Download or read book Tectonic Evolution of the Walvis Ridge and West African Margin South Atlantic Ocean written by Timothy Robert Baumgartner and published by . This book was released on 1973 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: The opening of the South Atlantic between 140 and 90 m. y. B.P. occurred about two poles of rotation. The initial pole of rotation was maintained until Africa and South America were completely separated. The subsequent removal of restraints imposed by the pre-existing structure of Africa and South America on the early spreading direction permitted a northward migration of the pole of rotation and concomitant reorientation of spreading direction, The NNE trending Cameroon-Gabon and southern Angola coastlines which offset the generally SSE trend of the west African margin between 5°N and the Walvis Ridge are proposed as initial transform offsets of the South Atlantic proto-rift. Location of these initial offsets was controlled by lineations of the Precambrian/Early Paleozoic belts of thermotectonic activity which occur between older, stable cratonic nuclei of Gondwana. Shorter offsets of the continental margin south of the Walvis Ridge and the two major offsets of the west African coastline north of the Walvis Ridge define a pole of rotation at 5°N, 26°w for the initial South Atlantic opening. A set of magnetic anomaly lineations near the continental margins of Angola and southwest Africa is described and named the Benguela sequence. These anomalies were formed during the initial phase of spreading and are displaced right-laterally almost 1000 kilometers across an extension of the continental offset along the southern Angola margin. This offset is named the Benguela Fracture Zone. The Benguela anomalies are correlated with anomalies of the Lynch sequence in the western North Atlantic. The change in direction between the two pre-Cenozoic phases of South Atlantic spreading is dated at roughly 120 m. y. B.P. based upon an extrapolation of the ages of anomalies in the Lynch sequence to the time of reorientation in the South Atlantic. Formation of the South Atlantic quiet zones occurred by sea-floor spreading about a pole of rotation at 21. 5°N, 14. 0°W during the second phase of opening. The present structure of the Walvis Ridge is controlled by nearly orthogonal NE and NW trending faults shown by seismic reflection profiling. The NE trending set of faults approximate small circles of the pole of rotation at 21. 5°N, 14. 0°W and appear to offset the Walvis Ridge topography in a right-lateral sense. Reorientation of spreading would have produced extension across the Benguela Fracture Zone; development of short offset spreading centers along the Benguela Fracture Zone during this reorientation is proposed to explain the right-lateral offsets of the Walvis Ridge topography. Lack of geophysical information on the lower crustal structure prevents a direct explanation of the present elevation of the Walvis Ridge. However the Walvis Ridge is probably underlain by a low density root produced by alteration of the lower crust and upper mantle materials beneath the Benguela Fracture Zone which began during the spreading reorientation. Asymmetric spreading over the Walvis Ridge may have permitted the zone of crustal accretion to remain near the older Benguela Fracture Zone long enough to allow the creation of an anomalously broad low-density root which is responsible for the uplift of the Walvis Ridge.
Download or read book Evolution of the South Atlantic written by E. S. W. Simpson and published by . This book was released on 1977 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Conjugate Divergent Margins written by Webster Mohriak and published by Geological Society of London. This book was released on 2013 with total page 569 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main focus of the book is the geological and geophysical interpretation of sedimentary basins along the South, Central and North Atlantic conjugate margins, but concepts derived from physical models, outcrop analogues and present-day margins are also discussed in some chapters. There is an encompassing description of several conjugate margins worldwide, based on recent geophysical and geological datasets. An overview of important aspects related to the geodynamic development and petroleum geology of Atlantic-type sedimentary basins is also included. Several chapters analyse genetic mechanisms and break-up processes associated with rift-phase structures and salt tectonics, providing a full description of conjugate margin basins based on deep seismic profiles and potential field methods.--
Download or read book Atlantic Rifts and Continental Margins written by Webster Mohriak and published by American Geophysical Union. This book was released on 2000-01-10 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reference on the geology and geophysics of continental margins contains a total of 15 papers developed from a session of the Fifth International Congress of the Brazilian Geophysical Society held in Sao Paulo, Brazil in 1997, as well as a number of other contributions. Subjects include the roots of the southeastern continental margin of Brazil, the mosaic of Terranes in central Europe, the evolution of the Angolan passive margin; geological and geophysical interpretation of the San Julian Basin offshore Argentina; and the tectonic evolution of the equatorial South Atlantic. Of likely interest to academic geoscientists working in basin analysis and those engaged in petroleum exploration. Member price, $52.50. Annotation copyrighted by Book News, Inc., Portland, OR.
Download or read book Tectonic DevelThermal History and Hydrocarbon Habitat Models of Transform Margins their Differences from Rifted Margins written by M. Nemčok and published by Geological Society of London Special Publications. This book was released on 2023-07-21 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transform margins form a significant portion of Earth’s continent–ocean transition and are integral to continental break-up, yet compared to other margins are poorly understood. This volume brings together new multidisciplinary research to document the structural, sedimentological and thermal evolution of transform margins, highlighting their relationship to continental structure, neighbouring oceanic segments, pull-apart basins and marginal plateaus. Special emphasis is given to the comparison of transform and rifted margins, and to the economic implications of transform margin structure and evolution. Transform case studies include the Agulhas–Falkland transform, Coromandal transform (East India), Davie margin and Limpopo transform (East Africa), Guyana transform margin, Demerara transform margin (Suriname), Romanche and St Paul transforms (equatorial Africa), Sagaing transform (Andaman Sea) and Zenith–Wallaby–Perth transform (West Australia). The broad-scale interplay between transform and rifted margin segments in the North and Central Atlantic, and Caribbean, is also examined.
Download or read book Communications of the Geological Survey of South West Africa Namibia written by and published by . This book was released on 1992 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Geology of Continental Margins written by C.A. Burk and published by Springer. This book was released on 2013-12-20 with total page 976 pages. Available in PDF, EPUB and Kindle. Book excerpt: The continental margins of the world constitute the most impressive and largest physiographic feature of the earth's surface, and one of fundamentally great geological significance. Continental margins have been the subject of increasing attention in recent years, an interest focused by a body of new data that has provided new insights into their character. This interest was further stimulated by the realization that, in addition to the abundant living resources, continental margins contain petroleum and mineral resources that are accessible with existing technology. This realization, along with their basic geological importance, has provoked further research into the nature of continental margins throughout the world. A summary of these findings, as related to both recent and ancient continental margins, is the subject of this book. At various times in the past we had been approached individually to prepare a basic reference to continental margins; we then proposed to do such a volume jointly. However, the stimulus for the present volume eventually arose from a Penrose Conference arranged through the Geological Society of America. This conference was attended by specialists of numerous disciplines and from throughout the world, many of whom insisted that such a volume would be both timely and useful. Consequently, we agreed to undertake the task of assembling this book, with the objectives of making it available as soon and as inexpensively as possible.
Download or read book Volcanic Rifted Margins written by Martin A. Menzies and published by Geological Society of America. This book was released on 2002 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sedimentation and Tectonics in Rift Basins Red Sea Gulf of Aden written by B.H. Purser and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sedimentation and Tectonics in Rift Basins: Red Sea - Gulf of Aden presents new case studies and synthesises the results of recent research on the sedimentological evolution of the Red Sea - Gulf of Aden rift system. This rift basin is generally regarded as the best natural geological laboratory in the world in which to study the processes of rift formation. Uplift of the rift margins in an arid climate results in extensive three-dimensional exposures of pre- and syn-rift strata and associated structures. These serve as analogues for the understanding and hydrocarbon exploration of deeper buried rift-systems on continental margins such as the North Sea and the Atlantic margins. The Red Sea - Gulf of Aden rift is also exceptional in that its stratigraphy spans all stages from pre-rift environments, syn-rift continental to marine environments through the rift to drift transition to post-rift sea-floor spreading. The work is arranged in eight sections: following a review of the sedimentology and stratigraphy of rift basins, the magmatism and structural evolution of the Red Sea - Gulf of Aden rift is reviewed. Subsequently, new case studies are presented of the early rifting environment, syn-rift sedimentation, tectonics and diagenesis, evaporites and salt tectonics. Post-rift sediments of the axial trough are then discussed along with studies of reefs, coastal zone and shelf sediments, and the tectonic geomorphology of the rift margin escarpment. This work results from extensive new research in the rift basin largely carried out under collaborative research projects by European and Middle Eastern geologists. It will be an invaluable reference work for geoscientists in the hydrocarbon, groundwater and mineral extraction industries, as well as for researchers in university departments of earth sciences, mining and physical geography.
Download or read book Petroleum Geoscience of the West Africa Margin written by T. Sabato Ceraldi and published by Geological Society of London. This book was released on 2017-01-05 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: The West African margin has enjoyed a rich and varied exploration history, remaining an exciting region for hydrocarbon discovery. Fusion of traditional approaches, imaginative ideas, leveraged with modern technologies is still yielding success. This volume examines the margin from regional to pore-scale, from surface-processes to deep crustal levels, drawing on input from academia and industry.
Download or read book Passive Margins written by K.R. McClay and published by Geological Society of London. This book was released on 2020-07-01 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume has evolved from papers written in memory of Professor David Roberts. They summarize the key findings of recent research on passive margins, from tectonics, bathymetry, stratigraphy and sedimentation, structural evolution and magmatism. Papers include analyses of the central and southern Atlantic margins of South America and Africa, papers on magmatism and extension in the NE Brazilian margin and on the Cote de Ivoire margin, rift architectures of the NW Red Sea margin, tectonics of the eastern Mediterranean margin, salt tectonics of passive margins of the Gulf of Mexico and Brazil, and papers on the NW Shelf margin of Australia. The volume provides readers with new insights into the complexities of passive margin systems that are in reality, not so passive.
Download or read book Geologic Evolution of Atlantic Continental Rises written by C.W. Poag and published by Springer. This book was released on 1992-08-31 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: Because of their great depth and distance from the shore, continental rises have been relatively insulated from geological explorations. Distinguished international experts offer new interpretations of continental-rise deposition at several different locations along the margins of the Atlantic Ocean in this volume. They provide findings generated by new measurement and imaging technology, complete with fold-out maps that display a panorama of erosional features for comparison with other ocean regions. New techniques for detecting and dating tectonic episodes that affect continental rise deposition will be especially useful to petroleum engineers involved in offshore oil exploration. Information is included on the role of massive slides in forming continental-rise deposits and interaction of sedimentation on modern continental rises.
Download or read book The Geology of the Atlantic Ocean written by Kenneth O. Emery and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 1063 pages. Available in PDF, EPUB and Kindle. Book excerpt: The explosion of interest, effort, and information about the ocean since about 1950 has produced many thousand scientific articles and many hun dred books. In fact, the outpouring has been so large that authors have been unable to read much of what has been published, so they have tended to concentrate their own work within smaller and smaller subfields of oceanog raphy. Summaries of information published in books have taken two main paths. One is the grouping of separately authored chapters into symposia type books, with their inevitable overlaps and gaps between chapters. The other is production of lightly researched books containing drawings and tables from previous pUblications, with due credit given but showing assem bly-line writing with little penetration of the unknown. Only a few books have combined new and previous data and thoughts into new maps and syntheses that relate the contributions of observed biological, chemical, geological, and physical processes to solve broad problems associated with the shape, composition, and history of the oceans. Such a broad synthesis is the objective of this book, in which we tried to bring together many of the pieces of research that were deemed to be of manageable size by their originators. The composite may form a sort of plateau above which later studies can rise, possibly benefited by our assem bly of data in the form of new maps and figures.
Download or read book The Morphostructure of the Atlantic Ocean Floor written by V.M. Litvin and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of the topography and structure of the ocean floor is one of the most important stages in ascertaining the geological structure and history of development of the Earth's oceanic crust. This, in its turn, provides a means for purposeful, scientifically-substantiated prospecting, exploration and development of the mineral resources of the ocean. The Atlantic Ocean has been geologically and geophysically studied to a great extent and many years of investigating its floor have revealed the laws governing the structure of the major forms of its submarine relief (e. g. , the continental shelf, the continental slope, the transition zones, the ocean bed, and the Mid-Oceanic Ridge). The basic features of the Earth's oceanic crust structure, anomalous geophysical fields, and the thickness and structure of its sedimentary cover have also been studied. Based on the investigations of the Atlantic Ocean floor and its surrounding continents, the presently prevalent concept of new global tectonics has appeared. A great number of works devoted to the results of geomorphological, geolog ical, and geophysical studies of the Atlantic Ocean floor have appeared. In the U. S. S. R. , such summarizing works as The Geomorphology of the Atlantic Ocean Floor [34], Types of Bottom Sediments of the Atlantic Ocean [24], The Geology of the Atlantic Ocean [38], and, somewhat earlier, Geophysical Studies of the Earth's Crust Structure in the Atlantic Ocean [13], have been published.
Download or read book Cenozoic Mammals of Africa written by Lars Werdelin and published by Univ of California Press. This book was released on 2010-07-20 with total page 1008 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This impressively comprehensive volume is a long-awaited and worthy successor to the now outdated 1978 classic, Evolution of African Mammals. A must-have reference work for everyone interested in mammalian evolution." David Pilbeam, Harvard University and the Peabody Museum of Archaeology and Ethnology --
Download or read book Geological Evolution of Ocean Basins written by Ocean Drilling Program and published by Geological Society of London. This book was released on 1998 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in the field of marine geoscience through the medium of deep-ocean drilling have been rapid and continue to be so. Part of this text reflects the results of findings from recent legs of the Ocean Drilling Programme. Other parts provide syntheses of the volume of drilling information collected over a period of more than 20 years, which provide a detailed picture of how oceans have evolved since the late Mesozoic. The book should be of interest to marine geologists, sedimentologists, palaeoceanographers and structural geologists.
Download or read book Dynamics of Passive Margins written by R. A. Scrutton and published by American Geophysical Union. This book was released on 1982 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
