- Wiley Online Library
... discrete shear zone beneath the overriding plate. Following this initial stage of subduction, the subducting lower crust and mantle lithosphere can retreat from the collision zone, permitting the sub-lithospheric mantle to upwell and intrude the overriding plate. As a result, the lower crust and man ...
... discrete shear zone beneath the overriding plate. Following this initial stage of subduction, the subducting lower crust and mantle lithosphere can retreat from the collision zone, permitting the sub-lithospheric mantle to upwell and intrude the overriding plate. As a result, the lower crust and man ...
Bathymetry of Mariana trench-arc system and formation of the
... Mariana Trench (western Pacific Ocean) is the deepest point on the Earth’s surface (10,920 m below sea level). Its location within a subduction trench, where one plate bends and descends below another, is not surprising. However, why is it located in the southernmost Mariana Trench and not at its ce ...
... Mariana Trench (western Pacific Ocean) is the deepest point on the Earth’s surface (10,920 m below sea level). Its location within a subduction trench, where one plate bends and descends below another, is not surprising. However, why is it located in the southernmost Mariana Trench and not at its ce ...
A review of the isotopic and trace element evidence for
... rocks, the prime example of mantle heterogeneity, is consistent with recycling of oceanic lithosphere back into mantle convective flow by some mechanism perhaps as early as the Eoarchean. This process could be plate subduction, but the geochemical effects of recycling do not unambiguously demand thi ...
... rocks, the prime example of mantle heterogeneity, is consistent with recycling of oceanic lithosphere back into mantle convective flow by some mechanism perhaps as early as the Eoarchean. This process could be plate subduction, but the geochemical effects of recycling do not unambiguously demand thi ...
Aseismic zone and earthquake segmentation associated with a
... oceanic plate, a veneer of thin sediments (200 ms) is present, which gradually thickens to 800 ms at the subduction front. The first 25 km of the frontal part of the accretionary prism consists of folded and faulted accreted sediments sloping gently seaward. The top of the oceanic crust is imaged al ...
... oceanic plate, a veneer of thin sediments (200 ms) is present, which gradually thickens to 800 ms at the subduction front. The first 25 km of the frontal part of the accretionary prism consists of folded and faulted accreted sediments sloping gently seaward. The top of the oceanic crust is imaged al ...
An Educational Resource for Visualizing the Global Seismic Wave
... wave field as shown in Figure 4 is exceptionally useful in visualizing how the wave field interacts with small-scale CMB structures such as ULVZs. Furthermore, from a research point ...
... wave field as shown in Figure 4 is exceptionally useful in visualizing how the wave field interacts with small-scale CMB structures such as ULVZs. Furthermore, from a research point ...
Geology
... plumes of rock that seem to march across the Earth in the direction opposite to the movement of the plates. A rising plume of molten rock eventually cools and solidifies. If it solidifies deep enough it will form great batholiths of granite. If it rises, it may burst out as a volcanic explosion gene ...
... plumes of rock that seem to march across the Earth in the direction opposite to the movement of the plates. A rising plume of molten rock eventually cools and solidifies. If it solidifies deep enough it will form great batholiths of granite. If it rises, it may burst out as a volcanic explosion gene ...
Searching to Learn - DigitalCommons@USU
... 12. Integrated Analysis on Gravity and Magnetic Fields of the Hailar Basin, NE China: Implications for Basement Structure and Deep Tectonics. Subjects: GRAVITY; MAGNETIC fields; GEOLOGY, Structural; PLATE tectonics; MANCHURIA (China); ...
... 12. Integrated Analysis on Gravity and Magnetic Fields of the Hailar Basin, NE China: Implications for Basement Structure and Deep Tectonics. Subjects: GRAVITY; MAGNETIC fields; GEOLOGY, Structural; PLATE tectonics; MANCHURIA (China); ...
as a PDF
... Langmuir 1988; Pearce & Parkinson 1993). U-series isotope constraints can be used to provide independent information on the process of partial melting in the mantle wedge above subduction zones. (a) Hydrous ° uxing The evidence that ®uids were still being added to the mantle wedge less than a few th ...
... Langmuir 1988; Pearce & Parkinson 1993). U-series isotope constraints can be used to provide independent information on the process of partial melting in the mantle wedge above subduction zones. (a) Hydrous ° uxing The evidence that ®uids were still being added to the mantle wedge less than a few th ...
Global scale models of the mantle flow field predicted by synthetic
... 1993; Karato and Karki, 2001; Cammarano et al., 2003). Accordingly, most studies use constant values of the velocity–density relationship as a function of depth. One key issue in interpreting the tomographic model is whether the observed seismic anomalies have a thermal or chemical origin and how to ...
... 1993; Karato and Karki, 2001; Cammarano et al., 2003). Accordingly, most studies use constant values of the velocity–density relationship as a function of depth. One key issue in interpreting the tomographic model is whether the observed seismic anomalies have a thermal or chemical origin and how to ...
Tethyan closure, Andean orogeny, and westward drift of the Pacific
... slabs are pushed westward. This cross-Pacific interaction provides an explanation for trench advance, which is observed in the western Pacific and is not easily explained by the local dynamics of subduction in which dense sinking slabs essentially tend to retreat from overriding plates. Thus, the basi ...
... slabs are pushed westward. This cross-Pacific interaction provides an explanation for trench advance, which is observed in the western Pacific and is not easily explained by the local dynamics of subduction in which dense sinking slabs essentially tend to retreat from overriding plates. Thus, the basi ...
Chemical composition of Earth`s primitive mantle and its variance: 2
... candidate for the source of the small-scale mantle heterogeneity. Anomalies in seismic wave velocity and scattering of seismic energy suggest the existence of lateral variations in the major element composition of the lower mantle (section 5.2). Those lateral variations are likely to be produced by ...
... candidate for the source of the small-scale mantle heterogeneity. Anomalies in seismic wave velocity and scattering of seismic energy suggest the existence of lateral variations in the major element composition of the lower mantle (section 5.2). Those lateral variations are likely to be produced by ...
The dynamic Earth
... Strong evidence for the theory of plate tectonics has been provided by the location of volcanoes and earthquakes, growing mountain ranges, spreading ocean ridges and the movement of the continents. However there is further evidence: • Two-hundred-million-year-old fossils of the same land animals hav ...
... Strong evidence for the theory of plate tectonics has been provided by the location of volcanoes and earthquakes, growing mountain ranges, spreading ocean ridges and the movement of the continents. However there is further evidence: • Two-hundred-million-year-old fossils of the same land animals hav ...
Background for Terrestrial Antineutrino Investigations: Radionuclide
... core-mantle boundary occluded in the core floaters, the low density, high temperature CaS and MgS atop the fluid core or, alternatively, they may be concentrated at the center of the Earth, depending upon respective precipitation and accumulation dynamics. Presently, there is no methodology by which ...
... core-mantle boundary occluded in the core floaters, the low density, high temperature CaS and MgS atop the fluid core or, alternatively, they may be concentrated at the center of the Earth, depending upon respective precipitation and accumulation dynamics. Presently, there is no methodology by which ...
The TauP Too~kit: Flexib/e Seismic Travel-time and Ray
... D i s t a n c e (deg) 9 Figore 2. Residual travel time, this code minus ttimes, of the first arriving P wave (top) and first arriving S wave (bottom). The compressional velocity model was used throughout the core, so the first arriving S wave beyond about 80 ~ is SKS and beyond about 130~ is SKIKS. ...
... D i s t a n c e (deg) 9 Figore 2. Residual travel time, this code minus ttimes, of the first arriving P wave (top) and first arriving S wave (bottom). The compressional velocity model was used throughout the core, so the first arriving S wave beyond about 80 ~ is SKS and beyond about 130~ is SKIKS. ...
Nature template - PC Word 97 - University of Colorado Boulder
... and it has a mean age of 80 million years [Parsons, 1982], we estimate 32 km3 per year. If this material were 0.1 percent water by weight, it would be 0.3 percent water by volume for a net flux of about 0.1 to 0.15 km3 per year of liquid-water equivalent. If subduction rates have been constant over ...
... and it has a mean age of 80 million years [Parsons, 1982], we estimate 32 km3 per year. If this material were 0.1 percent water by weight, it would be 0.3 percent water by volume for a net flux of about 0.1 to 0.15 km3 per year of liquid-water equivalent. If subduction rates have been constant over ...
Motion
... • Scientists think that some of the collisions along continentalcontinental convergent plate boundaries might have forced continental crust down into the upper mantle where it melted, intruded into the overlying rocks, and eventually cooled to form batholiths. ...
... • Scientists think that some of the collisions along continentalcontinental convergent plate boundaries might have forced continental crust down into the upper mantle where it melted, intruded into the overlying rocks, and eventually cooled to form batholiths. ...
- BIROn - Birkbeck Institutional Research Online
... source, with a typical subduction-related geochemical signature (i.e., high LILE/HFSE ratios, negative Nb, Ta and Ti anomalies; lower 87Sr/86Sr and higher 143Nd/144Nd radiogenic isotopic ratios), which is commonly suggested to reside within the mantle lithosphere. However genuine subduction-related ...
... source, with a typical subduction-related geochemical signature (i.e., high LILE/HFSE ratios, negative Nb, Ta and Ti anomalies; lower 87Sr/86Sr and higher 143Nd/144Nd radiogenic isotopic ratios), which is commonly suggested to reside within the mantle lithosphere. However genuine subduction-related ...
Upper Mantle Seismic Anisotropy Beneath the West Antarctic Rift
... surveys have identified rifts in the Pine Island and Ferrigno areas, both locations of gravity and magnetic anomalies consistent with other recently active rifts, that are mechanically related to the central WARS (Jordan et al. 2010; Bingham et al. 2012). These features show evidence for only small ...
... surveys have identified rifts in the Pine Island and Ferrigno areas, both locations of gravity and magnetic anomalies consistent with other recently active rifts, that are mechanically related to the central WARS (Jordan et al. 2010; Bingham et al. 2012). These features show evidence for only small ...
Cenozoic back-arc magmatism of the southern extra
... magma sources. Finally, some complex processes associated with subduction, such as ridge-trench collisions and/or slab erosion of the upper plate, may also have a significant role in back-arc magma genesis. One of the best places for studying continental backarc magmatism is the extra-Andean Patagon ...
... magma sources. Finally, some complex processes associated with subduction, such as ridge-trench collisions and/or slab erosion of the upper plate, may also have a significant role in back-arc magma genesis. One of the best places for studying continental backarc magmatism is the extra-Andean Patagon ...
Crustal and upper mantle structure of southernmost South America
... 36 km with thicker values toward the northeast, suggesting that there is little crustal thickening beneath the austral Andes. The average upper mantle velocities are similar to the preliminary reference Earth model (PREM) except that the southernmost region shows velocities of 5% slower than PREM. T ...
... 36 km with thicker values toward the northeast, suggesting that there is little crustal thickening beneath the austral Andes. The average upper mantle velocities are similar to the preliminary reference Earth model (PREM) except that the southernmost region shows velocities of 5% slower than PREM. T ...
Neo-Tethys geodynamics and mantle convection: from - HAL-Insu
... mantle. We suggest that alternating extension and compression in Africa could be explained by switching convection regimes. The extensional situation would correspond to steady-state whole-mantle convection, Africa being carried northward by a large-scale conveyor belt, while compression and obducti ...
... mantle. We suggest that alternating extension and compression in Africa could be explained by switching convection regimes. The extensional situation would correspond to steady-state whole-mantle convection, Africa being carried northward by a large-scale conveyor belt, while compression and obducti ...
Mantle plume
A mantle plume is a mechanism proposed in 1971 to explain volcanic regions of the earth that were not thought to be explicable by the then-new theory of plate tectonics. Some such volcanic regions lie far from tectonic plate boundaries, for example, Hawaii. Others represent unusually large-volume volcanism, whether on plate boundaries, e.g. Iceland, or basalt floods such as the Deccan or Siberian traps.A mantle plume is posited to exist where hot rock nucleates at the core-mantle boundary and rises through the Earth's mantle becoming a diapir in the Earth's crust. The currently active volcanic centers are known as ""hot spots"". In particular, the concept that mantle plumes are fixed relative to one another, and anchored at the core-mantle boundary, was thought to provide a natural explanation for the time-progressive chains of older volcanoes seen extending out from some such hot spots, such as the Hawaiian–Emperor seamount chain.The hypothesis of mantle plumes from depth is not universally accepted as explaining all such volcanism. It has required progressive hypothesis-elaboration leading to variant propositions such as mini-plumes and pulsing plumes. Another hypothesis for unusual volcanic regions is the ""Plate model"". This proposes shallower, passive leakage of magma from the mantle onto the Earth's surface where extension of the lithosphere permits it, attributing most volcanism to plate tectonic processes, with volcanoes far from plate boundaries resulting from intraplate extension.