Changing of the Lake Area and Records of Climate and Environment of Barkol Lake During Holocene

Key words: 
• Barkol Lake /
• changing of lake level /
• ancient climate /
• palaeoenvironment /
• Holocene

Abstract: The authors have studied 7 profiles in Barkol Lake and surrounding areas at northern foothills of Barkol Mount in the eastern Tianshan. By means of sedimentary facies analysis, OSL dating, grain size analysis and magnetic susceptibility measurement, the Holocene environmental evolution of Barkol Lakes were reconstructed. The glaciers of the East Tianshan area expanded during Last Glacial Maximum (LGM) at 14 000 a B.P. Water sealed in the glaciers of Barkol Mount, resulting in Barkol Lake shrink to the north to the #1 profile. The glaciers of Barkol Mount were shrank during 8 000~4 000 a B.P. Barkol Lake attained to the largest lake of the expansion since the beginning of the Holocene. The lake expanded to the south of the # 1 section, the  area amounted to  600 km². East Tianshan area was warm and humid during Holocene Optimum at 8 000~4 000 a B.P. subsequently the lake was gradually shrinking. The lakes area was  470 km² at 4 000~2 000 a B.P. and shrank to 380 km² at 2 000~1 000 a B.P.The lakes dried up at around 1 500 a B.P.  Appeared mud flat deposits in the current lake zone, subsequently Barkol Lake came into the small lake with the area changing at about 100km²  when expansion or dry. The changing of lake level of the Barkol was mainly controlled by the summer solar radiation of Northern Hemisphere, which was manifested in the expansion and shrank of the Northern Hemisphere ice sheets. the expansion of the Barkol Mount glaciers in the early Holocene and water injected into Barkol Lake by glaciers shrank in middle Holocene) . The Barkol influenced little by the East Asian summer monsoon, westerly circulation bring limited water to supple the area, which drive the Barkol to the arid environment during middle to late Holocene.