Archaean strike-slip faulting and related ensialic basins: evidence from the Pilbara Block, Australia
Archaean strike-slip faulting and related ensialic basins: evidence from the Pilbara Block, Australia
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DOI：
10.1017/s0016756800017386
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发表时间：
1987-11
影响因子：
2.3
通讯作者：
B. Krapež;M. Barley
中科院分区：
文献类型：
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作者：
B. Krapež;M. Barley
西澳大利亚Lalla Rookh盆地和Pilbara地块约2950 Ma的老Whim Creek带的太古代沉积和火山序列是在盆地中沉积的，其构造与现在的露头大致相同。盆地受断层控制，发育在深成环境中，上覆年龄较老(3500~3300 Ma)；变形变质表壳岩石和花岗岩类。盆地边缘断裂现在是走滑断裂格局的一部分，在区域岩基侵位的后期阶段活动。在这两种情况下，盆地充填的构造样式和样式都与与走滑断裂有关的年轻盆地相似。拉拉鲁克盆地以粗碎屑沉积为主，发育冲积扇、辫状河、扇三角洲和湖泊相。惠姆溪带含有双峰式火山岩和碎屑沉积，包括冲积相、水下扇体相、海底扇相和盆地相。区域走滑断裂作用以及拉拉鲁克盆地和惠姆克里克带的发育，记录了皮尔巴拉地块克拉通化过程中的重要一步。晚太古代沉积盆地，以粗碎屑相为主，毗邻主要走滑断裂，在其他克拉通中可能有类似的成因。
Abstract Archaean sedimentary and volcanic successions in the Lalla Rookh Basin and c. 2950 Ma old Whim Creek Belt in the Pilbara Block, Western Australia, were deposited in basins with roughly the same configuration as their present outcrop. Basins were fault-bounded and developed in an ensialic setting, overlying older (3500 to 3300 Ma old); deformed and metamorphosed supracrustal rocks and granitoids. The basin margin faults are now part of a pattern of strike–slip faults which were active during the later stages of regional batholith emplacement. In both cases, structural patterns and style of basin filling are similar to younger basins related to strike–slip faulting. The Lalla Rookh Basin was dominated by coarse clastic sedimentation, comprising alluvial–fan, braided–stream, fan–delta and lacustrine facies. The Whim Creek Belt contains bimodal volcanics and clastic sediments, which comprise alluvial, subaqueous fanglomerate, submarine-fan and basinal facies. Regional strike–slip faulting and the development of the Lalla Rookh Basin and Whim Creek Belt, in response to externally imposed deformation, records an important step in the cratonization of the Pilbara Block. Late Archaean sedimentary basins, dominated by coarse clastic facies and situated adjacent to major strike–slip faults, in other cratons may have a similar origin.