The Afar Volcanic Province Within the East African Rift System


Book Description

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.







Regional Geology and Tectonics


Book Description

Regional Geology and Tectonics: Volume 2: Phanerozoic Rift Systems and Sedimentary Basins, Second Edition, is the second volume in a three-volume series covering Phanerozoic regional geology and tectonics. Experience in analyzing and assessing rifts - locations where the Earth’s outer shell and crust have been stretched over time by seismic activity - is critical for exploration geologists in identifying Earth’s most lucrative hydrocarbon locations in which extraction is both efficient and safe. Vast compilations of related industry data present regional seismic lines and cross sections, and summaries of analogue and theoretical models are provided as an essential backdrop to the structure and stratigraphy of various geological settings. The new edition of Regional Geology and Tectonics: Volume 2: Phanerozoic Rift Systems and Sedimentary Basins features updated summaries of analogue and theoretical models. New to this edition are chapters on deepwater foldbelts and lithospheric extension as well as new case studies on volcanic and passive margin basins. Provides a practical reference for petroleum geologists that discusses the importance of rift systems and the structural evolution of the Earth Includes analyses of active rifts in East Africa, China, Siberia, the Gulf of Suez, and the Russian Arctic that provide immediately implementable petroleum exploration applications in regions heavily targeted by oil & gas companies Presents overviews of sequence stratigraphy in rifts and structural controls on clastic and carbonate sedimentation that are critical to the exact mapping of the most lucrative hydrocarbon locations by exploration geologists




Geology of Afar (East Africa)


Book Description

This book summarizes the geological knowledge accumulated on Afar in the last 60 years, demonstrating that it is, and will remain, a real “hot spot” for geological and geophysical research. It provides insights into the Earth processes along diverging plate boundaries, the study of both the continental and oceanic lithosphere and underlying asthenosphere, and margins and transitions including magmatic, volcanic, tectonic, sedimentary, hydrothermal and geodynamic processes. The Afar triangle is a geological depression that developed where the Gulf of Aden, Red Sea and East African Rift Valley meet. It is considered to be one of the Earth system’s most important mantle plumes. In 1967, when the first expedition was organized, there was little information on the geology of the area, and even geographic base maps were lacking. However, the first satellite photographs from the Apollo and Gemini space missions offered a complete picture of the Red Sea-Gulf of Aden region, providing a new vision of the Afar triangle. The book describes the unique geological features that make Afar the only place in the world where an oceanic plate boundary with all its successive steps of development can be observed in the open air. It also presents the Afar triangle as one of the cradles of first, now extinct hominids. The Middle Awash area contains sites of several fossil discoveries, such as the well-known Lucy. The hydrothermal processes in Afar provide conditions suitable for the study of the most primitive forms of life (archaebacterial) and it is also one of the few places where significant quantities of telluric energy are available at the surface for geothermal development. Further, the area has economically interesting mineral deposits and illustrates a number of current climate change issues. In addition to providing geological information, the book shows that Afar is an area where an individual human population developed with its own language and culture, and which adapted to the rugged landscape and extremely dry and hot climate. It is a valuable resource for scientists and students, and also serves the needs of the Afar nation, currently split in three different countries as a result of recent historical events.




Limnology, Climatology and Paleoclimatology of the East African Lakes


Book Description

The large lakes of the East African Rift Valley are among the oldest on Earth, and are vital resources for the people of their basins. They are unique among the large lakes of the world in terms of their sensitivity to climatic change, rich and diverse populations of endemic species, circulation dynamics and water-column chemistry, and long, continuous records of past climatic change. A comprehensive study of the large African lakes is long overdue. The scientific justification for such an effort is noted in the previous paragraph and is illustrated in great detail in this volume. Societal need for the sustainable utilization of these lakes offers an even more compelling reason for examination of biological food webs, water quality, and past climate variability in East Africa. The lakes provide the most important source of protein for the people of the African Rift Valley, and fish populations are shifting dramatically in response to fishing pressure, introduction of exotic species, land use impact on water quality, and perhaps climatic change. Current estimates of primary productivity, the underpinning of the food resource, are extremely crude and based on only a few spot measurements.




Rifts and Volcanoes


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Tectonics and Sedimentation


Book Description




Magmatic Rifting and Active Volcanism


Book Description

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.