PETROLOGY OF AZURE MOUNTAIN, ADIRONDACK MTS., NY

Azure Mountain, located near the hamlet of Santa Clara in the Adirondacks, is a popular hiking destination with a summit elevation of 2,518 ft. The mountain is the site of one of the region’s more well known glacial erratics, which is located on the southwest face of the summit. The purpose of this study was to investigate the petrography of both the mountain and the glacial erratic it hosts in order to better understand their petrology and determine if the glacial erratic was transported from some other rock unit or was derived from a local source. The mineral assemblage is fairly consistent from the base to the summit of the mountain, with variations only in modal percentages: potassium feldspar (orthoclase and microcline), quartz, plagioclase feldspar, hornblende, clinopyroxene, biotite, garnet, hematite, ilmenite, apatite and zircon. Much of the kspar is perthitic. Microprobe analysis shows the clinopyroxene is hedenbergite, and the garnet is almandine. No zoning was detected in the garnet. Compositionally, the rock is granite, part of McLellands AMCG suite for the Adirondacks. A similar mineral assemblage for the glacial erratic indicates its source is local.