Volcanoes: Mammoth Mountain & Long Valley Caldera

Volcanoes: Mammoth Mountain &

Long Valley Caldera

Both Mammoth Mountain and Long Valley Caldera are located in Eastern California, very close to the Nevada border. It takes about 6 hours to get from the San Fernando Valley to Mammoth Mountain.

Mammoth, in particular, lies near the Sierra Nevada mountain range – towering and beautiful peaks that are the leftover pieces from huge, ancient volcanoes which used to exist here.

The closeness of Mammoth Mountain and the Long Valley Caldera to the Sierra Nevada has given scientists possible clues to solve the tectonic mystery of how these volcanoes formed.

Some scientists believe that millions of years ago the plate boundary between the North American plate and the Pacific Ocean used to be much farther east than it currently is.
 
This means that California did not exist! And the coast of the Pacific Ocean instead was located on the California-Nevada border – right near where the Sierra Nevada is currently found.

The border between Nevada and the Pacific Ocean formed a convergent plate boundary, where the two plates are coming together or colliding.

There, a subduction zone formed between the North American plate and the Farallon plate (which doesn’t exist anymore).

This zone formed the Sierra Nevada range, and scientists believe that this could also be the mysterious cause of the Mammoth mountain volcano and the Long Valley Caldera.