Insight into collision zone dynamics from topography: numerical modelling results and observations
Insight into collision zone dynamics from topography: numerical modelling results and observations
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DOI：
10.5194/se-3-387-2012
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发表时间：
2012-11
期刊：
影响因子：
3.4
通讯作者：
A. Bottrill;J. Hunen;M. Allen
中科院分区：
文献类型：
--
作者：
A. Bottrill;J. Hunen;M. Allen
抽象的。俯冲和大陆碰撞动力学模型被用来预测上覆板块的动态地形变化。模拟结果表明，在俯冲、大陆碰撞和板块断裂过程中，上覆板块上的地形有明显的演变。一个突出的地形特征是初始碰撞后覆盖板块上的一个临时（几百万年）盆地。这种“碰撞地幔动力盆地”（CMDB）是由于板块变陡拉深，物质远离上覆板块基底而形成的。此外，在这个初始碰撞阶段，表面隆起的预测覆盖板块之间的缝合带和CMDB，由于俯冲的浮力大陆材料和均衡补偿。板块分离后，应力的重新分布和上覆板块的底侵作用使隆起进一步扩展到上覆板块。这种地形演变符合伊朗和土耳其东南部阿拉伯-欧亚碰撞带覆盖板块上的地层学。覆盖板块的沉积记录包含上渐新世-下中新世海相碳酸盐沉积在陆地碎屑沉积岩之间，以库姆组及其横向等同物为单位。这一地层学表明，在晚渐新世-早中新世期间，覆盖板块的表面在上升到海平面以上之前下沉到海平面以下，在同一地区没有记录到重大的挤压变形。我们模拟的地形变化与观察到的隆起和沉降非常吻合。
Abstract. Dynamic models of subduction and continental collision are used to predict dynamic topography changes on the overriding plate. The modelling results show a distinct evolution of topography on the overriding plate, during subduction, continental collision and slab break-off. A prominent topographic feature is a temporary (few Myrs) basin on the overriding plate after initial collision. This "collisional mantle dynamic basin" (CMDB) is caused by slab steepening drawing, material away from the base of the overriding plate. Also, during this initial collision phase, surface uplift is predicted on the overriding plate between the suture zone and the CMDB, due to the subduction of buoyant continental material and its isostatic compensation. After slab detachment, redistribution of stresses and underplating of the overriding plate cause the uplift to spread further into the overriding plate. This topographic evolution fits the stratigraphy found on the overriding plate of the Arabia-Eurasia collision zone in Iran and south east Turkey. The sedimentary record from the overriding plate contains Upper Oligocene-Lower Miocene marine carbonates deposited between terrestrial clastic sedimentary rocks, in units such as the Qom Formation and its lateral equivalents. This stratigraphy shows that during the Late Oligocene–Early Miocene the surface of the overriding plate sank below sea level before rising back above sea level, without major compressional deformation recorded in the same area. Our modelled topography changes fit well with this observed uplift and subsidence.