Lake Heihai is located about south of the city of Golmud in Golmud County, Haixi Prefecture, Qinghai Province, at an elevation of or above sea level in western China. It lies in a valley roughly long and wide between the Kunlun Mountains to the south and the Burhan Buda to the north. Earthquakes are common, as the lake lies near the major long Kunlun Fault. Covering, it stretches about from east to west and north to south. The deepest point is around below its surface. Two main streams feed into the lake, with a catchment of around. Meltwater flows from two small glaciated areas in the Kunluns. The west is about, the east about ; both appear to have retreated roughly since 1970. The outflow to the east is the source of the Kunlun River, the upper stretch of the Golmud River. With mean annual precipitation of and high evaporation rates, the lake's water is mesohaline. The mean annual temperature is, so much of the surrounding countryside is permafrostalpinegrassland, supporting dwarf cinquefoil and winterfat shrubs and sparse sedges and grasses. Polygonum sibiricum occupies moist saline sites close to the lake; drier land further from shore is characterized by Kobresia robusta on the sandier north side and Poa pachyantha on the south side.
History
During the Pleistocene, sediment from glaciers in the Kunlun temporarily blocked outflow of the valley's main meltwater stream, forming the present lake. Particularly strong winds weathered and shaped the surrounding rocks from 10080,000 years ago. At its maximum extent, an Ice Age glacier filled most of the present valley, which increased its catchment about. At times, probably around 50 kya, 13 kya, and 11.6 kya, Lake Heihai overflowed the present elevation difference to join with the smaller lake to its west, increasing its catchment by another and leaving lacustrine sediments across of now-dry land. During the mid-Holocene, from around 84,000 years ago, the climate was wetter and warmer, possibly from increased influence from the Indian or East Asian monsoon. By the late Holocene, the monsoon was no longer able to reach the lake and its environment became drier and windier again.
Culture
As the largest present lake in the Kunlun Mountains, it has become identified with the "Jade" or "Turquoise Pond" important in various myths involving the Queen Mother of the West. Lake Heihai has a stone temple to the Queen Mother and a large slab reading "Xiwangmu Yaochi".
