Accelerator Mass Spectrometry Dating of Meadowcroft Rockshelter Maize

Abstract

The Meadowcroft Rockshelter in southwestern Pennsylvania is best known for its pre-Clovis occupation. Potentially important for later times is the recovery of maize macrobotanical remains from higher strata dating as early as the 4th century BC based on radiometric radiocarbon (14C) dates on wood charcoal. These remains have been considered to be potentially as old as the earliest microbotanical evidence for maize in Michigan, New York and Québec recovered from directly dated charred cooking residues adhering to pottery. The results of accelerator mass spectrometry (AMS) dating 17 samples from maize specimens from all Meadowcroft strata producing maize, indicate that the specimens originated from historical use of the shelter, most likely after AD 1800. These results further emphasize the need to obtain direct dates on maize macrobotanical remains recovered from early contexts prior to the development and common use of AMS dating.

The Eads earthwork: Implications for Hopewell ceremonialism

“…However, recent direct AMS radiocarbon dating of Middle Woodland maize kernels postdate CE 900 (Simon et al ., 2021). The earliest known Middle Woodland maize cob reported from the Meadowcroft rockshelter postdates CE 1800 (Hart and Adovasio, 2022). Therefore, it is more likely that the Green Corn ceremony is a post-Hopewell syncretism with an Ancestral Algonquian summer solstice ceremony, which occurred with the diffusion of maize into the Ohio River valley.…”