Anisotropy and Deformation in the Earth's Mantle

Anisotropy and Deformation in the Earth's Mantle
Author: Maureen Devaney Long
Publisher:
Total Pages: 316
Release: 2006
Genre:
ISBN:

(Cont.) To characterize further the detailed pattern of flow and anisotropy, I evaluate a series of two-dimensional finite element models that describe the subduction of the Philippine Sea plate beneath southwestern Japan, and compare the resulting flow field, strain, and anisotropy in the mantle wedge to F-net shear wave splitting observations. To complement this forward modeling approach, I develop and implement a method for the 2.5-D inversion of shear wave splitting intensity measurements for anisotropic structure in the upper mantle. I present preliminary anisotropic models for southwestern Japan and discuss strategies for explicitly integrating the tomographic inversion of splitting intensity data with numerical models that describe geodynamic processes in the wedge. Finally, I describe a series of laboratory experiments characterizing deformation and the resulting lattice preferred orientation in magnesiowüstite, a lower mantle mineral, and discuss the implications for the interpretation of seismic anisotropy at the base of the mantle.

Plate Deformation from Cradle to Grave

Plate Deformation from Cradle to Grave
Author: Andy Nowacki
Publisher: Springer Science & Business Media
Total Pages: 177
Release: 2012-12-14
Genre: Science
ISBN: 3642348424

The Earth's rocky mantle convects to lose heat, which comes from the liquid iron core below. The mantle's interfaces - the core-mantle boundary, and the lithosphere - may hold the key to understanding mantle motion because of the seismic anisotropy present in these parts of the Earth. In this thesis, Andy Nowacki presents a precise but comprehensive review of the current state of the art in studying flow with anisotropy, mineral physics and geodynamics. New measurements of shear wave anisotropy in the lowermost mantle and at mid-ocean ridges are used to constrain mechanisms of creep and melt extraction in the mantle. A model of global flow is used to predict anisotropy in the deep Earth, and novel methods to forward model shear wave splitting are described. Future studies of mantle flow must incorporate the understanding gained in this thesis. The thesis contains a substantive introduction to the structure of the Earth, seismic anisotropy in general and in the core-mantle boundary region, and mid-ocean ridge processes. It also describes novel methods for forward modelling and interpreting shear wave splitting data. Three chapters present timely research into dynamics at divergent plate boundaries and at the core-mantle boundary.

Geodynamics of Lithosphere & Earth’s Mantle

Geodynamics of Lithosphere & Earth’s Mantle
Author: Jaroslava Plomerova
Publisher: Birkhäuser
Total Pages: 496
Release: 2012-12-06
Genre: Science
ISBN: 3034887779

Plate tectonics has significantly broadened our view of the dynamics of continental evolution, involving both the processes currently active at the surface and those extending deep into the interior of the Earth. Seismic anisotropy provides some of the most diagnostic evidence for mapping past and present deformation of the entire crustmantle system. This volume contains papers presented originally at an international workshop at the Chateau of Trest in the Czech Republic in 1996. This workshop brought together geophysicists and geologists who work in the field of observational and theoretical seismology, mineral and rock physics, gravity studies and geodynamic modelling. Topics include large-scale anisotropy of the Earth's mantle, mantle heterogeneity vs. anisotropy 3-D velocity and density structures and inferences on mantle dynamics, mineral and rock physics studies, and mathematical aspects of complex wave propagation.

Mantle Convection and Surface Expressions

Mantle Convection and Surface Expressions
Author: Hauke Marquardt
Publisher: John Wiley & Sons
Total Pages: 32
Release: 2021-07-07
Genre: Science
ISBN: 1119528615

A multidisciplinary perspective on the dynamic processes occurring in Earth's mantle The convective motion of material in Earth's mantle, powered by heat from the deep interior of our planet, drives plate tectonics at the surface, generating earthquakes and volcanic activity. It shapes our familiar surface landscapes, and also stabilizes the oceans and atmosphere on geologic timescales. Mantle Convection and Surface Expressions brings together perspectives from observational geophysics, numerical modelling, geochemistry, and mineral physics to build a holistic picture of the deep Earth. It explores the dynamic processes occurring in the mantle as well as the associated heat and material cycles. Volume highlights include: Perspectives from different scientific disciplines with an emphasis on exploring synergies Current state of the mantle, its physical properties, compositional structure, and dynamic evolution Transport of heat and material through the mantle as constrained by geophysical observations, geochemical data and geodynamic model predictions Surface expressions of mantle dynamics and its control on planetary evolution and habitability The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.

Geodynamics of Lithosphere and Earth's Mantle

Geodynamics of Lithosphere and Earth's Mantle
Author: Jaroslava Plomerova
Publisher: Springer Science & Business Media
Total Pages: 520
Release: 1998-04
Genre: Science
ISBN: 9783764359072

Reprint from Pure and Applied Geophysics (PAGEOPH), Volume 151 (1998), No. 2/3/4

Deformation-enhanced Fluid Transport in the Earth's Crust and Mantle

Deformation-enhanced Fluid Transport in the Earth's Crust and Mantle
Author: M.B. Holness
Publisher: Springer Science & Business Media
Total Pages: 360
Release: 1997-10-31
Genre: Science
ISBN: 9780412752902

30% discount for members of The Mineralogical Society of Britain and Ireland The movement of fluids through rocks has profound consequences for the transport of heat and matter within the Earth. Recently, considerable effort has been expended in determining the mechanisms and pathways of geological fluid flow, with much of this research concentrated on the effects of deformation on rock permeability. Although it is well known that fractures can act as conduits for fluid transport (as evidenced by abundant mineral-fined veins and sheet-like igneous intrusions), the role of ductile deformation has now been recognised as an important factor controlling rock permeability in environments as diverse as the mantle, the deep crust, and shallow crustal shear zones. This book brings together review and research articles united by the theme of deformation-enhanced fluid transport, with the aim of emphasizing the many common roots of this important body of work. Subjects covered include the movement of basaltic melts in the mantle; the segregation, ascent and emplacement of granitic melts in the crust; the flow through the crust of volatile fluids produced during metamorphic events; and the movement of aqueous fluids through fractured rocks near the Earth's surface. Deformation-Enhanced Fluid Transport in the Earth's Crust and Mantle will appeal to all geoscientists interested in the movement of fluids through the Earth. It will prove an invaluable reference work for those working in the field and will provide i useful introduction to this wide-ranging and rapidly evolving area of research for non-specialists.

The Core-Mantle Boundary Region

The Core-Mantle Boundary Region
Author: Michael Gurnis
Publisher: American Geophysical Union
Total Pages: 352
Release: 1998-02-04
Genre: Science
ISBN:

The two giant heat engines responsible for plate tectonics and the geodynamo dynamically interact at the core-mantle boundary of the Earth's interior. A multidisciplinary approach is required to determine the composition, structure, and dynamics of the interface. This volume describes original and fundamental research in seismology, geodynamics, mineral physics, and geomagnetism.

Experimental Deformation of Fosterite, Wadsleyite and Ringwoodite

Experimental Deformation of Fosterite, Wadsleyite and Ringwoodite
Author: Hélène Couvy
Publisher:
Total Pages: 5
Release: 2005
Genre:
ISBN:

L'objectif de ce travail est d'étudier la rhéologie du manteau terrestre à travers les propriétés mécaniques de la forsterite, de la wadsleyite et de la ringwoodite (Mg2SiO4). Les échantillons ont été déformés dans les presses multi enclumes Kawai et D-DIA. Les microstructures et les textures des échantillons ont été caractérisées par Microscopie Electronique en Transmission et par diffraction des électrons rétrodiffusés. A haute pression, [001] {hkO}.est dominant dans la forsterite. Les textures de la wadsleyite sont caractérisées par [100] parallèle à la direction de cisaillement et [001] normal au plan de cisaillement. Pour la ringwoodite, aucune texture fiable ne peut être proposée. Enfin, le changement de système de glissement dominant de la forsterite permet d'expliquer la faible anisotropie sismique observée dans la partie inférieure du manteau supérieur et la texture de la wadsleyite indique un écoulement horizontal dominant dans la partie supérieure de la zone de transition.