2:30 PM - 2:45 PM
[HQR04-09] Geochemical character of Quaternary tephra beds in sediment cores from IODP site U1344 in the central Bering Sea
Keywords:Bering Sea, deep-sea sediment core, tephra
The sediment core U1343, at 259 km southeast of the site U1344, which age model on the basis of the oxygen isotopic stratigraphy was established during the last 2.4 m.y. (Asahi, et al., 2014) has twenty-one tephra layers (Aoki. et al., 2012; 2015). The site U1344 located at more north of the Bering Sea and far from the supposed origins, such as the volcanic belts on the Kamchatka Peninsula, the Aleutian Islands, and the Alaska Peninsula. Therefore, we analyzed the small particles of volcanic glass shards under the 63-micrometer size and over 45-micrometer size in twenty-six samples by additions. The sample of 230.01m - 230.03 m (0.500 m.y.) includes many volcanic glass shards seemed to be deposited as cryptotephra.
We present the consideration on tephra correlations between the sediment cores at the site of U1344 and U1343 and the geochemical character of Quaternary tephra in the center of Bering Sea.