Cenozoic geodynamic evolution of the Andaman–Sumatra subduction margin: Current understanding
Cenozoic geodynamic evolution of the Andaman–Sumatra subduction margin: Current understanding
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安达曼-苏门答腊俯冲边缘的新生代地球动力学演化：目前的认识
DOI：
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
Prosanta K. Khan
中科院分区：
文献类型：
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作者：
P. Chakraborty;Prosanta K. Khan
安达曼-苏门答腊边缘显示了一个独特的伸展俯冲-增生复合体的结构，它们是爪哇海沟，构造（外弧）棱柱，银盘，前弧，海洋隆起，内弧火山和具有活跃扩张的伸展弧后。本文回顾了现有的知识，并分析了一些新的数据的表面和地下签名的操作大地构造的边缘。自白垩纪以来，与俯冲有关的变形沿着海沟一直在连续或间歇地发生。斜向俯冲引发了北方苏门答腊-安达曼板块的走滑运动，并在俯冲带和复杂的右旋断层系统之间形成了一个银板。这条始于始新世的狭长断层延伸穿过苏门答腊近海的外弧脊，并继续穿过安达曼海，连接北部的实皆市断层。区域板块动力学对简单的俯冲相关增生过程的主导作用导致了沿该边缘沿着各种构造特征的沉积盆地的发展和演化。一些南北走向的白垩纪蛇绿岩碎片，与始新世海沟斜坡沉积物一起出现在不同的结构水平上，被一系列东倾逆冲断层抬升和侵位，形成外弧棱柱。南北向和东西向走滑断层控制了沉降，导致弧前盆地的发育，并记录了混合硅质碎屑-碳酸盐体系中渐新世至中新世-上新世的沉积。安达曼海弧后的开启经历了两个阶段：早期（约11 Ma）的伸展和裂谷作用，随后是4-5 Ma以来的扩张。 安达曼地区弧内火山活动的历史可以追溯到中新世早期，自中新世以来，弧火山活动一直伴随着从长英质到玄武质成分的演变。
The Andaman–Sumatra margin displays a unique set‐up of extensional subduction–accretion complexes, which are the Java Trench, a tectonic (outer arc) prism, a sliver plate, a forearc, oceanic rises, inner‐arc volcanoes, and an extensional back‐arc with active spreading. Existing knowledge is reviewed in this paper, and some new data on the surface and subsurface signatures for operative geotectonics of this margin is analyzed. Subduction‐related deformation along the trench has been operating either continuously or intermittently since the Cretaceous. The oblique subduction has initiated strike–slip motion in the northern Sumatra–Andaman sector, and has formed a sliver plate between the subduction zone and a complex, right‐lateral fault system. The sliver fault, initiated in the Eocene, extended through the outer‐arc ridge offshore from Sumatra, and continued through the Andaman Sea connecting the Sagaing Fault in the north. Dominance of regional plate dynamics over simple subduction‐related accretionary processes led to the development and evolution of sedimentary basins of widely varied tectonic character along this margin. A number of north–south‐trending dismembered ophiolite slices of Cretaceous age, occurring at different structural levels with Eocene trench‐slope sediments, were uplifted and emplaced by a series of east‐dipping thrusts to shape the outer‐arc prism. North–south and east–west strike–slip faults controlled the subsidence, resulting in the development of a forearc basins and record Oligocene to Miocene–Pliocene sedimentation within mixed siliciclastic–carbonate systems. The opening of the Andaman Sea back‐arc occurred in two phases: an early (∼11 Ma) stretching and rifting, followed by spreading since 4–5 Ma. The history of inner‐arc volcanic activity in the Andaman region extends to the early Miocene, and since the Miocene arc volcanism has been associated with an evolution from felsic to basaltic composition.