Holocene temperature reconstruction in the central of Tibetan plateau: evidence from alkenones and GDGTs

Holocene temperature changes have been more controversial due to the strong discrepancy between global temperature reconstruction and climate modeling. It requires reliable and quantitative temperature records across the world to understand Holocene temperature conundrum. The polyunsaturated long-chain alkenones (LCAs) and glycerol dialkyl glycerol tetraethers (GDGTs) serve as proxies for paleotemperatures in lake and ocean sediments. However, the extent and differences of temperature variability using these two proxies is not well understood. Tibetan plateau is highly sensitive to global climate changes due to its high average elevation (> 4000 m), but few quantitative records are available on the plateau to assess its sensitivity to climate forcings. Here, we present records at a Holocene sediment core at a lake on the Tibetan Plateau to investigate how LCAs and GDGTs respond to climate forcings during the Holocene. Our results show that both LCAs and GDGTs could quantitatively reconstruct temperature variability during the Holocene and display similar variation. However, the amplitude of GDGTs-based temperature records is much larger than that of LCAs, which could be attributed to the difference in the niche for the producers of LCAs and GDGTs. The results also suggest that it should be extremely careful to examine the mechanisms for the biological proxies during the process of global reconstruction.