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Structural Symptoms of Continental Rifting

Bruce R. Rosendahl, Carl F. Burgess, Stephan Sander, J. Lambiasse

The great rift lakes of East Africa, exemplified by Lake Tanganyika, consist of arcuate-shaped half-grabens that tend to alternate polarity along the strike of the rift. Where adjacent half-grabens of opposing asymmetry do not overlap each other, the transition between them is demarked by high-relief "accommodation zones." By definition, such zones accommodate the opposing subsidence of adjacent half-grabens via translational motion oblique to the rift's axis. In places where adjacent half-grabens overlap each other, the accommodation zones tend to be lower relief antiformal features. This structural configuration profoundly influences depositional processes in Tanganyika because it determines not only where discrete basins can exist, but also the distribution of sediment ry facies within those basins, both in space and time. The Tanganyika theme of rifting seems to be repeated in many other continental rifts. When approached in this fashion, we believe that many of the structural and stratigraphic complexities of rift basins can be unraveled.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.