Pisco Formation
The Pisco Formation is a geologic formation located in Peru, on the southern coastal desert of Ica and Arequipa. The approximately 640 metres (2,100 ft) thick formation was deposited in the Pisco Basin, spanning an age from the Middle Miocene up to the Early Pleistocene, roughly from 15 to 2 Ma. The tuffaceous sandstones, diatomaceous siltstones, conglomerates and dolomites were deposited in a lagoonal to near-shore environment, in bays similar to other Pacific South American formations as the Bahía Inglesa and Coquimbo Formations of Chile.
| Pisco Formation | |
|---|---|
| Stratigraphic range: Mid Miocene-Early Pleistocene (Colloncuran-Uquian) ~ | |
Lithology and sediments of the Pisco Formation across its allomembers | |
| Type | Geological formation |
| Unit of | Pisco Basin |
| Overlies | Chilcatay & Caballas Formations |
| Thickness | 640 m (2,100 ft) |
| Lithology | |
| Primary | Tuffaceous sandstone, diatomaceous siltstone |
| Other | Conglomerate, dolomite |
| Location | |
| Coordinates | 15.7°S 74.5°W |
| Approximate paleocoordinates | 15.8°S 73.8°W |
| Region | Arequipa & Ica Regions |
| Country | Peru |
| Extent | From Pisco to Yauca |
| Type section | |
| Named for | Pisco |
Outcrops of the formation in Peru | |
Several specialists consider the Pisco Formation one of the most important Lagerstätten, based on the large amount of exceptionally preserved marine fossils, including sharks (most notably megalodon), penguins, whales, dolphins, birds, marine crocodiles and aquatic giant sloths.
Famous fossils found in these layers include the giant raptorial sperm whale Livyatan, the aquatic sloth Thalassocnus, the sperm whale Acrophyseter, and the walrus-like dolphin Odobenocetops.