaur Herrerasaurus is the most numerous of these dinosaur fossils. Another important putative dinosaur with primitive characteristics is Eoraptor lunensis, found in Ischigualasto in the early 1990s.