Electrical structures in the northwest margin of the Junggar basin: implications for its late Paleozoic geodynamics

Sheng Zhang, Yixian Xu, Li Jiang, Bo Yang, Ying Liu, W. L. Griffin, Yong Luo, Rong Huang, Yong Zhou, Liangliang Zhang

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Recent geological, geochemical and geophysical data have inclined to support the presence of a remnant Paleozoic oceanic lithosphere beneath the Western Junggar, southwestern Chinese Altaids. However, regional high-resolution geophysical data have been rarely deployed to image its geometry, making it difficult to trace its evolution and final geodynamic setting. Presently, two magnetotelluric (MT) profiles are deployed across the northwest margin of the Junggar basin and the southern Darbut belt to image the electrical structure of the crust and lithospheric mantle. High-quality data at 102 sites and the quasi-2D indications of phase tensor skew angles and impedance phase ellipses for relatively short periods (up to 500 s) allow us to invert the two profile data by a 2-D scheme. The resistivity cross-section of a NW-SE striking LINE2 sheds light on a fossil intraoceanic subduction system, and reveals the Miaoergou intrusions as a bowl-like pluton, indicating that the multi-phase intrusions primarily formed in a post-collisional setting. The resistivity cross-section of striking NE-SW LINE1 reveals a possible oceanic slab with relatively lower resistivity underlying the low-resistivity sedimentary strata and high-resistivity mélange. Given that the profile of LINE1 cuts the out-rise zone of a subducted slab developed during the late Paleozoic, the 2-D resistivity model may thus represent the zone that have experienced heterogeneous deformation, reflecting subduction with barrier variation parallel to the ancient trench. Moreover, as shown in previous results, the new MT data also illustrate that the Darbut Fault is a thin-skinned structure, which has been erased at depths during the subsequent magmatism.

LanguageEnglish
Pages473-483
Number of pages11
JournalTectonophysics
Volume717
DOIs
Publication statusPublished - 16 Oct 2017

Fingerprint

geodynamics
electrical resistivity
margins
Paleozoic
basin
intrusion
slab
slabs
subduction
profiles
cross section
cross sections
ellipse
fossils
ellipses
oceanic lithosphere
strata
data quality
lithosphere
pluton

Keywords

  • Western Junggar
  • Magnetotelluric
  • 2-D electrical imaging
  • Intraoceanic subduction
  • The Darbut fault
  • Central Asian Orogenic Belt (CAOB)

Cite this

Zhang, Sheng ; Xu, Yixian ; Jiang, Li ; Yang, Bo ; Liu, Ying ; Griffin, W. L. ; Luo, Yong ; Huang, Rong ; Zhou, Yong ; Zhang, Liangliang. / Electrical structures in the northwest margin of the Junggar basin : implications for its late Paleozoic geodynamics. In: Tectonophysics. 2017 ; Vol. 717. pp. 473-483.
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Electrical structures in the northwest margin of the Junggar basin : implications for its late Paleozoic geodynamics. / Zhang, Sheng; Xu, Yixian; Jiang, Li; Yang, Bo; Liu, Ying; Griffin, W. L.; Luo, Yong; Huang, Rong; Zhou, Yong; Zhang, Liangliang.

In: Tectonophysics, Vol. 717, 16.10.2017, p. 473-483.

Research output: Contribution to journalArticleResearchpeer-review

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