Geodynamics Of Rifting

This volume contains papers giving an interdisciplinary review of 12 major rift systems from North and South America, Africa, Europe and Asia. These papers are written by an international group of academic and industrial specialists each of whom is most knowledgeable about the respective rift. The analyzed rifts were selected on the basis of availability of an as-complete-as-possible geological and geophysical data base. Thirteen papers deal with geodynamic processes governing the evolution of rifts. A comprehensive digest of the available stratigraphic, structural, geophysical and petrological data, together with an extensive list of references, is provided for each of the analyzed rift systems. The megatectonic setting and dynamics of evolution of each basin is discussed. Geodynamic models are tested against the record of the analyzed rifts. The question of "active" as against "passive" rifting is addressed. The rifts analyzed range in age from Precambrian to Recent and cover a wide spectrum of megatectonic settings. There is discussion of the evolution of rifts in a plate-tectonic frame. The case histories are followed by discussions addressing the global setting of rifts and geodynamic processes active during the development of rifted basins.

Published by the American Geophysical Union as part of the Geodynamics Series, Volume 8. During the past decade of the International Geodynamics Program many publications dealing with specific rift areas of the Earth's surface have appeared. Most of them followed symposia that were held in the respective rift zones. Among the rifts thus treated are the Rhinegraben, Afar, Iceland, the Baikal rift, the Oslo paleorift, the Rio Grande rift and the Dead Sea rift. Furthermore, publications dealing with studies of the ocean floor have discussed many oceanic rift areas.

This book provides a summary of geodynamic results from Iceland that presently are found in a great number of scientific articles, but have not been collected before in a book. The ever increasing number of scientists interested in geology and geophysics of Iceland should find the book a "must" to gain knowledge about previous work and the status of knowledge about Iceland.

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.

The large scale structure of the earth is caused by geodynamic processes which are explained using energetic, kinematic and dynamic descriptions. While "geodynamic processes" are understood to include a large variety of processes and the term is used by earth scientists quite loosely, the methods of their description involve well defined fields. Energetic descriptions are in volved with distribution of energy in our planet, typically expressed in terms of heat and temperature. Kinematic descriptions describe movements using velocities, strains and strain rates and Dynamic descriptions indicate how stresses and forces behave. As structural and metamorphic geologists we document in the field only the consequences of geological processes. The underlying causes are much harder to constrain directly. However, it is absolutely crucial to understand these causes or: "driving forces", if we are to explain the tectonic evolution of our planet. This book deals with the dynamic description of geological processes. Our descriptions relate causes and consequences - tectonic processes with field observations. In many cases, we will use equations as a concise form to describe processes and observations in nature. As we will be dealing mostly with large scale tectonic questions, the observations that we shall use are also on a large scale. For example, we shall use observations on the elevation (Fig. 1.1, 1.2) and heat flow of mountain ranges, the thickness of continents and the water depth of the oceans.

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.

The beginning of the new millennium has been particularly devastating in terms of natural disasters associated with tectonic plate boundaries, such as earthquakes in Sumatra, Chile, Japan, Tahiti, and Nepal; the Indian Ocean and the Pacific Ocean tsunamis; and volcanoes in Indonesia, Chile, Iceland that have produced large quantities of ash causing major disruption to aviation. In total, half a million people were killed by such natural disasters. These recurring events have increased our awareness of the destructive power of natural hazards and the major risks associated with them. While we have come a long way in the search for understanding such natural phenomena, and although our knowledge of Earth dynamics and plate tectonics has improved enormously, there are still fundamental uncertainties in our understanding of natural hazards. Increased understanding is crucial to improve our capacity for hazard prediction and mitigation. Volume highlights include: Main concepts associated with tectonic plate boundaries Novel studies on boundary-related natural hazards Fundamental concepts that improve hazard prediction and mitigation Plate Boundaries and Natural Hazards will be a valuable resource for scientists and students in the fields of geophysics, geochemistry, plate tectonics, natural hazards, and climate science. Read an interview with the editors to find out more: https://eos.org/editors-vox/plate-boundaries-and-natural-hazards