Extensional deformation and development of deep basins associated with the sinistral transcurrent fault zone of the Scotia–Antarctic plate boundary
Extensional deformation and development of deep basins associated with the sinistral transcurrent fault zone of the Scotia–Antarctic plate boundary
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与斯科舍-南极板块边界左旋横流断裂带相关的深盆地的伸展变形和发育
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发表时间：
2007
期刊：
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通讯作者：
E. Suriñach
中科院分区：
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作者：
F. Bohoyo;J. Galindo‐Zaldívar;A. Jabaloy;A. Maldonado;J. Rodríguez;A. Schreider;E. Suriñach
斯科舍-南极板块边界沿着斯科舍弧的南分支延伸，位于与前菲尼克斯板块以西（57°W）和与三明治板块以东（30°W）的三个交汇点之间。形成现今岛弧形态的主要机制是30-35 Ma期间斯科舍和三明治板块的发育，与南美洲和南极半岛之间大陆连接的断裂有关。苏格兰-南极板块边界是一个非常复杂的构造带，因为海洋和大陆元素都涉及其中。现今的左旋横流运动可能始于8 Ma前。我们在该地区观察到的主要活动构造包括释放弯曲和抑制弯曲，以及相关的深伸展和挤压盆地，以及可能的拉分盆地。板块边界的西段穿过破碎的大陆地壳：西南斯科舍海岭，广泛发育拉分盆地和释放弯曲，深度超过5000米，充满了不对称的沉积楔。南奥克尼微大陆的北方边界，在中部，有大洋和大陆地壳接触沿着一个大的逆冲带。最后，南斯科舍海脊的东段位于发现滩内，这是一块来自前弧形的大陆地壳。在其南部边界，走滑和正断层产生了一个5500米深的槽，可以解释为拉分盆地。在南斯科舍海脊的东部和西部，尽管大陆地壳极度减薄，但盆地没有显示出洋壳的发展。这种几何形状取决于所涉地壳独特的流变行为，变形集中在流变性较弱的大陆块内。
Abstract The Scotia–Antarctic plate boundary extends along the southern branch of the Scotia Arc, between triple junctions with the former Phoenix plate to the west (57°W) and with the Sandwich plate to the east (30°W). The main mechanism responsible for the present arc configuration is the development of the Scotia and Sandwich plates from 30–35 Ma, related to breakup of the continental connection between South America and the Antarctic Peninsula. The Scotia–Antarctic plate boundary is a very complex tectonic zone, because both oceanic and continental elements are involved. Present-day sinistral transcurrent motion probably began 8 Ma ago. The main active structures that we observed in the area include releasing and restraining bends, with related deep extensional and compressional basins, and probable pull-apart basins. The western sector of the plate boundary crosses fragmented continental crust: the Western South Scotia Ridge, with widespread development of pull-apart basins and releasing bends deeper than 5000 m, filled by asymmetrical sedimentary wedges. The northern border of the South Orkney microcontinent, in the central sector, has oceanic and continental crust in contact along a large thrust zone. Finally, the eastern sector of the South Scotia Ridge is located within Discovery Bank, a piece of continental crust from a former arc. On its southern border, strike-slip and normal faults produce a 5500-m-deep trough that may be interpreted as a pull-apart basin. In the eastern and western South Scotia Ridge, despite extreme continental-crustal thinning, the basins show no development of oceanic crust. This geometry is conditioned by the distinctive rheological behaviour of the crust involved, with the bulk concentration of deformation within the rheologically weaker continental blocks.