The Great Desert


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On the Jemez Mountains expedition of The Great Desert Workshop, we saw three other types of volcanos. Images from space are c/o Earth Sciences and Image Analysis Laboratory, NASA Johnson Space Center.

Caldera Complex


The Valles Caldera is the type example, the best preserved in the world, of a caldera complex volcano. It is described in excruciating detail on the Valles Caldera pages and on the Valles Caldera Geology pages. This Space Shuttle image is STS062-100-195, c/o NASA.
Yellowstone National Park is on a caldera complex volcano, in fact three of them piled on each other. The most recent is dead-center in this Space Lab orbiter image SL3-121-2357 (c/o NASA). The geology of the Yellowstone calderas is difficult to see from orbit or the air, but detailed field mapping has shown that Yellowstone has collapse calderas, ash-flow tuffs, resurgent domes, and young obsidian domes and flows.



Lava domes form when thick lava squeezes slowly onto the Earth's surface. Lava domes are common in and around caldera complex volcanos, as is this small one (Cerro La Jara) surrounded by grass in the Valles Grande. Lava domes are made of thick obsidian or rhyolite lava, which is much stiffer than the basalt lavas which make cinder cones and shield volcanos. Other domes in the Valles complex are shown on the Valles Caldera pages and on the Valles Caldera Geology pages Credit.
Wilson Butte is a small obsidian/rhyolite dome inside the Long Valley caldera volcano in eastern California. The ponderosa pine trees, for scale, are about 100 feet tall. The image is from the U.S. Geological Survey.

Cone-less Flows


The Banco Bonito flow, centered in this image, is in the Valles Caldera. We saw it from the lunch overlook stop and drove over it on the way to the Valle Grande. The Banco Bonito flow issues from the ground without and obvious cone or hill as its source. Space shuttle image STS062-100-195.
This obsidian flow is inside the Newberry Crater basaltic shield volcano. It apparently erupted in historical times, as there are Indian legends about its formation. It has no obvious dome or other 'volcano' at its source -- it just oozed out of the ground and flowed downhill. Composite of two images taken on the LPI teacher training workshop in 2001 to the Cascade volcanos.Credit.