艾比湖二千余年来环境演变的地球化学记录  

Paleolimnology of Aiby Lake during the Last 2 500 Years Inferred from Geochemical Records

作　　者：谢宏琴[1] 贾国东[1] 彭平安[1] 穆桂金[2] 

机构地区：[1]中科院广州地球化学研究所有机地球化学国家重点实验室 [2]中科院新疆生态与地理研究所,新疆乌鲁木齐830011

出　　处：《干旱区地理》2005年第2期205-209,共5页Arid Land Geography

基　　金：国家重大基础研究项目(G1999043502)资助

摘　　要：通过对新疆艾比湖Ash孔二千余年以来沉积的总有机碳含量及其碳同位素、碳酸盐含量及Mg/Ca比值等环境指标综合分析,数据显示:约在公元前500～400年,艾比湖水体面积较小,对应的气候偏干。约公元前400～公元1400年,水体面积较大,处于高水位时期,气候较为湿润,但此时期内的气候也有小幅的冷暖和干湿变化。其中在公元800～1300年期间艾比湖沉积记录显示水生生物对沉积有机质的贡献达到最大,而陆源有机质输入不明显,表明此时湖水水位可能达到二千余年来的最高,这一时段基本对应于中世纪暖期。从碳酸盐含量及Mg/Ca比值指标来看,该地区中世纪暖期可能有一个干湿的波动。公元1400年以来,艾比湖水位下降,其中在15世纪中和19世纪初是两次较为干燥的时期,与其他地区的小冰期气候相对应。In this paper,TOC contents,δ13C org values,TIC contents and Mg/Ca molar ratios were studied for the Ash core sediments obtained from the Aiby lake of North Xinjiang.TOC content and δ13C org values of Aiby lake sediments well correlated with the TIC contents and Mg/Ca molar ratios.The results show:from about 500BC to 400BC,The TOC contents,δ13C org values and TIC contents was lower,Mg/Ca molar ratios was higher.It reflects a smaller water body of Aiby lake and drier climate.Then based on these date’s changes:TOC contents,δ13C org values and TIC contents became higher,Mg/Ca molar ratios became lower,well indicating the lake went into a relative stable stage with relative high lake level,and the climate was relatively wet from 400BC to 1 400 AD.Two substages were identified for this long wet period,with the late stag(e300 AD-1 400 AD) more wet than the early one.During 800 AD to 1 300 AD sediment records revealed the sedimented organic matter was almost aquatic origin,indicating the highest lake level since the last 2500 years,basically corresponding to the Medieval Warm Period (MWP).TIC contents and Mg/Ca ratios show a small change from wet to arid,and then to wet again during the period.After the relative long-term wet climate,it became more and more arider,and Aiby lake level descended continuously since 1 400 AD,Because Aiby lake sediments show TOC contents、δ13C org values and TIC contents decreased,and Mg/Ca molar ratios increased during this period,the well-known Little Ice Age(LIA)can also be indicated from our sedimentary records.

关 键 词：艾比湖 地球化学记录 环境演变 碳酸盐含量 中世纪暖期 有机碳含量 沉积有机质 陆源有机质 湖水位下降 小冰期气候 碳同位素 综合分析 环境指标 数据显示 干湿变化 水生生物 沉积记录 19世纪 高水位 比值 面积 水体 

分 类 号：P531[天文地球—古生物学与地层学]