Marine Reservoir Effect and Its Influence on Radiocarbon Dating of Human Bones from Coastal Sites: A Case Study from the Dakou Site on Tuoji Island, Shandong

Abstract

The marine reservoir effect (MRE) can cause the radiocarbon dates of marine-derived samples and populations with long-term marine-based diets to appear older than their true calendar ages. To date, its impact on the radiocarbon dating of coastal archaeological sites in China remains underexplored. To address this gap, this study focuses on the Dakou site on Tuoji Island, Shandong. We applied radiocarbon dating and stable carbon and nitrogen isotope analysis of bone collagen to human remains from the site’s Longshan and Yueshi culture burials. Isotopic results revealed high δ ¹⁵ N values, demonstrating the population’s extensive exploitation of marine resources. Therefore, without targeted corrections, their skeletal radiocarbon dates exhibited an age offset of over 250 years, contradicting the typological sequence of the pottery grave goods. To accurately correct for this age offset, this study applied the global Marine20 curve alongside the Qingdao regional parameter (ΔR _QD =−234±60). At a 95.4% probability, the recalibrated chronological ranges securely span 2285–1564 cal BCE for the Phase I (Longshan culture) burials and 2046–1482 cal BCE for the Phase II (Yueshi culture) burials. Ultimately, this study establishes the essential methodological requirement of MRE correction for prehistoric coastal populations.