Mineralogy and carbonate geochemistry of the Dali Lake sediments: Implications for paleohydrological changes in the East Asian summer monsoon margin during the Holocene
Mineralogy and carbonate geochemistry of the Dali Lake sediments: Implications for paleohydrological changes in the East Asian summer monsoon margin during the Holocene
复制标题
大理湖沉积物的矿物学和碳酸盐地球化学：全新世东亚夏季风边缘古水文变化的意义
DOI：
10.1016/j.quaint.2018.03.019
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发表时间：
2019-08-30
影响因子：
2.2
通讯作者：
Liu, Yanhong
中科院分区：
文献类型：
--
作者：
Fan, Jiawei;Xiao, Jule;Liu, Yanhong
高原湖泊的水文变化既受当地水文过程的影响，也受区域气候变化的影响。通过对内蒙古高原大荔湖沉积物柱状样中矿物、元素和稳定同位素的高分辨率绝对定年记录，探讨了全新世东亚夏季风（EASM）北方边缘水文气候变化的模式和机制。外来矿物（石英，微斜长石和钠长石）的百分比增加，内生/自生矿物（方解石，镁方解石和石膏）的百分比减少，以及减少的Ca和Mg浓度值和δ O-18和δ C-13的内生方解石表明过量的水输入到湖泊蒸发损失，反之亦然。这些数据表明，大理湖的水文平衡控制在9800 calyr BP之前，强烈的蒸发，然后在9800和5900 calyr BR之间的湖泊由显着增加的入湖水量。从5900到4850卡年BP，水输入到湖泊显着减少。自4850 cal yr BP以来，流入水维持在较低水平。此外，在9800-7700和7700-5900 cal yr BP高湖平面时期，大理湖沉积物的矿物学和碳酸盐地球化学特征表明，在高湖平面时期，大理湖主要由冰雪融水补给，而在高湖平面时期，大理湖主要由区域性降水补给。这些结果表明，东亚夏季风边缘全新世水文变化与区域气温和降水变化密切相关，而区域气温和降水变化最终受控于北方半球夏季日照、北方高纬冰盖、全球海平面以及北大西洋和热带西太平洋的物理化学条件的变化。轨道和千年时间尺度。研究结果支持东亚夏季风强度最大值出现在北方东亚夏季风区中全新世。(C)2018 Elsevier Ltd和INQUA。All rights reserved.
Hydrological variations in individual plateau lakes respond from both local hydrological processes and regional climatic changes. This study presents high resolution, absolutely-dated records of minerals in bulk samples and elements and stable isotopes of endogenic calcites from a sediment core from Dali Lake in Inner Mongolian Plateau, aiming to investigate the patterns and mechanisms of Holocene hydrological and climatic changes in the modern northern margin of the East Asian summer monsoon (EASM). Increases in the percentages of allogenic minerals (quartz, microcline and albite) and decreases in the percentages of endogenic/authigenic minerals (calcite, Mg-calcite and gypsum), together with decreases in the values of Ca and Mg concentrations and delta O-18 and delta C-13 of endogenic calcites indicate an excess of water input to the lake over evaporative losses, and vice versa. These data suggest that the hydrological balance of Dali Lake was controlled by strong evaporation before 9800 cal yr BP, and then the lake was supplied by significantly increased inflowing water between 9800 and 5900 cal yr BR. From 5900 to 4850 cal yr BP, the water input to the lake significantly decreased. Since 4850 cal yr BP, the inflowing water maintained a low level. In addition, the distinct characteristics of mineralogy and carbonate geochemistry of the Dali Lake sediments during the periods of high lake level between 9800-7700 and 7700-5900 cal yr BP imply that the lake was mainly fed by snow/ice melt water in the former period and then by regional precipitation in the latter period, which was further supported by the pollen records from the same sediment core. These results suggest that Holocene hydrological variations in the EASM margin were closely related to changes in regional temperature and precipitation which were ultimately controlled by changes in the Northern Hemisphere summer insolation, northern high latitude ice sheets, global sea level and physicochemical conditions of the North Atlantic and western tropical Pacific on orbital and millennial timescales. The datasets in this study support that the maximum EASM intensity occurred during the middle Holocene in the northern EASM regions. (C) 2018 Elsevier Ltd and INQUA. All rights reserved.