C01_P10

Optically stimulated luminescence dating of marine sediments from the Bering Sea

Sugisaki S¹, Buylaert J, Murray A³, Uchida M⁴, Stephan R⁴, Mantoku K⁴, Sakai S⁵, Harada N⁶, Tada R⁷

¹Geological Survey of Japan, AIST, Tsukuba, Japan, ²Department of Physics, Technical University of Denmark, Roskilde, Denmark, ³Nordic Laboratory for Luminescence Dating, Department of Earth Sciences, Aarhus University, Roskilde, Denmark, ⁴Earth System Division, National Institute for Environmental Studies, Tsukuba, Japan, ⁵Biogeochemistry Research Center, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan, ⁶Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan, ⁷Institute for Geo-Cosmology, Chiba Institute of Technology, Narashino, Japan

Marine sediments contain important archives of past ocean and climate changes, but at high latitudes, such as the polar regions, the absence of carbonate has prevented the construction of accurate chronological models. To establish an age model, a method which does not rely on carbonate is needed. Optically stimulated luminescence (OSL) dating makes use of the omnipresent quartz and feldspar grains in the sediment so there is no limitation in the presence of the dosimeter.

In this study, we have investigated the potential of fine-grained (4-11 µm) quartz OSL dating to establish a chronology for deep sea sediment core (MR0604 PC23A, 60˚09.52’N, 179˚27.82’W, water depth of 1,002m) from the Bering Sea. In addition, we check the accuracy of OSL ages by comparison with AMS ¹⁴C dating on planktonic foraminifera and with marine oxygen isotope stratigraphy where possible.

The obtained OSL ages are in good agreement with AMS ¹⁴C ages during Younger Dryas (YD) and Heinrich Event H0, however, there is an offset between the OSL and AMS ¹⁴C ages during MIS 3. Our study confirms that OSL dating using fine-grained quartz that is distributed all over the ocean has great potential in the establishment of an absolute chronology for deep sea sediments.