The El Tranquilo Group is a geologic group dating to roughly between 228 and 200

million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago). ...

and covering part of the

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch ...

. The El Tranquilo Group is found in the Austral Basin of Santa Cruz Province of

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

. Fossil flora and purported fossils of the

prosauropod Sauropodomorpha ( ; from Greek, meaning "lizard-footed forms") is an extinct clade of long-necked, herbivorous, saurischian dinosaurs that includes the sauropods and their ancestral relatives. Sauropods generally grew to very large sizes, had lon ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

Mussaurus ''Mussaurus'' (meaning " mouse lizard") is a genus of herbivorous sauropodomorph dinosaur that lived in southern Argentina during the Early Jurassic, with a maximum age of 192.78 ± 0.14 Ma. It receives its name from the small size of the sk ...

'' have been recovered from the El Tranquilo Sandstone. In older publications, the group was defined as a formation.El Tranquilo Formation
from the Paleobiology Database The group contains the

Laguna Colorada Formation The Laguna Colorada Formation is a geological formation of the Austral Basin in Patagonia, Argentina. The formation belongs to the El Tranquilo Group and dates back to the Early Jurassic, with a maximum age of 192.78 ± 0.14 Ma.Weishampel, Da ...

References

{{reflist Geologic groups of South America Geologic formations of Argentina Upper Triassic Series Late Triassic South America Triassic System of South America Triassic Argentina Sandstone formations Groups Fossiliferous stratigraphic units of South America Paleontology in Argentina