EGU22-2045
https://doi.org/10.5194/egusphere-egu22-2045
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Structures and geodynamics of the Mongolian tract of the Central AsianOrogenic Belt constrained by potential field analyses

Alexandra Guy1, Karel Schulmann1,2, Igor Soejono1, Nils Holzrichter3, Ondrej Lexa4, and Marc Munschy2
Alexandra Guy et al.
  • 1Czech Geological Survey, Centre for Lithospheric Research, Praha 1, Czechia (alexandra.guy@gmail.com)
  • 2Institut de Physique du Globe de Strasbourg – CNRS UMR7516, Université de Strasbourg, France
  • 3Institute of Geosciences, Christian-Albrechts-Universität, Kiel, Germany
  • 4Institute of Petrology and Structural Geology, Charles University, Prague, Czech Republic

A multidisciplinary approach integrating potential field analysis with geological and geochemical data provides new insights into the understanding of the crustal structure and evolution of the Mongolian collage. Magnetic and gravity data demonstrate the inconsistency between the geologically defined terranes and the geophysical domains in the southwestern part of the Mongolian collage. The combination of potential field analysis and modelling with whole rock geochemistry and isotopic mapping of Carboniferous–Permian granitoids indicates the presence of a homogeneous lower crust composed of a felsic to intermediate juvenile material beneath geophysically heterogeneous upper crust. This feature is interpreted as a result of a trench-directed lower crustal emplacement of an arc type crust underplating deformed Paleozoic oceanic crust. The potential field data also confirmed the occurrence of two orthogonal late Devonian and Permian–Triassic deformation upper crustal fabrics at the scale of the southwestern Mongolian collage. The prominent magnetic highs correspond to the tectono-metamorphic domains and magmatic provinces. The gravity anomalies highlight a periodicity of the signal correlating with alternating Permian–Triassic high and low strain zones, forming a zone of major deformation wrapping around the hinge of Mongolian orocline. The geometry and kinematics of dextral and sinistral transpressive faults are explained to result from the reactivation of Permian–Triassic deformation zones in the Cenozoic stress field.

How to cite: Guy, A., Schulmann, K., Soejono, I., Holzrichter, N., Lexa, O., and Munschy, M.: Structures and geodynamics of the Mongolian tract of the Central AsianOrogenic Belt constrained by potential field analyses, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2045, https://doi.org/10.5194/egusphere-egu22-2045, 2022.