Los Pinos Formation

The Los Pinos Formation is a volcaniclastic geologic unit in northern New Mexico, exposed mainly in the Tusas Mountains and extending into parts of the southwestern San Luis Basin. Deposited from the late Oligocene into the late Miocene, it preserves sediments from volcanic erosion along with interbedded tuffs and basalt flows. Its two penecontemporaneous members record different source regions: the Esquibel Member contains mostly intermediate volcanic debris from the San Juan volcanic field to the north, while the Cordito Member is dominated by rhyolitic material from volcanic sources to the east. The formation is an important record of volcanic erosion, sediment transport, and basin development in north-central New Mexico.

New Mexico · United States