Mid-late Holocene variability of TEX86 temperature on the inner shelf of the East China Sea

To understand the long-term environmental evolution of the East China Sea (ECS) and adjacent areas, decadal sea surface temperature (SST) induced by TEX86 (tetraether index of tetraethers consisting of 86 carbons) index was reconstructed in Core T08 on the inner shelf of the ECS over the past 3725 years. Core-top TEXH86 temperature was 23.2 °, close to the mean annual SST 22.9 ° at Site T08. BIT (branched and isopreniod tetraether) index and GDGT-0/GDGT-5 ratio indicated that the influences of terrestrial input and methanogens were negligible on TEX86 index, respectively. During the period of 3725-2000 yr BP, TEXH86 temperature had low values, fluctuating around 20 °, which suggested the weakened Kuroshio Current (KC) or the eastward shifting of the KC axis. From 2000 to 750 yr BP, TEXH86 temperature gradually increased to 23 °, indicating enhanced KC influence on Site T08. Significant reduction of TEXH86 temperature around 400 yr BP corresponded to Little Ice Age (LIA). Spectral analysis reveals that TEXH86 temperature series exhibit 175, 80, and 68-year periodicities, consistent with the characteristic periodicities of solar activity.