GEOLOGIC MAP OF THE BEARWALLOW MOUNTAIN 7.5’ QUADRANGLE, CATRON COUNTY, NEW MEXICO
The quadrangle is comprised of late Oligocene rhyolite and ash-flow tuffs of the Fanney Rhyolite and the Deadwood Gulch member, and andesite to basaltic lava flows of the Mineral Creek and Bearwallow Mountain andesites. Three normal faults orientations are observed within the quadrangle. Normal faults associated with the Bursum caldera, are east-west and northeast-southwest trending. These faults are the result of the collapse of the caldera. Fanney Rhyolite lava flows are oriented along these faults and host secondary mineral deposits. North-south trending faults dipping to the west are younger and are the result of extension related to the Basin and Range to the west. Andesitic to basaltic lava flows of the Bearwallow Mountain Andesite cover the northern section of the quadrangle and postdate normal fault activity. Radial dikes within the Bearwallow Mountain Andesite suggest a volcanic center located at Bearwallow Mountain.
We present a new geologic map of the Bearwallow Mountain 7.5’ quadrangle at 1:24,000 scale, supported by stratigraphic sections, cross sections, and magnetic and very low frequency electromagnetic surveys. We provide an improved geologic framework for understanding the Bursum caldera collapse structure, post-collapse extension, and the possibility of economic deposits related to the Mogollon Mining District.