Peekamon Ponmanee, P. Kanjanapayont, B. Grasemann, U. Klötzli, M. Choowong
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引用次数: 6
摘要
北西走向的湄平剪切带在泰国西部的德克地区暴露出高品位变质岩,即所谓的兰桑片麻岩。走滑带内岩性主要为正长岩和副长岩。利用Fry方法进行二维应变分析,得到xy平面的平均有限应变比R s = 1.35-1.69。根据剪切带糜棱质片麻岩的运动涡度分析,其运动涡度值为wk = 0.8 ~ 1.0,平均值为wk = 0.95。结果表明,湄平剪切带内均质变形岩石具有较强的单剪切分量,纯剪切分量较小,约占15%。露头和微观尺度的运动学指标均显示出左旋走滑剪切作用。认为湄平剪切带具有地壳尺度的左旋挤压作用。
Quantitative finite strain analysis of high-grade metamorphic rocks within the Mae Ping shear zone, western Thailand
The NW trending Mae Ping shear zone exposes high-grade metamorphic rocks, the so called Lansang gneiss in the Tak region, western Thailand. The lithologies within the strike-slip zone mainly consist of orthogneisses and paragneisses. Using Fry’s method for 2-dimensional strain analysis we find that the averaged finite strain ratio (R s ) of the XY-plane is R s = 1.35-1.69. Based on the kinematic vorticity analysis of the mylonitic gneisses in the shear zone, the kinematic vorticity number is W k = 0.8-1.0 with an average of W k = 0.95. The results imply that the homogeneously deforming rocks within the Mae Ping shear zone have a strong simple shear component with a minor pure shear contribution of about 15 %. The kinematic indictors from both outcrop and micro scopic scales indicate a sinistral strike-slip shear sense. We conclude that the Mae Ping shear zone accommodated crustal scale sinistral transpression.
期刊介绍:
AUSTRIAN JOURNAL OF EARTH SCIENCES is the official journal of the Austrian Geological, Mineralogical and Palaeontological Societies, hosted by a country that is famous for its spectacular mountains that are the birthplace for many geological and mineralogical concepts in modern Earth science.
AUSTRIAN JOURNAL OF EARTH SCIENCE focuses on all aspects relevant to the geosciences of the Alps, Bohemian Massif and surrounding areas. Contributions on other regions are welcome if they embed their findings into a conceptual framework that relates the contribution to Alpine-type orogens and Alpine regions in general, and are thus relevant to an international audience. Contributions are subject to peer review and editorial control according to SCI guidelines to ensure that the required standard of scientific excellence is maintained.