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Structural Framework of a Complex Transform Margin: Deep Ivorian Basin, Blocks 104 and 105, Ivory Coast

T. E. Miskelly, Jr.1, W. E. Galloway1, and T. Ziegler2
1University of Texas, Austin, TX
2Petroleum Geo-Services, Inc., London, England

A 3D seismic data set was used to analyze the structural framework within an extensional basin adjacent to a transform margin. The data set consists of a 1800 km2 3D seismic survey covering offshore blocks 104 and 105, Ivory Coast. The complex structural pattern in the area is a continuation of wrench faulting along the Saint Paul Fracture Zone to the southeast, and consists of rotated fault blocks similar to those found west of the Romanche Fracture Zone on the eastern side of the Ivory Coast Basin. Existing models for transform margins and pull-apart basins are used to illustrate the complex structural history of the largely undrilled area. Syn- and post-depositional normal faults, reverse faults, and flower structures are identified in the data. Three distinct stages of development, and their related tectonosedimentary regimes, were identified using seismic stratal relationships: 1) pre-rift lacustrine, 2) active rift margin, and 3) post-rift passive margin. Structure maps for each horizon outline the major faults, synclines and anticlines. The interactions of identified structures control the depositional systems, sediment dispersal pathways, areas of slope bypass and localization of erosional features.

AAPG Search and Discovery Article #90905©2001 AAPG Southwest Section Meeting, Dallas, Texas