The accommodation space in the Ischigualasto-Villa Unión Basin was filled by an approximately 3.5 kilometres (11,000 ft) thick succession of volcaniclastic, eolian, alluvial, fluvial and lacustrine deposits in various geologic formations.

The basin is of paleontological significance as it hosts several fossiliferous stratigraphic units providing many fossils of early dinosaurs, synapsids, turtles, mammals, the earliest crocodylomorphs, fish, amphibians and flora, as well as ichnofossils.

[1] The basin is a rift basin that started forming early in the break-up of Pangea and its southern latitude paleocontinent Gondwana in the Late Permian to Early Triassic, providing a sedimentary column of approximately 3.5 kilometres (11,000 ft) of Triassic sediments.

This sequence is separated from the overlying Agua de la Peña Group by a regional unconformity.

[3] The Ischigualasto-Villa Unión Basin is renowned for hosting the Triassic-age lagerstätten of the Chañares and Ischigualasto formations.