| 辽宁及其邻区高精度航磁数据分析:对区域性断裂带与岩石圈热结构约束 |
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| 引用本文： | 高维,舒晴,郭志宏,孟庆奎,张凯淞,陈丽梅.辽宁及其邻区高精度航磁数据分析:对区域性断裂带与岩石圈热结构约束[J].地球科学,2022,47(9):3401-3416. |
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| 作者姓名： | 高维 舒晴 郭志宏 孟庆奎 张凯淞 陈丽梅 |
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| 作者单位： | 1.中国自然资源航空物探遥感中心，北京 100083 |
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| 基金项目： | 自然资源部中国地质调查局二级项目DD2189410自然资源部中国地质调查局二级项目DD20190001自然资源部中国地质调查局二级项目DD20190003自然资源部中国地质调查局二级项目DD20190037 |
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| 摘 要： | 高精度航磁数据分析与挖掘是揭示区域性断裂带空间展布与岩石圈热结构的重要手段之一.为了揭示辽宁及其邻区航磁异常与区域性断裂带关系，估算其居里面深度与岩石圈厚度，本文在对航磁数据进行化极的基础上，利用功率谱法反演了研究区居里面深度；采用一维稳态热传导方程，计算了辽东?渤海湾地区岩石圈厚度.研究表明:（1）辽东、辽西与渤海湾地区存在多条北东向/北北东向航磁异常带，它们是晚中生代以来太平洋板片俯冲作用背景下，活动大陆边缘长期伸展与短暂挤压状态交替演变的产物；而辽北地区被北东向磁异常带错断的近东西/北西西向航磁异常带，则是古亚洲洋闭合后碰撞造山晚期伸展抬升至中地壳层次的构造形迹.（2）辽宁及其邻区居里面深度在16~40 km之间，平均深度为28 km，阜新与盘锦等居里面隆起区对应的大地热流值相对偏高；而沈阳与辽源居里面坳陷区对应的大地热流值偏低.（3）辽宁及其邻区岩石圈厚度具有空间非均匀性，变化范围为70~150 km，平均值为100 km；郯庐断裂带附近的营口?鞍山地区下方岩石圈厚度最薄，为60~80 km；辽东与渤海湾地区岩石圈厚度空间非均匀性可能是晚中生代以来太平洋板片俯冲诱导的上升流与克拉通岩石圈内部先存的构造薄弱带共同作用的结果.
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| 关 键 词： | 辽宁 航磁异常 居里面深度 岩石圈厚度 地球物理 |
| 收稿时间： | 2022-03-11 |
Analysis of High Precision Aeromagnetic Data in Liaoning and Its Adjacent Areas: Constraints on Regional Fault Zones and Lithospheric Thermal Structure |
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| Abstract: | Analysis and mining of high-precision aeromagnetic data is one of the important methods to reveal the spatial distribution of regional deep fault zones and lithospheric thermal structure. In order to reveal the relationship between the aeromagnetic anomaly and the regional fault zones and estimate the Curie-point depths and lithospheric thicknesses in Liaoning and its adjacent areas, the Curie-point depths are calculated by the power spectrum method, based on reduction to pole of aeromagnetic data. Meanwhile, the lithospheric thicknesses of the eastern segments of Liaoning are calculated by the 1D stable thermal conduction equations. Our new aeromagnetic data reveals that: (1) There are several NE/NNE striking aeromagnetic anomaly zones in the eastern and western parts of Liaoning and the Bohai Bay, which are interpreted as the products of the alternation of long-term extension and brief compression of the active continental margins under the background of the Pacific Plate subduction since the Late Mesozoic. The near NW/NWW striking aeromagnetic anomaly zones in the northern segments of Liaoning, which are interrupted by the NE/NNE striking magnetic anomaly zones, are interpreted as the tectonic traces which were extended and uplifted to the middle crust after the closure of the Paleo-Asian Ocean during the late collisional orogeny. (2) Our aeromagnetic anomalies also show that the estimated Curie-point depths of Liaoning and its adjacent areas ranges from 16 km to 40 km, with an average depth of 28 km. The heat flow values of the Fuxin and Panjin Curie uplifted are relatively higher. However, the heat flow values of the Shenyang and Liaoyuan Curie depression are relatively lower. (3) The estimated lithospheric thicknesses of the Liaoning and its adjacent areas show spatial heterogeneity, ranging from 70 km to 150 km with an average of 100 km. The estimated lithospheric thickness of the Yingkou-Anshan area near the Tan-Lu fault zone is the thinnest with a thickness of 60-80 km. The spatial heterogeneity of regional thermal lithospheric thicknesses in the eastern segments of Liaoning and Bohai Bay most likely results from the combined effects of the spatially heterogeneous distribution of wet upwellings triggered by the subducted Pacific slab and pre-existing weak zones in the cratonic lithosphere since the Late Mesozoic. |
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