Quantitative finite strain analysis of the quartz mylonites within the Three Pagodas shear zone, western Thailand

IF 1.7 4区地球科学 Q2 Earth and Planetary Sciences

Austrian Journal of Earth Sciences Pub Date : 2018-12-01 DOI:10.17738/ajes.2018.0011

P. Kanjanapayont, Peekamon Ponmanee, B. Grasemann, U. Klötzli, Prayath Nantasin

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引用次数: 2

Abstract

Abstract The NW–trending Three Pagodas shear zone exposes a high–grade metamorphic complex named Thabsila gneiss in the Kanchanaburi region, western Thailand. The quartz mylonites within this strike–slip zone were selected for strain analysis. 2–dimensional strain analysis indicates that the averaged strain ratio (Rs) for the lower greenschist facies increment of XZ– plane is Rs = 1.60–1.97 by using the Fry’s method. Kinematic vorticity analysis of the quartz mylonites in the shear zone showed that the mean kinematic vorticity number of this increment is Wk = 0.75–0.99 with an average at 0.90 ±0.07. The results implied that the quartz mylonites within the Three Pagodas shear zone have a dominant simple shear component of about 72% with a small pure shear component. A sinistral shear sense is indicated by kinematic indicators from macro– to micro–scale. We conclude that the Three Pagodas shear zone deformed in the process of sinstral shear–dominated transpression, which is similar to the Mae Ping shear zone in the north.

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泰国西部三塔剪切带石英糜棱岩的定量有限应变分析

摘要：在泰国西部的Kanchanaburi地区，NW走向的三塔剪切带暴露出一个名为Thabsila片麻岩的高级变质杂岩。选择该走滑带内的石英糜棱岩进行应变分析。二维应变分析表明，使用Fry方法，XZ平面下绿片岩相增量的平均应变比（Rs）为Rs=1.60–1.97。剪切带石英糜棱岩的运动涡度分析表明，该增量的平均运动涡度值为Wk=0.75–0.99，平均值为0.90±0.07。结果表明，三塔剪切带内的石英糜棱岩具有约72%的主要简单剪切成分和较小的纯剪切成分。从宏观到微观的运动学指标表明了左旋剪切感。我们得出结论，三塔剪切带在以左旋剪切为主的转换挤压过程中发生了变形，与北部的梅坪剪切带相似。

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来源期刊

Austrian Journal of Earth Sciences Earth and Planetary Sciences-Paleontology

CiteScore

3.10

自引率

0.00%

发文量

审稿时长

>12 weeks

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.