Structural Development of Southern Morocco: Interaction of Tectonics and Deposition
Published:December 01, 2005
Michal Nemcok, Charles Stuart, MarylinP. Segall, Richardson B. Allen, Chelsea Christensen, Steven A. Hermeston, Ian Davison, 2005. "Structural Development of Southern Morocco: Interaction of Tectonics and Deposition", Petroleum Systems of Divergent Continental Margin Basins, Paul J. Post, Norman C. Rosen, Donald L. Olson, Stephen L. Palmes, Kevin T. Lyons, Geoffrey B. Newton
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Interpretation of magnetic, gravity, seismic, and geological data shows that the curvilinear Late Paleozoic orogen affected the location of Central Atlantic syn-rift faults. While northeast-southwest striking thrust faults were perpendicular to extension, prominent curvatures, such as the Pennsylvania salient, introduced structural complexities. East-northeast/west-southwest striking, dextral, transpressional strike-slip faults of this salient became reactivated during Carnian-Toarcian rifting. They formed sinistral, transtensional strike-slip “rails” that prevented the Georges Bank–Tarfaya Central Atlantic segment from orthogonal rifting, causing formation of a pull-apart basin system. Central Atlantic segments to the south and north underwent almost orthogonal rifting. “Rails” lost their function after the continental breakup, except for minor younger reactivations. They were not kinematically linked to younger oceanic fracture zones.
Atlantic segments initiated by normal rifting differ from the segment initiated by the Georges Bank–Tarfaya strike-slip fault zone. They contain Upper Triassic-Lower Jurassic evaporites having salt-detached gravity glides, while the connecting transfer segment does not. Their structural grain is relatively simple, divided mostly by northeast-southwest striking normal faults. Northwest-southeast striking oceanic fracture zones kinematically link with continental faults in a few places, controlling the sediment transport pathways across the uplifted continental margin.
The connecting Georges Bank–Tarfaya Central Atlantic segment, initiated as a sinistral transfer-zone, has a complex structural grain, characterized by numerous small depocenters and culminations. Their boundaries are formed by east-northeast/west-southwest striking, sinistral, strike-slip, north-northeast/south-southwest, striking normal and west-northwest/east-southeast striking, dextral, strike-slip faults. Sediment transport pathways have complex trajectories, weaving through local depocenters.