Active Volcanism And Continental Rifting In Africa

A major rifting episode began in the Afar region of northern Ethiopia in September 2005. Over a ten-day period, c. 2.5 km3 of magma were intruded along a 60 km-long dyke separating the Arabian and Nubian plates. Over the next five years, a further 13 dyke intrusions caused continued extension, eruptions and seismicity. This activity led to a renewed international focus on the role of magmatism in rifting, with major international collaborative projects working in Afar and Ethiopia to study the ongoing activity and to place it in a broader context. This book brings together articles that explore the role of magmatism in rifting, from the initiation of continental break-up through to full seafloor spreading. We also explore the hazards related to rifting and the associated volcanism. This work has implications for our understanding of how continents break-up and the associated distribution of resources in rift basins and continental margins.

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.

A unique interdisciplinary approach to disaster risk research, including global hazards and case-studies, for researchers, graduate students and professionals.

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

This multi-author book has been prepared by an international group of geoscientists that have been active in rift research since the late 1960s. In 1984, an informal, grass-roots study group was initiated to compare individual research results and to explore in greater depth the apparent differences and similarities in the interpretations from various rift systems. The group became known as the CREST working group, an acronym of Continental Rifts: Evolution, Structure and Tectonics, which not surprisingly became the title of this book. Continental Rifts: Evolution, Structure, Tectonics presents an overview of the present state of understanding and knowledge of the processes of continental rifting from a multidisciplinary, lithospheric scale perspective. The chapters have been structured on each rift system in approximately the same synoptic sequence, so as to facilitate comparisons of rifts by the reader. The book complements its predecessors by presenting a more unified picture. It succeeds in presenting the status of a representative majority of the continental rift systems that have been at the forefront of recent research. For students and experienced researchers alike, this book will be of significant value in assessing the current state of knowledge and in serving as a framework for future research.

Magmatic continental rifts often constitute the earliest stage of nascent plate boundaries. These extensional tectonic provinces are characterized by ubiquitous normal faulting and volcanic activity; the spatial pattern, the geometry, and the age of these normal faults can help to unravel the spatiotemporal relationships between extensional deformation, magmatism, and long-wavelength crustal deformation of continental rift provinces. This study focuses on the active faulting in the Kenya Rift of the Cenozoic East African Rift System (EARS) with a focus on the mid-Pleistocene to the present-day. To examine the early stages of continental break-up in the EARS, this thesis presents a time-averaged minimum extension rate for the inner graben of the Northern Kenya Rift (NKR) for the last 0.5 m.y. Using the TanDEM-X digital elevation model, fault-scarp geometries and associated throws are determined across the volcano-tectonic axis of the inner graben of the NKR. By integrating existing geochronology of faulted units with new 40Ar/39Ar ...