彭红霞^1,2,,
吴昆¹,
邓清禄³,
卫玉杰¹,
彭珂¹
1. 中国地质大学(武汉)公共管理学院, 湖北 武汉 430074
2. 中国地质大学(武汉)地质过程与矿产资源国家重点实验室, 湖北 武汉 430074
3. 中国地质大学(武汉)工程学院, 湖北 武汉 430074

基金项目: 国家自然科学基金项目（批准号：41202124）、国家重点基础研究发展规划项目（973项目）（批准号：2011CB710601）和湖北省自然科学基金项目（批准号：2016175160）共同资助


详细信息

作者简介: 彭红霞, 女, 45岁, 副教授, 主要从事第四纪环境演变研究, E-mail:penghongxia@sina.com

中图分类号: P597

收稿日期:2017-12-28
修回日期:2018-03-18
刊出日期:2018-05-30

²³⁰Th/²³⁸U chronology of Huangtupo landslide in Three-Gorges Reservoir area by MC-ICPMS

Peng Hongxia^1,2,,
Wu Kun¹,
Deng Qinglu³,
Wei Yujie¹,
Peng Ke¹
1. Faculty of Public Administration, China University of Geosciences(Wuhan), Wuhan 430074, Hubei
2. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences(Wuhan), Wuhan 430074, Hubei
3. Faculty of Engineering, China University of Geosciences(Wuhan), Wuhan 430074, Hubei


MSC: P597

--> Received Date: 28 December 2017
Revised Date: 18 March 2018
Publish Date: 30 May 2018


摘要
摘要:开展地质历史时期滑坡的年代学研究，是正确认识重大滑坡灾害历史发育过程、现状与未来发展趋势的重要基础之一。论文以三峡库区巴东县黄土坡滑坡为研究对象，在资料收集和野外调查基础上，在黄土坡滑坡临江Ⅰ号滑坡体3#支洞滑坡带上采集4个方解石晶体样品，并开展了MC-ICPMS ²³⁰Th年代学分析。黄土坡滑坡3#支洞次生方解石的U含量变化在30.9×10^-9~45.6×10^-9g/g之间，²³⁴U/²³⁸U比值波动在1.362~2.673范围，基本能满足高精度U-Th测年的要求。4个样品碎屑Th校正²³⁰Th年龄分别为155.2±18.6 ka B.P.、134.6±5.6 ka B.P.、70.9±8.5 ka B.P.和103.3±18.2 ka B.P.。年代结果表明，三峡黄土坡Ⅰ号临江滑坡体的滑动时代在155.2~70.9 ka之间。这些年龄数据虽然具有较大的误差，但年龄存在明显差异，可能反映了不同滑坡期次，印证了黄土坡滑坡滑坡体的多期次性，是一个发生频率高、多个崩滑堆积体和滑坡组成的特大型复合滑坡。定年结果与野外调查以及前人的研究结果一致，表明挑选滑坡体滑带纯净的次生方解石进行U-Th测年是研究大型滑坡年代学的一种有效手段。最后，将黄土坡滑坡年代期次与长江三峡及邻区新构造运动、地貌过程、气候变化和其他滑坡活动期进行对比分析，发现三峡库区黄土坡滑坡在新构造快速抬升时期广泛发育，并与暖湿多雨期相对应，表明黄土坡滑坡的发育演化受到新构造运动和气候变化耦合作用的控制。
关键词: U-Th年龄/
MC-lCPMS/
黄土坡滑坡/
三峡库区/
滑坡演化

Abstract:Landslide has become one of the highest frequency and largest loss of various types of geological disasters. Dating their ages and reproducing their sequences in Quaternary period is the foundation of confirming the history and relationships and forecasting the development trend in the future. U-Th dating is a radiometric technique commonly used to determine the age of calcium carbonate materials. U-Th disequilibrium dating of secondary calcite can provide information on the timing of the Huangtupo landslide(31°06'01″N, 110°18'03″E) Badong County in the Three-Gorge Reservoir area. 4 calcite samples were collected from Branch 3 of Slump Ⅰ of the Huangtupo tunnel during excavation and investigated by MC-lCPMS. Results showed that the U content ranges in 30.9×10^-9~45.6×10^-9g/g with ratio of ²³⁴U/²³⁸U fluctuating in 1.362~2.673 and can meet the requirement of high precision U-Th chronology. We obtained four ages of 155.2±18.6 ka B.P., 134.6±5.6 ka B.P., 70.9±8.5 ka B.P. and 103.3±18.2 ka B.P. These apparent ages indicated Huangtupo landslide evolution occurred between 155.2~70.9 ka of the late Middle Pleistocene to early Late Pleistocene and involved multiple active sliding events. Huangtupo landslide ages of U-series are in good agreement with field investigation and previous research. This shows that U-Th approach by dating pure secondary calcite from the giant landslide is a kind of effective method to studying on the chronology of giant landslide. Correlation analysis between Huangtupo landslide and neotectonic, geomorphological process, climate change in the Three-Gorges and adjacent area show that Hangtupo extentive developed in the neotectonic period of rapid uplift and warm and wet climate. All results showed the Huangtupo landslide is a complex and multiple active sliding paleolandslide system and is response to joint governing processes of neotectonic movement and climate change.
Key words:U-Th dating/
MC-lCPMS/
Huangtupo landslide/
Three-Gorges Reservoir area/
landslide evolution



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