From oblique accretion to transpression in the evolution of the Altaid collage: New insights from West Junggar, northwestern China
From oblique accretion to transpression in the evolution of the Altaid collage: New insights from West Junggar, northwestern China
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DOI：
10.1016/j.gr.2011.07.015
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发表时间：
2012-03
影响因子：
6.1
通讯作者：
Flavien Choulet;M. Faure;Dominique Cluzel;Yan Chen;Wei Lin;Bo Wang
中科院分区：
文献类型：
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作者：
Flavien Choulet;M. Faure;Dominique Cluzel;Yan Chen;Wei Lin;Bo Wang
沿着活动边缘，板块会聚所产生的构造特征强烈地受到俯冲带几何形状的控制。西准噶尔是中亚古生代巨型拼贴的一部分，西克拉玛依单元代表了一个由弧前沉积岩和蛇绿混杂岩组成的石炭纪增生杂岩。准同步直立褶皱和垂直轴褶皱的出现表明，平移挤压作用在西准噶尔构造演化中起着重要作用。石炭纪晚期（Latest Carboniferous）碱性侵入岩的形成晚于早期褶皱作用，与石炭纪杂岩的增生作用同步。二叠纪达拉布特左行断裂叠加石炭纪韧性剪切作用，使西克拉玛依单元断裂约1000m。相距100公里。斜向收敛可能是由哈萨克造山带的屈曲和它的部分之间的相对旋转引起的。取决于会聚带的形状，直立褶皱和垂直轴褶皱，或者，应变分配响应的走滑脆性断层。西准噶尔增生杂岩单元的侧向叠瓦构造可能是由左行脆性断裂作用引起的。
Along active margins, tectonic features that develop in response to plate convergence are strongly controlled by subduction zone geometry. In West Junggar, a segment of the giant Palaeozoic collage of Central Asia, the West Karamay Unit represents a Carboniferous accretionary complex composed of fore-arc sedimentary rocks and ophiolitic mélanges. The occurrence of quasi-synchronous upright folds and folds with vertical axes suggests that transpression plays a significant role in the tectonic evolution of the West Junggar. Latest Carboniferous (ca. 300Ma) alkaline plutons postdate this early phase of folding, which was synchronous with accretion of the Carboniferous complex. The Permian Dalabute sinistral fault overprints Carboniferous ductile shearing and split the West Karamay Unit ca. 100km apart. Oblique convergence may have been provoked by the buckling of the Kazakh orocline and relative rotations between its segments. Depending upon the shape of the convergence zone, either upright folds and fold with vertical axes, or alternatively, strike–slip brittle faults developed in response to strain partitioning. Sinistral brittle faulting may account for the lateral imbrication of units in the West Junggar accretionary complex.