INTERDISCIPLINARY PERSPECTIVES OF TANA VOLCANO, HUMAN-ENVIRONMENT INTERACTIONS AND PREHISTORIC RESOURCE ACQUISITION THROUGHOUT THE HOLOCENE, ALEUTIAN ISLANDS, AK

An interdisciplinary team of archaeologists, paleoecologists, geologists and undergraduate students spent twenty-day field seasons on the Islands of Four Mountains in 2014 and 2015 to investigate how climate change, geologic hazards, and ecosystem resources affected the Unangan peoples who inhabited these islands by at least 3,400 years BP. In turn, the investigated archeological midden deposits record how humans impacted the ecosystem and utilized stone resources between the punctuation of volcanic eruptions. Faunal remains and a nearby peat bog core that contains tephras will provide greater detail of the human-ecosystem relations through the millennia of the occupations. Through our investigation on Chuginadak Island we provide the first evidence of the history of Tana volcano, its glaciation, and that this provided lithic resources to villages established on this island. In contrast to its near and currently active neighbor Mt. Cleveland volcano, the Plio(?)-Pleistocene edifice of Tana volcano consists primarily of silicic andesite and dacite (62-67 wt.% SiO₂) though later volcanic activity was mafic (49.5 wt. % SiO₂). Active fumaroles and hot springs as well as stratigraphic relationships and geomorphology suggest that the latest volcanic activity of Tana likely occurred in the Holocene. Extensive hydrothermal alteration of the volcanic edifice created a variety of cryptocrystalline silica (e.g., opal and jasper) that subsequent glaciation distributed in glacial tills and streambeds. Although a minor constituent of the cultural lithic debitage, rare flakes of gray opal testify to its use in the making of stone tools in prehistory.