East African Rifts

Developments in Geotectonics, 7: East African Rifts focuses on the movements, structure, and behavior of the East African rift system. The selection first offers information on the surface structure and plate tectonics of Afar; tectonic and magmatic significance of volcanism in the Afar depression; and preliminary interpretation of the gravity field of Afar, northeast Ethiopia. Discussions focus on crustal models of Afar based on gravity and seismic data, tectonics, volcanism, geological setting, and crustal extension. The text also elaborates on the gravity survey of the central part of the Ethiopian Rift Valley and an aeromagnetic survey of the Afar triangle of Ethiopia. The book examines the arrangement and development of continental rift zones, East African rift development, and the seismicity of the East African rift system. Topics include earthquake mechanisms, seismicity, and the main categories of rift zones. The manuscript is a dependable reference for readers interested in the East African rifts.

The seismically and volcanically active East African Rift System is an ideal laboratory for continental break-up processes: it encompasses all stages of rift development. Its northernmost sectors within the Afar volcanic province include failed rifts, nascent sea-floor spreading, and youthful passive continental margins associated with one or more mantle plumes. A number of models have been proposed to explain the success and failure of continental rift zones, but there remains no consensus on how strain localizes to achieve rupture of initially 125-250 km-thick plates, or on the interaction between the plates and asthenospheric processes. This collection of papers provides new structural, stratigraphic, geochemical and geophysical data and numerical models needed to resolve fundamental questions concerning continental break-up and mantle plume processes. The focus is on how mantle melt intrudes and is distributed through the plate, and how this magma intrusion process controls along-axis segmentation and facilitates break-up.

Presents key results of hydrocarbon exploration activities by Amoco and other oil companies during the 1980s and 1990s in a number of rift segments in East Africa. Early chapters give a detailed review of the geological and geophysical data of the main regions explored, and later chapters present ge

The African continent is unique in that it has escaped widespread orogenic activity after the Pan African orogenic event. Therefore, the African Plate provides the world's best example of the relationship between extensional magmatism and structural setting. This first complete and up-to-date review, written by leading scientists, discusses the evolutionary model and offers a new and reliable basis for scientists working on plate tectonics and extensional areas in other continents.

This new volume on the Geology of East Africa provides a concise account of the multi-faceted regional geology and stratigraphy of East Africa, that is Kenya, Tanzania and Uganda. Much of the data presented, however, is highly relevant to the surrounding countries and regions as well. Professionals and students, intending to delve into the details of the geological history of that region will appreciate the present volume as a stepping-stone, paving the way to additional studies of the numerous references given in this work.

Traditionally, investigations of the rheology and deformation of the lithosphere (the rigid or mechanically strong outer layer of the Earth, which contains the crust and the uppermost part of the mantle) have taken place at one scale in the laboratory and at an entirely different scale in the field. Laboratory experiments are generally restricted to centimeter-sized samples and day- or year-length times, while geological processes occur over tens to hundreds of kilometers and millions of years. The application of laboratory results to geological systems necessitates extensive extrapolation in both temporal and spatial scales, as well as a detailed understanding of the dominant physical mechanisms. The development of an understanding of large-scale processes requires an integrated approach. This book explores the current cutting-edge interdisciplinary research in lithospheric rheology and provides a broad summary of the rheology and deformation of the continental lithosphere in both extensional and compressional settings. Individual chapters explore contemporary research resulting from laboratory, observational, and theoretical experiments.