The Upper Mantle Geoid: Implications for Continental Structure and
... zones along the western Pacific Rim, there is little correlation between the geoid and surface features such as continents (with the notable exception of the Andes) and mid-ocean ridges (Kaula, 1967). As pointed out in previous studies (Vanicek and Christou, 1994) large-scale lithospheric features s ...
... zones along the western Pacific Rim, there is little correlation between the geoid and surface features such as continents (with the notable exception of the Andes) and mid-ocean ridges (Kaula, 1967). As pointed out in previous studies (Vanicek and Christou, 1994) large-scale lithospheric features s ...
Supercontinents, mantle dynamics and plate
... The periodic assembly and dispersal of supercontinents through the history of the Earth had considerable impact on mantle dynamics and surface processes. Here we synthesize some of the conceptual models on supercontinent amalgamation and disruption and combine it with recent information from numeric ...
... The periodic assembly and dispersal of supercontinents through the history of the Earth had considerable impact on mantle dynamics and surface processes. Here we synthesize some of the conceptual models on supercontinent amalgamation and disruption and combine it with recent information from numeric ...
Full text PDF - Geochemical Perspectives
... thing I have learned through my career in science is to never completely believe anything – as Einstein remarked, God is subtle; it’s easy to be wrong. Furthermore, this is, of course, my own perspective and there are as many perspectives as workers in the field. I have placed a lot of emphasis on t ...
... thing I have learned through my career in science is to never completely believe anything – as Einstein remarked, God is subtle; it’s easy to be wrong. Furthermore, this is, of course, my own perspective and there are as many perspectives as workers in the field. I have placed a lot of emphasis on t ...
KENT C. CONDIE
... and graduate students in the Earth Sciences. The rapid accumulation of data on plate tectonics, mantle evolution, and the origin of continents in the last decade has necessitated continued updating of the course. The book is written for an advanced undergraduate or graduate student, and it assumes a ...
... and graduate students in the Earth Sciences. The rapid accumulation of data on plate tectonics, mantle evolution, and the origin of continents in the last decade has necessitated continued updating of the course. The book is written for an advanced undergraduate or graduate student, and it assumes a ...
PDF of this page - UVM Catalogue
... GEOL 001. Earth System Science. 0 or 4 Credits. Introduction to the earth as a closed system, the cycling of materials and energy within it, and its interactions with the hydrosphere and atmosphere. No credit for GEOL 001 and either GEOL 005, GEOL 006, GEOL 008, or GEOL 011. GEOL 005. Mt - Lake:Geol ...
... GEOL 001. Earth System Science. 0 or 4 Credits. Introduction to the earth as a closed system, the cycling of materials and energy within it, and its interactions with the hydrosphere and atmosphere. No credit for GEOL 001 and either GEOL 005, GEOL 006, GEOL 008, or GEOL 011. GEOL 005. Mt - Lake:Geol ...
Geophysical Constraints on Mantle Composition
... determined, which are useful in studies of velocity anisotropy. The technique requires only small samples, and because visible light is employed, the samples may be placed in an optically transparent diamond-anvil cell (DAC) in order to make measurements at elevated pressures and temperatures. DAC s ...
... determined, which are useful in studies of velocity anisotropy. The technique requires only small samples, and because visible light is employed, the samples may be placed in an optically transparent diamond-anvil cell (DAC) in order to make measurements at elevated pressures and temperatures. DAC s ...
Mantle Mixing - Earth and Environmental Sciences
... history of upper mantle depletion recorded by 87Sr/86Sr and 143Nd/144Nd in MORB (e.g. DePaolo & Wasserburg 1976; O’Nions et al 1979; Allègre et al 1979; Kurz et al 1982). The complement of this idea is that the undegassed and primitive volatile rich component corresponds to the actual preservation o ...
... history of upper mantle depletion recorded by 87Sr/86Sr and 143Nd/144Nd in MORB (e.g. DePaolo & Wasserburg 1976; O’Nions et al 1979; Allègre et al 1979; Kurz et al 1982). The complement of this idea is that the undegassed and primitive volatile rich component corresponds to the actual preservation o ...
MANTLE MIXING - Earth and Environmental Sciences
... calculated with the assumption that the lower mantle has primitive (or BSE) U + Th concentrations and has essentially remained a closed system for 4.5 Ga. From an assumed initial solar 3He/4He ratio of 120Ra, this reservoir has evolved to the observed 3He/4He ratio of ∼35Ra, which is equal to the hi ...
... calculated with the assumption that the lower mantle has primitive (or BSE) U + Th concentrations and has essentially remained a closed system for 4.5 Ga. From an assumed initial solar 3He/4He ratio of 120Ra, this reservoir has evolved to the observed 3He/4He ratio of ∼35Ra, which is equal to the hi ...
Mantle mixing - Earth and Environmental Sciences
... core of the convection cell this heterogeneity is barely deformed at all. The dramatic difference in mixing efficiency between two different heterogeneities with slightly different initial condition is maintained over long computational time in this convection model, as is illustrated in Figure 2. T ...
... core of the convection cell this heterogeneity is barely deformed at all. The dramatic difference in mixing efficiency between two different heterogeneities with slightly different initial condition is maintained over long computational time in this convection model, as is illustrated in Figure 2. T ...
Dynamical geochemistry of the mantle
... models that have not simultaneously satisfied the geophysical and geochemical constraints. Whereas geophysical inferences have led to a picture of the mantle with no major vertical compositional variation, apart from the D00 zone in the lowest 200–300 km (Davies and Richards, 1992; Grand et al., 199 ...
... models that have not simultaneously satisfied the geophysical and geochemical constraints. Whereas geophysical inferences have led to a picture of the mantle with no major vertical compositional variation, apart from the D00 zone in the lowest 200–300 km (Davies and Richards, 1992; Grand et al., 199 ...
The viscosity of Earthв€™s lower mantle inferred from sinking speed
... effectively replaces more sophisticated mechanisms as the lowtemperature plasticity (Peierls creep). The yield stress of the subducting slabs is assumed to be 0.5 GPa, which corresponds to the yield strength of olivine at about 900 °C (Billen, 2010). The rheological description in our models varies ...
... effectively replaces more sophisticated mechanisms as the lowtemperature plasticity (Peierls creep). The yield stress of the subducting slabs is assumed to be 0.5 GPa, which corresponds to the yield strength of olivine at about 900 °C (Billen, 2010). The rheological description in our models varies ...
Building and Destroying Continental Mantle - Cin
... demands an intrinsically stronger (more viscous) mantle, which effectively renders continents as rigid boundary layers physically isolated from the convecting mantle (Cooper et al. 2004, Hirth & Kohlstedt 1996, Lee et al. 2005, Lenardic et al. 2003). One widely accepted hypothesis is that continenta ...
... demands an intrinsically stronger (more viscous) mantle, which effectively renders continents as rigid boundary layers physically isolated from the convecting mantle (Cooper et al. 2004, Hirth & Kohlstedt 1996, Lee et al. 2005, Lenardic et al. 2003). One widely accepted hypothesis is that continenta ...
Radiogenic Isotope Geochemistry of the Mantle
... A principal objective of geology is to understand how the Earth evolved from its initial state to its present one. Radiogenic isotope geochemistry is uniquely suited for this sort of study because an isotope ratio such as 87Sr/86Sr is a function not only of the differentiation processes which fracti ...
... A principal objective of geology is to understand how the Earth evolved from its initial state to its present one. Radiogenic isotope geochemistry is uniquely suited for this sort of study because an isotope ratio such as 87Sr/86Sr is a function not only of the differentiation processes which fracti ...
Punctuated tectonic evolution of the earth
... theory) convection and two criteria for when layering may break down. The resulting models yield not just the pulses that would be expected, but longer phases of behavior as well. More generally, these models demonstrate a repertoire of behavior that is implicit in our present understanding of mantl ...
... theory) convection and two criteria for when layering may break down. The resulting models yield not just the pulses that would be expected, but longer phases of behavior as well. More generally, these models demonstrate a repertoire of behavior that is implicit in our present understanding of mantl ...
Crystal preferred orientation of an amphibole experimentally
... beneath Urach in southwestern Germany11, and a strong radial anisotropy was noted in the lower crust in the extensional provinces of the western United States, suggesting that this radial anisotropy results from the crystal preferred orientation (CPO) of anisotropic crustal minerals7. Several models ...
... beneath Urach in southwestern Germany11, and a strong radial anisotropy was noted in the lower crust in the extensional provinces of the western United States, suggesting that this radial anisotropy results from the crystal preferred orientation (CPO) of anisotropic crustal minerals7. Several models ...
Characteristic thermal regimes of plate tectonics
... Earth. For example, we may ask when did the lithosphere first behave as a mosaic of plates—that is, a mosaic of largely torsionally rigid lithosphere elements bounded by zones of generation, destruction, or transform displacement—and how far back in Earth history may we identify independent horizont ...
... Earth. For example, we may ask when did the lithosphere first behave as a mosaic of plates—that is, a mosaic of largely torsionally rigid lithosphere elements bounded by zones of generation, destruction, or transform displacement—and how far back in Earth history may we identify independent horizont ...
On Earth`s Mantle Constitution and Structure from Joint Analysis of
... geophysical methods based on seismic, geodetic, gravity, and electromagnetic sounding studies play prominent roles because of their ability to define structure on large scale lengths and depths based on measurements acquired from surface instrumentation. Global seismic tomography images, for example ...
... geophysical methods based on seismic, geodetic, gravity, and electromagnetic sounding studies play prominent roles because of their ability to define structure on large scale lengths and depths based on measurements acquired from surface instrumentation. Global seismic tomography images, for example ...
Contribution of gravitational potential energy differences to the
... et al. 2006, 2008). The assumption that goes with the thin sheet approximation is that the gradients of shear tractions at the base of the plate are negligibly small compared to the force of gravity acting on density. In terms of a thin sheet approach, the sources of stress within the lithosphere ca ...
... et al. 2006, 2008). The assumption that goes with the thin sheet approximation is that the gradients of shear tractions at the base of the plate are negligibly small compared to the force of gravity acting on density. In terms of a thin sheet approach, the sources of stress within the lithosphere ca ...
History of geomagnetism
The history of geomagnetism is concerned with the history of the study of Earth's magnetic field. It encompasses the history of navigation using compasses, studies of the prehistoric magnetic field (archeomagnetism and paleomagnetism), and applications to plate tectonics.Magnetism has been known since prehistory, but knowledge of the Earth's field developed slowly. The horizontal direction of the Earth's field was first measured in the fourth century BC but the vertical direction was not measured until 1544 AD and the intensity was first measured in 1791. At first, compasses were thought to point towards locations in the heavens, then towards magnetic mountains. A modern experimental approach to understanding the Earth's field began with de Magnete, a book published by William Gilbert in 1600. His experiments with a magnetic model of the Earth convinced him that the Earth itself is a large magnet.