Sarmiento Formation | |
---|---|
Stratigraphic range: Bartonian-Burdigalian (Casamayoran-Colhuehuapian) ~ | |
Sub-units | Colhué Huapí Member, Gran Barranca Member, Puesto Almendra Member, Rosado Member, Trelew Member, and Vera Member |
Underlies | Chenque Formation Gaiman Formation |
Overlies | Koluel Kaike Formation (Río Chico Group) |
Thickness | 319 metres |
Lithology | |
Primary | Sandstone, mudstone |
Other | Limestone |
Location | |
Country | Argentina |
Extent | Golfo San Jorge Basin |
Type section | |
Named for | Sarmiento, Chubut |
Region | Chubut Province |
Country | Argentina |
Thickness at type section | 319 metres (1,047 ft) (tuffs) |
Location of the Sarmiento Formation within Argentina |
The Sarmiento Formation (Spanish: Formación Sarmiento), in older literature described as the Casamayor Formation, is a geological formation in Chubut Province, Argentina, in central Patagonia, which spans around 30 million years from the mid-Eocene to the early Miocene. It predominantly consists of pyroclastic deposits,[1] which were deposited in a semi-arid environment.[2] It is divided up into a number of members.[1] The diverse fauna of the Sarmiento Formation, including a variety of birds, crocodilians, turtles and snakes, also includes many mammals such as South American native ungulates (notoungulates, litopterns, astrapotheres) as well as armadillos, and caviomorph rodents.[3]
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