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3D magnetotelluric inversion reveals the superposition of tectonic systems in the northern Songliao Basin
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  • Tianqi Wang,
  • Guoqing Ma,
  • Jiangtao Han,
  • Wenyu Liu,
  • Zikun Zhou,
  • Jianqiang Kang
Tianqi Wang
Jilin University
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Guoqing Ma
Jilin University
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Jiangtao Han
Jilin University

Corresponding Author:[email protected]

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Wenyu Liu
University of the Chinese Academy of Sciences
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Zikun Zhou
Jilin University
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Jianqiang Kang
Jilin University
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Abstract

The creation and evolution of the Songliao Basin is closely related to the closure of the Paleo-Asian Ocean and the Mongolia-Okhotsk Ocean, and the subduction of the Paleo-Pacific Ocean. In an attempt to demonstrate the various attributes of the lithospheric structure under structural superimposition and transformation of the Songliao Basin, this work used full impedance 3D inversion to obtain a 3D electrical structural model of the northern Songliao Basin for the first time. The results showed there are NE-trending high-resistance anomalies and sporadic low-resistance anomalies at the depth of less than 10 km. At 15-30 km, there are several NE- and NW-trending high-conductivity anomalies and there is a large area of SN-oriented high conductor at 50 km. The outcomes of the investigation demonstrate: 1) The high-resistance anomalies found in the NE direction of the upper crust are consistent with the position of the volcanic rocks predicted by the reflection earthquake, whereas the low-resistance anomalies correspond to the distribution of shallow faults and rifts. They constitute the main components of the upper crust of the Songliao Basin; 2) The high conductivity anomalies occurring at the intersection of the central depression zone and the north plunge zone represent the thinnest position of the lithosphere in the Songliao Basin; 3) The high-conductor anomalies in crust-mantle can be attributed to the paleo-shear zones which were generated in the collage of micro-continents during the Paleo-Asian Ocean closure, and reactivated under the continuous transformation of the Mongolia-Okhotsk and the Paleo-Pacific tectonic systems in the later period.