--> Abstract: Structure of a Typical Transform Rift Continental Margin: The Ivory Coast Ghana Continental Margin, by J. Mascle, C. Basile, B. Pontoise, F. Sage, and B. O'Brien; #91012 (1992).

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ABSTRACT: Structure of a Typical Transform Rift Continental Margin: The Ivory Coast Ghana Continental Margin

MASCLE, JEAN, Laboratoire de Geodynamique Sous-Marine, Villefranche-Sur-Mer, France, C. BASILE, Universite de Rennes, Rennes, France, B. PONTOISE,* ORSTOM, Villefranche-Sur-Mer, France, F. SAGE, Laboratoire de Geodynamique Sous-Marine, Villefranche Sur-Mer, France, and B. O'BRIEN, Southwestern University, Georgetown, TX

A dense set of seismic reflection (single channel and multichannel) and refraction data (recorded using Ocean Bottom Seismometers) has been collected over large areas of the Ivory Coast and Ghana continental margin within the equatorial Atlantic. These data are at the basis of a detailed analysis of both the structural-sedimentary framework and the crustal section of this segment of a typical transtensive margin generated during a dominantly transform rifting episode in Cretaceous times. Three main domains can be distinguished: (1) a divergent margin segment that corresponds to most of the deep Ivory Coast basin; this area is characterized by typical extensional features derived from a progressive crustal stretching; (2) a main transform boundary zone, still expressed in the present-d y morphology by an important marginal ridge, the Ivory Coast Ghana ridge, more than 150 km in length and up to 3 km in elevation; this boundary zone results from accommodation of shear stress, during rifting, along the main transcurrent fault system; (3) an intermediate area, in between the two previous ones, has been submitted to both extensional and shear mechanisms.

The resulting structural analysis has been tentatively compared to analogic modeling in order to better understand the chronology of deformation, the control on sedimentation, and the potential structural reworking. Seismic reflection and refraction data are, moreover, integrated in order to support future scientific drilling proposals.

 

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)