The tools found were made of obsidian, a type of volcanic glass that is very hard and brittle.
The material was mined in a quarry in Central Oregon, but the place where the remains of the tools were found was 4 thousand km away from the quarry. This is the oldest evidence of the presence of western obsidian in the continental United States. Usually, ancient people used obsidian to create sharp tools.
During the work, the authors studied areas of the relief flooded 8-10 thousand years ago, which were previously inhabited by plants, animals and people, and now are located at the bottom of Lake Huron, one of the Great Lakes of the USA and Canada. At a depth of 32 m, between two hunting buildings, archaeologists discovered two obsidian flakes.
This find is really interesting because it shows how important underwater archeology is. The preservation of ancient underwater monuments is unparalleled on land.
Ashley Lemke, Associate Professor, Department of Sociology and Anthropology, University of Arlington
The Lake Huron find is part of a major study aimed at understanding the social and economic organization of caribou hunters at the end of the last ice age. The water level was then much lower. Scientists have discovered, for example, stone walls of dwellings, which are now at a depth of 30 meters under water.