Download or read book Mantle Flow and Melt Generation Beneath Mid ocean Ridges written by Yang Shen and published by . This book was released on 1995 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mantle Flow and Melt Generation at Mid ocean Ridges written by Jason Phipps Morgan and published by . This book was released on 1992 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mantle Upwelling Melt Generation and Magma Transport Beneath Mid ocean Ridges written by Laura Magde and published by . This book was released on 1997 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis combines surface observations with laboratory studies and geodynamic modeling to study a variety of aspects of the oceanic crustal-production system. Modeling the crustal and mantle contributions to the axial gravity and topography observed at the East Pacific Rise shows that the retained melt fraction in the mantle is small (
Download or read book Geophysical Monograph written by and published by . This book was released on 1956 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Depth of Mid ocean Ridges Through Earth s Evolution and a Two phase Study of Melt Focusing at Mid ocean Ridges written by Shi Sim and published by . This book was released on 2018 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mid-ocean ridges are prominent features of plate tectonics, stretching for more than 60,000 km in the major ocean basins. Organisms thrive at mid-ocean ridges making it a unique system that connects life, water and plate tectonics. This thesis evaluates the evolution of the global ridge system and considers the processes of melt focusing beneath mid-ocean ridges using two phase flow models. First, I use whole Earth mantle convection models to understand how the global ridge system might have changed over Earth's evolution along with the depths of ocean. I show that mid-ocean ridges have remained submerged over geologic time and that its average depths have not varied by more than 500 m. Mid-ocean ridges contribute to 90% of global magmatism and yet melt generation and extraction are not well understood due to the difficulty in surveying these systems submerged under a few kilometers of ocean. Active seismic and magnetotelluric surveys suggest that melt is generated in a wide region beneath mid-ocean ridges (Forsyth et al., 1998; Key et al., 2013) and yet the oceanic crust is formed within a narrow neo-volcanic zone at the ridge axis (Macdonald, 1984). Several mechanisms to focus melt have been proposed (Spiegelman and McKenzie, 1987; Phipps-Morgan, 1987; Sparks and Parmentier, 1991; Aharonov et al., 1995). I present new open source two phase models, Melt in the Mantle beneath Mid-ocean ridges (M3LT), based on TerraFERMA, the Transparent Finite Element Rapid Model Assembler (Wilson et al., 2017), a software for coupled multi-physics problems. Our multi-phase flow models incorporate realistic viscosities and thermal feedbacks. To ensure reproducibility, the models are openly available in the form of TerraFERMA mark up language files. I present a suite of models varying the half spreading rates. The melt generated in our models produce oceanic crustal thicknesses within geophysical observations. We use these models to review and illustrate three mechanisms that are responsible for melt focusing namely, ridge suction, decompaction layers and melting rate focusing (recently observed mechanism). I show that decompaction layers and melting rate focusing are the dominant mechanisms for focusing melt at mid-ocean ridges. Model results show that the melting rate focusing persists regardless of half spreading rates, while the proportion of melt focused by decompaction layers increases with half spreading rate.
Download or read book Mid Ocean Ridges written by Johnson Robin Cann and published by Cambridge University Press. This book was released on 1999-07-22 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covers the most important problems that arise at mid-ocean ridges; for researchers working in the earth sciences.
Download or read book Mantle Upwelling Melt Generation and Magma Transport Beneath Mid ocean Ridges written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: By Laura Suzan Magde.
Download or read book Mantle Xenoliths written by Peter H. Nixon and published by John Wiley & Sons. This book was released on 1987 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: The eruption of deep-seated xenoliths in basaltic, alnoitic, kimberlitic, etc volcanoes provides the geologist with an important direct means of examining the fragments of the earth's mantle and lower crust.
Download or read book Physics and Chemistry of Partially Molten Rocks written by N. Bagdassarov and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: Partial melting occurs in a variety of geological environments, from granitic partial melts in the continental crust, to basaltic or carbonate partial melts in the upper mantle. Partial melting is the first stage of magmatism and therefore plays a role of primary importance in the chemical differentiation of the Earth and in the transport of heat to the Earth surface. This special volume contains contributions presented at the symposium `Physics and Chemistry of Partially Molten Systems' of the EUG 9 meeting, held in Strasbourg, France, on March 23-27, 1997. It is intended to provide a current understanding of the physics of partial melting and melt segregation and covers topics such as the rheology of partially molten systems, the topology of partial melts, modelling of partial melting processes, and field observations of partial melts. Audience: This book is intended for a broad readership, including graduate students, specializing in petrology and geodynamics. The volume may be recommended as a textbook for graduate courses on petrology, geomaterial sciences and geophysics.
Download or read book Interactions Between Mantle Plumes and Mid ocean Ridges written by Jennifer E. Georgen and published by . This book was released on 2001 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis studies interactions between mid-ocean ridges and mantle plumes. Chapter 1 investigates the effects of the Marion and Bouvet hotspots on the ultra-slow spreading, highly-segmented Southwest Indian Ridge (SWIR). Gravity data indicate that Marion and Bouvet impart high-amplitude mantle Bouguer anomaly lows to the ridge axis, and suggest that long-offset transforms may diminish along-axis plume flow. Chapter 2 presents a series of 3D numerical models designed to quantify the sensitivity of along-axis plume-driven mantle flow to transform offset length, spreading rate, and mantle viscosity structure. The calculations illustrate that long-offset transforms in ultra-slow spreading environments may indeed significantly curtail plume dispersion. Chapter 3, an investigation of helium isotope systematics along the western SWIR (9 deg - 24 deg E), reports uniformly low 3He/He ratios of 6.3-7.3 RIRa, compared to values of 8+1 R for normal mid-ocean ridge basalt. There is no evidence for influence of the Bouvet plume on this section of the SWIR from elevated 3He/4He ratios. Chapter 4 studies 3D mantle flow and temperature patterns beneath oceanic ridge-ridge-ridge triple junctions (TJs). For the slowest-spreading ridge, model results for non-hotspot-affected TJs like the Rodrigues TJ predict (1) an increase of temperature and upwelling velocity within a few hundred kilometers of the TJ to approach those of the fastest-spreading ridge, and (2) a strong component of along-axis flow directed away from the TJ. For hotspot-affected TJs like the Azores TJ, this along-axis flow is predicted to advect a hotspot thermal anomaly away from its deep-seated source.
Download or read book Encyclopedia of Geochemistry written by William M. White and published by Springer. This book was released on 2018-07-24 with total page 1680 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Encyclopedia is a complete and authoritative reference work for this rapidly evolving field. Over 200 international scientists, each experts in their specialties, have written over 330 separate topics on different aspects of geochemistry including geochemical thermodynamics and kinetics, isotope and organic geochemistry, meteorites and cosmochemistry, the carbon cycle and climate, trace elements, geochemistry of high and low temperature processes, and ore deposition, to name just a few. The geochemical behavior of the elements is described as is the state of the art in analytical geochemistry. Each topic incorporates cross-referencing to related articles, and also has its own reference list to lead the reader to the essential articles within the published literature. The entries are arranged alphabetically, for easy access, and the subject and citation indices are comprehensive and extensive. Geochemistry applies chemical techniques and approaches to understanding the Earth and how it works. It touches upon almost every aspect of earth science, ranging from applied topics such as the search for energy and mineral resources, environmental pollution, and climate change to more basic questions such as the Earth’s origin and composition, the origin and evolution of life, rock weathering and metamorphism, and the pattern of ocean and mantle circulation. Geochemistry allows us to assign absolute ages to events in Earth’s history, to trace the flow of ocean water both now and in the past, trace sediments into subduction zones and arc volcanoes, and trace petroleum to its source rock and ultimately the environment in which it formed. The earliest of evidence of life is chemical and isotopic traces, not fossils, preserved in rocks. Geochemistry has allowed us to unravel the history of the ice ages and thereby deduce their cause. Geochemistry allows us to determine the swings in Earth’s surface temperatures during the ice ages, determine the temperatures and pressures at which rocks have been metamorphosed, and the rates at which ancient magma chambers cooled and crystallized. The field has grown rapidly more sophisticated, in both analytical techniques that can determine elemental concentrations or isotope ratios with exquisite precision and in computational modeling on scales ranging from atomic to planetary.
Download or read book Deep Carbon written by Beth N. Orcutt and published by Cambridge University Press. This book was released on 2019-10-17 with total page 687 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive guide to carbon inside Earth - its quantities, movements, forms, origins, changes over time and impact on planetary processes. This title is also available as Open Access on Cambridge Core.
Download or read book Melting and Melt Migration in Heterogeneous Mantle Beneath Mid ocean Ridges written by Samuel Weatherley and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mantle and Lower Crust Exposed in Oceanic Ridges and in Ophiolites written by R.L.M Vissers and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume follows a Specialized Symposium on "Mantle denudation in slow spreading ridges and in ophiolites", held at the XII EUG Meeting in Strasbourg, spring 1993. During the meeting it was felt that the contribu tions to the Symposium justified a volume presenting its main scientific achievements. The present title of the volume shows that the center of inter est has slightly shifted with respect to the initial objective: in order to under stand the processes involved in accretion taking place at oceanic ridges, it is crucial to study the interaction between uppermost mantle and lower crust. The approach favored here is that of petrological and structural analysis of oceanic rocks in present-day oceanic ridges combined with similar studies in ophiolites. Rock specimen collected by submersibles or dredge hauls in oceanic ridge environments provide a "ground truth". However, except for areas such as the MARK (Mid-Atlantic Ridge ne ar Kane fracture zone) where, thanks to multiple submersible dives, the local geology is known with aprecision even better than in many onshore ophiolites, mutual rela tionships between uppermost mantle and lower crust are poorly known. In contrast, onshore ophiolites provide a necessary large-scale picture built up over many years of structural and petrological mapping.
Download or read book Encyclopedia of Marine Geosciences written by Jan Harff and published by Springer. This book was released on 2021-01-14 with total page 1000 pages. Available in PDF, EPUB and Kindle. Book excerpt: Globally growing demand of energy and mineral resources, reliable future projection of climate processes and the protection of coasts to mitigate the threats of disasters and hazards require a comprehensive understanding of the structure, ongoing processes and genesis of the marine geosphere. Beyond the “classical” research fields in marine geology in current time more general concepts have been evolved integrating marine geophysics, hydrography, marine biology, climatology and ecology. As an umbrella the term “marine geosciences” has been broadly accepted for this new complex field of research and the solutions of practical tasks in the marine realm. The “Encyclopedia of Marine Geosciences” comprises the current knowledge in marine geosciences whereby not only basic but also applied and technical sciences are covered. Through this concept a broad scale of users in the field of marine sciences and techniques is addressed from students and scholars in academia to engineers and decision makers in industry and politics.
Download or read book GEOPHYSICS AND GEOCHEMISTRY Volume II written by Jan Lastovicka and published by EOLSS Publications. This book was released on 2009-11-28 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: Geophysics and Geochemistry is a component of Encyclopedia of Earth and Atmospheric Sciences in the global Encyclopedia of Life Support Systems (EOLSS), which is an integrated compendium of twenty one Encyclopedias. Geophysics and Geochemistry are two closely intertwined and collaborating branches of Earth’s sciences. The content of the Theme on Geophysics and Geochemistry is organized with state-of-the-art presentations covering eight main topics: Foundations of Geophysics and Geochemistry; Geophysical Systems; Seismology and Volcanology; Geomagnetism and Geoelectricity; Aeronomy and Magnetosphere; Gravimetry; Geochemistry and Cosmochemistry; Planetology – Comparative Planetology of Earth-like Planets and Astrobiology which are then expanded into multiple subtopics, each as a chapter. These three volumes are aimed at the following a wide spectrum of audiences from the merely curious to those seeking in-depth knowledge: University and College students Educators, Professional practitioners, Research personnel and Policy analysts, managers, and decision makers and NGOs
Download or read book The Galapagos written by Karen S. Harpp and published by John Wiley & Sons. This book was released on 2014-07-22 with total page 443 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Galápagos Islands are renown for their unique flora and fauna, inspiring Charles Darwin in the elaboration of his theory of evolution. Yet in his Voyage of the Beagle, published in 1839, Darwin also remarked on the fascinating geology and volcanic origin of these enchanted Islands. Since then, the Galápagos continue to provide scientists with inspiration and invaluable information about ocean island formation and evolution, mantle plumes, and the deep Earth. Motivated by an interdisciplinary Chapman Conference held in the Islands, this AGU volume provides cross-disciplinary collection of recent research into the origin and nature of ocean islands, from their deepest roots in Earth's mantle, to volcanism, surface processes, and the interface between geology and biodiversity. Volume highlights include: Case studies in biogeographical, hydrological, and chronological perspective Understanding the connection between geological processes and biodiversity Synthesis of decades of interdisciplinary research in physical processes from surface to deep interior of the earth In-depth discussion of the concept of the island acting as a natural laboratory for earth scientists Integrated understanding of the Galápagos region from a geological perspective Collectively, The Galápagos presents case studies illustrating the Galápagos Archipelago as a dynamic natural laboratory for the earth sciences. This book would be of special interest to a multidisciplinary audience in earth sciences, including petrologists, volcanologists, geochronologists, geochemists, and geobiologists.
