The geology of three extrusive bodies in central Alaska Range

Abstract

The Buzzard Creek basalt, Jumbo Dome, and Sugar Loaf Mountain occur in the Central Alaska Range. The purpose of this study is to determine the age, nature, geothermal potential, and possible genetic relationships between these igneous bodies. The areas were investigated by mapping, radiometric dating, and petrologic studies. The Buzzard Creek basalt appears to have formed by a maar eruption about 3,000 years ago. Seismic evidence suggests this basalt may be related to current subduction in the area. Jumbo Dome consists of calc-alkaline andesite and is probably Pleistocene in age. Sugar Loaf Mountain is composed of Mid-Tertiary rhyolite. Geochemistry suggests that the Sugar Loaf Mountain rhyolite and Jumbo Dome andesite may also be subduction-related. Differences in age and geochemistry indicate there is no genetic relationship between the rocks of the three areas. The ages, type of volcanic features', and snow melt patterns suggest that these three areas have low geothermal potential.