Long Valley Caldera

Resurgent Dome in the Long Valley Caldera, California

The resurgent dome is a broad area of the central caldera floor that was pushed upward within 100,000 years or less of the caldera-forming eruption 760,000 years ago.

Most of this about 400 m (1300 ft) of uplift was caused by upward pressure related to the intrusion of rhyolite sills into the Bishop Tuff. The resurgent dome is made of layers of lava flows, tephra, and pyroclastic flows that were erupted onto the caldera floor soon after the caldera formed. The uplift arched and faulted these volcanic rocks to form a central highland area about 10 km (6.2 mi) in diameter and as high as 500 m (1,640 f) above the surrounding caldera floor.

Resurgent dome in Long Valley caldera, viewed toward the east-south...

The high point of the resurgent dome in the left center is Gilbert Peak. The west moat of the caldera forms the lowland in the foreground.

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

Resurgent dome in Long Valley caldera (dark, tree-covered hills in ...

This photograph of the resurgent dome was taken from along the Lake Mary Road between the town of Mammoth Lakes (middle foreground) and the Lakes Basin. Glass Mountain is the high point on the northeast rim of Long Valley caldera (skyline on left), and the White Mountains form the skyline on the right side of the photograph.

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