邓宾, 刘树根, 刘顺, 等. 2010: 川西北松潘-甘孜褶皱带较场弧形构造显微应变机制. 地质通报, 29(5): 697-706.
    引用本文: 邓宾, 刘树根, 刘顺, 等. 2010: 川西北松潘-甘孜褶皱带较场弧形构造显微应变机制. 地质通报, 29(5): 697-706.
    DENG Bin, LIU Shu-gen, LIU Shun, et al.. 2010: he micro-strain mechanism of Jiaochang arc structure in Songpan-Garze fold belt, Sichuan, China.. Geological Bulletin of China, 29(5): 697-706.
    Citation: DENG Bin, LIU Shu-gen, LIU Shun, et al.. 2010: he micro-strain mechanism of Jiaochang arc structure in Songpan-Garze fold belt, Sichuan, China.. Geological Bulletin of China, 29(5): 697-706.

    川西北松潘-甘孜褶皱带较场弧形构造显微应变机制

    he micro-strain mechanism of Jiaochang arc structure in Songpan-Garze fold belt, Sichuan, China.

    • 摘要: 区域显微结构构造特征及其变形机制已经成为造山带运动学、动力学机制及模型的重要约束。对松潘-甘孜褶皱带较场弧形带15个定向构造样品显微薄片的研究表明:弧形带以中—浅层共轴挤压同变形-变质作用为主,形成残缕构造、对称眼球构造、膝折构造等;弧形带构造变形具有典型对称性应变的特征,东西两翼应变强度大致相当(γ≌1.8)、压缩率大致相等(C≌27%),由北向南相同单元内应变特征具有一定的增强趋势(而不同单元之间具有微弱减小的趋势),尤其是弗林指数K值(K>1)由北向南具有明显增大的特征,总体为三轴长椭球应变,为伸长型应变型式。较场弧形带的显微应变特征与典型弧形构造的“走滑成因”机制非对称性的特征迥异,其成因应归于以南北向主应力所控制的差异应力-应变机制。

       

      Abstract: The Jiaochang arc belt is characterized by synorogenic, multiphasic, coaxial compressional deformation and metamorphism, which is under the mid-shallow layer setting, and has some typical microtectonics, such as rotated helicitic structure, symmetric pressure shadow and kind structure etc. Based on 15 orientated samples′ microscopic features, dominant striking micro-strain feature of Jiaochang is symmetry, meanwhile magnitude of strain is roughly similar(γ≌1.8) in the western and eastern arc limbs, and percentage of compression is roughly equal(C≌27%) too. There is increasing tendency for micro-strain feature in the same unit from north to south, while there is decreasing tendency in different units, as well as the Flinn index (K>1). The strain pattern is triaxial prolate strain. The symmetrically micro-structural feature in Jiaochang is significantly different to the unsymmetrical feature about "strike-slip" mechanism of arc belt, attributed to differential stress-strain mechanism controlled by the north to south main stress.

       

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