PROTEROZOIC CRYSTALLINE ROCKS IN THE WET MOUNTAINS AND VICINITY, CENTRAL COLORADO

 

JEFFREY B. NOBLETT¹, ROBERT L. CULLERS², AND M. E. BICKFORD³

¹Colorado College, Colorado Springs, Colorado 80903; ²Department of Geology, Kansas State University, Manhattan, Kansas 66506; ³Department of Geology, University of Kansas, Lawrence, Kansas 66045

 

 

Abstract—The oldest rocks in the Wet Mountains were metamorphosed about 1700 m.y. ago. They include biotite gneiss, granitic gneiss and amphibolite together with minor occurrences of charnockitic gneiss, quartzite and other units. The metamorphic rocks were intruded by late tectonic granitic rocks of the Crampton Mountain-Twin Mountain batholith and Garell Peak stock during the Boulder Creek intrusive event about 1700-1650 m.y. ago. A second major period of intrusion (Silver Plume event) occurred about 1400 m.y. ago and produced numerous granitic plutons including those at Williams Creek, Oak Creek and West McCoy Gulch. The youngest of these intrusions is the 1360 m.y. San Isabel batholith. Proterozoic rocks in the Wet Mountains were brought to the surface during Phanerozoic faulting and folding.