Hydration rate of Hopewell obsidian in Ohio

Abstract

Evidence indicates that obsidian hydration rate dating can be used to date the time of exposure of a fresh surface of obsidian. An estimated site temperature constant for Ohio and constants derived by artificially hydrating obsidian from the same source as the obsidian found in Ohio were used to determine that obsidian from a Hopewell mound in Ohio was chipped 227 ± 62 AD. This date corresponds to radiocarbon dates of 230 ± 80 AD and 280 ± 55 AD from a Hopewell occupation site near the mound.