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干旱区地理 ›› 2022, Vol. 45 ›› Issue (2): 435-444.doi: 10.12118/j.issn.1000–6060.2021.295

• 地表过程研究 • 上一篇    下一篇

高海拔干旱区湖泊沉积物多指标记录的环境变化研究——以阿克赛钦湖为例

项超生1(),汪勇2(),王君波3,马庆峰3,王世航1   

  1. 1.安徽理工大学空间信息与测绘工程学院,安徽 淮南 232001
    2.安徽师范大学地理与旅游学院/江淮流域地表过程与区域响应安徽省重点实验室,安徽 芜湖 241002
    3.中国科学院青藏高原研究所青藏高原环境变化与地表过程重点实验室,北京 100101
  • 收稿日期:2021-06-29 修回日期:2021-11-01 出版日期:2022-03-25 发布日期:2022-04-02
  • 通讯作者: 汪勇
  • 作者简介:项超生(1995-),男,硕士研究生,主要从事湖泊沉积与过去环境变化等方面研究. E-mail: xcs1957840332@163.com
  • 基金资助:
    国家自然科学基金项目(41771228);第二次青藏高原综合科学考察研究(2019QZKK0202);安徽师范大学校博士启动金项目资助(2017XJJ36)

Environmental changes recorded by multiproxy of lake sediments in the high-altitude and arid area: A case of Lake Aksayqin

XIANG Chaosheng1(),WANG Yong2(),WANG Junbo3,MA Qingfeng3,WANG Shihang1   

  1. 1. School of Spatial Informatics and Geomatics Engineering, Anhui University of Science & Technology, Huainan 232001, Anhui, China
    2. Key Laboratory of Earth Surface Processes and Regional Response in the Yangtze-Huaihe River Basin, School of Geography and Tourism, Anhui Normal University, Wuhu 241002, Anhui, China
    3. Key Laboratory of Tibetan Environment Changes and Land Surface Processes (TEL), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
  • Received:2021-06-29 Revised:2021-11-01 Online:2022-03-25 Published:2022-04-02
  • Contact: Yong WANG

摘要:

青藏高原西北部湖泊沉积物记录了丰富的区域气候环境变化信息,对于揭示青藏高原西风-季风环流系统变化及其相互作用过程具有重要意义。通过对青藏高原西北部高海拔干旱区典型湖泊阿克赛钦湖沉积岩芯粒度、总无机碳(Total inorganic carbon,TIC)、总有机碳(Total organic carbon,TOC)、总氮(Total nitrogen,TN)、碳氮比(C/N)和磁化率等环境代用指标的分析,探讨阿克赛钦湖不同沉积深度范围内湖泊水动力搬运条件、湖面变化及湖区冷暖变化等湖泊环境变化过程。结果表明:阿克赛钦湖沉积物有机质含量低,湖泊沉积物以粉砂为主,黏土次之,砂含量最少。多指标记录的环境变化大致分为以下4个阶段:第Ⅰ阶段(531~480 cm)气候相对温暖,流域蒸发较弱,湖泊水生生产力低,为湖泊水动力搬运条件弱的深水环境。第Ⅱ阶段(480~380 cm)气候寒冷干燥,流域蒸发强烈,湖泊水生生产力相对较高,为湖泊水动力搬运条件强的浅水环境。第Ⅲ阶段(380~160 cm)气候逐渐转暖,入湖水量增多,湖面扩张,湖泊水动力搬运条件逐渐减弱。第Ⅳ阶段(160~0 cm)气候寒冷干燥,流域蒸发增强,湖泊水生生产力低,为湖泊水动力搬运条件弱的深水环境。研究结果可为青藏高原西北部过去气候变化重建及西风-季风变化关系研究提供基础科学数据与理论支撑。

关键词: 多指标, 阿克赛钦湖, 环境变化, 湖泊沉积, 青藏高原

Abstract:

Lake Aksayqin, a typical large high-altitude lake located in the arid area of the northwestern Tibetan Plateau in China, is ideal for studying the changes in the Westerlies and Indian Summer Monsoon and the interplay between them. To reconstruct the paleoclimate changes of the lake, a 5.31 m long lake sediment core (AKLC15-1) was obtained at a water depth of 16.40 m. The grain size characteristics of the lake core were analyzed to investigate the hydrodynamics and lake-level changes. Based on the changes of multiple indicators, such as grain size results, total inorganic carbon, total organic carbon, total nitrogen, and magnetic susceptibility, we primarily discuss the changes in the lake environment, such as hydrodynamic transport conditions, lake surface changes, and cold and warm changes in the lake area under different sedimentary depths. The results show that the Lake Aksayqin area experiences a high rate of evaporation; the lake water is mainly supplied by glacier meltwater; and the organic matter content in lake sediments is low and mainly comes from endogenous aquatic organisms. The sediments of Lake Aksayqin are mainly composed of silt (70.48%), clay (27.64%), and sand (1.88%). The environmental change can be roughly divided into four stages. The first stage (531-480 cm) has a relatively warm climate, weakening evaporation in the basin, low aquatic productivity of the lake, and a deep-water environment with weak hydrodynamic transport conditions. In the second stage (480-380 cm), the climate is cold and dry, the evaporation in the basin is extremely strong, and the aquatic productivity of the lake is relatively high, which is a shallow water environment with strong hydrodynamic transport conditions. In the third stage (380-160 cm), the climate gradually warms. The amount of water entering the lake increases, the lake surface expands, and the hydrodynamic transport conditions of the lake gradually weaken. The fourth stage (160-0 cm) has a cold and dry climate with enhanced evaporation of the basin. The productivity of the lake is low; it has a deep-water environment with weak hydrodynamic transport conditions. This study will provide basic scientific data and theoretical support for reconstructing climatic changes and the relationship between the Westerlies and Indian Summer Monsoon in the northwestern Tibetan Plateau.

Key words: multiple indicators, Lake Aksayqin, environmental changes, lake sediment, Tibetan Plateau