| 河西走廊花海剖面晚冰期以来年代学及沉积特征研究 |
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| 引用本文： | 王乃昂,李卓仑,李育,朱金峰.河西走廊花海剖面晚冰期以来年代学及沉积特征研究[J].沉积学报,2011,29(3):552-560. |
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| 作者姓名： | 王乃昂 李卓仑 李育 朱金峰 |
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| 作者单位： | 兰州大学资源环境学院 兰州大学干旱区水循环与水资源研究中心 兰州 730000 |
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| 基金项目： | 高等学校博士点专科基金项目(编号:20090211110025); 国家自然科学基金项目(批准号:50879033); 兰州大学中央高校基本科研业务费专项资金(编号:lzujbky-2010-221)联合资助 |
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| 摘 要： | 选择位于河西走廊的花海古湖泊沉积剖面作为研究对象,根据13个普通14C和5个AMS14C年代结果,以沉积物岩性特征为主要指标,建立了晚冰期以来花海湖泊沉积的年代框架及环境变化过程.结果表明:花海地区新仙女木期和晚冰期花海湖泊主要以芒硝沉积为主,指示了较低的温度环境.芒硝沉积中的淤泥细线为短暂升温标志,芒硝-淤泥-芒硝的...
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| 关 键 词： | 晚冰期 新仙女木气修事件 年代学 河西走廊 花海 |
| 收稿时间： | 1900-01-01 |
The Chronology and Characteristics of Sediments Since Late Glacial in Huahai Lake,Hexi Corridor,NW China |
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| WANG Nai-ang,LI Zhuo-lun,LI YU,ZHU Jin-feng.The Chronology and Characteristics of Sediments Since Late Glacial in Huahai Lake,Hexi Corridor,NW China[J].Acta Sedimentologica Sinica,2011,29(3):552-560. |
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| Authors: | WANG Nai-ang LI Zhuo-lun LI YU ZHU Jin-feng |
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| Institution: | College of Earth and Environmental Sciences, Center for Hydrologic Cycle and Water Resources in Arid Region, 〖JZ〗Lanzhou University, Lanzhou 730000 |
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| Abstract: | From the profile which is located in the Hexi Corridor, NW China. 13 samples were collected for conventional 14C dating and 5 samples were collected for AMS 14C dating. The materials used for 14C dating were seeds, mud and wood. Based on the dating results, we reconstructed the age framework of Huahai Lake since the Late Glacial period. And then, we concluded that the sediments between 0.73～6.83 m were deposited during Holocene. Between 6.83~7.35 m, the sediments were deposited during the early Holocene and the late Younger Dryas.The sediments of 7.35~10.44 m were deposited during the Late Glacial and early Younger Dryas. Based on the mineral analysis of the sediments during the Younger Dryas and late glacial, mirabilite was the main component in the sediments, indicating the low temperature environment. According to the chemical composition analysis , the main ingredient of the pure mirabilite deposition is Na2SO4 ·10H2O, which is an indicator of the cold dry environment; and the lower the temperature is good for the mineral crystallizing processes. The solubility curve of SO2 4 in Na2SO4 NaCl H2O indicated that, in low surrounding temperature, the concentration of SO2 4 was lower in saturation Na2SO4, and simply increasing the lake level could not improve the ability of mirabilite solution, which was not powerful enough to break off the deposition. The main reason of the interruption for mirabilite deposition may be transient warming events. Therefore, the rhythm deposition formation of mirabilite silt mirabilite indicated the periodic changes of temperature during the late glacial and the Younger Dryas. According to the characteristics of the sediments and lithology, we reconstructed the millennium scale effective moisture conditions during the Holocene period. Before 10.47 cal ka BP, the sediments color appears dark brown, purple brown based, indicating a typical oxidizing environment,and this oxidative environment can not appear in the deep lake environment. There are no obvious lacustrine depositions layers at the beginning of Holocene（before10.4 cal ka BP）, 6.30~3.73 m, and instead the layers are formed mainly on alluvial and eolian depositions, while the eolian depositions layers sandwiched between two alluvial depositions layers.The climate was relatively arid, and the alluvial and aeolian sediments prevailed during this period. Between 10.47 cal ka BP and 8.87 cal ka BP, the climate changed from arid to humid. During 8.87~5.5 cal ka BP the lake was relatively deep, and the climate was relatively humid. From 5.5 cal ka BP, there was little sediment in the section, showing that the lake became to dry up since then. This Holocene environmental change in millennium scale was different from the westerlies in the arid Central Asian areas, but it was not the same as the environmental change in the eastern part of China, which was controlled by Asian monsoon. So the Holocene environment of the Huahai Lake region was affected by the Westerlies and the East Asian monsoon. |
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| Keywords: | the Late Glacial Younger Dryas Event chronology Hexi Corridor Huahai Lake |
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