Craton stability and longevity
... Cratons – the most ancient parts of the continents, are characterized by their old crust and thick lithosphere. Most cratonic lithosphere (e.g. that beneath the Kaapvaal, Siberia and Slave cratons) has a thickness up to 200-250 km (Boyd, 1973; Boyd et al., 1997; Gung et al., 2003; Mather et al., 201 ...
... Cratons – the most ancient parts of the continents, are characterized by their old crust and thick lithosphere. Most cratonic lithosphere (e.g. that beneath the Kaapvaal, Siberia and Slave cratons) has a thickness up to 200-250 km (Boyd, 1973; Boyd et al., 1997; Gung et al., 2003; Mather et al., 201 ...
Geophysical and Petrological Constraints on Ocean Plate Dynamics
... petrological constraints, I conclude that the upper asthenosphere does not contain substantial melt, which suggests that either a thermal or hydration mechanism supports plate motion. Oceanic plate motion has dramatically changed the surface of the Earth over time, and evidence for ancient plate mot ...
... petrological constraints, I conclude that the upper asthenosphere does not contain substantial melt, which suggests that either a thermal or hydration mechanism supports plate motion. Oceanic plate motion has dramatically changed the surface of the Earth over time, and evidence for ancient plate mot ...
Mantle Exhumation in an Early Paleozoic Passive Margin, Northern
... mantle during rifting of continental lithosphere at least 25 km thick subjected continental margin metasediments to conditions above the fluid-absent metapelite solidus. The contrasting strength of upper mantle and crustal lithologies during extension may explain the structural juxtaposition and bou ...
... mantle during rifting of continental lithosphere at least 25 km thick subjected continental margin metasediments to conditions above the fluid-absent metapelite solidus. The contrasting strength of upper mantle and crustal lithologies during extension may explain the structural juxtaposition and bou ...
Oceanic corrugated surfaces and the strength of the axial
... This may relate to a decrease in spreading rate with time, from 30 km/ myr prior to A6C, to ~16 km/myr between A6 and A6C, and to ~14 km/myr since A6 (Sauter et al., 2008; Patriat et al., 2008). The two largest groups of corrugated surfaces (numbers 29 to 37, and 9 to 13; Fig. 1) initiated on opposi ...
... This may relate to a decrease in spreading rate with time, from 30 km/ myr prior to A6C, to ~16 km/myr between A6 and A6C, and to ~14 km/myr since A6 (Sauter et al., 2008; Patriat et al., 2008). The two largest groups of corrugated surfaces (numbers 29 to 37, and 9 to 13; Fig. 1) initiated on opposi ...
Physical properties of upper oceanic crust
... The first three of these situations were partly addressed at Holes 395A (young and slow), 504B (young and moderate to fast), and 418A (old and slow). Legs 129 and 185 drilled the fourth end-member: Hole 801C, located in the Pigafetta Basin at 1838.50N, 15621.60E, northwest Pacific Ocean (Figure 1) ...
... The first three of these situations were partly addressed at Holes 395A (young and slow), 504B (young and moderate to fast), and 418A (old and slow). Legs 129 and 185 drilled the fourth end-member: Hole 801C, located in the Pigafetta Basin at 1838.50N, 15621.60E, northwest Pacific Ocean (Figure 1) ...
2.03 Sampling Mantle Heterogeneity through Oceanic Basalts
... preferential melting of phases, such as phlogopite, which have higher Rb/Sr, and therefore also higher 87Sr/86Sr ratios than the bulk rock, in order to explain unusually high 87Sr/86Sr ratios in OIBs (e.g., O’Nions and Pankhurst, 1974; Vollmer, 1976). Hofmann and Hart (1978) reviewed this subject in ...
... preferential melting of phases, such as phlogopite, which have higher Rb/Sr, and therefore also higher 87Sr/86Sr ratios than the bulk rock, in order to explain unusually high 87Sr/86Sr ratios in OIBs (e.g., O’Nions and Pankhurst, 1974; Vollmer, 1976). Hofmann and Hart (1978) reviewed this subject in ...
Magma Genesis and Mantle Dynamics at the Harrat Ash
... Israel (Mor, 1993; Heimann et al., 1996; Weinstein et al., 2006). The numbers give K/Ar and 40Ar/39Ar ages in million years. Data sources: Giannérini et al. (1988), Mouty et al. (1992), Sharkov et al. (1994) and this study. ...
... Israel (Mor, 1993; Heimann et al., 1996; Weinstein et al., 2006). The numbers give K/Ar and 40Ar/39Ar ages in million years. Data sources: Giannérini et al. (1988), Mouty et al. (1992), Sharkov et al. (1994) and this study. ...
Anderson and Natland, 2005
... throwback to the principle of multiple working hypotheses adhered to by several generations of geologists. The idea that volcanoes at the Earth’s surface are fueled by hot, narrow tubes of ascending mantle originating just above the core, 3000 km away, is truly an extraordinary one. Carl Sagan (1934 ...
... throwback to the principle of multiple working hypotheses adhered to by several generations of geologists. The idea that volcanoes at the Earth’s surface are fueled by hot, narrow tubes of ascending mantle originating just above the core, 3000 km away, is truly an extraordinary one. Carl Sagan (1934 ...
MANTLE MIXING - Earth and Environmental Sciences
... presented by Allègre et al. (1987). Concurrent work on the difference between the U/Th ratio derived from the Pb and Th isotopes in OIB and MORB resulted in a model that postulated a small but significant mass flux from the lower mantle into the upper mantle (Galer & O’Nions 1985). This in turn pro ...
... presented by Allègre et al. (1987). Concurrent work on the difference between the U/Th ratio derived from the Pb and Th isotopes in OIB and MORB resulted in a model that postulated a small but significant mass flux from the lower mantle into the upper mantle (Galer & O’Nions 1985). This in turn pro ...
Chapter 15. The Hard Rock Cafe
... properties for the lower lithosphere. In the depth interval 200-400 km both eclogite and peridotite can satisfy the seismic data. Garnet pyroxenites and eclogites are also found among the rocks brought up fi·om the mantle as xenoliths, and they have physical properties that overlap those of the ultr ...
... properties for the lower lithosphere. In the depth interval 200-400 km both eclogite and peridotite can satisfy the seismic data. Garnet pyroxenites and eclogites are also found among the rocks brought up fi·om the mantle as xenoliths, and they have physical properties that overlap those of the ultr ...
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... Just as a midoceanic rise crest is the descends into the mantle. morphologic signature of a fully developed divergent plate juncture, an developed conarc-crench system is the morphologic signature of a fully vergent plate juncture. The trench marks the subduction zone where magmatic arc, which may T ...
... Just as a midoceanic rise crest is the descends into the mantle. morphologic signature of a fully developed divergent plate juncture, an developed conarc-crench system is the morphologic signature of a fully vergent plate juncture. The trench marks the subduction zone where magmatic arc, which may T ...
P-and S-wave velocities of the lowermost crustal rocks from the
... clarifying the nature and growth of the Earth’s crust (e.g. Rudnick, 1995; Taylor and McLennan, 1995; Tatsumi, 2005). ...
... clarifying the nature and growth of the Earth’s crust (e.g. Rudnick, 1995; Taylor and McLennan, 1995; Tatsumi, 2005). ...
Assessment of inelastic response of buildings using force
... models the primary curve is considered as the response curve under monotonic load. In this model the primary curve is used to define the limits for member strength. On the primary curve two points have to be defined as cracking and yielding loads (Vcr and Vy) and the corresponding displacements (Dcr ...
... models the primary curve is considered as the response curve under monotonic load. In this model the primary curve is used to define the limits for member strength. On the primary curve two points have to be defined as cracking and yielding loads (Vcr and Vy) and the corresponding displacements (Dcr ...
Mountain Building Web Activity
... Be sure to include in your answer: • Whether faster average erosion rates will occur in regions with steep relief or regions with gradual relief (or whether erosion rates will be unaffected by relief) • Which of the climates above (glacial, temperate or tropical) will have the fastest average erosio ...
... Be sure to include in your answer: • Whether faster average erosion rates will occur in regions with steep relief or regions with gradual relief (or whether erosion rates will be unaffected by relief) • Which of the climates above (glacial, temperate or tropical) will have the fastest average erosio ...
Walla Walla County Hazard Identification and Vulnerability Analysis
... suddenly, releasing energy in waves that travel through the earth's crust and cause the shaking that we feel during an earthquake. A fault is a fracture or zone of fractures between two blocks of rock. Faults allow the blocks to move relative to each other. This movement may occur rapidly, in the fo ...
... suddenly, releasing energy in waves that travel through the earth's crust and cause the shaking that we feel during an earthquake. A fault is a fracture or zone of fractures between two blocks of rock. Faults allow the blocks to move relative to each other. This movement may occur rapidly, in the fo ...
Detailed rupture imaging of the 25 April 2015 Nepal earthquake
... destructively interfere if they are not. For a given grid point, the start time of coherent energy bursts represents the onset time of the rupture at that position, and the integrated power indicates the relative intensity of P wave radiation at that point. The source depth is poorly constrained by ...
... destructively interfere if they are not. For a given grid point, the start time of coherent energy bursts represents the onset time of the rupture at that position, and the integrated power indicates the relative intensity of P wave radiation at that point. The source depth is poorly constrained by ...
SCIENCE CHINA Magmatism during continental collision
... How to distinguish anorogenic magmatism, arc magmatism related to oceanic subduction and collisional magmatism related to continental subduction/collision/collapse is still a knotty problem when studying in some old orogenic belts. Many literatures try to use geochemical discrimination diagrams to i ...
... How to distinguish anorogenic magmatism, arc magmatism related to oceanic subduction and collisional magmatism related to continental subduction/collision/collapse is still a knotty problem when studying in some old orogenic belts. Many literatures try to use geochemical discrimination diagrams to i ...
`Azores Hotspot`a Wetspot?
... et al., 2005; Jean-Baptiste et al., 2009). The Azorean basalts show an increasing enrichment in incompatible elements and radiogenic Sr^Nd^Pb signatures with increasing distance from the MAR (e.g. Turner et al., 1997; Moreira et al., 1999; Bourdon et al., 2005; Beier et al., 2008, 2010). It has also ...
... et al., 2005; Jean-Baptiste et al., 2009). The Azorean basalts show an increasing enrichment in incompatible elements and radiogenic Sr^Nd^Pb signatures with increasing distance from the MAR (e.g. Turner et al., 1997; Moreira et al., 1999; Bourdon et al., 2005; Beier et al., 2008, 2010). It has also ...
science china - Woods Hole Oceanographic Institution
... et al. [15] considered the Madagascar Plateau as the continental crust, but neither hole at the sites totally penetrated the sediment layer. Seismic velocity profile data shows that the northern and southern parts of the Madagascar Plateau (with 31°S as the boundary) are more inclined to be consider ...
... et al. [15] considered the Madagascar Plateau as the continental crust, but neither hole at the sites totally penetrated the sediment layer. Seismic velocity profile data shows that the northern and southern parts of the Madagascar Plateau (with 31°S as the boundary) are more inclined to be consider ...
Immobile Element Fingerprinting of Ophiolites
... (Miyashiro 1973), and there followed a sometimes acrimouse of geochemistry to name the rock types, identify the nious debate about their precise setting of formation which tectonic setting and interpret fully their origin. All parts of is now well documented in the literature (e.g. Pearce and the op ...
... (Miyashiro 1973), and there followed a sometimes acrimouse of geochemistry to name the rock types, identify the nious debate about their precise setting of formation which tectonic setting and interpret fully their origin. All parts of is now well documented in the literature (e.g. Pearce and the op ...
Elastic Wave Propagation in Anisotropic Media: Migration
... properties of each layer. This method is based upon an approximate skewed hyperbolic moveout formula involving three measured bulk velocities for each reflector. The primary benefits of this technique are: 1) it allows for fast traveltime computation; 2) it makes possible an extremely rapid estimati ...
... properties of each layer. This method is based upon an approximate skewed hyperbolic moveout formula involving three measured bulk velocities for each reflector. The primary benefits of this technique are: 1) it allows for fast traveltime computation; 2) it makes possible an extremely rapid estimati ...
Uplift and subsidence from oblique slip: the Ganos
... vertical component of deformation is controlled by oblique slip on the non-vertical north-dipping Ganos and Tekirdağ segments of the North Anatolian Fault. We compare Holocene with Quaternary structure across the bend using new and recently published data and conclude the following. First, bend-rel ...
... vertical component of deformation is controlled by oblique slip on the non-vertical north-dipping Ganos and Tekirdağ segments of the North Anatolian Fault. We compare Holocene with Quaternary structure across the bend using new and recently published data and conclude the following. First, bend-rel ...
Seismic response and anisotropy of a model hcp iron inner core
... We present a framework for simulating the measurement of seismic anisotropy in a model inner core by computing travel time residuals of synthetic seismic rays propagated through the model. The method is first tested on simple inner core structural models consisting of layers with distinct anisotropy ...
... We present a framework for simulating the measurement of seismic anisotropy in a model inner core by computing travel time residuals of synthetic seismic rays propagated through the model. The method is first tested on simple inner core structural models consisting of layers with distinct anisotropy ...
Lithosphere delamination in continental collisional orogens: A
... slopes are limited by prescribing the maximum stable slope angle “θmax”. In the numerical models, tan(θmax) = 0.1 is applied, which is maintained at each time step by computing an instantaneous mass redistribution in the regions of unstable surface slopes. Our parameter studies indicate that variabi ...
... slopes are limited by prescribing the maximum stable slope angle “θmax”. In the numerical models, tan(θmax) = 0.1 is applied, which is maintained at each time step by computing an instantaneous mass redistribution in the regions of unstable surface slopes. Our parameter studies indicate that variabi ...
Earthscope
Earthscope is an earth science program using geological and geophysical techniques to explore the structure and evolution of the North American continent and to understand the processes controlling earthquakes and volcanoes. The project has three components: USARRAY, the Plate Boundary Observatory, and the San Andreas Fault Observatory at Depth.The project is funded by the National Science Foundation (NSF), and the data produced is publicly accessible in real-time. Organizations associated with the project include UNAVCO, the Incorporated Research Institutions for Seismology (IRIS), Stanford University, the United States Geological Survey (USGS) and National Aeronautics and Space Administration (NASA). Several international organizations also contribute to the initiative.