毛星^1,2,,
叶高峰^1,,,
张雨轩^3,1,
金胜¹,
魏文博¹
1. 中国地质大学地球物理与信息技术学院, 北京 100083
2. 中铁第五勘察设计院集团有限公司, 北京 102600
3. 中煤天津设计工程有限责任公司, 天津 300120

基金项目: "深部探测技术与实验研究"专项第一项目（Sinoprobe-01）和中国地质调查局项目（DD20160082，DD20190012）共同资助


详细信息

作者简介: 毛星, 男, 1985年生, 在读博士, 高级工程师, 主要从事铁路工程物探研究.E-mail: maoxing_1@163.com

通讯作者: 叶高峰, 男, 1977年生, 教授、博士生导师, 主要从事地电学和电法勘探的教学和研究.E-mail: ygf@cugb.edu.cn

中图分类号: P631

收稿日期:2020-11-05
修回日期:2021-09-10
上线日期:2021-11-10

Electric structure of the southern section of the Jiangnan orogenic belt and its tectonic implications

MAO Xing^1,2,,
YE GaoFeng^1,,,
ZHANG YuXuan^3,1,
JIN Sheng¹,
WEI WenBo¹
1. School of Geophysics and Information Technology, China university of Geosciences, Beijing 100083, China
2. China Railway Fifth Survey and Design Institute Group Co., LTD, Beijing 102600, China
3. China Coal Group Tianjin Design Engineering Co., Ltd., Tianjin 300120, China


More Information

Corresponding author: YE GaoFeng,E-mail:ygf@cugb.edu.cn

MSC: P631

--> Received Date: 05 November 2020
Revised Date: 10 September 2021
Available Online: 10 November 2021


摘要
摘要:华南板块是中国大陆的重要组成部分，普遍认为其由华夏和扬子地块沿江南造山带拼合而成，之后又经历了多期次的构造、岩浆活动.对华南板块的形成与演化研究一直是热点问题.本文采用一条始于扬子地块内部并南东向穿越江南造山带南段、华夏地块的大地电磁测深剖面，经过数据处理与分析，反演与模型验证等工作后，获得了可靠的岩石圈二维电阻率模型，并对江南造山带南段的边界、扬子地块和华夏地块与江南造山带的接触关系等重要问题进行了讨论.电阻率模型显示扬子地块、江南造山带南段和华夏地块之间电阻率差异明显，其中华夏地块岩石圈整体表现为大范围的高阻，扬子地块由浅至深表现为高-低-高阻的层状结构，而两者之间的江南造山带南段深部表现为明显的低阻.根据电阻率模型的特征，得出如下主要结论：江南造山带南段西界为开远-平塘断裂，东界为萍乡-茶陵断裂；江南造山带南段深部的大范围低阻区域是二叠纪沉积岩的电性反映；华夏地块下方南东向倾斜低阻区解释为早三叠纪右江盆地持续下沉导致江南造山带俯冲到华夏地块之下的电性反映.
关键词: 江南造山带南段/
岩石圈电阻率模型/
俯冲/
大地电磁测深/
扬子地块与华夏地块

Abstract:The South China plate is an important part of mainland China, generally considered to be resulted from the amalgamation between the Cathaysia and Yangtze blocks along the Jiangnan orogenic belt, after which it has undergone many periods of tectonic and magmatic activities. The research on the formation and evolution of the South China plate has long been a focused issue. This work built on a magnetotelluric sounding profile that starts in the Yangtze block and crosses the southern section of the Jiangnan orogenic belt and the Cathaysia block in a NW direction. After data processing, analysis, inversion and model verification, a reliable two-dimensional lithospheric resistivity model was constructed. With the two-dimensional resistivity model, a couple of important issues such as the boundary of the southern section of the Jiangnan orogenic belt and the contact relationship among the Yangtze block, the Cathaysia block and the Jiangnan orogenic belt were discussed. The resistivity model shows that the resistivity differences between these three tectonic units are obvious. The lithosphere of the Cathaysia block is featured by high resistivity as a whole, the Yangtze block shows a high-low-high resistivity layered structure from shallow to deep, and the deep part of the southern Jiangnan orogenic belt between the two blocks exhibits remarkable low resistivity. From the resistivity model, it is concluded that the western boundary of the southern section of the Jiangnan orogenic belt should be the Kaiyuan-Pingtang fault, and the eastern boundary is the Pingxiang-Chaling fault. The large-scale low-resistivity area in the deep southern part of the Jiangnan orogenic belt is interpreted as electrical expression of the Permian sedimentary rocks. The southeast ward tilting resistivity gradient belt between the Jiangnan orogenic belt and the Cathaysia block is interpreted as the continuous subsidence of the Youjiang basin in the Early Triassic, which caused the Jiangnan orogenic belt to subduct beneath the Cathaysia block.
Key words:Southern section of the Jiangnan orogenic belt/
Lithospheric resistivity model/
Subduction/
Magnetotelluric sounding/
Yangtze block and Cathaysia block



PDF全文下载地址:

http://www.geophy.cn/data/article/export-pdf?id=c3844768-58b8-4336-ab97-fba1f188d560