--> Abstract: 3D Tectonosedimentary Models of Three Major Sectors in the East African Rift System: A Contribution to Understanding the Interplay Between Tectonic Activity and Depositional Environments in Modern and Ancient Rifts, by C. Le Turdu, J-J. Tiercelin, J. Rolet, K. E. Lezzar, J-P. Xavier, J-P. Richert, and R. W. Renaut; #90942 (1997).

Datapages, Inc.Print this page

Abstract: 3D tectonosedimentary models of three major sectors in the East African Rift System: a contribution to understanding the interplay between tectonic activity and depositional environments in modern and ancient rifts

LE TURDU CAROLINE, JEAN-JACQUES TIERCELIN, JOEL ROLET, KIRAM EDDINE LEZZAR, JEAN-PAUL XAVIER, JEAN-PAUL RICHERT, ROBIN WINSTON RENAUT

A synthesis is presented of a 3-year Ph.D. study on the East African Rift undertaken during a contract with Elf Petroleum Norge. This project combined detailed interpretation of 3D images constructed from SPOT satellite data, with subsurface investigative methods, and a better understanding of surface faulting obtained from fieldwork. Using this integrated approach may lead to increasing sophistication of 3D structural and sedimentary models for several segments of the East African Rift system, and contribute to a better understanding of the interplay between tectonic activity and depositional environments in ancient rift sequences.

Three target areas were chosen: the Langano-Abiyata-Shala lake basins in the Main Ethiopian Rift, the Baringo-Bogoria and Lake Magadi basins in the Kenya Rift, and the Lake Tanganyika Rift Basin. A range of different methods were used: 3D SPOT imagery techniques, geophysical methods (seismic reflection data, magnetotellurics and electrical sounding), sediment core analysis, and data collected in the field using classical methods.

From these studies, three new 3D tectonosedimentary models, that incorporate the deep geometry of the basins, are presented, and some unusual and significant results are discussed for each target area. For example, the influence of pre-existing features on fault geometry is particularly strong in the Kenya Rift. From field and seismic data, the relationship of sediment fill to basin geometry is especially well seen in the thick sediment sequences of the Main Ethiopian Rift and in the Tanganyika Basin. The relationship between hydrothermal activity and tectonic features are examined in each target area, with emphasis on the hydrothermal fields at Lake Bogoria and the sublacustrine fields of the Tanganyika Rift Basin.

These 3D tectonosedimentary models are integrated in a general kinematic model applicable for the whole East African Rift. In addition, several peculiar structural and sedimentary features of those models are compared with structures observed in the North Sea Rift.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria