Toward the reconciliation of seismological and petrological
... Such quasi-laminar models were introduced by Furumura and Kennett [2005] to explain efficient guiding of high-frequency waves to the surface in subduction zone settings from events as deep as 500–600 km. Shito et al. [2013] have shown that they can model propagation from intermediate-depth earthquake ...
... Such quasi-laminar models were introduced by Furumura and Kennett [2005] to explain efficient guiding of high-frequency waves to the surface in subduction zone settings from events as deep as 500–600 km. Shito et al. [2013] have shown that they can model propagation from intermediate-depth earthquake ...
09_chapter 1
... the concept of hot spots (Wilson 1963). Wilson felt that the Hawaiian island chain, which is located in the middle of large oceanic plate, could not be explained by shallow mantle processes required by Plate Tectonics. Wilson model for the Hawaiian volcanic chain called for generation of magmas from ...
... the concept of hot spots (Wilson 1963). Wilson felt that the Hawaiian island chain, which is located in the middle of large oceanic plate, could not be explained by shallow mantle processes required by Plate Tectonics. Wilson model for the Hawaiian volcanic chain called for generation of magmas from ...
extended basement beneath the intracratonic rifted basins of the
... Unconformities, bedding planes, thrust faults and folding in the Paleozoic and Precambrian rocks can be interpreted from the seismic data if we ignore the random noise and the severe multiple problem and make use of the Avalon-terrane regional style of deformation and faulting. However, as can be no ...
... Unconformities, bedding planes, thrust faults and folding in the Paleozoic and Precambrian rocks can be interpreted from the seismic data if we ignore the random noise and the severe multiple problem and make use of the Avalon-terrane regional style of deformation and faulting. However, as can be no ...
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, ...
Volatile Cycling of H2O, CO2, F, and Cl in the HIMU Mantle: A New
... exception of MGA-B-47-RAC3, do not reach the point of extreme magmatic evolution where TiO2 concentrations are affected by fractionation of the Ti-rich phase. In sample MGA-B-47, there is one inclusion with TiO2 significantly higher than the whole rock and melt inclusion analyses. The melt inclusions ...
... exception of MGA-B-47-RAC3, do not reach the point of extreme magmatic evolution where TiO2 concentrations are affected by fractionation of the Ti-rich phase. In sample MGA-B-47, there is one inclusion with TiO2 significantly higher than the whole rock and melt inclusion analyses. The melt inclusions ...
Subduction of the oceanic Hikurangi Plateau and its impact on the
... one of the most extreme volcanic events on Earth, characterized through eruption of vast amounts of lava in a geologically short period1. Oceanic LIPs either accrete and obduct, adding to the continental landmass2–4 or in rare cases recycle back into the Earth’s mantle via subduction. Known examples ...
... one of the most extreme volcanic events on Earth, characterized through eruption of vast amounts of lava in a geologically short period1. Oceanic LIPs either accrete and obduct, adding to the continental landmass2–4 or in rare cases recycle back into the Earth’s mantle via subduction. Known examples ...
The continental tectosphere and Earth`s long
... concluded that there is no systematic difference in the geoid signal between oceanic and continental regions. But, Souriau and Souriau Ž1983. demonstrated that there is a significant correlation between the geoid Žspherical harmonic degrees l s 3–12. and the tectonic regionalization of Okal Ž1977.. ...
... concluded that there is no systematic difference in the geoid signal between oceanic and continental regions. But, Souriau and Souriau Ž1983. demonstrated that there is a significant correlation between the geoid Žspherical harmonic degrees l s 3–12. and the tectonic regionalization of Okal Ž1977.. ...
PDF - University of Arizona
... The North Anatolian Fault (NAF), located in northern Turkey, is one of the largest active continental strike-slip faults on Earth and forms the northern margin of the Anatolian plate (Barka 1996; Piper 1997; Sengor 2005; Stein 1997). The tectonics of the Anatolian region is controlled by the motions ...
... The North Anatolian Fault (NAF), located in northern Turkey, is one of the largest active continental strike-slip faults on Earth and forms the northern margin of the Anatolian plate (Barka 1996; Piper 1997; Sengor 2005; Stein 1997). The tectonics of the Anatolian region is controlled by the motions ...
Origin and time evolution of subduction polarity reversal from plate
... of the proto–South China Sea plate and owes its current location to triple junction migration and slab rollback. This analysis sheds new light on the plate tectonic context of the Taiwan orogeny and questions the hypothesis that northern Taiwan can be considered an older, more mature equivalent of s ...
... of the proto–South China Sea plate and owes its current location to triple junction migration and slab rollback. This analysis sheds new light on the plate tectonic context of the Taiwan orogeny and questions the hypothesis that northern Taiwan can be considered an older, more mature equivalent of s ...
intrinsic Q - University of Leeds
... Seismic observations: frequency shift of low-frequency events over extended period of time. Results of numerical modelling verify change in frequency of ...
... Seismic observations: frequency shift of low-frequency events over extended period of time. Results of numerical modelling verify change in frequency of ...
Geochemistry, Geophysics, Geosystems Supporting Information for
... Rurutu hotspot lavas and are shifted toward an EM1 component; D44-HIMU lavas plot below the shallow array formed by Samoan lavas. Uo Mamae hosts a clear EM1 signature [e.g., Pearce et al. 2007; Regelous et al. 2008] that also plots below the Samoan array (at lower 143Nd/144Nd for a given 87Sr/86Sr) ...
... Rurutu hotspot lavas and are shifted toward an EM1 component; D44-HIMU lavas plot below the shallow array formed by Samoan lavas. Uo Mamae hosts a clear EM1 signature [e.g., Pearce et al. 2007; Regelous et al. 2008] that also plots below the Samoan array (at lower 143Nd/144Nd for a given 87Sr/86Sr) ...
Polarized plate tectonics
... (Pyrenees). This rift, started by the anticlockwise Cretaceous rotation of Iberia, aborted since its axis is far from being orthogonal to the mantle flow direction and it is almost contemporary with the formation of the Pyrenees. Another example of aborted rift is the Benue basin, in Centralwestern ...
... (Pyrenees). This rift, started by the anticlockwise Cretaceous rotation of Iberia, aborted since its axis is far from being orthogonal to the mantle flow direction and it is almost contemporary with the formation of the Pyrenees. Another example of aborted rift is the Benue basin, in Centralwestern ...
Lower crustal earthquakes near the Ethiopian rift induced by
... in the lower crust beneath the NW plateau and may be important in accommodating minor amounts of extensional strain outside the MER [Keranen et al., 2009]. Such a wide zone of magmatism in the lower crust is spatially coincident with similarly distributed brittle failure in the middle to upper crust ...
... in the lower crust beneath the NW plateau and may be important in accommodating minor amounts of extensional strain outside the MER [Keranen et al., 2009]. Such a wide zone of magmatism in the lower crust is spatially coincident with similarly distributed brittle failure in the middle to upper crust ...
PDF
... Figure 2. Structure of subducted slabs as inferred from mantle tomography (from Kárason and van der Hilst [2000]). Red lines show the surface projection of each section. The base of each section is the core-mantle boundary (CMB); dashed lines show the location of mantle discontinuities at 410, 660, ...
... Figure 2. Structure of subducted slabs as inferred from mantle tomography (from Kárason and van der Hilst [2000]). Red lines show the surface projection of each section. The base of each section is the core-mantle boundary (CMB); dashed lines show the location of mantle discontinuities at 410, 660, ...
Crustal and upper mantle structure of northern Tibet imaged with
... coincident with the distribution of Plio-Pleistocene volcanic rocks in northern Tibet and the location where upwelling asthenosphere is predicted by models requiring delamination as a response to crustal thickening [Molnar, 1988; England and Houseman, 1989]. More recent surface wave studies have con ...
... coincident with the distribution of Plio-Pleistocene volcanic rocks in northern Tibet and the location where upwelling asthenosphere is predicted by models requiring delamination as a response to crustal thickening [Molnar, 1988; England and Houseman, 1989]. More recent surface wave studies have con ...
Mechanisms for the formation of ridge-axis topography at
... or combined effects of mantle temperate, crustal thickness variations (eq. 2), and the presence of rift and transform valleys (eq. 3). 4.1 Effect of mantle temperature variations (DT ) The thermal subsidence history of the global ocean basins follows the relatively well-defined square-root-of-age re ...
... or combined effects of mantle temperate, crustal thickness variations (eq. 2), and the presence of rift and transform valleys (eq. 3). 4.1 Effect of mantle temperature variations (DT ) The thermal subsidence history of the global ocean basins follows the relatively well-defined square-root-of-age re ...
Geology
... observed range of the crustal refraction phase, which reflects the thickness of crust, is more than three times as long as that of the Bonin section (right panel in Fig. 2) (Fig. DR5). This difference indicates a considerable increase of crustal volume toward the Izu arc. The final seismic image usi ...
... observed range of the crustal refraction phase, which reflects the thickness of crust, is more than three times as long as that of the Bonin section (right panel in Fig. 2) (Fig. DR5). This difference indicates a considerable increase of crustal volume toward the Izu arc. The final seismic image usi ...
Lecture 31: Stable Isotope Applications II
... magmatic systems, another factor limiting the fractionation of stable isotopes is the limited variety of bonds that O is likely to form. Silicate liquids have short-range structure. Most of the oxygen is not present as free ions, but is bound to silicon atoms to form silica tetrahedra in the melt, w ...
... magmatic systems, another factor limiting the fractionation of stable isotopes is the limited variety of bonds that O is likely to form. Silicate liquids have short-range structure. Most of the oxygen is not present as free ions, but is bound to silicon atoms to form silica tetrahedra in the melt, w ...
Shear wave anisotropy beneath the Cascadia subduction zone and
... anisotropy may be related to present-day subduction-induced deformation of the mantle beneath the subducting plate. The delay times show an increase with distance from the deformation front (trench), which may be indicative of 3–5 per cent anisotropy within the forearc mantle wedge, with a fast dire ...
... anisotropy may be related to present-day subduction-induced deformation of the mantle beneath the subducting plate. The delay times show an increase with distance from the deformation front (trench), which may be indicative of 3–5 per cent anisotropy within the forearc mantle wedge, with a fast dire ...
Petrology and tectonics of Phanerozoic continent formation: From
... continent formation. We combine new trace-element data on lower crustal xenoliths from the Mesozoic Sierra Nevada Batholith with an extensive grid-based geochemical map of the Peninsular Ranges Batholith, the southern equivalent of the Sierras. Collectively, these observations give a three-dimension ...
... continent formation. We combine new trace-element data on lower crustal xenoliths from the Mesozoic Sierra Nevada Batholith with an extensive grid-based geochemical map of the Peninsular Ranges Batholith, the southern equivalent of the Sierras. Collectively, these observations give a three-dimension ...
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.