Constraints on the viscosity of the continental crust and mantle from
... crustal thickness of 50– 60 km in western Mongolia, and with forward modeling of gravity data [Petit et al., 2002], which indicates a 48 km thick crust. In addition, wide-angle seismic data show crustal thicknesses of 45 km south of lake Baikal, about 500 km to the northeast of the Bolnay rupture bu ...
... crustal thickness of 50– 60 km in western Mongolia, and with forward modeling of gravity data [Petit et al., 2002], which indicates a 48 km thick crust. In addition, wide-angle seismic data show crustal thicknesses of 45 km south of lake Baikal, about 500 km to the northeast of the Bolnay rupture bu ...
Isostasy and structure of the lower crust and upper mantle in the
... along the northern edge of the Yilgarn Craton and contains evidence for remelting of the crust and tectonic activity in the Proterozoic. The velocity in the upper crust is 6.0-6.2 km.s-l, and increases to 6.4-6.55 km.s·l at 10 to 16 km depth throughout the region, and to 6.7-7.0 km.s·l at 32 km dept ...
... along the northern edge of the Yilgarn Craton and contains evidence for remelting of the crust and tectonic activity in the Proterozoic. The velocity in the upper crust is 6.0-6.2 km.s-l, and increases to 6.4-6.55 km.s·l at 10 to 16 km depth throughout the region, and to 6.7-7.0 km.s·l at 32 km dept ...
Influence of mantle dynamics on the topographic evolution of the
... state, and none of these attempts have won universal acceptance. Numerous causes of the Tibetan extension have been proposed: gravitational collapse driven by excess gravitational potential energy arising from the buoyant crustal root and the upwelled asthenosphere [Chen and Molnar, 1983; Dewey et a ...
... state, and none of these attempts have won universal acceptance. Numerous causes of the Tibetan extension have been proposed: gravitational collapse driven by excess gravitational potential energy arising from the buoyant crustal root and the upwelled asthenosphere [Chen and Molnar, 1983; Dewey et a ...
Lithospheric layering in the North American craton
... in the northeastern Superior craton also follows the trends of the geological sutures of the Superior province29. Fossil subductions, revealed as strong mantle reflectors and high-velocity bodies from active and passive seismic studies30–32 are found beneath most of these suture zones and generally ...
... in the northeastern Superior craton also follows the trends of the geological sutures of the Superior province29. Fossil subductions, revealed as strong mantle reflectors and high-velocity bodies from active and passive seismic studies30–32 are found beneath most of these suture zones and generally ...
133_2011_Coblentz et al_Geosystems_Rocky Mtns
... [2003] was that for most continental areas there exists no clear relationship between elevation and crustal thickness and pure Airy‐type correlation between elevation and crustal thickness is limited to continental regions with either very thick (>55 km) or very thin (<20 km) crust. The implication ...
... [2003] was that for most continental areas there exists no clear relationship between elevation and crustal thickness and pure Airy‐type correlation between elevation and crustal thickness is limited to continental regions with either very thick (>55 km) or very thin (<20 km) crust. The implication ...
Subsurface Geophysical Surveying in Archaeology
... correction, velocity analysis, and seismic velocities. 9. Stacking and stacked seismic sections, Seismic migration and migrated seismic sections 10. Introduction to interpretation ...
... correction, velocity analysis, and seismic velocities. 9. Stacking and stacked seismic sections, Seismic migration and migrated seismic sections 10. Introduction to interpretation ...
Morphology of the distorted subducted Pacific slab beneath the
... Gorbatov and Kennett (2003) together with a new P-wave tomographic inversion were produced from the same arrival-time data. The detailed joint inversion datasets used an inversion algorithm introduced by Kennett et al. (1998) that was then adapted by Gorbatov and Kennett (2003) to include 3D ray tra ...
... Gorbatov and Kennett (2003) together with a new P-wave tomographic inversion were produced from the same arrival-time data. The detailed joint inversion datasets used an inversion algorithm introduced by Kennett et al. (1998) that was then adapted by Gorbatov and Kennett (2003) to include 3D ray tra ...
a slab window vs. stalled slab
... the Monterey and Arguello microplates in central and southern California. The temporal existence, precise location, and dimensions of the contingent slabless windows in the Monterey^Arguello area is rather uncertain [9,16]. A 3-D ¢nite di¡erence model is constructed in which the lithospheric plates ...
... the Monterey and Arguello microplates in central and southern California. The temporal existence, precise location, and dimensions of the contingent slabless windows in the Monterey^Arguello area is rather uncertain [9,16]. A 3-D ¢nite di¡erence model is constructed in which the lithospheric plates ...
Lithospheric deformation during the early stages of continental
... Incorporating the ability of the model to self-consistently strain soften and to localize strain may be an important agent for initializing and sustaining deformation during the collision of rigid lithospheric plates (e.g., Pysklywec et al., 2000; see results below). A small block of weak material ( ...
... Incorporating the ability of the model to self-consistently strain soften and to localize strain may be an important agent for initializing and sustaining deformation during the collision of rigid lithospheric plates (e.g., Pysklywec et al., 2000; see results below). A small block of weak material ( ...
Cascadia subducting plate fluids channelled to fore
... and a downdip tapering transition zone that extends to where there is no rupture displacement. Although there is undoubtedly variability among great events, this appears to be a good approximation to the longterm average [e.g., Leonard et al., 2010]. The corresponding interseismic period has a fully ...
... and a downdip tapering transition zone that extends to where there is no rupture displacement. Although there is undoubtedly variability among great events, this appears to be a good approximation to the longterm average [e.g., Leonard et al., 2010]. The corresponding interseismic period has a fully ...
Structural Geology Introduction/Review of Basic Principles
... compact the sediment, compressing clays together, clays act as binding agents. 2) cementation - solutions carry ions into pours between sediments, with time ions may be precipitated as cements under appropriate chemical condition. Common cements include calcite, silica, and iron oxide. 3. Sed. rocks ...
... compact the sediment, compressing clays together, clays act as binding agents. 2) cementation - solutions carry ions into pours between sediments, with time ions may be precipitated as cements under appropriate chemical condition. Common cements include calcite, silica, and iron oxide. 3. Sed. rocks ...
conductivity structure of crust and upper mantle beneath the
... shapes with resistivity less than 4Ωm. Beneath the Bangong-Nujiang and Jinshajiang River sutures, the highconductivity bodies in the crust tend to extend toward the upper mantle, implying existence of a low-resistivity conduit between crust and mantle. Based on the observed electric structure of cru ...
... shapes with resistivity less than 4Ωm. Beneath the Bangong-Nujiang and Jinshajiang River sutures, the highconductivity bodies in the crust tend to extend toward the upper mantle, implying existence of a low-resistivity conduit between crust and mantle. Based on the observed electric structure of cru ...
Geochemical investigation of serpentinized oceanic lithospheric
... water/rock ratios rather than the very high water/rock ratios characteristic of serpentinization of exhumed mantle at the seafloor such as seen in abyssal peridotites. These observations were taken to indicate that serpentinization occurred by the addition of seawater to ultramafic protoliths while ...
... water/rock ratios rather than the very high water/rock ratios characteristic of serpentinization of exhumed mantle at the seafloor such as seen in abyssal peridotites. These observations were taken to indicate that serpentinization occurred by the addition of seawater to ultramafic protoliths while ...
Uppermost mantle structure of the eastern margin of the Tibetan
... across LFB. Those results suggest that the eastward movement of the Tibetan Plateau with a weak mid-lower crust is blocked by the strong lithosphere of the Sichuan Basin as suggested by higher velocity in the deep crust and upper mantle (Clark and Royden, 2000). This model provides one possible expl ...
... across LFB. Those results suggest that the eastward movement of the Tibetan Plateau with a weak mid-lower crust is blocked by the strong lithosphere of the Sichuan Basin as suggested by higher velocity in the deep crust and upper mantle (Clark and Royden, 2000). This model provides one possible expl ...
Chapter 11 - Wide-angle refraction and reflection - U
... over 100 km are required. If the target is relatively shallow, such as potentially hydrocarbon-bearing sediments beneath basalt flows, offsets of 10 20 km may suffice. But one common factor in all wide-angle profiles is that powerful seismic sources are usually required, because seismic energy suffe ...
... over 100 km are required. If the target is relatively shallow, such as potentially hydrocarbon-bearing sediments beneath basalt flows, offsets of 10 20 km may suffice. But one common factor in all wide-angle profiles is that powerful seismic sources are usually required, because seismic energy suffe ...
Full-text PDF (final published version)
... In the modern tectonic cycle, partial melting creates oceanic crust at mid-ocean ridges and continental crust at convergent margins and, as a consequence, gives rise to a melt-depleted mantle (Hofmann, 1988). Subduction returns oceanic crust and part of the continents into the mantle. Chemical geody ...
... In the modern tectonic cycle, partial melting creates oceanic crust at mid-ocean ridges and continental crust at convergent margins and, as a consequence, gives rise to a melt-depleted mantle (Hofmann, 1988). Subduction returns oceanic crust and part of the continents into the mantle. Chemical geody ...
Garzione, C. N., P. Molnar, J. C. Libarkin, and B, MacFadden (2006), Rapid Late Miocene rise
... Eastern and Western Cordillera and between 59 and 64 km in the central Altiplano [28,29]. Seismic tomography of the mantle between 168 and 208S shows low Pwave speeds below the Altiplano–Eastern Cordillera transition and relatively high P-wave speeds below the central Altiplano and Subandean zone [3 ...
... Eastern and Western Cordillera and between 59 and 64 km in the central Altiplano [28,29]. Seismic tomography of the mantle between 168 and 208S shows low Pwave speeds below the Altiplano–Eastern Cordillera transition and relatively high P-wave speeds below the central Altiplano and Subandean zone [3 ...
Extinct spreading center in the Labrador Sea
... OSLER AND LOUDEN: EXTINCT SPREADING CENTER IN LABRADOR SEA ...
... OSLER AND LOUDEN: EXTINCT SPREADING CENTER IN LABRADOR SEA ...
How Did Early Earth Become Our Modern World?
... moderately volatile elements such as Na and S compared with other meteorite groups and Earth (Palme & O’Neill 2003). The isotopic results have reopened a long-running debate (Herndon 1979, Javoy 1995) about whether carbonaceous or enstatite chondrites serve as better reference points to model the bu ...
... moderately volatile elements such as Na and S compared with other meteorite groups and Earth (Palme & O’Neill 2003). The isotopic results have reopened a long-running debate (Herndon 1979, Javoy 1995) about whether carbonaceous or enstatite chondrites serve as better reference points to model the bu ...
Anorogenic plateau formation: The importance of density
... [1] Away from active plate boundaries the relationships between spatiotemporal variations in density and geothermal gradient are important for understanding the evolution of topography in continental interiors. In this context the classic concept of the continental lithosphere as comprising three st ...
... [1] Away from active plate boundaries the relationships between spatiotemporal variations in density and geothermal gradient are important for understanding the evolution of topography in continental interiors. In this context the classic concept of the continental lithosphere as comprising three st ...
Eds. I. S. Evans, R. Dikau, E. Tokunaga, H. Ohmori... © by TERRAPUB, Tokyo, 2003.
... isostatic compensation that is on the border with astenosphere. It seems that both factors—high temperatures and dynamic prop of lithosphere plates are the result of an influence by anomalous mantle that generates intensive manifestation of magmatic processes on the ocean floor surface. Such phenome ...
... isostatic compensation that is on the border with astenosphere. It seems that both factors—high temperatures and dynamic prop of lithosphere plates are the result of an influence by anomalous mantle that generates intensive manifestation of magmatic processes on the ocean floor surface. Such phenome ...
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.