地球物理学进展 ›› 2018, Vol. 33 ›› Issue (4): 1419-1429.doi: 10.6038/pg2018BB0234

• 固体地球物理及空间物理学(大气、行星、地球动力学、重磁电及地震学、地热学) • 上一篇    下一篇

郯庐断裂带江苏段及邻区航磁异常与深部构造特征

王德华,张景发,王鑫(),姜文亮,田甜   

  1. 中国地震局地壳应力研究所(地壳动力学重点实验室),北京 100085
  • 收稿日期:2017-10-02 修回日期:2017-06-26 出版日期:2018-08-20 发布日期:2018-09-13
  • 通讯作者: 王鑫 E-mail:wangxinjapan@163.com
  • 作者简介:王德华,男,1994年生,在读硕士,主要从事重磁场深部构造及地球动力学研究.(E-mail: wangdehuacea@163.com)
  • 基金资助:
    中国地震局地壳应力研究所中央级公益性科研院所基本科研业务专项(ZDJ2016-17);宿迁市地震活断层探测及地震危险性分析项目共同资助

Analysis of aeromagnetic anomalies and deep structures of Jiangsu segment of Tan-Lu fault zone and its adjacent region

WANG De-hua,ZHANG Jing-fa,WANG Xin(),JIANG Wen-liang,Tian Tian   

  1. Key Laboratory of Crustal Dynamics, Institute of Crustal Dynamics, China Earthquake Administration, Beijing 100085, China
  • Received:2017-10-02 Revised:2017-06-26 Online:2018-08-20 Published:2018-09-13
  • Contact: Xin WANG E-mail:wangxinjapan@163.com

摘要:

收集了郯庐断裂带江苏段及周边地区较大比例尺的航磁异常数据,通过水平及垂向求导、欧拉反褶积处理、居里面反演及剖面建模,系统分析了区域地壳磁性结构、断层空间展布及深部构造特征,并揭示了其与地热、地震以及岩浆活动的相互关系.研究表明:(1)区域航磁异常场具有明显的分区性,线性特征明显的航磁异常高值区基本由断裂主控,为岩浆沿断层侵入、灌入导致,而线性特征不明显的航磁异常高值或者低值区主要与磁性基底的埋深有关,其中郯庐断裂带形成NNE向的串珠状高磁性异常条带.(2)航磁场及其方向导数图显示区域发育17条主要断裂,其中郯庐断裂带与周边的10条断裂处岩浆活动剧烈;欧拉反褶积结果显示研究区磁性基底埋深在郯庐断裂带处及其两侧不同构造单元处存在差异;居里面反演结果表明郯庐断裂带为居里面坳陷区,该处为热流值及地温梯度低值区.剖面建模结果揭示郯庐断裂带底部可能存在大范围的基性及超基性岩浆岩,且推测断层剖面延伸形态为张扭性的“负花状构造”.(3)以无锡—宿迁断裂为界,郯庐断裂带南北两侧在原始航磁场、航磁梯度场以及欧拉反褶积结果中均体现出了明显的分段性,表现为北侧航磁异常值更高、航磁梯度场波动更加剧烈且磁性基底埋深更浅.

关键词: 郯庐断裂带江苏段, 航磁异常, 深部构造, 欧拉反褶积, 居里面, 岩浆活动

Abstract:

By operating derivative disposal in horizontal and vertical directions, Euler deconvolution, inversion of Curie surface and profile modeling based on large-scale aeromagnetic date, we systematically analyzed the regional crustal magnetic structure, the spatial distribution of faults and the deep structure characteristics of the Jiangsu segment of the Tan-Lu fault zone, and then revealed the relationships among these characteristics and geothermy, earthquakes and magmatic activities in this area. Our research shows that:(1) The aeromagnetic anomalies of the study area have obvious zoned features, and high aeromagnetic anomaly areas with good linear characteristics are controlled by faults which have been intruded by magmas, while high or low aeromagnetic anomaly areas without linear characteristics are controlled by the buried depth of basement, and there is a NNE high beaded magnetic anomaly belt in the Tan-Lu fault zone. (2) According to our interpretation, there are 17 main faults in the research area, and we think 10 of them have been influenced by magmatic activities. The Euler inversion results show that there are big differences of the buried depth of the crystalline basement among the Tan-Lu fault zone and its two sides, and the inversion results of Curie surface show that the Curie surface is deeper in the Tan-Lu fault zone, which suggests that this place has a low value of heat flow and temperature gradient. Profile modeling results reveal there are large-scale basic and ultrabasic igneous rocks in the bottom of the crust in Tan-Lu fault zone, and the extending form of the faults should be “ minus flower structure”, which indicates a tenso-shear property of the crust. (3) With Wuxi-Suqian fault as the boundary, the northern part of Tan-lu fault zone is different from the southern part in original aeromagnetic field, aeromagnetic gradient field and Euler deconvolution results, and we found the north side has higher aeromagnetic anomalies, more volatile aeromagnetic gradient and shallower crystalline basement.

Key words: Jiangsu segment of Tan-Lu fault zone, aeromagnetic anomaly, deep structure, Euler deconvolution, Curie interface, magmatic activity

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