(Table 1) Different age analysis from sediment cores XP98-PC-4 and XP98-PC-2

• Main Authors: Seki, Osamu, Kawamura, Kimitaka, Ikehara, Minoru, Nakatsuka, Takeshi, Oba, Tadamichi
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2004
• Subjects: Event label; DEPTH, sediment/rock; Gear; Age model; Piston corer; Age, 14C AMS; Okhotsk; Pacific; okhotsk sea
• Online Access: https://dx.doi.org/10.1594/pangaea.802149; https://doi.pangaea.de/10.1594/PANGAEA.802149

Sea-surface temperatures (SSTs) in the Sea of Okhotsk were reconstructed based on alkenone unsaturation indices in two sediment cores. Alkenone-SSTs were found to range from 3 to 9 °C over the last 85 kyr with higher SST values in warm periods: Holocene and the oxygen isotope stage (OIS) 5a. In the last glacial periods (OIS 4 and 3), average alkenone SST was estimated to be 4 °C, which was 4 °C lower than the Holocene on average. However, alkenone SSTs around the last glacial maximum (LGM) are as high as those of the Holocene. The variation patterns of U37K' in the Okhotsk Sea were found to be similar to those reported in the Sea of Japan [Org. Chem. 32 (2001) 57] over the last 30 kyr, although the SSTs were lower in the Sea of Okhotsk. The higher U37K' values around the LGM may be a rather common phenomenon in semi-closed marginal seas such as the Japan Sea and the Okhotsk Sea, which are both adjacent to the northwestern Pacific. Such an anomaly in the LGM may have been caused by either a seasonal shift of coccolith blooming or a contribution from a different strain or species that produces alkenones : AMS: 14C ages by accelerator mass spectrometer; OIS: ages were estimated by oxygen isotope stage events;MS: ages were estimated by comparison of magnetic susceptibility in that of PC-2 dating of the ash layer was determined by comparison of PC-2 with PC-1 sediment core.