REGIONAL STRATIGRAPHY, K-AR AGES, AND TECTONIC IMPLICATIONS OF CENOZOIC VOLCANIC-ROCKS, SOUTHEASTERN CALIFORNIA

This paper presents the results of regional mapping, petrography, and major-element chemical analyses of the volcanic rocks of southeastern California along with 32 newly obtained K-Ar age determinations. The authors, studies of volcanic clasts in sedimentary deposits along the San Andreas fault (and their possible tectonic significance) are still in progress. Volcanic and volcaniclastic rocks of early-to-mid Cenozoic age crop out within linear mountain ranges of southeastern California, east of the San Andreas fault. Regional mapping and 32 newly obtained K-Ar age determinations disclose a tripartite stratigraphic division of major volcanic rock units at individual volcanic centers.