Applications of TEX86 and MBT/CBT indices to paleotemperature estimations in Holocene sediments from the Chuktchi Shelf

Paleotemperature estimation is required to understand environmental changes in the Arctic region. We investigated the molecular distribution of glycerol dialkyl glycerol tetraethers (GDGTs) to explore possibilities in the paleotemprature estimation in the Chuktchi-Alaskan margin sediments. We analyzed selected samples from cores HLY0501-JPC5 and HLY0501-JPC8 retrieved during the leg 1 of the Healy-Oden Trans-Arctic Expedition (HOTRAX) of 2005. The regioisomer of creanarchaeol was not detected in all the analyzed samples. This is the unique character specific in sediments from this region. We try to apply several calibrations proposed by Kim et al. (2008) and Kim et al. (2010) to estimate paleotemperatures from GDGT compositions and found that the GDGT-1 (TEX86L) calibration of Kim et al. (2010) gives the most probable values. We also apply MBT/CBT index to estimate paleo-air temperatures. The calibration based on the world soils by Wijers et al. (2008) gives the most probable values. We thus are optimistic about temperature estimates using TEX86 and MBT/CBT indices in the Chukchi-Alaskan margin.