Crustal growth at active continental margins: Numerical
... 2D coupled petrological–thermomechanical numerical model of an oceanic-continental subduction zone. This model includes spontaneous slab retreat and bending, dehydration of subducted crust, aqueous fluid transport, partial melting, melt extraction and melt emplacement in form of extrusive volcanics a ...
... 2D coupled petrological–thermomechanical numerical model of an oceanic-continental subduction zone. This model includes spontaneous slab retreat and bending, dehydration of subducted crust, aqueous fluid transport, partial melting, melt extraction and melt emplacement in form of extrusive volcanics a ...
Plate motions, slab dynamics and back
... slab age, whereas Jarrard (1986) found many advancing trenches, and no clear relation with slab age, and concluded that not only the slab rollback is globally negligible, but also that mantle flow effects were possibly important. Since these earlier studies there has been a general improvement of av ...
... slab age, whereas Jarrard (1986) found many advancing trenches, and no clear relation with slab age, and concluded that not only the slab rollback is globally negligible, but also that mantle flow effects were possibly important. Since these earlier studies there has been a general improvement of av ...
Plate Tectonics - cloudfront.net
... • Identical rocks, of the same type and age, are found on both sides of the Atlantic Ocean. Wegener said the rocks had formed side by side and that the land had since moved apart. • Mountain ranges with the same rock types, structures, and ages are now on opposite sides of the Atlantic Ocean. The Ap ...
... • Identical rocks, of the same type and age, are found on both sides of the Atlantic Ocean. Wegener said the rocks had formed side by side and that the land had since moved apart. • Mountain ranges with the same rock types, structures, and ages are now on opposite sides of the Atlantic Ocean. The Ap ...
Introduction: Anatomy of rifting: Tectonics and magmatism in
... Eruptive centers along ridges form the longest continuous chain of volcanoes on our planet (Sandwell et al., 2014). Knowledge of fundamental processes such as melt production in the mantle, melt migration and ponding in the lithosphere, and melt injection into the upper crust is necessary to underst ...
... Eruptive centers along ridges form the longest continuous chain of volcanoes on our planet (Sandwell et al., 2014). Knowledge of fundamental processes such as melt production in the mantle, melt migration and ponding in the lithosphere, and melt injection into the upper crust is necessary to underst ...
Constraints on the source parameters of low
... eGf analysis of two different LFE families near Parkfield, CA (families 37102 and 37140, Figure 2). These families were chosen based on their close spatial proximity to multiple potential eGfs, and at each station and component we stack ~100 detections of each LFE family to increase the signal-to-noi ...
... eGf analysis of two different LFE families near Parkfield, CA (families 37102 and 37140, Figure 2). These families were chosen based on their close spatial proximity to multiple potential eGfs, and at each station and component we stack ~100 detections of each LFE family to increase the signal-to-noi ...
The tectonic regime along the Andes: Present
... toward or away from the trench line within an asthenospheric reference frame (Dewey 1980). This is correct only in a passive mantle model (Scholz and Campos 1995), because if a global westward motion of the lithosphere is considered these premises are not valid (see discussion in Doglioni et al. 200 ...
... toward or away from the trench line within an asthenospheric reference frame (Dewey 1980). This is correct only in a passive mantle model (Scholz and Campos 1995), because if a global westward motion of the lithosphere is considered these premises are not valid (see discussion in Doglioni et al. 200 ...
Depositional History and Tectonic Regimes within and in
... strike-slip faulting along the NW-SE trending Tornquist Zone in the south-western margin of the Fennoscandian Shield. The faulting was associated with volcanic activity and intrusion of dyke swarms, dated at 300 - 240 Ma. The Permian rifting and volcanism is demonstrated by ca. 400 km long Oslo Rift ...
... strike-slip faulting along the NW-SE trending Tornquist Zone in the south-western margin of the Fennoscandian Shield. The faulting was associated with volcanic activity and intrusion of dyke swarms, dated at 300 - 240 Ma. The Permian rifting and volcanism is demonstrated by ca. 400 km long Oslo Rift ...
Geodynamic models of Cordilleran orogens
... as it is cooler and therefore denser than the underlying material. Eclogitization and densification of the lower crust during orogenic shortening, and especially during magmatism, may provide an additional driving force (e.g., Kay and Kay, 1993; Ducea and Saleeby, 1998; Jull and Kelemen, 2001; Sobol ...
... as it is cooler and therefore denser than the underlying material. Eclogitization and densification of the lower crust during orogenic shortening, and especially during magmatism, may provide an additional driving force (e.g., Kay and Kay, 1993; Ducea and Saleeby, 1998; Jull and Kelemen, 2001; Sobol ...
Thermal and metamorphic environment of subduction zone episodic
... truncated at the tip of the mantle wedge to satisfy surface heat flow measurements. Note that the choice of mantle rheology does not significantly affect the temperatures calculated for the shallow fore arc, unless flow in the mantle wedge corner were to extend updip to depths <50 km, which would be ...
... truncated at the tip of the mantle wedge to satisfy surface heat flow measurements. Note that the choice of mantle rheology does not significantly affect the temperatures calculated for the shallow fore arc, unless flow in the mantle wedge corner were to extend updip to depths <50 km, which would be ...
Composition of the depleted mantle
... DM. The age of this single depletion event is an average age of the depletion of the DM; actual formation of the reservoir is not related to a single event, but is expected to be continuous. Using this approach it is assumed that processes operating on the mantle resulting in chemical change and for ...
... DM. The age of this single depletion event is an average age of the depletion of the DM; actual formation of the reservoir is not related to a single event, but is expected to be continuous. Using this approach it is assumed that processes operating on the mantle resulting in chemical change and for ...
Lecture 38
... This diagram generalizes the REE patterns for the three main tectonic settings where volcanism occurs on earth: spreading centers, convergent margins, and intra-plate (both oceanic and continental). The difference between REE patterns in BCR-1 and MORB is common in many igneous rocks from around the ...
... This diagram generalizes the REE patterns for the three main tectonic settings where volcanism occurs on earth: spreading centers, convergent margins, and intra-plate (both oceanic and continental). The difference between REE patterns in BCR-1 and MORB is common in many igneous rocks from around the ...
Physics and Chemistry of Deep Continental Crust
... from other convective processes, such as subduction of oceanic lithosphere. Subduction is related to plate tectonics and is a manifestation of large-scale mantle convection, wherein the dominant length scale of advective heat and mass transfer is the entire mantle. Subduction involves long-lived and ...
... from other convective processes, such as subduction of oceanic lithosphere. Subduction is related to plate tectonics and is a manifestation of large-scale mantle convection, wherein the dominant length scale of advective heat and mass transfer is the entire mantle. Subduction involves long-lived and ...
here - GeoPRISMS
... understand the complex interplay of processes that and rates of processes are measurable today, so govern continental margin evolution globally,” and most field experiments occurred in active plate encompasses what are perhaps some of the largest boundary systems. challenges in solid Earth science. ...
... understand the complex interplay of processes that and rates of processes are measurable today, so govern continental margin evolution globally,” and most field experiments occurred in active plate encompasses what are perhaps some of the largest boundary systems. challenges in solid Earth science. ...
Experimental_laboratory_files/2004_The source of Granites
... have puzzled geologists for decades, and still they do. The study of these paradoxes may help us understand the complex processes involved in the generation of granite batholiths. Here, I show that a combination of geological, experimental and geochemical arguments may be used in a new hypothesis fo ...
... have puzzled geologists for decades, and still they do. The study of these paradoxes may help us understand the complex processes involved in the generation of granite batholiths. Here, I show that a combination of geological, experimental and geochemical arguments may be used in a new hypothesis fo ...
An ultraslow-spreading class of ocean ridge
... characterized by intermittent volcanism and a lack of transform faults. We find that the mantle beneath such ridges is emplaced continuously to the seafloor over large regions. The differences between ultraslow- and slow-spreading ridges are as great as those between slow- and fast-spreading ridges. ...
... characterized by intermittent volcanism and a lack of transform faults. We find that the mantle beneath such ridges is emplaced continuously to the seafloor over large regions. The differences between ultraslow- and slow-spreading ridges are as great as those between slow- and fast-spreading ridges. ...
An ultraslow-spreading class of ocean ridge
... characterized by intermittent volcanism and a lack of transform faults. We find that the mantle beneath such ridges is emplaced continuously to the seafloor over large regions. The differences between ultraslow- and slow-spreading ridges are as great as those between slow- and fast-spreading ridges. ...
... characterized by intermittent volcanism and a lack of transform faults. We find that the mantle beneath such ridges is emplaced continuously to the seafloor over large regions. The differences between ultraslow- and slow-spreading ridges are as great as those between slow- and fast-spreading ridges. ...
IODP Proposal Cover Sheet
... Many first-order questions about the processes of crustal accretion and interaction between the lithosphere and hydrosphere will be addressed on the journey to the Moho. A first-order understanding of the nature of the Moho and the crust also requires investigation of slowspread crust. Selected regi ...
... Many first-order questions about the processes of crustal accretion and interaction between the lithosphere and hydrosphere will be addressed on the journey to the Moho. A first-order understanding of the nature of the Moho and the crust also requires investigation of slowspread crust. Selected regi ...
34 - School of Ocean and Earth Science and Technology
... The Composition of Earth’s crust G The depletion of siderophiles in both types of crust implies that the crust largely formed after core formation. (It’s possible that an early crust existed while the core was forming; if so, it must have been destroyed later by plate tectonics or late-stage bombar ...
... The Composition of Earth’s crust G The depletion of siderophiles in both types of crust implies that the crust largely formed after core formation. (It’s possible that an early crust existed while the core was forming; if so, it must have been destroyed later by plate tectonics or late-stage bombar ...
pdf file - University of Victoria
... Lower crust flow has previously been concluded for several areas of tectonically thickened orogenic crust. The most studied currently active case is the Tibet high plateau and its flanks (e.g., Clark and Royden, 2000; Beaumont et al., 2001; 2004; 2006; Godin et al., 2006; Klemperer, 2006; Harris, 20 ...
... Lower crust flow has previously been concluded for several areas of tectonically thickened orogenic crust. The most studied currently active case is the Tibet high plateau and its flanks (e.g., Clark and Royden, 2000; Beaumont et al., 2001; 2004; 2006; Godin et al., 2006; Klemperer, 2006; Harris, 20 ...
nature ano evolution of the subcontinental mantle lithosphere below
... mantle as welI as of the crust. An important implication of plate tectonics is the distinction between relatively hot asthenosphere in which convective circulation may result in a general homogenization, and the relatively cool lithosphere in which small scale heterogeneities resulting from magmatic ...
... mantle as welI as of the crust. An important implication of plate tectonics is the distinction between relatively hot asthenosphere in which convective circulation may result in a general homogenization, and the relatively cool lithosphere in which small scale heterogeneities resulting from magmatic ...
Fig. 1 - Durham University Community
... basalts (MORB) is widely accepted as reflecting their depleted mantle source. Because ocean ridges are mostly passive features in the sense that the sub-ridge mantle rises and melts by decompression in response to plate separation, it follows that MORB sample the uppermost asthenospheric mantle. As a ...
... basalts (MORB) is widely accepted as reflecting their depleted mantle source. Because ocean ridges are mostly passive features in the sense that the sub-ridge mantle rises and melts by decompression in response to plate separation, it follows that MORB sample the uppermost asthenospheric mantle. As a ...
A 3-D geodynamic model of lateral crustal flow
... that started ~ 70 Ma, with ~500-km of total shortening in the Bolivian Andes and ~150 km of shortening south of 25°S. However, the pre-Neogene shortening history is not well constrained. Based on her reconstructed shortening history we consider an alternative model (model B in Fig. 2) in which the a ...
... that started ~ 70 Ma, with ~500-km of total shortening in the Bolivian Andes and ~150 km of shortening south of 25°S. However, the pre-Neogene shortening history is not well constrained. Based on her reconstructed shortening history we consider an alternative model (model B in Fig. 2) in which the a ...
Spontaneous development of arcuate single‐sided subduction in
... Subduction zones are one of the most prominent features on a planet that undergoes plate tectonics, not only in terms of surface morphology but also in terms of the planet’s dynamic evolution. Its importance for the dynamics is highlighted by the fact that the sinking portions of a plate (i.e., slab ...
... Subduction zones are one of the most prominent features on a planet that undergoes plate tectonics, not only in terms of surface morphology but also in terms of the planet’s dynamic evolution. Its importance for the dynamics is highlighted by the fact that the sinking portions of a plate (i.e., slab ...
Geophysical Constraints on Mantle Composition
... Mathematical inversion of large numbers of travel times, observed at a variety of distances between source (earthquake) and receiver (seismometer), results in velocity profiles that represent the variation of VP and VS (or Vj) as functions of depth. The changes in velocities across seismic ‘disconti ...
... Mathematical inversion of large numbers of travel times, observed at a variety of distances between source (earthquake) and receiver (seismometer), results in velocity profiles that represent the variation of VP and VS (or Vj) as functions of depth. The changes in velocities across seismic ‘disconti ...
Post-glacial rebound
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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.