Trace element copper distribution and areal geology in a portion of the Clearwater Mountains, Alaska

Abstract

The study concerns that portion of the Clearwater Mountains defined by north latitudes 63' 03' and 63' 08' and west longitudes 147' 09' and 147' 30'. Outcrop within the area consists predominantly of a sequence of intercalated andesitic and basaltic flows. Sedimentary rocks are present but comprise a very small percentage of the total section. Dikes and a small pluton are also present. The prevailing attitude of the volcanic and sedimentary rocks is east-northeast with a consistent north dip. A Triassic age is accepted for the volcanic and sedimentary rocks. Areal and local sampling indicates that all rock types are abnormally high in trace copper content, and average background is 1000 ppm. Copper distribution suggests a syngenetic origin. Frequent small copper deposits crop out along the north side of the area. The deposits are epigcnctic and are structurally controlled. The origin of these deposits may have potential exploration significance.