Los Rastros Formation

The Los Rastros Formation is a Ladinian to Carnian fossiliferous formation of the Agua de la Peña Group in the Ischigualasto-Villa Unión Basin in northwestern Argentina. Fossil theropod tracks, as well as many insects, fossil fish of "Myriolepis", bivalves and crustaceans and flora have been reported from the formation.
Description.
The formation overlies the Chañares Formation (and/or the Ischicuca Formation), and is overlain by the Ischigualasto Formation. The formation belongs to the Agua de la Peña Group of the Ischigualasto-Villa Unión Basin, where it is exposed in the Ischigualasto Provincial Park, a World Heritage site in Argentina. The up to thick formation of claystones, mudstones and sandstones was deposited in a deltaic to lacustrine environment during the first post-rift sequence in the basin.
A CA-TIMS U-Pb zircon age of 234.47 ± 0.44 Ma from the lower Los Rastros Formation was published in 2020. The acquired age demonstrates that most of the overlying lacustrine strata within the basin were deposited during or after the Carnian Pluvial Event (CPE) that lasted from 237 to 227 Ma approximately.
Fossil content.
The following fossils among others have been recovered from the formation:
Blattoptera (cockroaches and their relatives)
Coleoptera (beetles and their relatives)
Hemiptera (true bugs and their relatives)
Unknown