DIVISION AND CHARACTERISTICS OF THE GEOTECTONIC UNITS OF YUNLING EPICONTINENTAL ARC IN NORTHWEST YUNNAN
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摘要: 为进一步查明滇西北云岭陆缘弧的地质构造特征，经实地调研与资料收集整理，将该区划分为6个四级大地构造单元.即：雪龙山岩群（Pt1Xl）、德钦断块（Pz1）、攀天阁酸性火山岩浆弧（T2）、工农弧间盆地（T2）、崔依比中基性火山岩浆弧（T1-2）、鲁甸火山弧-同碰撞花岗岩（T）.前2个单元属岛弧基底，后4个单元属岛弧主体.各单元的岩石组合、变形变质特征有明显差异.岛弧主体形成于早三叠世-晚三叠世早期，是金沙江洋盆向西俯冲消减、碰撞造山的产物.岛弧主体之上被上三叠统角度不整合覆盖.Abstract: With field survey and data processing, the structural characteristics of the Yunling epicontinental arc in Northwest Yunnan are clarified. This region is divided into 6 four-grade tectonic units, i.e. Xuelongshan Rock Group (Pt1Xl), Deqing Blocks (Pz1), Pantiange acidic volcanic magmatic arc (T2), Gongnong inter-arc basin (T2), Cuiyibi intermediate-basic volcanic magmatic arc(T1-2), and Ludian volcanic arc-syn-collisional granite(T). The former two units belong to the basements of island arcs; while latter four, the main bodies. The rock associations and deformation-metamorphism of each unit are various obviously. The main bodies of island arcs were formed from Early Triassic to early Late Triassic, as a product of the westward subduction and collisional orogeny of Jinshajiang ocean basin. The main bodies of island arcs are covered by Upper Triassic strata in angular unconformity.
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