GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 260-3
Presentation Time: 9:00 AM-6:30 PM


LEWIS, Angela R.1, BEBBER, Michelle R.2, EREN, Metin2 and WILLIAMS, Jeremy C.1, (1)Department of Geology, Kent State University, PO Box 5190, Kent, OH 44242-0001, (2)Department of Anthropology, Kent State University, PO Box 5190, Kent, OH 44242-0001

Chert forms from biologically or inorganically induced aqueous precipitation of silica. Central Ohio chert formed in marine limestone from the Lower Pennsylvanian Upper Mercer member of the Pottsville formation and Middle Pennsylvanian Vanport member of the Allegheny Formation (323 – 315 Ma) were readily available used by prehistoric people to make stone tools. Chert stone tools recovered from Northern and Central Ohio were analyzed for major elemental composition and compared to tool types and loss on ignition (LOI). Generally high SiO2 wt. % corresponded with LOI values of 4% or less. Stone tools from Northern and Central Ohio (R2 = 0.55, n = 185) were more similar to cherts from the Upper Mercer than from other chert formations in Ohio. Non-silicate portion of greater than 2% LOI samples were composed of predominately Fe2O3, CaO, and Al2O3 which were statistically significantly from each other (H = 19.912 p = 0.000, H = 19.245 p = 0.000 and H = 4.694, p = 0.030, respectively). High and low CaO groups were not statistically significant for Fe2O3 (H = 0.847, p = 0.358) although high CaO samples contained low amounts of Fe2O3 and low CaO had high amounts of Fe2O3 Tools recovered from the Welling site in Central Ohio had the largest proportion of high SiO2 wt. % (at least 90 wt %) and less than 2% LOI, and were therefore better quality tools compared to stone tools from Northern Ohio. Lack of abundant, readily accessible chert in Northern Ohio suggests stone tools were more likely to have originated in Central Ohio and transported north by prehistoric people. The most abundant non-silicate oxides in all the stone tools were Fe2O3, Al2O3 and CaO. Parent limestone likely supplied the majority of CaO and at least some Fe2O3, while Al2O3 accumulated as a weathering byproduct. Inverse distribution of CaO and Fe2O3 could indicate differences in the original limestone material or separate chert formation mechanisms that formed the nodular and bedded chert present in the Upper Mercer. High and low CaO chert were present in tools from both Central and Northern Ohio so CaO variation could have been present in either the same prehistoric quarry near the Welling site or from separate quarries in other regions of the Upper Mercer. Positive correlation of tool type, CaO and Fe2O3 with LOI could indicate increased tool quality in the absence of parent material.