青藏高原达则错沉积物有机碳同位素特征及古气候环境意义  

Characteristics of Compositions of Organic Matter δ^(13)C in Lake Sediments from Dagze Co in Tibetan Plateau and Its Paleoclimatic and Paleoenvironmental Significance

作　　者：李秀美 范宝伟 侯居峙[3] 王明达 贺跃 Li Xiumei;Fan Baowei;Hou Juzhi;Wang Mingda;He Yue(School of Geographic Sciences,Henan Key Laboratory for Synergistic Prevention of Water and Soil Environmental Pollution,Southern Henan Center for Mineral Rock and Gem-Jade Identification and Processing,Xinyang Normal University,Xinyang 464000,China;Xinyang Key Laboratory of Climate Change&Environmental Evolution,Xinyang 464000,China;Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China;School of Geography,Liaoning Normal University,Dalian 116029,China;School of Resources,Hebei GEO University,Shijiazhuang 050031,China)

机构地区：[1]信阳师范学院地理科学学院,河南省水土环境污染协同防治重点实验室,豫南岩矿宝玉石鉴定及加工中心,河南信阳464000 [2]信阳市气候与环境演变重点实验室,河南信阳464000 [3]中国科学院青藏高原研究所,北京100101 [4]辽宁师范大学地理科学学院,辽宁大连116029 [5]河北地质大学地球科学学院,河北石家庄050031

出　　处：《地球科学》2022年第6期2275-2286,共12页Earth Science

基　　金：国家自然科学基金项目(No.41901105);信阳师范学院“南湖学者奖励计划”青年项目。

摘　　要：通过对达则错沉积岩心有机质碳同位素(δ^(13)C)和碳氮比(C/N)的分析,结合岩心浮游生物记录、营养盐记录以及温度和降水记录,探讨了过去一千年达则错沉积物有机质δ^(13)C的气候环境指示意义.结果表明,达则错沉积物有机质主要以湖泊自生的水生生物碎屑混合物为主;过去一千年,达则错在受人类活动显著影响之前,气候变化是影响沉积物有机质δ^(13)C形成的主要因素,在1050~1200 AD和1450~1650 AD气候寒冷干燥时段有机质δ^(13)C值显著偏重,反之则相反;过去150年,湖泊沉积物有机质δ^(13)C显著偏重,主要受人类活动导致湖泊营养盐浓度变化影响.本研究还表明对于营养结构较为单一,且西藏拟溞为绝对优势动物物种的半对流型湖泊,应用C/N值判断湖泊有机质来源是不可靠的,需要综合湖泊地理背景谨慎判断.Based on the analyses of δ^(13)C and C/N ratio of organic matter in Dagze Co sediments,combined with the records of plankton,nutrient salts,temperature and precipitation,the climatic and environmental implications of organic matter δ^(13)C in Dagze Co sediments during the past 1 000 years were discussed.The results indicate that organic matter of Dagze Co sediment was mainly composed of the autogenous aquatic bioclasts from the lake.Prior to the significant impact of human activities during the past thousand years,climate change was the main factor affecting the formation of δ^(13)C in the Dagze Co sediments.The δ^(13)C value of organic matter was significantly heavier during the cold and dry periods of 1050-1200 AD and 1450-1650 AD,and was considerably lighter during the warmer and wetter periods of 950-1050 AD,1200-1450 AD and 1650-1850 AD.However,in the past 150 years,theδ^(13)C of organic matter in lake sediments was dramatically heavier,which was mainly affected by changes in the concentration of nutrients caused by human activities.This study also shows that the application of C/N value to determine the source of organic matter in Dagze Co,which is semi-convective and with a single nutrient structure,is not reliable,and it is necessary to combine field factors.

关 键 词：C/N比值 有机碳同位素 气候变化 生态 达则错 青藏高原 

分 类 号：P532[天文地球—古生物学与地层学]