Geology of the Chiricahua Mountains

Cochise College                                             
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Roger Weller, geology instructor

wellerr@cochise.edu    last edited:  5/8/08

Chiricahua Mountains

general geology
 

The Chiricahua Mountains are geologically similar to neighboring ranges to the east in New Mexico. These ranges are largely made up of Tertiary volcanics, including rhyolitic ash-flow deposits, rhyolitic to basaltic flows, and associated breccias. The volcanic deposits are part of a large volcanic field, which includes the Chiricahua Mountains, the central and southern Peloncillo Mountains, and the Animas Mountains.

Six major ash flows and a capping rhyolitic volcanic flow make up the Rhyolite Canyon Formation in the Chiricahua Monument region. The ash flows are distinguished from each other by their color, jointing, texture, phenocrysts, composition, and weathering characteristics.  A light brownish gray welded rhyolitic tuff and a brittle, pinkish-gray welded rhyolite tuff are the only rocks forming prominent columns in the Monument.  The light brownish gray, column-forming, welded rhyolite tuff has been radiometrically age dated at about 25 million years old.
 

maps

Maps of the Chiricahua Mountains 

views
Views of the Chiricahua Mountains

references
Published references related to the Chiricahua Mountains
 

student presentations on the Chiricahua Mountains
Hiking in the Chiricahua National Monument, Arizona-Vivian Lewis  (Fall 2005)
The Chiricahua National Park, Arizona-Kim McGee  (Fall 2005)
A View of the Chiricahua Mountains: From the Air-Charles Garrett  (Spring 2006)