POTENTIAL COOL WATER ORIGINS OF A PERMIAN CARBONATE UNIT IN THE ALEXANDER TERRANE, ALASKA

In the Alexander terrane in the Prince of Wales region of Alaska, an overlooked, unammed Permian carbonate unit crops out on the eastern shore of Suemez Island. The first mention of the unit appears in Buddington and Chapin’s United States Geological Survey Bulletin 800 from 1929, but the unit was only mentioned -- not measured, described, or mapped. Fieldwork conducted in the summer of 2015 involved measuring and collecting fossil/lithological samples of the Permian section. The section has been measured where exposed, described, and the taxa are being identified and cataloged. Preliminary results indicate the Permian unit is a slightly-folded, blue to gray limestone with cool or cold water origins that has undergone pervasive silicification. Macro-fossils are sparse but include bryozoans and brachiopods. The bedding in the unit may indicate seasonal storm events where macro-fossils are concentrated in beds with a chaotic orientation and a possible mixing zone of both siliceous and carbonate materials from the shelf slope. Utilizing the fossils and sedimentary structures, correlation of the overlooked unit to other Permian units in the Alexander terrane is possible. The research provides information about depositional environments, the paleoecology, and the paleoclimate of the Permian unit.