内蒙古黄旗海湖泊沉积物δ^(13)C_(org)记录的环境演变信息  

AN ORGANIC CARBON ISOTOPIC RECORD FROM SEDIMENTS OF THE HUANGQIHAI LAKE,INNER MONGOLIA: IMPLICATIONS OF ENVIRONMENTAL EVOLUTION

作　　者：申洪源[1] 张红梅[2] 贾玉连[3] 

机构地区：[1]临沂师范学院地理与旅游系,山东临沂276005 [2]临沂师范学院图书馆,山东临沂276005 [3]江西师范大学地理与环境学院,南昌330027

出　　处：《海洋地质与第四纪地质》2005年第4期35-40,共6页Marine Geology & Quaternary Geology

基　　金：中国科学院知识创新工程重大项目(CXNIJLAS-A01-2;KZCX2-SW-118)

摘　　要：处于高纬度和高海拔地区的内蒙古黄旗海湖泊沉积物δ13Corg的变化反映了气候环境的变化。特殊的自然环境条件造成黄旗海湖泊沉积物δ13Corg偏负段对应暖湿环境,偏正段对应冷干环境。自8.2 kaBP开始,δ13Corg值显著降低,表明本区气候转暖;8.2~4.0 kaBP是全新世大暖期,这一时期黄旗海为高湖面,在7.8 kaBP左右本区气候最为暖湿。4.0~2.2 kaBP,δ13Corg值明显偏正,指示气候变为冷干,全新世大暖期结束。在研究时段内δ13Corg值相对于-23.5‰均值的正负偏移主要反映了湖泊有机质生产率和保存条件的变化。这种变化与当时的气候,尤其是湖泊水位的波动有直接关系。Section （H3） at 1.64 m depth from the south bank of Huangqihai Lake, Inner Mongolia recorded paleoclimatic and paleoenvironmental changes during 8. 3 and 2.2 kaBP. Bulk organic carbon isotopic composition （δ^13Corg） of H3 section is analyzed and the relation between δ^13Corg record from the shallow closeddrainage lake and environmental evolution is discussed. The positive values of δ^13Corg indicate that the cli mate in the period of time was cold and dry,while the negative values of δ^13Corg indicate that the climate in the period of time was warm and wet. Results suggest that the climate at Huangqihai Lake was warm and wet during 8. 3 and 7.4 kaBP, and δ^13Corg values of the sediments are 0.46‰ lower than the average in the whole period of time of study. There is about 2.66‰ shift in δ^13Corg values in the whole period of time, and it was mostly related to the rapid increase in the organic productivity of the paleo-lake. The substantial fall in δ^13Corg values of the sediments from Huangqihai Lake of 8. 2 kaBP provides evidence for an abrupt warming of the regional climate at that time. The period （8.2-4. 0 kaBP） is Megathermal Maximum in Holocene and is regarded as the period of high stand of Huangqihai Lake. Thereinto, it was the warmest at about 7.8 kaBP. During 4.0 and 2.2 kaBP, the δ^13Corg average value is -22.8‰ （obviously positive）, which indicates that the climate was quite cold and dry after 4.0 kaBP. The Megathermal Maximum period ended and the climate drastically deteriorated after 4.0 kaBP. Variation in δ^13Corg during the whole period of time is characterized by both negative and positive excursions from the line of the average δ^13Corg value of -23.5‰. These excursions may principally reflect the change in productivity and preserving condition of organic matter in the lake, which in some way link to the climate, especially to the lake-level fluctuations.

关 键 词：湖泊沉积物 有机碳同位素 环境演变 黄旗海 

分 类 号：P941.78[天文地球—自然地理学]