Los Bastos Formation

Los Bastos Formation
Stratigraphic range: Early-mid Coniacian ~89.8–88 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Geological formation
Unit of	Neuquén Group  Río Neuquén Subgroup
Underlies	Sierra Barrosa Formation
Overlies	Portezuelo Formation
Thickness	Up to 35 m (115 ft)
Lithology
Primary	Mudstone
Other	Sandstone
Location
Coordinates	38°50′20″S 68°47′05″W / 38.83889°S 68.78472°W / -38.83889; -68.78472
Approximate paleocoordinates	42°18′S 49°00′W / 42.3°S 49.0°W / -42.3; -49.0
Region	Mendoza Province Neuquén Province
Country	Argentina
Extent	Neuquén Basin
Type section
Named for	Los Bastos Field
Named by	2010
Year defined	Garrido
Los Bastos Formation (Argentina)

Los Bastos Formation is a geologic formation of the Neuquén Basin in the northern Patagonian provinces of Mendoza and Neuquén. The formation dates to the Late Cretaceous, early to middle Coniacian, and belongs to the Río Neuquén Subgroup of the Neuquén Group. The formation overlies the Portezuelo Formation, in which it was formerly included and is overlain by the Sierra Barrosa Formation. Los Bastos Formation comprises mudstones and sandstones deposited in a fluvial environment. A meridiolestid mammal were recovered from the formation.