Metamorphic reworking of a high pressure–low temperature
... immediately after HP metamorphism whereas the northern association was retrograded during a later collision that thrust it northward at ca. 70 Ma. They were subsequently juxtaposed opposite each other by major strike slip motion. This model implies that the HP rocks on opposing sides of the Motagua ...
... immediately after HP metamorphism whereas the northern association was retrograded during a later collision that thrust it northward at ca. 70 Ma. They were subsequently juxtaposed opposite each other by major strike slip motion. This model implies that the HP rocks on opposing sides of the Motagua ...
Released Items from the ATLAST Plate Tectonics Teacher Assessment
... Idea: The outer portion of Earth—including both the continents and the seafloor beneath the oceans— consists of huge plates of solid rock. The plates move very slowly (a few centimeters per year). Plate movement causes abutting plates to interact with one another. Interactions between plates result ...
... Idea: The outer portion of Earth—including both the continents and the seafloor beneath the oceans— consists of huge plates of solid rock. The plates move very slowly (a few centimeters per year). Plate movement causes abutting plates to interact with one another. Interactions between plates result ...
The plume head-lithosphere interactions near intra - HAL-Insu
... considerably higher temperatures (750 – 800°C). This infers the presence of a weak separation layer (lower or middle crust) between the strong upper or intermediate crust and mantle lithosphere (e.g., Watts and Burov, 2003; Burov and Watts, 2006). The weak layer between the strong upper crust and l ...
... considerably higher temperatures (750 – 800°C). This infers the presence of a weak separation layer (lower or middle crust) between the strong upper or intermediate crust and mantle lithosphere (e.g., Watts and Burov, 2003; Burov and Watts, 2006). The weak layer between the strong upper crust and l ...
Building and Destroying Continental Mantle - Cin
... Ocean basins are the surface expression of solid-state mantle convection with a mobile lid. Heat transfer in Earth’s deep interior is driven by thermally buoyant upwellings, but when the upwelling reaches the surface of Earth, the mechanism of vertical heat transfer becomes dominated by conduction, ...
... Ocean basins are the surface expression of solid-state mantle convection with a mobile lid. Heat transfer in Earth’s deep interior is driven by thermally buoyant upwellings, but when the upwelling reaches the surface of Earth, the mechanism of vertical heat transfer becomes dominated by conduction, ...
The Origin, Evolution and Present State of Subcontinental Lithosphere
... lithosphere. Because (1) the lithosphere thinning is the largest in scale in a global context, (2) the genetically-related Mesozoic-Cenozoic volcanism is wide-spread with abundant mantle materials (xenoliths), and (3) there are also abundant geophysical data (seismic, heat flow, gravity etc.) availa ...
... lithosphere. Because (1) the lithosphere thinning is the largest in scale in a global context, (2) the genetically-related Mesozoic-Cenozoic volcanism is wide-spread with abundant mantle materials (xenoliths), and (3) there are also abundant geophysical data (seismic, heat flow, gravity etc.) availa ...
Geological Society of America Bulletin
... differentiation in particular tectonic environments. Their geochemical characteristics, internal structure, and thickness vary with spreading rate, proximity to plumes or trenches, mantle temperature, mantle fertility, and the availability of fluids. Subductionrelated ophiolites include suprasubduct ...
... differentiation in particular tectonic environments. Their geochemical characteristics, internal structure, and thickness vary with spreading rate, proximity to plumes or trenches, mantle temperature, mantle fertility, and the availability of fluids. Subductionrelated ophiolites include suprasubduct ...
Deep-mantle contributions to the surface dynamics of the North
... At shallow depths (down to about 150 km) the seismic structure of North America in model TX05WM (Fig. 2) is dominated by the contrast between the very slow western margin of North America and the much faster eastern and central portion of the continent. Below the continental high-velocity root, cent ...
... At shallow depths (down to about 150 km) the seismic structure of North America in model TX05WM (Fig. 2) is dominated by the contrast between the very slow western margin of North America and the much faster eastern and central portion of the continent. Below the continental high-velocity root, cent ...
Variations in magmatic processes along the East Greenland
... a compilation of 30-wide-angle seismic velocity models from several publications along the entire East Greenland margin. Compiled maps show the depth to basement, depth to Moho, crustal thickness and thickness of high velocity lower crust (HVLC; with velocities above 7.0 km s−1 ). First, we present ...
... a compilation of 30-wide-angle seismic velocity models from several publications along the entire East Greenland margin. Compiled maps show the depth to basement, depth to Moho, crustal thickness and thickness of high velocity lower crust (HVLC; with velocities above 7.0 km s−1 ). First, we present ...
Destruction of the North China Craton
... movement of eastern China in the latter part of the Mesozoic, or the “Platform Reactivation” theory founded by professor Guoda Chen during the period of 1956–1960 [2]. Since the 1980s, several important ideas, such as continental deep subduction [3] (the Qinling-Dabie Mountains on the southern margi ...
... movement of eastern China in the latter part of the Mesozoic, or the “Platform Reactivation” theory founded by professor Guoda Chen during the period of 1956–1960 [2]. Since the 1980s, several important ideas, such as continental deep subduction [3] (the Qinling-Dabie Mountains on the southern margi ...
Mechanisms of crustal growth in large igneous
... interpreted as underplated high-Mg gabbros. SDR are made up of aerial or sub-aerial lavas, but also contain volcanic ejecta (e.g. hyaloclastites, tuffs, etc.). The tectonic significance of SDR has been discussed principally in Eldholm et al. (1995) and Geoffroy (2005). It is noteworthy that an inner ...
... interpreted as underplated high-Mg gabbros. SDR are made up of aerial or sub-aerial lavas, but also contain volcanic ejecta (e.g. hyaloclastites, tuffs, etc.). The tectonic significance of SDR has been discussed principally in Eldholm et al. (1995) and Geoffroy (2005). It is noteworthy that an inner ...
Marine Geology: Exploring the New Frontiers of the Ocean (The
... axis, completing a single rotation every 14 hours, thus maintaining high temperatures throughout the planet. Present-day plate tectonic processes could not have operated under such hot conditions, which produced more vertical bubbling than horizontal sliding. Therefore, modern-style plate tectonic p ...
... axis, completing a single rotation every 14 hours, thus maintaining high temperatures throughout the planet. Present-day plate tectonic processes could not have operated under such hot conditions, which produced more vertical bubbling than horizontal sliding. Therefore, modern-style plate tectonic p ...
PDF
... much of Cretaceous time. Collision of Kohistan with the Karakorum caused a new, north-dipping subduction zone to form on the south side of Kohistan, leading to collision with India in early Tertiary time. Keywords: Himalayas, Pakistan, island arcs, isotopes. ...
... much of Cretaceous time. Collision of Kohistan with the Karakorum caused a new, north-dipping subduction zone to form on the south side of Kohistan, leading to collision with India in early Tertiary time. Keywords: Himalayas, Pakistan, island arcs, isotopes. ...
Izu detachment hypothesis: A proposal of a unified cause for... event and the Tokai slow event
... Kozushima. Nishimura et al. (2001) and Ito and Yoshioka (2002) estimated a slightly larger volume of intrusion. These models of dike intrusion cannot explain the movements in central Honshu (Fig. 2). I show this using Yamaoka’s (2000) model as an example. Figure 7(a) shows the displacement vectors d ...
... Kozushima. Nishimura et al. (2001) and Ito and Yoshioka (2002) estimated a slightly larger volume of intrusion. These models of dike intrusion cannot explain the movements in central Honshu (Fig. 2). I show this using Yamaoka’s (2000) model as an example. Figure 7(a) shows the displacement vectors d ...
`emplacement` of an ophiolite?
... a mixed MORB and island arc tholeiite affinity (LeMoigne et al. 1996). The degree of decompressional melting of MORB mantle, caused by ridge subduction, was apparently less rigorous than that typically occurring at mid-ocean ridges because of the capping of the melting column by the continental edge ...
... a mixed MORB and island arc tholeiite affinity (LeMoigne et al. 1996). The degree of decompressional melting of MORB mantle, caused by ridge subduction, was apparently less rigorous than that typically occurring at mid-ocean ridges because of the capping of the melting column by the continental edge ...
Geology of Greenland Survey Bulletin 177, 89-95
... The chemical compositions of the tholeiitic metabasalts at Ivisârtoq and in the Fiskenæsset region resemble that of the homogeneous amphibolite in the Fiskefjord area with respect to most major and trace elements, and it may be significant that they also have relatively low TiO2 contents (see Hall e ...
... The chemical compositions of the tholeiitic metabasalts at Ivisârtoq and in the Fiskenæsset region resemble that of the homogeneous amphibolite in the Fiskefjord area with respect to most major and trace elements, and it may be significant that they also have relatively low TiO2 contents (see Hall e ...
The Asia–Kohistan–India Collision: Review and Discussion
... hanging plate. Blue lines extensional sites with barbed lines in ...
... hanging plate. Blue lines extensional sites with barbed lines in ...
The Relation Between Mantle Dynamics and Plate Tectonics: A Primer
... tle’s gravitational potential energy through convective overturn (and of course that radiogenic heating and core cooling continue to replenish the mantle’s gravitational potential energy). However, the precise picture of how plate motions are caused by convection is far from complete. With the recog ...
... tle’s gravitational potential energy through convective overturn (and of course that radiogenic heating and core cooling continue to replenish the mantle’s gravitational potential energy). However, the precise picture of how plate motions are caused by convection is far from complete. With the recog ...
A Primer
... tle’s gravitational potential energy through convective overturn (and of course that radiogenic heating and core cooling continue to replenish the mantle’s gravitational potential energy). However, the precise picture of how plate motions are caused by convection is far from complete. With the recog ...
... tle’s gravitational potential energy through convective overturn (and of course that radiogenic heating and core cooling continue to replenish the mantle’s gravitational potential energy). However, the precise picture of how plate motions are caused by convection is far from complete. With the recog ...
A trace element perspective on the source of ocean island basalts
... contribution to the petrogenesis of global OIB. Continental materials through subduction erosion can certainly contribute to mantle compositional heterogeneity and may contribute towards some enriched component in OIB source regions. Overall, OIB are not only enriched in incompatible elements, but a ...
... contribution to the petrogenesis of global OIB. Continental materials through subduction erosion can certainly contribute to mantle compositional heterogeneity and may contribute towards some enriched component in OIB source regions. Overall, OIB are not only enriched in incompatible elements, but a ...
Bathymetry of the Pacific Plate and its Implications
... predictions from the HSC and plate models and examine its correlation with recent seismic models for the Pacific lithosphere and shallow upper mantle [Ritzwoller et al., 2004] and for mantle plumes [Montelli et al., 2004]. We focus on the Pacific plate for three reasons. 1) The effect of sediments o ...
... predictions from the HSC and plate models and examine its correlation with recent seismic models for the Pacific lithosphere and shallow upper mantle [Ritzwoller et al., 2004] and for mantle plumes [Montelli et al., 2004]. We focus on the Pacific plate for three reasons. 1) The effect of sediments o ...
Continent-sized anomalous zones with low
... material from the surrounding mantle, underlying core and potentially from volatile elements transported into the deep Earth by subducted plates. Upwelling mantle plumes may originate from the thermochemical piles, so the unusual chemical composition of the piles could be the source of distinct trac ...
... material from the surrounding mantle, underlying core and potentially from volatile elements transported into the deep Earth by subducted plates. Upwelling mantle plumes may originate from the thermochemical piles, so the unusual chemical composition of the piles could be the source of distinct trac ...
Origin of dipping structures in fast
... et al., 2012). Plate reorganization was accompanied by an increase of the spreading rate (74 mm/yr half rate, Engebretson et al., 1984; 54 mm/yr half rate, Lonsdale, 1988) at the Pacific– Kula ridge and is preserved in unsubducted oceanic crust off the Alaska Peninsula. The fossil triple junction lef ...
... et al., 2012). Plate reorganization was accompanied by an increase of the spreading rate (74 mm/yr half rate, Engebretson et al., 1984; 54 mm/yr half rate, Lonsdale, 1988) at the Pacific– Kula ridge and is preserved in unsubducted oceanic crust off the Alaska Peninsula. The fossil triple junction lef ...
Uppermost mantle structure of the North China Craton: Constraints
... Spatial variations of lithospheric thinning and dynamic processes in the North China Craton could inevitably induce the velocity heterogeneity in the uppermost mantle. In this study, we used Pn arrivals from permanent seismic stations in North China and surrounding regions to construct a tomographic ...
... Spatial variations of lithospheric thinning and dynamic processes in the North China Craton could inevitably induce the velocity heterogeneity in the uppermost mantle. In this study, we used Pn arrivals from permanent seismic stations in North China and surrounding regions to construct a tomographic ...
1 Bathymetry of the Pacific Plate and its Implications for Thermal
... particularly, with the HSC-Plate depth-age relation recently developed by Hillier and Watts [2005] with an entirely different approach for the North Pacific Ocean. Residual topography with respect to Hillier and Watts’ HSC-Plate model shows two distinct topographic highs: the Hawaiian swell and Sout ...
... particularly, with the HSC-Plate depth-age relation recently developed by Hillier and Watts [2005] with an entirely different approach for the North Pacific Ocean. Residual topography with respect to Hillier and Watts’ HSC-Plate model shows two distinct topographic highs: the Hawaiian swell and Sout ...
47. the ocean/continent transition beneath the iberia abyssal plain
... broke away from Newfoundland in the Early Cretaceous as rifting propagated from south to north. The ocean/continent transition off Newfoundland seems to occur ~50 km seaward of the shelf edge near the base of the continental slope. Off west Iberia, the ocean/continent transition is defined by an 80- ...
... broke away from Newfoundland in the Early Cretaceous as rifting propagated from south to north. The ocean/continent transition off Newfoundland seems to occur ~50 km seaward of the shelf edge near the base of the continental slope. Off west Iberia, the ocean/continent transition is defined by an 80- ...
Oceanic trench
The oceanic trenches are hemispheric-scale long but narrow topographic depressions of the sea floor. They are also the deepest parts of the ocean floor. Oceanic trenches are a distinctive morphological feature of convergent plate boundaries, along which lithospheric plates move towards each other at rates that vary from a few mm to over ten cm per year. A trench marks the position at which the flexed, subducting slab begins to descend beneath another lithospheric slab. Trenches are generally parallel to a volcanic island arc, and about 200 km (120 mi) from a volcanic arc. Oceanic trenches typically extend 3 to 4 km (1.9 to 2.5 mi) below the level of the surrounding oceanic floor. The greatest ocean depth to be sounded is in the Challenger Deep of the Mariana Trench, at a depth of 11,034 m (36,201 ft) below sea level. Oceanic lithosphere moves into trenches at a global rate of about 3 km2/yr.