| 1960年以来青海湖沉积物粒度的时空分布及其控制因素 |
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| 引用本文： | 张志杰,周玉文,陈嵘,周川闽,孙伟伟.1960年以来青海湖沉积物粒度的时空分布及其控制因素[J].高校地质学报,2019,25(4):623. |
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| 作者姓名： | 张志杰 周玉文 陈嵘 周川闽 孙伟伟 |
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| 作者单位： | 中国石油勘探开发研究院,北京,100083;中国科学院南京地理与湖泊研究所,湖泊与环境国家重点实验室,南京210008 |
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| 基金项目： | 中国石油科技项目;中国湖泊沉积物底质调查专项;国家自然科学基金;中科院南京地理与湖泊研究所自主部署项目 |
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| 摘 要： | 对大型湖泊盆地沉积物粒度组成进行研究，有助于解读全球致密油气和页岩油气勘探开发与其记录的古气候信息。
文章对青海湖沉积物粒度时空分布进行了详细的研究，通过采集覆盖大部分湖区的27根近现代沉积岩芯，并对湖心的三根
典型沉积岩芯进行了137Cs测定获取沉积岩芯的年龄；基于磁化率地层年龄模式，建立了整个湖区沉积岩芯的年代框架。粒
度分析结果显示，青海湖岩芯沉积物的粒度分布呈多峰，以细颗粒沉积为主，其中粉砂含量60%~70%，粘粒组分为10%~
35%，砂粒组分低于20%。青海湖沉积物的粒度变化在空间上相对较复杂，中值粒径呈现明显的砂岛附近、西部和西南湖
区高，其他湖区低的特征。在时间上，大体上自1960年到2017年呈现变粗的趋势，砂粒组分增多，粘粒组分减少。这些粒
度的时空变化可能是受风砂活动、流域土壤侵蚀、河流径流变化、湖平面变化和人类活动共同作用而成。
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| 关 键 词： | 粒度 时空变化 青海湖 1960年 2017年 |
Spatio-Temporal Distributions and Controls of Grain Size in the Sediments from the Qinghai Lake since the 1960 AD |
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| ZHANG Zhijie,ZHOUYuwen,CHENRong,ZHOUChuanmin,SUN Weiwei.Spatio-Temporal Distributions and Controls of Grain Size in the Sediments from the Qinghai Lake since the 1960 AD[J].Geological Journal of China Universities,2019,25(4):623. |
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| Authors: | ZHANG Zhijie ZHOUYuwen CHENRong ZHOUChuanmin SUN Weiwei |
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| Abstract: | The study on grain size in the sediments from the large lake basins is helpful to interpret global exploration of tight oil-gas
and shale oil-gas as well as their recorded paleoclimate information. In this paper, the spatial and temporal distribution of grain size in
the Qinghai Lake, the largest lake in China, was studied in detail. Twenty seven cores covering almost the whole lake area spanning the
last 60 years were drilled, and the three typical cores were dated by 210Pb and 137Cs. Based on the magnetic susceptibility age model, the
age framework of sedimentary cores in the whole lake area was established. Results show that sediments in the Qinghai Lake have
multimodal distribution in the grain size and mainly consist of fine grains (< 63 μm). The silt content ranges from 60% to 70%, the clay
component ranges from 10% to 35%, and the sand component is less than 20%. Therefore, the variation of grain size in the Qinghai
Lake sediments is relatively complex on the spatial scale. The median grain size is high in the areas around the Sand Island, the western
and southwestern lakes, while it is low in other lake areas. In the temporal scale, the grain size is roughly coarse, the sand component
increased and the clay component decreased from 1960 AD to 2017AD. The temporal and spatial variations of grain size may be caused
by the combined action of wind and sand activities, soil erosion in the basin, and the changes of river runoff and lake levels. |
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| Keywords: | grain size spatial-temporal variation Qinghai Lake 1960 AD 2010 AD |
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