Xu et al., Glycerol dialkyl glycerol tetraethers in surface sediments from three Pacific trenches

We used HPLC-MS to analyzed core Glycerol dialkyl glycerol tetraethers (GDGTs) in three Pacific trenches, namely New Britain Trench, Kermedec Trench and Atacama Trench. Our data suggests that sedimentary organic matter in three trenches is mainly derived from marine organic matter. However, the higher BIT index, lower pentamethylated/hexamethylated brGDGT and more negative δ13C support the enrichment of terrestrial OC at trench axis compared to adjacent non-hadal sites. The application of TetraEther indeX of tetraethers consisting of 86 carbon atoms (TEX86) results in sea surface temperature (SST) of 18.9–23.7 oC in KT, 28.6–30.2 oC in NBT and 17.9–20.4 oC in AT that are close to in-situ observation SST with a mean deviation of 1.1±1.4 oC over the past ca 130 years. Thus, TEX86 still appears valid as a paleo-SST proxy in the hadal environments.<br>