Attenuation Tomography Beneath the Rocky Mountain Front
... only half of the measured velocity contrast is attributable to changes in temperature, a Q of 50 coupled with ∆VS of 4.5% implies a change in temperature of only 200 K. Attenuation models coupled with velocity models can also lead to models of the unrelaxed velocity [Minster and Anderson, 1981] whic ...
... only half of the measured velocity contrast is attributable to changes in temperature, a Q of 50 coupled with ∆VS of 4.5% implies a change in temperature of only 200 K. Attenuation models coupled with velocity models can also lead to models of the unrelaxed velocity [Minster and Anderson, 1981] whic ...
On Earth`s Mantle Constitution and Structure from Joint Analysis of
... 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, have provided a window into Earth’s interior. These models have linked velocity anom ...
... 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, have provided a window into Earth’s interior. These models have linked velocity anom ...
Imaging crustal and upper mantle structure beneath the Colorado
... rounding regions of the southwestern United States was made with finite frequency Rayleigh wave tomography using EarthScope/USArray data. The goal of our study is to examine the Colorado Plateau lithospheric modification that has resulted from Cenozoic tectonism and magmatism. We have inverted for t ...
... rounding regions of the southwestern United States was made with finite frequency Rayleigh wave tomography using EarthScope/USArray data. The goal of our study is to examine the Colorado Plateau lithospheric modification that has resulted from Cenozoic tectonism and magmatism. We have inverted for t ...
Continental breakup and the onset of ultraslow seafloor spreading
... and isolate it off Flemish Cap. In this scenario, the strong Z reflection is the seaward continuation of S, transferred to the Newfoundland margin. Without direct sampling, this possibility cannot be eliminated, but it is not favored for several reasons. First, Reston et al. (1996) showed that S is ...
... and isolate it off Flemish Cap. In this scenario, the strong Z reflection is the seaward continuation of S, transferred to the Newfoundland margin. Without direct sampling, this possibility cannot be eliminated, but it is not favored for several reasons. First, Reston et al. (1996) showed that S is ...
Petrological models of magma evolution and deep crustal structure
... the Moho may represent a density [ 181 and/or a rheological [ 191 trap that inhibits the ascent of partial melts. We explore a range of Moho depths (lo- 17 km) which are appropriate to the oceanic environment. We then compare the crustal velocities structure observed beneath oceanic plateaus and hot ...
... the Moho may represent a density [ 181 and/or a rheological [ 191 trap that inhibits the ascent of partial melts. We explore a range of Moho depths (lo- 17 km) which are appropriate to the oceanic environment. We then compare the crustal velocities structure observed beneath oceanic plateaus and hot ...
Factors influencing magmatism during continental break
... Deccan Traps. However we do not find the typical set of geophysical characteristics reported at other ...
... Deccan Traps. However we do not find the typical set of geophysical characteristics reported at other ...
Primary magmas and mantle temperatures
... dehydration reactions, towards higher pressure and higher temperature assemblages. The average crust of ocean basins is basaltic in composition and reacts to quartz eclogite or coesite eclogite in the pressure range of 1 to 5 GPa (~ 30 to 170 km). Within widely accepted models of plate tectonics, in ...
... dehydration reactions, towards higher pressure and higher temperature assemblages. The average crust of ocean basins is basaltic in composition and reacts to quartz eclogite or coesite eclogite in the pressure range of 1 to 5 GPa (~ 30 to 170 km). Within widely accepted models of plate tectonics, in ...
MANTLE MIXING - Earth and Environmental Sciences
... into the oceans (Lupton & Craig 1975, Farley et al. 1995), combined with the average production of basalt at ridges (Parsons 1981) and an assumption of the extent of MORB melting. An estimate of 20% partial melting at mid-oceanic ridges gives a MORB source mantle He concentration of 1.3 × 109 atoms ...
... into the oceans (Lupton & Craig 1975, Farley et al. 1995), combined with the average production of basalt at ridges (Parsons 1981) and an assumption of the extent of MORB melting. An estimate of 20% partial melting at mid-oceanic ridges gives a MORB source mantle He concentration of 1.3 × 109 atoms ...
Physically Based Terrain Generation
... Terrain and landscapes are in a central role in the game and movie industries. For example, player of a modern role playing game travels and explores vast imaginary worlds and many fictional movies today rely on computer assisted graphics for various visual effects and production of realistic yet un ...
... Terrain and landscapes are in a central role in the game and movie industries. For example, player of a modern role playing game travels and explores vast imaginary worlds and many fictional movies today rely on computer assisted graphics for various visual effects and production of realistic yet un ...
Origin of ocean island basalts: A new perspective from petrology
... Lu/176Hf) of the DM along these curves are then constrained at any given time in the last 2.5 Gyr. [8] The significant coupling between radiogenic isotopes and incompatible element abundances and ratios in many OIB suites, seamount lavas, and MORB [e.g., Saunders et al., 1988; Sun and McDonough, 198 ...
... Lu/176Hf) of the DM along these curves are then constrained at any given time in the last 2.5 Gyr. [8] The significant coupling between radiogenic isotopes and incompatible element abundances and ratios in many OIB suites, seamount lavas, and MORB [e.g., Saunders et al., 1988; Sun and McDonough, 198 ...
101 Questions and Answers Concerning
... basaltic in composition, that this basalt had been generated at a mid-ocean ridge via partial melting of mantle rock below as part of the seafloor spreading process, and that all of crustal basement rocks of today’s ocean floor were no older than Mesozoic in age. Among the implications were that the ...
... basaltic in composition, that this basalt had been generated at a mid-ocean ridge via partial melting of mantle rock below as part of the seafloor spreading process, and that all of crustal basement rocks of today’s ocean floor were no older than Mesozoic in age. Among the implications were that the ...
93. Lee, C. - Squarespace
... magmas. If continental arc magmas tend to be more andesitic, as often believed, it follows that they may begin more water-rich than island arc magmas, which are basaltic. In any case, if intermediate arc magmas are formed dominantly by crystal–liquid fractionation, large volumes of complementary mafi ...
... magmas. If continental arc magmas tend to be more andesitic, as often believed, it follows that they may begin more water-rich than island arc magmas, which are basaltic. In any case, if intermediate arc magmas are formed dominantly by crystal–liquid fractionation, large volumes of complementary mafi ...
Divergent Plate Boundaries - North Coast Distance Education
... Remarkably, the midoceanic ridge is a nearly continuous feature around the entire globe, like the seam of a baseball (Figure 19.1). The ridge extends from the Arctic Basin, down through the center of the Atlantic, into the Indian Ocean, and across the South Pacific, ending in the Gulf of California, ...
... Remarkably, the midoceanic ridge is a nearly continuous feature around the entire globe, like the seam of a baseball (Figure 19.1). The ridge extends from the Arctic Basin, down through the center of the Atlantic, into the Indian Ocean, and across the South Pacific, ending in the Gulf of California, ...
Full-text PDF (final published version)
... long-term isolation of elements that are incompatible in the crystal structure of common mantle minerals and there is a complementary signature in the mantle (Armstrong, 1968; DePaolo and Wasserburg, 1976; O'Nions et al., 1979). While the continental crust is readily accessible, direct samples of th ...
... long-term isolation of elements that are incompatible in the crystal structure of common mantle minerals and there is a complementary signature in the mantle (Armstrong, 1968; DePaolo and Wasserburg, 1976; O'Nions et al., 1979). While the continental crust is readily accessible, direct samples of th ...
the Zero Paradox Noble Gas Mantle
... volcanism from the deep mantle and sample a more volatile rich and less depleted portion of the mantle. The boundary between these reservoirs has often been assumed to be at 670 km, where either a chemical boundary, or the endothermic phase change from spinel to perovskite/magnesiowuestite structure ...
... volcanism from the deep mantle and sample a more volatile rich and less depleted portion of the mantle. The boundary between these reservoirs has often been assumed to be at 670 km, where either a chemical boundary, or the endothermic phase change from spinel to perovskite/magnesiowuestite structure ...
The Eclogite Engine: Chemical geodynamics as
... A basic premise of this chapter is that the large volume changes associated with partial melting, and other phase changes, and the large density differences between eclogites and peridotites may be as important as thermal expansion in mantle dynamics. Another premise is that melt volumes and melt co ...
... A basic premise of this chapter is that the large volume changes associated with partial melting, and other phase changes, and the large density differences between eclogites and peridotites may be as important as thermal expansion in mantle dynamics. Another premise is that melt volumes and melt co ...
Chapter 2 The Way the Earth Works: Plate Tectonics
... If the southern part of Pangaea had straddled the South Pole at the end of the Paleozoic Era, then during this same time interval, southern North America, southern Europe, and northwestern Africa would have straddled the equator and would have had tropical or subtropical climates. Wegener searched f ...
... If the southern part of Pangaea had straddled the South Pole at the end of the Paleozoic Era, then during this same time interval, southern North America, southern Europe, and northwestern Africa would have straddled the equator and would have had tropical or subtropical climates. Wegener searched f ...
The continental tectosphere and Earth`s long
... Ž1977. ŽTable 2. and Mauk Ž1977. ŽTable 3. contain six, seven, and 20 regions, respectively. Both GTR1 and the regionalization of Mauk Ž1977. are defined on a grid of 58 = 58 cells, whereas the model of Okal Ž1977. is defined using 158 = 158 and 108 = 158 cells. The regionalization of Mauk Ž1977. al ...
... Ž1977. ŽTable 2. and Mauk Ž1977. ŽTable 3. contain six, seven, and 20 regions, respectively. Both GTR1 and the regionalization of Mauk Ž1977. are defined on a grid of 58 = 58 cells, whereas the model of Okal Ž1977. is defined using 158 = 158 and 108 = 158 cells. The regionalization of Mauk Ž1977. al ...
A relatively reduced Hadean continental crust and - HAL
... silicic melts reach zircon saturation at reasonable values (<100 ppm), while natural peralkaline melts have very high Zr solubility (thousands of ppm to several wt%), which prevents them from crystallizing zircons (Watson, 1979) in the temperature range recorded by most, if not all, crustal zircons, ...
... silicic melts reach zircon saturation at reasonable values (<100 ppm), while natural peralkaline melts have very high Zr solubility (thousands of ppm to several wt%), which prevents them from crystallizing zircons (Watson, 1979) in the temperature range recorded by most, if not all, crustal zircons, ...
View - GFZpublic
... assumption. However, the strong temperature dependence and the non-linear stress^strain rate relation of continental rheology may result in strain rates that are unrealistically high by several orders of magnitude for long-term intraplate deformation when applying the CF model to a weak lithosphere ...
... assumption. However, the strong temperature dependence and the non-linear stress^strain rate relation of continental rheology may result in strain rates that are unrealistically high by several orders of magnitude for long-term intraplate deformation when applying the CF model to a weak lithosphere ...
Plate Tectonics Conceptest
... subduction zones. Continents can break up or combine but total volume remains the same. The Good Earth/Chapter 4: Plate Tectonics ...
... subduction zones. Continents can break up or combine but total volume remains the same. The Good Earth/Chapter 4: Plate Tectonics ...
Immobile Element Fingerprinting of Ophiolites
... points of either the metamorphosed lavas themselves or their surrounding sediments. A number of key elements (e.g. Th, Nb, Zr) may be mobile under these conditions. Using the Cann (1970) correlation-based method (FIG. 2) to confi rm which elements are immobile is therefore a wise precaution. To do t ...
... points of either the metamorphosed lavas themselves or their surrounding sediments. A number of key elements (e.g. Th, Nb, Zr) may be mobile under these conditions. Using the Cann (1970) correlation-based method (FIG. 2) to confi rm which elements are immobile is therefore a wise precaution. To do t ...
Living Things - Mountain View Middle School
... You will be able to explain the process of seafloor spreading. You will be able to list the evidence for sea-floor spreading. You will be able to describe the process of subduction at deep-ocean trenches. ...
... You will be able to explain the process of seafloor spreading. You will be able to list the evidence for sea-floor spreading. You will be able to describe the process of subduction at deep-ocean trenches. ...
22 Hotspots and Mantle Plumes
... Like the plate tectonic system, mantle plumes are a type of convection that slowly stirs the mantle. However, plate tectonics and mantle plumes are related to two distinct types of convection. One is the convection involved in plate motion, wherein material rises at divergent plate boundaries and de ...
... Like the plate tectonic system, mantle plumes are a type of convection that slowly stirs the mantle. However, plate tectonics and mantle plumes are related to two distinct types of convection. One is the convection involved in plate motion, wherein material rises at divergent plate boundaries and de ...
Post-glacial rebound
Post-glacial rebound (sometimes called continental rebound) is the rise of land masses that were depressed by the huge weight of ice sheets during the last glacial period, through a process known as isostatic depression. Post-glacial rebound and isostatic depression are different parts of a process known as either glacial isostasy, glacial isostatic adjustment, or glacioisostasy. Glacioisostasy is the solid Earth deformation associated with changes in ice mass distribution. The most obvious and direct affects of post-glacial rebound are readily apparent in northern Europe (especially Scotland, Estonia, Latvia, Fennoscandia, and northern Denmark), Siberia, Canada, the Great Lakes of Canada and the United States, the coastal region of the US state of Maine, parts of Patagonia, and Antarctica. However, through processes known as ocean siphoning and continental levering, the effects of post-glacial rebound on sea-level are felt globally far from the locations of current and former ice sheets.