Magma Composition and Igneous Rocks By Dr. James Brophy
... for all four rocks listed in \Table 2.1. The figure clearly shows that as the SiO2 content of each successive rock increases, the abundances of FeO, MgO and CaO decrease systematically. At the same time, the abundances of Na2O and K2O increase systematically. It turns out that these relations hold t ...
... for all four rocks listed in \Table 2.1. The figure clearly shows that as the SiO2 content of each successive rock increases, the abundances of FeO, MgO and CaO decrease systematically. At the same time, the abundances of Na2O and K2O increase systematically. It turns out that these relations hold t ...
Chapter1 General Introduction
... our view on the lower continental crust comes largely from a few uplifted slices of the crust in collisional orogens and from xenoliths in younger volcanics. ...
... our view on the lower continental crust comes largely from a few uplifted slices of the crust in collisional orogens and from xenoliths in younger volcanics. ...
The plume head-lithosphere interactions near intra - HAL-Insu
... Mantle plumes are regarded as focused mantle upwellings that originate from deep mantle sources (e.g., Campbell et al., 1989; Campbell and Griffiths, 1990; Olson, 1990). If the link with the source region is continuous, such upwellings are considered as mantle plumes senso stricto, otherwise they ar ...
... Mantle plumes are regarded as focused mantle upwellings that originate from deep mantle sources (e.g., Campbell et al., 1989; Campbell and Griffiths, 1990; Olson, 1990). If the link with the source region is continuous, such upwellings are considered as mantle plumes senso stricto, otherwise they ar ...
Papers presented to the Conference on Heat and Detachment in
... increase in yield stress with depth. With increasing temperature, rock deformation occurs predominantly by ductile flow. Flow laws for many rocks and minerals have been experimentally_%etermined for stresses up to 1-2 GPa and strain rates down to 10 Isec. These results can be extrapolated to geologi ...
... increase in yield stress with depth. With increasing temperature, rock deformation occurs predominantly by ductile flow. Flow laws for many rocks and minerals have been experimentally_%etermined for stresses up to 1-2 GPa and strain rates down to 10 Isec. These results can be extrapolated to geologi ...
Earth and Planetary Science Letters Recycled crust in the
... provinces (LIPs), characterized by high degrees of partial melting, high mantle potential temperatures (T p ), and widespread lava flows (>105 km2 ) (Richards et al., 1989; Coffin and Eldholm, 1994; Herzberg and Gazel, 2009). These events were sometimes so large that they affected environmental change ...
... provinces (LIPs), characterized by high degrees of partial melting, high mantle potential temperatures (T p ), and widespread lava flows (>105 km2 ) (Richards et al., 1989; Coffin and Eldholm, 1994; Herzberg and Gazel, 2009). These events were sometimes so large that they affected environmental change ...
Correlated geophysical, geochemical, and volcanological
... Figure 2. Geophysical, volcanological, and geochemical variations along the western GSC showing the following: (a) depth of ridge axis (black line) and Galápagos swell (blue line); swell depth is corrected for variations in axial topography along western GSC. (b) Mantle Bouguer anomaly (black line) ...
... Figure 2. Geophysical, volcanological, and geochemical variations along the western GSC showing the following: (a) depth of ridge axis (black line) and Galápagos swell (blue line); swell depth is corrected for variations in axial topography along western GSC. (b) Mantle Bouguer anomaly (black line) ...
Recycled crust in the Galápagos Plume source at 70 Ma
... provinces (LIPs), characterized by high degrees of partial melting, high mantle potential temperatures (T p ), and widespread lava flows (>105 km2 ) (Richards et al., 1989; Coffin and Eldholm, 1994; Herzberg and Gazel, 2009). These events were sometimes so large that they affected environmental change ...
... provinces (LIPs), characterized by high degrees of partial melting, high mantle potential temperatures (T p ), and widespread lava flows (>105 km2 ) (Richards et al., 1989; Coffin and Eldholm, 1994; Herzberg and Gazel, 2009). These events were sometimes so large that they affected environmental change ...
Deformation of Indian Ocean lithosphere
... deformation in the continents, may be equally useful for estimating the vertically averaged properties of deforming oceanic lithosphere. For example, Zatman et al. [2001, 2005] used simple analytical and numerical models of a thin viscous sheet to explore the relation between the pole of relative mo ...
... deformation in the continents, may be equally useful for estimating the vertically averaged properties of deforming oceanic lithosphere. For example, Zatman et al. [2001, 2005] used simple analytical and numerical models of a thin viscous sheet to explore the relation between the pole of relative mo ...
A geological model for the structure of ridge segments in slow
... The axes of mid-oceanridges are offset by discontinuities and Laughton, 1977], and adjacentspreadingaxes often overwhich divide the oceancrust into spreadingsegments(Figure lap, with crustal ridges or septa cutting acrossthe discontinu1) [Macdonald et al., 1991]. First-order discontinuities in ities ...
... The axes of mid-oceanridges are offset by discontinuities and Laughton, 1977], and adjacentspreadingaxes often overwhich divide the oceancrust into spreadingsegments(Figure lap, with crustal ridges or septa cutting acrossthe discontinu1) [Macdonald et al., 1991]. First-order discontinuities in ities ...
Conditions for a crustal block to be sheared off from the subducted
... such phenomena shearing-off and investigate the mechanical conditions for shearing-off to occur in the continental lithosphere. The buoyancy of the crustal block does not work selectively as a driving force until it has been sheared off and I suppose that shearing-off occurs when the shear traction ...
... such phenomena shearing-off and investigate the mechanical conditions for shearing-off to occur in the continental lithosphere. The buoyancy of the crustal block does not work selectively as a driving force until it has been sheared off and I suppose that shearing-off occurs when the shear traction ...
SeiSmological grand challengeS in UnderStanding earth`S
... elasticity, and applied mathematics. Modern seismological systems utilize state-of-theart digital ground motion recording sensors and real-time communications systems, and anyone can openly access many seismological data archives. Seismologists “keep their ear” on Earth’s internal systems, listening ...
... elasticity, and applied mathematics. Modern seismological systems utilize state-of-theart digital ground motion recording sensors and real-time communications systems, and anyone can openly access many seismological data archives. Seismologists “keep their ear” on Earth’s internal systems, listening ...
Two-dimensional simulations of surface deformation caused by slab
... Detachment of the deeper part of subducted lithosphere causes changes in a subduction zone system which may be observed on the Earth’s surface. Constraints on the expected magnitudes of these surface effects can aid in the interpretation of geological observations near convergent plate margins where ...
... Detachment of the deeper part of subducted lithosphere causes changes in a subduction zone system which may be observed on the Earth’s surface. Constraints on the expected magnitudes of these surface effects can aid in the interpretation of geological observations near convergent plate margins where ...
Weakening of the subduction interface and its effects on surface
... 1 m to 10 km). For temperatures, velocities, and coordinates, each element has nine nodal points. For pressure, only the four corner nodes of each element are used. The total number of temperature nodal points is about 29,300. Details of the mesh vary between different test cases to allow optimal ...
... 1 m to 10 km). For temperatures, velocities, and coordinates, each element has nine nodal points. For pressure, only the four corner nodes of each element are used. The total number of temperature nodal points is about 29,300. Details of the mesh vary between different test cases to allow optimal ...
Weakness of the lower continental crust: a condition for
... pressure) (Meissner and Wever, 1988). (b) Smoothing effect of semibrittle zones (Chester et al., 1993). (c) Effects of delamination (under collapse). Former mafic lower crust has disappeared and left a laminated, reflective zone with rather low average velocity (Meissner et al., 1991). ...
... pressure) (Meissner and Wever, 1988). (b) Smoothing effect of semibrittle zones (Chester et al., 1993). (c) Effects of delamination (under collapse). Former mafic lower crust has disappeared and left a laminated, reflective zone with rather low average velocity (Meissner et al., 1991). ...
extension systems - The Web site cannot be found
... Extension systems are zones where plates split into two or more smaller blocks that move apart. To accommodate the separation, dominantly normal faults and even open fissures lead to stretching, rupture and lengthening of crustal rocks. At the same time, the lithosphere is thinned and the asthenosph ...
... Extension systems are zones where plates split into two or more smaller blocks that move apart. To accommodate the separation, dominantly normal faults and even open fissures lead to stretching, rupture and lengthening of crustal rocks. At the same time, the lithosphere is thinned and the asthenosph ...
︎PDF - Fabio Crameri
... emerging mobile surface plates in mantle convection simulations, is a long-standing challenge. The majority of mantle convection models featuring a mobile lid thus impose some aspect such as plate velocity, trench velocity, or weak zones [see Bercovici et al., 2000; Lowman, 2011, and references ther ...
... emerging mobile surface plates in mantle convection simulations, is a long-standing challenge. The majority of mantle convection models featuring a mobile lid thus impose some aspect such as plate velocity, trench velocity, or weak zones [see Bercovici et al., 2000; Lowman, 2011, and references ther ...
Global Tectonics - dynamicearth.de
... (Section 11.3.1) whose resistant qualities have contributed to the long-term survival of the Archean continental lithosphere (Carlson et al., 2005). The beginning of the Archean Eon approximately coincides with the age of the oldest continental crust. A conventional view places this age at approxima ...
... (Section 11.3.1) whose resistant qualities have contributed to the long-term survival of the Archean continental lithosphere (Carlson et al., 2005). The beginning of the Archean Eon approximately coincides with the age of the oldest continental crust. A conventional view places this age at approxima ...
The Moho - EarthByte
... crust. It is identified as a first order discontinuity where the seismic P-wave velocity increases from typically 6.5–7.0 km/s to above 8.0 km/ s in continental lithosphere, and from about 6.8–7.3 km/s to above 7.6 km/s in oceanic lithosphere (e.g. White et al., 1992). The Moho is generally interprete ...
... crust. It is identified as a first order discontinuity where the seismic P-wave velocity increases from typically 6.5–7.0 km/s to above 8.0 km/ s in continental lithosphere, and from about 6.8–7.3 km/s to above 7.6 km/s in oceanic lithosphere (e.g. White et al., 1992). The Moho is generally interprete ...
Asymmetry of high-velocity lower crust on the South
... Anomaly M4 can be mapped along the entire margin (Fig. 1), and this will serve in the present study as a time marker for the regime of seafloor spreading in oceanic lithosphere. Onshore, by far the largest concentration of magmatic activity was in the Paraná–Etendeka province of Brazil and Namibia, ...
... Anomaly M4 can be mapped along the entire margin (Fig. 1), and this will serve in the present study as a time marker for the regime of seafloor spreading in oceanic lithosphere. Onshore, by far the largest concentration of magmatic activity was in the Paraná–Etendeka province of Brazil and Namibia, ...
Receiver function constraints on crustal seismic velocities and
... unique transitional continental spreading leading to the formation of new magmatic crust [Mohr, 1989; Kazmin and Byakov, 2000], which possibly originated around 16 Ma [Wolfenden et al., 2005] and has been shown to generate oceanic-type magnetic anomaly patterns [Bridges et al., 2012]. 1.3. Crustal S ...
... unique transitional continental spreading leading to the formation of new magmatic crust [Mohr, 1989; Kazmin and Byakov, 2000], which possibly originated around 16 Ma [Wolfenden et al., 2005] and has been shown to generate oceanic-type magnetic anomaly patterns [Bridges et al., 2012]. 1.3. Crustal S ...
Terrestrial Heat Flow and the Mantle Convection Hypothesis
... pattern. The results are compared with observed heat flow. Subject to the assumptions of the models, the results suggest that sub-oceanic mantle convection currents, if they exist, are overlain by a layer 50- 100km thick which is stationary or moves much less rapidly. This appears to rule out the me ...
... pattern. The results are compared with observed heat flow. Subject to the assumptions of the models, the results suggest that sub-oceanic mantle convection currents, if they exist, are overlain by a layer 50- 100km thick which is stationary or moves much less rapidly. This appears to rule out the me ...
Evolution and diversity of subduction zones controlled by slab width
... Lesser Antilles slabs4,25, and ridge push from the Mid-Atlantic Ridge25. Stagnation zone development and intermittent trench advance at the centre of wide slabs can therefore explain enigmatic features of the Central Andes, including mountain building above ...
... Lesser Antilles slabs4,25, and ridge push from the Mid-Atlantic Ridge25. Stagnation zone development and intermittent trench advance at the centre of wide slabs can therefore explain enigmatic features of the Central Andes, including mountain building above ...
Constraints on asthenospheric flow from the depths of oceanic
... [2003] proposed a conceptual model in which the asthenosphere under the EPR could be thinned by increased asthenospheric consumption resulting from a combination of plate divergence and spreading center migration with respect to the lower mantle. Because the fast spreading, slowly migrating EPR conv ...
... [2003] proposed a conceptual model in which the asthenosphere under the EPR could be thinned by increased asthenospheric consumption resulting from a combination of plate divergence and spreading center migration with respect to the lower mantle. Because the fast spreading, slowly migrating EPR conv ...
Continental Margin Deformation along the Andean Subduction zone
... that characterize the Chilean subduction zone, and especially specific areas that are discussed in comparison to our models (section 3). The experienced reader may directly jump to section 4, in which we explain our modeling assumptions, based on a 2D La ...
... that characterize the Chilean subduction zone, and especially specific areas that are discussed in comparison to our models (section 3). The experienced reader may directly jump to section 4, in which we explain our modeling assumptions, based on a 2D La ...
Crustal thickness of V-shaped ridges south of the Azores: -39
... segments are associated with centered axial highs and mantle Bouguer gravity lows, indicating focused magmatic accretion [Lin et al., 1990] and representing crustal thickness variations of ~2 km in amplitude [Detrick et al., 1995]. Despite the proximity to the hostspot, the outcrop of peridotites at ...
... segments are associated with centered axial highs and mantle Bouguer gravity lows, indicating focused magmatic accretion [Lin et al., 1990] and representing crustal thickness variations of ~2 km in amplitude [Detrick et al., 1995]. Despite the proximity to the hostspot, the outcrop of peridotites at ...
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.