A similar to 30,000-year record of environmental changes inferred from Lake Chen Co, Southern Tibet

• Published in: Journal of paleolimnology 2009-10, Vol.42 (3), p.343
• Main Authors: Zhu, Liping, Zhen, Xiaolin, Wang, Junbo, Lü, Houyuan, Xie, Manping, Kitagawa, Hiroyki, Possnert, Göran
• Format: Article
• Language: English
• Subjects: 000 years; Earth sciences; Environmental changes; Geovetenskap; Ion Physics; Jonfysik; Lake sediments; NATURAL SCIENCES; NATURVETENSKAP; Tibetan Plateau
• ISSN: 1573-0417; 0921-2728
• DOI: 10.1007/s10933-008-9280-9

Climatic and environmental changes since the last glacial period are important to our understanding of global environmental change. There   are few records from Southern Tibet, one of the most climatically   sensitive areas on earth. Here we present a study of the lake sediments   (TC1 core) from Lake Chen Co, Southern Tibet. Two sediment cores were   drilled using a hydraulic borer in Terrace 1 of Lake Chen Co. AMS C-14   dating of the sediments showed that the sequence spanned > 30,000   years. Analyses of present lake hydrology indicated that glacier melt   water is very important to maintaining the lake level. Sediment   variables such as grain size, TOC, TN, C/N, Fe/Mn, CaCO3, and pollen   were analyzed. Warm and moderately humid conditions dominated during   the interval 30,000-26,500 cal year BP. From 26,500 to 20,000 cal year   BP, chemical variables and pollen assemblages indicate a cold/dry   environment, and pollen amounts and assemblages suggest a decline in   vegetation. From 20,000 to 18,000 cal year BP, the environment shifted   from cold/dry to warm/humid and vegetation rebounded. The environment   transitioned to cold/humid during 16,500-10,500 cal year BP, with a   cold/dry event around 14,500 cal year BP. After 10,500 cal year BP, the   environment in this region tended to be warm/dry, but exhibited three   stages. From 10,500 to 9,000 cal year BP, there was a short warm/humid   period, but a shift to cold/dry conditions occurred around 9,000 cal   year BP. Thereafter, from 9,000 to 6,000 cal year BP, there was a   change from cold/dry to warm/humid conditions, with the warmest period   around 6,000 cal year BP. After 6,000 cal year BP, the environment   cooled rapidly, but then displayed a warming trend. Chemical variables   indicate that a relatively warm/dry event occurred around 5,500-5,000   cal year BP, which is supported by time-lagged pollen assemblages   around 4,800 cal year BP. Our lake sediment sequence exhibits   environmental changes since 30,000 cal year BP, and most features agree   with records from the Greenland GISP2 ice core and with other sequences   from the Tibetan Plateau. This indicates that environmental changes   inferred from Lake Chen Co, Southern Tibet were globally significant.