Angostura Colorada Formation

The Angostura Colorada Formation is a Campanian to Maastrichtian geologic formation of the Neuquén Basin and North Patagonian Massif in the Río Negro Province of Argentina. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation.
Description.
The Angostura Colorada Formation was defined by Volkhaimer in 1973 and unconformably overlies the Late Triassic volcanics of the Sañicó Formation. The formation is partly overlain by the Huitrera and Collón Cura Formations, and in other parts by the Coli Toro Member of the Los Alamitos Formation. The formation, outcropping south of Comallo, comprises sandstones, claystones and conglomerates deposited in a fluvial environment.