ISSN 1002-1027  CN 11-2952/G2

Acta scientiarum naturalium Universitatis Pekinensis

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An Initial Research on the Extension Deformation Belt in the Archean Metamorphic Rocks in the Northern Taihang Mountains

TANG Xianmei, LIU Shuwen   

  1. Department of Geology, Peking University, Beijing, 100871
  • Received:1996-11-21 Online:1997-07-20 Published:1997-07-20

Abstract: The Archean metamorphic rocks in the northern Taihang Mountains can be divided into Fuping Gneiss Complex (FPGC), Nanying Gneiss (NYG) and Wanzi Layering Series (WZLS) from bottom to top. A large low-angle-extension deformation belt, along which NYG was emplaced, was found between FPGC and WZLS. A series of ductile deformation structures, including a-type and sheath folds, mineral stretching lineations and augen structures, are found in the main deformation belt, where rocks have been foliated heavily. Shear criteria indicate a top-to-the-west sense of shear. A series of small shear zones, which are parallel to the main deformation belt, are formed in the foot wall, while in the hanging wall ductile-brittle normal faults are popular. The PT-paths of the two walls are clockwise, implying that the crust evoluted from early thicking by folding through thinning by stretching and finally being denuded by lifting.