Formation Mechanism of the Dabashan Foreland Arc-Shaped Structural belt
Formation Mechanism of the Dabashan Foreland Arc-Shaped Structural belt
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发表时间：
2010
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通讯作者：
Zhang Yueqiao
中科院分区：
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作者：
Zhang Yueqiao
本文根据野外观察和构造测量资料，描述了大巴山前陆弧形构造带的基本特征、展布格局、分带性、分段性、垂向分层、变形样式、叠加褶皱和古应力场，并讨论了控制该构造弧形成的主要因素。指出大巴山前陆弧的形成与发展不同于经典的碰撞造山模式，它经历了3个不同的阶段：古生代沿扬子陆缘拉张裂陷形成原始边界条件;中晚三叠世碰撞造山启动;中晚侏罗世陆内造山最终形成。弧形的城口-房县断裂带不仅控制了早古生代的沉积和岩浆活动，而且对前陆弧的形成起着关键作用，两条断裂带上的基底隆起是重要的边界条件。利用室内砂箱模型模拟了大巴山前陆弧的形成过程和边界条件。该模型是根据真实的地质资料建立的。
Based on field observations and structural measurements,this paper describes basic features of the Dabashan foreland arc-shaped structural belt,its distribution pattern,zonation,segmentation,vertical stratification,deformation pattern,superimposed folding and paleostress field,then discusses main factors controlling the formation of this structural arc. It pointed out that the formation and development of the Dabashan foreland arc are different from classical model of collisional mountain built-up; it was shaped through three different stages:original boundary conditions formed during Paleozoic extension and rifting along the marginal zone of the Yangze; initiation during Middle-Late Triassic collisional orogen; and final formation during Middle-Late Jurassic intra-continental orogen. The arc-shaped Chengkou-Fangxian fault zone not only controls the Early Paleozoic deposition and magmatism,but also played key role in the foreland arc formation,and the basement uplifts at the two syntax acted as important boundary conditions. Sandbox modeling was carried out in the laboratory to model the formation and boundary condition of the Dabashan foreland arc. The model was set-up according to the real geologic data.