| 大兴安岭与两侧盆地结合地带深部电性结构与岩石圈尺度构造关系 |
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| 引用本文： | 梁宏达,高锐,侯贺晟,金胜,韩江涛,韩松,刘国兴.大兴安岭与两侧盆地结合地带深部电性结构与岩石圈尺度构造关系[J].地球物理学报,2016,59(5):1696-1704. |
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| 作者姓名： | 梁宏达 高锐 侯贺晟 金胜 韩江涛 韩松 刘国兴 |
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| 作者单位： | 1. 中国地质大学(北京)地球物理与信息技术学院, 北京 100083;2. 中国地质科学院地质研究所, 国土资源部深部探测与地球动力学重点实验室, 北京 100037;3. 吉林大学地球探测科学与技术学院, 长春 130026 |
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| 基金项目： | "深部探测技术实验与集成"项目(SinoProbe-02),国家自然科学基金项目(41430213, 41474081)及中国地质调查工作项目(1212011220754)联合资助. |
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| 摘 要： | 横跨大兴安岭与海拉尔盆地和松辽盆地结合地带的大地电磁测深剖面揭示了盆山构造的深部电性结构.剖面西起海拉尔盆地东缘,向东延伸穿过大兴安岭中部,一直到达松辽盆地西缘.本文对剖面测点的二维偏离度、构造走向等进行了计算和分析,采用非线性共轭梯度(NLCG)二维反演方法对TM模式的数据进行了反演,获得了该剖面的地壳、上地幔电性结构模型,划分出三个典型构造单元:海拉尔盆地、大兴安岭和松辽盆地.研究结果表明,海拉尔盆地东缘和松辽盆地西缘浅部都呈低阻特征,但松辽盆地西缘深部电性结构比较复杂,而大兴安岭整体呈高阻特征.海拉尔盆地东缘可能属于兴安块体,松辽盆地西缘与大兴安岭接触关系复杂.海拉尔盆地东缘岩石圈厚度约为110km,大兴安岭岩石圈厚度约为110~150km.大兴安岭上地壳基本呈高阻特征,可能为多次叠置的岩浆岩,代表大兴安岭经历了多期次岩浆作用;中下地壳横向存在较大范围低阻体,可能反映了大兴安岭地壳内部非刚性的特点;残存在岩石圈地幔的高阻异常,说明其下地壳可能发生过拆沉作用.大兴安岭与松辽盆地结合带存在一个岩石圈尺度的西倾低阻带,向下延伸到岩石圈底部,可能是早期松嫩地块向兴安地块俯冲并以软碰撞形式拼合的构造遗迹.
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| 关 键 词： | 海拉尔盆地 大兴安岭 松辽盆地 大地电磁测深 深部电性结构 岩石圈尺度构造关系 |
| 收稿时间： | 2015-03-02 |
Deep electrical structure beneath the Da Hinggan Ling and the junction zone with adjacent basins and their tectonic relationship at a lithospheric scale |
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| LIANG Hong-Da,GAO Rui,HOU He-Sheng,JIN Sheng,HAN Jiang-Tao,HAN Song,LIU Guo-Xing.Deep electrical structure beneath the Da Hinggan Ling and the junction zone with adjacent basins and their tectonic relationship at a lithospheric scale[J].Chinese Journal of Geophysics,2016,59(5):1696-1704. |
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| Authors: | LIANG Hong-Da GAO Rui HOU He-Sheng JIN Sheng HAN Jiang-Tao HAN Song LIU Guo-Xing |
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| Institution: | 1. School of Geophysics and Information Technology, China University of Geosciences, Beijing 100083, China;2. Institute of Geology, Chinese Academy of Geological Science, Key Laboratory of Earthprobe and Geodynamics, Ministry of Land and Resources of the People's Republic of China, Beijing 100037, China;3. Geo-exploration Science and Technology Institute, Jilin University, Changchun 130026, China |
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| Abstract: | The magnetotelluric (MT) profile across the Da Hinggan Ling and the junction zone with the Hailar basin and Songliao basin was measured to reveal the deep electrical structure of the basin-mountain system. Data processing and analysis include calculation of the 2D skewness and electric strike of the MT profile, and NLCG 2D inversion on apparent resistivity and phase data of TM mode. An electrical structure model of crust and upper mantle was established. It shows that the eastern margin of the Hailar basin and the western margin of the Songliao basin exhibit a low-resistivity feature in the shallow, but the latter has a complex electrical structure at depth. The Da Hinggan Ling exhibits an overall high resistivity feature. The eastern margin of the Hailar basin may belong to the Xing'an terrane, while the relationship between the western margin of the Songliao basin and the Da Hinggan Ling is complex. The lithosphere-asthenosphere boundary (LAB) may be at the depth of 110 km at the eastern margin of the Hailar basin, and at 110~150 km depth below the Da Hinggan Ling. The upper crust of the Da Hinggan Ling may be overlapping volcanic rocks and granites representing multi-periodic magmatic activities. Extensive horizontal low resistivity bodies in the middle-lower crust imply that the crust is non-rigid. The large high-resistivity body in the lithospheric mantle suggests the lower crust may have undergone delamination. While the west-dipping low resistivity zone may be tectonic traces resulting from the subduction of the Songnen terrane beneath the Xing'an terrane, which ceased in the later strike-slip and extensional environment. |
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| Keywords: | Hailar basin Da Hinggan Ling Songliao basin Magnetotelluric Deep electrical structure Tectonic relationship at a lithosphere scale |
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