哈萨克斯坦巴尔喀什湖沉积物粒度特征及其对区域环境变化的响应  

Grain-size characteristics of lacustrine sediments in Balkhash Lake,Kazakhstan and its response to regional environmental changes

作　　者：贺振杰 马龙[1,2,3] 吉力力·阿不都外力 刘文[1,2,3] Gulnura ISSANOVA Galymzhan SAPAROV[2,5] 黄坤[1,2,3] HE Zhenjie;MA Long;Jilili ABUDUWAILI;LIU Wen;Gulnura ISSANOVA;Galymzhan SAPAROV;HUANG Kun(State Key Laboratory of Desert and Oasis Ecology,Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Urumqi 830011,Xinjiang,China;Research Center for Ecology and Environment of Central Asia,Chinese Academy of Sciences,Urumqi 830011,Xinjiang,China;University of Chinese Academy of Sciences,Beijing 100049,China;Faculty of Geography and Environmental Sciences,Al-Farabi Kazakh National University,Almaty 050040,Kazakhstan;Kazakh Research Institute of Soil Science and Agrochemistry Named after U.U.Uspanov,Almaty 050060,Kazakhstan)

机构地区：[1]中国科学院新疆生态与地理研究所,荒漠与绿洲生态国家重点实验室,新疆乌鲁木齐830011 [2]中国科学院中亚生态与环境研究中心,新疆乌鲁木齐830011 [3]中国科学院大学,北京100049 [4]Faculty of Geography and Environmental Sciences,Al-Farabi Kazakh National University,Almaty 050040,Kazakhstan [5]Kazakh Research Institute of Soil Science and Agrochemistry Named after U.U.Uspanov,Almaty 050060,Kazakhstan

出　　处：《干旱区地理》2021年第5期1317-1327,共11页Arid Land Geography

基　　金：国家自然科学基金(U1903115);新疆维吾尔自治区天山青年计划(2018Q008)。

摘　　要：湖泊沉积物中的粒度参数记载了丰富的流域环境变化信息,可为无器测资料地区重建古环境变化序列提供可靠的途径。通过对巴尔喀什湖岩芯沉积物中粒度、磁化率等环境代用指标的分析,结合放射性137Cs定年以及流域气候、湖泊水位等器测记录数据,研究了巴尔喀什湖沉积物中粒度变化特征及其环境指示意义。结果表明:巴尔喀什湖沉积物中黏土质(<4μm)组分平均含量为20.32%,细粉砂质(4~16μm)为40.13%,中粉砂质(16~32μm)为22.86%,粗粉砂质(32~64μm)为10.55%,砂质(>64μm)为6.13%。通过粒径标准-偏差法提取了沉积物中环境细颗粒敏感组分(F1,6.61~10.00μm)和粗颗粒敏感组分(F2,45.71~69.18μm)。研究表明在人类活动影响不断加强的背景下,粒度敏感组分的含量变化不能敏感的反映湖泊水位、入湖径流乃至区域气候的变化,而与沉积物中磁化率所反映的人类活动强度变化存在较为显著的相关关系(r=0.870,P<0.01),这可能与人类活动增强导致的流域内富含磁性物质的细颗粒碎屑物质被搬运入湖有关,湖泊沉积物中磁化率升高的同时,湖泊沉积物中细颗粒物质增加。研究结果可为长时间尺度下古环境重建研究提供重要参考依据,同时也对揭示流域人类活动对湖泊环境的影响具有一定的科学意义。Lake sediment grain-size data give a wealth of information regarding watershed environmental change and can provide a reliable method to reconstruct paleoenvironmental changes in areas without instrumental data. Through the analysis of environmental proxies, such as grain size and the magnetic susceptibility of the core sediments of Lake Balkhash, combined with radioactive 137Cs dating and instrumental data including the regional climate and lake water level, characteristics regarding the grain size of the sediments of Lake Balkhash in Kazakhstan and their environmental meanings were established. The results show that the average contents of the clay components (<4 μm), fine silt (4-16 μm), medium silt (16-32 μm), coarse silt (32-64 μm), and sand (>64 μm) in the lake sediment were 20.32%, 40.13%, 22.86%, 10.55%, and 6.13%, respectively. The proportions of the environmentally sensitive components F1 (6.61-10.00 μm) and F2 (45.71-69.18 μm) in the sediment were extracted via the method of standard deviation versus grain size. The present study shows that, due to the increasing influence of human activities, changes in the content of the sensitive components of grain size cannot accurately reflect changes in lake water level, lake runoff, and even regional climate. Changes in sediment composition are instead related to changes in the intensity of human activities as reflected by the magnetic susceptibility of sediments, which shows significant correlation with human activity (r=0.870, P<0.01). It is observed that the increase in the magnetic susceptibility of the lake sediments is due to the increase in human activities in the watershed, which causes the transport of fine-grained detrital materials rich in magnetic materials into the lake. These research findings can provide an important reference for studies regarding paleoenvironment reconstruction on a long- term scale and have a clear scientific significance for understanding of the impact of human activities in the basin on lake environments.

关 键 词：哈萨克斯坦 巴尔喀什湖 湖泊沉积物 粒度 环境变化 

分 类 号：P512.2[天文地球—地质学] P343.3