Evaluating the size and extent of paleolakes in central Tibet during the late Pleistocene

Subhorizontal lake shorelines allow a geodynamic test of the size and extent of a hypothesized paleolake in central Tibet, the East Qiangtang Lake (EQL), during the last interglacial period (marine isotope stage (MIS) 5e). Reconstructions based on relict lake deposits suggest that the EQL would have been similar to 400m deep and over similar to 66,000km(2). Models of flexural rebound driven by lake recession predict that shorelines near the EQL center, at the present-day location of Siling Co, would have rebounded 60-90m above their initial elevation. New Cl-36 chronology of the highest relict shorelines around Siling Co indicates that they reflect lake levels between 110 and 190ka. These shorelines, however, are presently >300m below their predicted elevations, implying a substantially smaller water load. Our results reveal that the expansion of Tibetan lakes during MIS 5e was relatively limited. Instead, individual lakes were supplied by river networks, much as they are today.