7,300-year multi-proxy record of the sediment cores TOC 11-04 and TRGC 14-06 from Taro Co, Tibetan Plateau, P.R. China

Here we present results from a paleolimnological study on the currently endorheic Central Tibetan lake Taro Co. We critically compare a record from the central part of the lake to a record from the near-shore area, using multiple proxies of sedimentological and paleoecological (chironomid, diatom, pollen) indicators. The results show three stages of lake-wide ecosystem change (> ca. 5,000, ca. 5,000 to ca. 2,200 and < ca. 2,200 cal. yr. BP) along a continuous drying trend throughout the Mid and Late Holocene. Besides this lake-wide, regional development, we observe two local events in the sediment core from the southeastern part of the lake, including (1) a hiatus between 10,600 and 4,900 cal. yr. BP and (2) a 1,300 year-long period of distinctly different paleoenvironmental conditions (4,900–3,600 cal. yr. BP). We hypothesize that both events were caused by the relocation of a river southeast of the near-shore core location. We propose that the first relocation resulted in an erosion event that removed sediment and caused the hiatus. During the following 1,300 years the core location in the southeastern basin was potentially located on the river delta before another river relocation at 4,000 cal. yr. BP established the modern prodelta situation.