Bottom sediments in siling-co in central Tibet reveal that late in the last glacial period the area around the lake was arid, water inflow was small and the level of the lake was low. In the early postglacial period it become markedly humid and the water level rose rapidly because of large inflows from surrounding basins. The climate was humid and the level of the lake high during the hypsithermal. At about 2000--4000 yr B.P. it again become arid within a short time and the water level dropped sharply. After this short arid interval and low water level, it again become humid and the water inflow increased sharply. Large inflows continued for a time after which it again began to get arid. ¿American Geophysical Union 1991