Tectonic Implications of Perm-Triassic Paleomagnetic Results from North and South China

  1. John W. Hillhouse
  1. Xixi Zhao and
  2. Robert S. Coe

Published Online: 18 MAR 2013

DOI: 10.1029/GM050p0267

Deep Structure and Past Kinematics of Accreted Terranes

Deep Structure and Past Kinematics of Accreted Terranes

How to Cite

Zhao, X. and Coe, R. S. (1989) Tectonic Implications of Perm-Triassic Paleomagnetic Results from North and South China, in Deep Structure and Past Kinematics of Accreted Terranes (ed J. W. Hillhouse), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM050p0267

Author Information

  1. Earth Sciences Board, University of California, Santa Cruz

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780875904542

Online ISBN: 9781118666609

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Keywords:

  • Geology, Structural—Congresses;
  • Geodynamics—Congresses;
  • Earth—Crust—Congresses

Summary

Late Permian and Early Triassic paleomagnetic results of our own and others show that the North China Block (NCB), South China Block (SCB), and Siberia were not in their present positions relative to each other. Paleomagnetic poles for the NCB that derived from our studies of Permian rocks at several localities in Shanxi and Hebei provinces are concordant with poles from other studies of Permian rocks in Shanxi, Gansu, and Inner Mongolia. In addition, our poles for the Permian Emeishan Basalts and those from many other studies of the same formation over a sizeable portion of the SCB are consistent if we reinterpret the polarity of several of them. Early Triassic poles from both blocks are fairly close to the Late Permian ones, and greatly increase the areal extent covered by the data for the SCB. The equatorial paleolatitudes inferred by the data from both blocks are similar, but the mean declination for the SCB is rotated clockwise more than 60 degrees with respect to that for the NCB. To explain these results we propose a simple tectonic model in which initial collision of the blocks occurred in the Early Triassic near the eastern end of their boundary and progressed westward as the SCB rotated clockwise 67 degrees relative to the NCB. Eastward thinning and eventual disappearance of Triassic marine sediments on the northern margin of the SCB support this model. A simple alternative model involves sinistral movement on a transform fault that wraps around the SCB to the north and west, but evidence for the large Mesozoic displacement (2,500 km minimum) is presently lacking. Jurassic and Cretaceous poles for North and South China and for Siberia are overlapping, but no fold or reversal tests are available for the Jurassic data from China. Thus, the major movements between the three blocks were completed at least by the Late Cretaceous, perhaps during Jurassic time.