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The Lake Huangqihai sediments in organic matter and organic carbon isotope studies of paleoclimate significance

Author: WangXiaoYan
Tutor: YuJunQing
School: Qinghai Institute of Salt Lakes , Chinese Academy of Sciences
Course: Geochemistry
Keywords: Lake Huangqihai Lakebed cores Organic matter Carbon isotope Postglacial climate change
CLC: P593
Type: Master's thesis
Year: 2000
Downloads: 285
Quote: 4
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Abstract


Types of lakes located in different climatic zones and ecological environment is an important window of human observation and understanding of global change in the past, predict the future ecological environment trends. In recent years, the lake sedimentary organic matter and stable carbon isotope (δ 13 C org ) is used to obtain the regional climate and environmental change information in the rapid development of domestic and foreign achievements is attention. Stored in the various lake core δ 13 C org records reveal atmospheric CO 2 concentration changes since the late Pleistocene, the lake level fluctuations in the Lake District of ecology and vegetation changes, and changes in regional temperature and other environmental information. Each of the three 11-meter-long core pillar drill from the Nei Mengcha right front the flag Huangqihai lakes central deepwater area, a multidisciplinary comprehensive testing and research is ongoing. This paper focuses on the part of the research report on HQH4 hole core. Through the study of the hole core of organic matter (OM) content and δ of 13 C org , explore the shallow-water the closed lake sediments in semiarid area δ 13 < / sup> C org and OM records with the ice since the late association of climate and environmental changes. The results show that the Huangqihai Lakes region before the arrival of the Holocene climate is cold and dry lake organic productivity is much lower than the Holocene (organic matter content thirteen times lower than the Holocene). Correspondingly, the δ 13 C org values ??than the Holocene average 2.77% higher. In addition, the cross-section of the entire sedimentary cores δ 13 C org the OM presented a good negative correlation (negative correlation coefficient r = 0.782). Preliminary determination Huangqihai lake organic productivity to rise significantly in the early-Holocene lake nutrient levels is likely due to the time of rapid regional climate warming caused due to the rapidly increasing. Corresponding δ 13 C org reduce largely organic yield increased direct relationship. While the δ 13 C org values ??mean the positive and negative offset relative -26.4 ‰ isotopes mainly reflect organic matter productivity and save the changes in the conditions of the lake during the Holocene. This change and the climate, in particular, fluctuations in the water level in the lake has a direct correlation. The radiocarbon chronology determination work currently under way. According to the sedimentary laminae count years Law of the hole, get Huangqihai lakes Holocene average sedimentation rate of 0.805mm / year. According to the above findings and sedimentary stratigraphy, the main stage of the evolution of the climate and environment of the late yellow flag sea ice was divided, and lakeshore with previous findings of the sedimentary section and Nordic postglacial climate division made a preliminary comparison and discussion.

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CLC: > Astronomy,Earth Sciences > Geology > Geochemistry > Biogeochemistry,gas geochemistry
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