Long Valley Caldera

Cinder Cones in the Long Valley Area, California

Several small cinder cones are located on the floor and rim of Long Valley caldera.

The youngest cones in the area include Red Cones 5 km (3.1 mi) south of Mammoth Mountain and Black Point on the north shore of Mono Lake. Geologists estimate that Red Cones may have erupted as recently as about 8,000 years ago and Black Point about 13,000 years ago. The other cones on the caldera floor and along the rim range in age from 190,000 to 17,000 years.

Small red cinder cone perched on the west wall of Long Valley Calde...

Small red cinder cone perched on the west wall of Long Valley Caldera, viewed from the top of Mammoth Mountain toward the north.

(Credit: Brantley, S. R. Public domain.)

Small red cinder cone erupted on top of Mammoth Crest, viewed from ...

Small red cinder cone erupted on top of Mammoth Crest, viewed from Horseshoe Lake toward the south-southwest.

(Credit: Wieprecht, D. E. Public domain.)

​​​​​​​

Red Cones (lower left) viewed from atop Mammoth Mountain toward the...

Red Cones (lower left) viewed from atop Mammoth Mountain toward the southwest.

(Credit: Brantley, S. R. Public domain.)

Red Cones near Mammoth Mountain, viewed from the air toward the eas...

Red Cones near Mammoth Mountain, viewed from the air toward the east-northeast.

(Credit: Miller, C. D. Public domain.)