Determining local marine reservoir effect ΔR correction factors for Cuba

Summary

The atmosphere constantly produces radiocarbon, 14C, which dissolves in the oceans as carbon dioxide. Theoretically, radiocarbon concentrations are equilibrated between the atmosphere, hydrosphere, and biosphere. However, in some regions old seawater at the bottom of the oceans returns significantly older radiocarbon dates as water sinks down the water column, causing the isotopic decay of 14C to increase with depth. This creates a delay of ~200-500 years for the atmospheric carbon to be completely distributed through the ocean’s water column, producing the Marine Reservoir Effect (MRE). This results in different radiocarbon content between terrestrial and marine organisms. In a local context, coastline shape, ocean bottom topography, currents, trade winds, and local climate, control the upwelling and mixing of deep and surface water. Radiocarbon dates obtained from biogenic calcite and aragonite precipitated from these mixed waters reflects a unique regional age variance, known as its ΔR value. Therefore, in areas of upwelling, marine carbonates are 14C deficient and return radiocarbon dates that may be significantly older or younger than terrestrially dated materials of the same age. This study examines the local MRE and the associated ΔR correction factors for Cuba and discusses the implications of these for some Cuban archeological sites.

This Resource is Part of the Following Collections

• Society for American Archaeology 82nd Annual Meeting, Vancouver, BC (2017)

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Record Identifiers

Abstract Id(s): 17174