HOLOCENE ENVIRONMENTAL AND CULTURAL TRANSITION IN IFRI OUDADANE, NE MOROCCO, INFERRED FROM OXYGEN STABLE ISOTOPES OF THE TOPSHELL PHORCUS TURBINATUS

Ifri Oudadane, located in NE Morocco, is a recently discovered and excavated coastal archeological site that records the shift from an Epipaleolithic hunter-gatherer lifestyle (~10.8 - 7.6 ka cal BP) to Neolithic food production (~7.6 - 6.3 ka cal BP). Prehistoric humans heavily collected and consumed Phorcus turbinatus (Gastropoda: Trochidae) throughout this transitional cultural period. These well-preserved gastropod shells offer an excellent opportunity to determine whether or not such cultural transition could have been in part associated with an environmental shift in the Mediterranean Maghreb. The present work reconstructs Holocene paleotemperatures from the oxygen stable isotopes of archeological shells ranging in age from ~10.8 to ~6.3 cal ka BP. Shell margin results suggest that even though shellfish were collected year-round at all cultural periods, sea surface temperatures were, on average, 1.2°C cooler during the Epipaleolithic than during the Early Neolithic B. Intrashell isotopic results along ontogeny also illustrate significantly cooler shell growth temperatures during the Epipaleolithic than during the Early Neolithic in the study area. This study supports the idea that the investigated transitional cultural period in Northwest Africa was plausibly caused or reinforced by local environmental change.