| 景德镇-温州大地电磁剖面深部电性结构研究 |
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| 引用本文： | 韩松,刘国兴,韩江涛.景德镇-温州大地电磁剖面深部电性结构研究[J].地质科学,2016,0(1):86-98. |
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| 作者姓名： | 韩松 刘国兴 韩江涛 |
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| 作者单位： | 吉林大学地球探测科学与技术学院 长春 130026 |
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| 摘 要： | 华南大陆历经长期复杂的构造演化,其浅部复杂而多样的构造形态与深部壳幔结构及其动力学机制有着密切联系,但当前的深部探测资料有限,深部构造并不明确。为了研究华南的深部岩石圈结构状态,布设了多条宽频长周期大地电磁联合探测剖面。通过对景德镇-温州剖面的数据处理,获得了该剖面的岩石圈电性结构模型。分析表明:华夏地块与扬子地块东部的江南造山带以江绍断裂为界;华夏地块整体呈现高阻特征,可能具有深部岩石圈背景的上虞-政和-大浦断裂将其分为华夏褶皱带与东南沿海岩浆岩带;扬子地块东部的江南造山带整体电阻率较低,结构更破碎,受到深部改造明显,岩石圈底界约为110 km;剖面发现3处低阻带通道,可能与软流圈上涌相关;江绍断裂呈喇叭状向深部张开,华夏地块与扬子地块的裂解拼合可能与断裂深部的高导体活动有关。华夏地块与扬子地块的接触状态呈现为双向汇聚,华夏地块在上地幔挤入扬子地块,深部接触边界可能越过江绍断裂带。
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| 关 键 词： | 大地电磁 电性结构 华夏地块 扬子地块 江绍断裂 |
| 收稿时间： | 2015-03-08 |
| 修稿时间： | 2015-03-08; |
Deep electrical structure of Jingdezhen-Wenzhou magnetotelluric profile |
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| Han Song,Liu Guoxing,Han Jiangtao.Deep electrical structure of Jingdezhen-Wenzhou magnetotelluric profile[J].Chinese Journal of Geology,2016,0(1):86-98. |
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| Authors: | Han Song Liu Guoxing Han Jiangtao |
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| Institution: | Geo-exploration Science and Technology Institute, Jilin University, Changchun 130026 |
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| Abstract: | The South China block has experienced a long and complicated tectonic evolution history which formed the present tectonic features. The surface tectonic structure is complex and diverse which has an inevitable contact with the deep structure. However, the detection of deep structure is limited and current deep state remain undefined. To investigate the deep lithospheric structure of the South China region, we have completed a series of joint detection profiles of broad band magnetotelluric(MT)and long period MT under the auspices of SinoProbe-02 project. The profile introduced is Jingdezhen-Wenzhou profile located in the northeast part of the South China region with a length of about 400 km. Based on the data analyses, the 2D inversions were conducted and the lithospheric electrical structure model was finally obtained. The inversion model reveals that:The profile mainly consists of the Cathaysia block and Jiangnan orogen which borders the East Yangtze block while the Jiangshao fault is the boundary fault of the two block. The Cathaysia block is generally resistive which is consistent with the strong magmatic activity and the stable Precambrian settings. It consists of two sub-tectonic unit, Cathaysia folded belt and the southeast coast magmatic belt. The Shangyu-Zhenghe-Dapu fault serving as the boundary fault may be a lithospheric fault. The structure of Jiangnan orogen seems more fractured and conductive which indicate that the Jiangnan orogen has experienced deep reconstruction. The lithosphere asthenosphere boundary(LAB)is detected in the northwest part of Jiangnan orogen with a depth of about 110 km. There are also three upwelling channel observed in the different location of the profile which are C1-C3 channel, C2-C3 channel and the relatively conductive zone between R4 and R5. These structures shows the reconstruction process from the deep. The trumpet shaped Jiangshao fault which is the coupling zone of Yangtze block and Cathaysia block opens to the deep and its characteristics reveals the deep agent of the former cracking-closure process. The coupling characteristcs turn to be a convergence structure and the Cathaysia block wedged into the Yangtze block in the upper mantle with the deep boundary went across the Jiangshao fault. |
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| Keywords: | Magnetotelluric Electrical structure Cathaysia block Yangtze block Jiangshao fault |
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