叶远达^1,2,,
徐海^3,,,
蓝江湖¹,
严东娜^1,2,
周慷恩^1,2,
吴慧贤^1,2,
张继效^1,2,
盛恩国¹,
郁科科¹,
刘斌¹
1. 中国科学院地球环境研究所, 黄土与第四纪地质国家重点实验室, 陕西 西安 710061
2. 中国科学院大学, 北京 100049
3. 天津大学表层地球系统科学研究院, 天津 300072

基金项目: 国家自然科学基金项目（批准号：41761144070和41672169）资助


详细信息

作者简介: 叶远达, 男, 27岁, 硕士研究生, 第四纪地质学专业, E-mail:yeyuanda@ieecas.cn

通讯作者: 徐海, E-mail:xuhai@tju.edu.cn

中图分类号: P512.2;P532;P941.78

收稿日期:2018-04-02
修回日期:2018-05-16
刊出日期:2018-07-30

Sedimentary grain size at Lake Chenghai, Yunnan Province: Indicator for water depth

Ye Yuanda^1,2,,
Xu Hai^3,,,
Lan Jianghu¹,
Yan Dongna^1,2,
Zhou Kang^1,2,
Wu Huixian^1,2,
Zhang Jixiao^1,2,
Sheng En¹,
Yu Keke¹,
Liu Bin¹
1. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, Shaanxi
2. University of Chinese Academy of Sciences, Beijing 100049
3. Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072


More Information

Corresponding author: Xu Hai,E-mail:xuhai@tju.edu.cn

MSC: P512.2;P532;P941.78

--> Received Date: 02 April 2018
Revised Date: 16 May 2018
Publish Date: 30 July 2018


摘要
摘要:不同湖泊盆地构造以及流域水文过程的差异导致湖泊沉积物粒度的指示意义有所不同。文章以云南程海表层岩芯为研究对象，分析取自不同水深的表层岩芯沉积物粒度（1 cm、5 cm以及¹³⁷Cs-峰层位）和碳酸盐含量（2cm、5cm以及¹³⁷Cs-峰层位），探讨其与水深的空间相关性；通过对垂直钻孔岩芯粒度的分析，并结合过去50余年来的湖泊水位记录，探讨沉积物"粒度-水深"在时间尺度上的关系。结果表明：1）在空间分布上，沉积物平均粒径和水深呈显著反相关关系，即程海沉积物平均粒径随水深增加（减小）而变细（变粗），且该"粒度-水深"空间分布模式得到沉积物碳酸盐含量空间分布规律的支持；2）在时间尺度上，水深的时段沉积物粒度细，水浅的时段沉积物粒度粗；与"粒度-水深"的空间关系一致。我们推测上述"粒度-水深"的时空变化关系与湖泊面积变化导致的采样点与岸边/河口的距离有关。在此基础上，进一步分析了程海近千年的沉积物粒度与水位变化关系：中世纪暖期和现代暖期粒度偏粗，程海处于低湖面；小冰期程海沉积物平均粒度偏细，对应于高湖面。上述基于"粒度-水深"关系推导的水位变化与我们前期基于岸边地质证据得出的水位变化，以及历史文献记载的水位变化一致，验证了本文获得的"粒度-水深"关系的可靠性。
关键词: 程海/
水位变化/
粒度/
碳酸盐含量

Abstract:Sedimentary grain size is widely used as an indicator of lake water depth, surface runoff intensity, and climatic changes, etc. However, as different lakes have variable topography and hydrological processes, the climatic/environmental significance of sedimentary grain size is variable. In this paper, we studied the relationship between sedimentary grain size and water depth at Lake Chenghai(26°27'~26°28'N, 100°38'~100°41'E), northwest Yunnan Province, Southwestern China. We determined the sedimentary grain size(1cm, 5cm and ¹³⁷Cs-peak layer) and the carbonate content (2 cm, 5 cm and ¹³⁷Cs-peak layer) of surface sediments in the cores collected at different water depth in Lake Chenghai, and studied the spatial correlation between grain size and water depth. We also examined the relationship between grain size of a vertical-down core and the observed lake level variations during the past 50 years. The results show that there is a significant inverse spatial correlation between the sedimentary grain size and water depth, i.e., coarser grain size correlates to shallower water depth, and vice versa. This spatial "grain size-water depth" relation is verified by the spatial relationship between water depth and sedimentary carbonate contents. The temporal relationship between grain size and water depth is similar to that on spatial scale. We propose that the spatiotemporal relationship between grain size and water depth at Lake Chenghai is related to the variations in distance from the sampling sites to the lake shoreline/riverine estuary caused by changes in lake areas(or lake levels). We further verified the relationship between sedimentary grain size and historical lake levels during the past millennium. The sedimentary grain size was coarse during the warm periods, like the Medieval Warm period(MWP) and the modern warm period, while it was fine during the Little Ice Age(LIA), indicating lower lake levels during MWP and modern warm epoch but higher lake levels during the LIA, which is consistent with the lake levels revealed from beach evidence and those inferred from historical literatures.
Key words:Lake Chenghai/
lake level change/
grain size/
carbonate content



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