四川甘孜州措普湖沉积物微量元素记录的近200年环境变化  

Environmental Changes Recorded by Trace Elements in Sediments of Cuopu Lake,Ganzi Prefecture,Sichuan Province in Recent 200 Years

作　　者：刘梦佳 何梦颖[1,2] 胡竹君 黄涛[1,3] 黄昌春 张志刚[1,2] 王红 Liu Mengjia;He Mengying;Hu Zhujun;Huang Tao;Huang Changchun;Zhang Zhigang;Wang Hong(School of Geography,Nanjing Normal University,Nanjing 210023,China;Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application,Nanjing 210023,China;Jiangsu Province Key Laboratory of Materials Cycling and Pollution Control,Nanjing 210023,China;School of the Environment,Nanjing Normal University,Nanjing 210023,China)

机构地区：[1]南京师范大学地理科学学院,江苏南京210023 [2]江苏省地理信息资源开发与利用协同创新中心,江苏南京210023 [3]江苏省物质循环与污染控制重点实验室,江苏南京210023 [4]南京师范大学环境学院,江苏南京210023

出　　处：《地球科学》2024年第6期2186-2198,共13页Earth Science

基　　金：国家自然科学基金项目(Nos.41602180,41773097)。

摘　　要：青藏高原东缘分布的小型湖泊由于其特殊的地理位置,受人类活动影响较小,其沉积记录对气候环境变化的响应具有区域性意义,特别在恢复短时间尺度气候及区域沉积环境方面有着独特的优势,然而目前鲜有研究涉及.对四川省甘孜州措普湖湖心45 cm的沉积岩心样品进行了微量元素地球化学分析,重建了当地过去近200年中的气候演变过程.结果表明:近200年来,沉积岩心中稀土元素具有基本相同的垂向变化趋势,均在1841—1920年的小冰期时保持低值,在1890年左右受地震间接影响达到最低值,之后随气候回暖而增加;微量元素主成分分析表明大部分微量元素的变化受区域流域侵蚀风化因子控制,能够反映风化作用的强弱;Rb、Ba、Sr等3种元素受湿度因子主控,指示了区域湿润度的变化.结合多种微量元素环境代用指标及沉积物粒度组成的变化特征,可将措普湖在1841—2017年间的气候环境演化过程划分为5个阶段:冷干(1841—1904年)、温湿(1904—1923年)、温干(1923—1944年)、暖湿(1944—1967年)、暖干(1967—2017年).Small lakes distributed in the eastern edge of the Qinghai-Xizang plateau are less affected by human activities due to their special geographical location.Their sedimentary records have regional significance in response to climate and environmental changes,especially in restoring short-time scale climate and regional sedimentary environment.However,there are few studies involved at present.In this paper,trace element geochemical analysis was carried out on the sedimentary core samples of 45 cm in the center of Cuopu Lake in Ganzi Prefecture,Sichuan Province,and the local climate evolution process in the past 200 years was reconstructed.The results show that in recent 200 years,rare earth elements have basically the same longitudinal variation trend,and they all keep low values during the little ice age from 1841 to 1920,and reached the lowest value due to the indirect influence of the earthquake around 1890,and then increased with the warming of the climate.According to the principal component analysis of trace elements,the change of most trace elements is controlled by the erosion and weathering factors of the basin,which can reflect the strength of regional weathering;Rb,Ba,Sr are mainly controlled by humidity factor and can be used to restore the change of humidity.Combined with the change characteristics of various trace element environmental substitution indexes and sediment particle size composition,the climate and environment evolution process of Cuopu Lake from 1841 to 2017 is divided into 5 stages:cold-dry(1841—1904),mild-moist(1904—1923),mild-dry(1923—1944),warm-moist(1944—1966)and warm-dry(1967—2017).

关 键 词：青藏高原 措普湖 微量元素 沉积环境变化 沉积学 

分 类 号：P532[天文地球—古生物学与地层学]