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imaging the upper mantle beneath turkey and surrounding regions
... This study includes two interdependent sections. The first section presents an analysis of Pn travel times to determine Pn velocity, Pn anisotropy and crustal thickness variations beneath Turkey and surroundings. Between 1999 and 2010, more than 50 000 Pn arrivals are compiled from 700 regional eart ...
... This study includes two interdependent sections. The first section presents an analysis of Pn travel times to determine Pn velocity, Pn anisotropy and crustal thickness variations beneath Turkey and surroundings. Between 1999 and 2010, more than 50 000 Pn arrivals are compiled from 700 regional eart ...
The Yellowstone magmatic system from the
... explaining the magnitude of CO 2 discharge, and constraining dynamic at depths of 5 to 10 km, which is models of the magmatic system for volcanic hazard assessment. often interpreted as a magma reservoir. Several of these studies also image the top of a second The interaction of the North American P ...
... explaining the magnitude of CO 2 discharge, and constraining dynamic at depths of 5 to 10 km, which is models of the magmatic system for volcanic hazard assessment. often interpreted as a magma reservoir. Several of these studies also image the top of a second The interaction of the North American P ...
the Zero Paradox Noble Gas Mantle
... create and destroy the geochemical record of the Earth’s past. Two apparently incompatible conceptual models of whole Earth behavior have been championed by different sections of the Earth Sciences. The geochemical community has favored a layered model of the mantle in which a shallow well mixed, vo ...
... create and destroy the geochemical record of the Earth’s past. Two apparently incompatible conceptual models of whole Earth behavior have been championed by different sections of the Earth Sciences. The geochemical community has favored a layered model of the mantle in which a shallow well mixed, vo ...
Mantle Mixing - Earth and Environmental Sciences
... geochemistry of ocean island basalts (OIBs) were explained by mixing of the depleted upper mantle with primitive mantle (c.f. DePaolo & Wasserburg 1976; O’Nions et al 1979; Allègre et al ...
... geochemistry of ocean island basalts (OIBs) were explained by mixing of the depleted upper mantle with primitive mantle (c.f. DePaolo & Wasserburg 1976; O’Nions et al 1979; Allègre et al ...
Significance of seismic reflections beneath a tilted
... from the TehachapiMountains. The CALCRUST reflection profile aimed principally at there it was taken south, toward line 4 of the Consortium for addressingthe structuralrelationshipof the gneissand schist, Continental Reflection Profiling (COCORP) Mojave Desert their distribution in the crust, and th ...
... from the TehachapiMountains. The CALCRUST reflection profile aimed principally at there it was taken south, toward line 4 of the Consortium for addressingthe structuralrelationshipof the gneissand schist, Continental Reflection Profiling (COCORP) Mojave Desert their distribution in the crust, and th ...
(PDF 8mb)
... to the plate boundary coupling is expressed as both vertical and horizontal tectonics along crustal-scale faults such as the Denali Fault system. Results from this study will have both regional and broad scale tectonic implications. In particular, results from this project will help define what cons ...
... to the plate boundary coupling is expressed as both vertical and horizontal tectonics along crustal-scale faults such as the Denali Fault system. Results from this study will have both regional and broad scale tectonic implications. In particular, results from this project will help define what cons ...
4.4 billion years of crustal maturation: oxygen isotope ratios of
... 0:0612ðwt:%SiO2 Þ þ 2:5 (Valley et al. 1994; Lackey 2005). For comparison with the crust, two vertical lines show the mantle range of d18O(Zrc) at 5.3±0.3&. Fresh basalts (WR) are close, but slightly above the range for mantle zircon, but altered basalts plot at higher or lower values depending o ...
... 0:0612ðwt:%SiO2 Þ þ 2:5 (Valley et al. 1994; Lackey 2005). For comparison with the crust, two vertical lines show the mantle range of d18O(Zrc) at 5.3±0.3&. Fresh basalts (WR) are close, but slightly above the range for mantle zircon, but altered basalts plot at higher or lower values depending o ...
Izu detachment hypothesis: A proposal of a unified cause for... event and the Tokai slow event
... horizontal displacements continued for almost three months (∼85 days). Because the horizontal movements amounting to 3 cm in the Izu Peninsula (Fig. 2) cannot be explained by the dike intrusion alone, Yamaoka (2000) and Nishimura et al. (2001) assumed a creep dislocation source at the northern end o ...
... horizontal displacements continued for almost three months (∼85 days). Because the horizontal movements amounting to 3 cm in the Izu Peninsula (Fig. 2) cannot be explained by the dike intrusion alone, Yamaoka (2000) and Nishimura et al. (2001) assumed a creep dislocation source at the northern end o ...
Catastrophic Granite Formation Rapid Melting of
... The timescale for the generation of granitic magmas and their subsequent intrusion, crystallization, and cooling as plutons is no longer incompatible with the biblical time frames of the global, year-long Flood cataclysm and of 6,000–7,000 years for earth history. Though partial melting in the lower ...
... The timescale for the generation of granitic magmas and their subsequent intrusion, crystallization, and cooling as plutons is no longer incompatible with the biblical time frames of the global, year-long Flood cataclysm and of 6,000–7,000 years for earth history. Though partial melting in the lower ...
Ignimbrite flare-up and deformation in the southern Sierra Madre
... Therefore this first part of the extensional history remains to be explained. In summary, despite a number of studies published in the last two decades the causes of the ignimbrite flare-up and extension in the SMO are still not completely understood. [4] This paper presents new geologic, geochronol ...
... Therefore this first part of the extensional history remains to be explained. In summary, despite a number of studies published in the last two decades the causes of the ignimbrite flare-up and extension in the SMO are still not completely understood. [4] This paper presents new geologic, geochronol ...
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... accretionary, and that these existed near continents. New continental crust also forms where thick piles of oceanic crust – oceanic plateaux, formed above mantle “hotspots” – collide with arcs, such as the Miocene collision of the Ontong-Java Plateau with the Solomon arc (Mann and Taira, 2004). Cont ...
... accretionary, and that these existed near continents. New continental crust also forms where thick piles of oceanic crust – oceanic plateaux, formed above mantle “hotspots” – collide with arcs, such as the Miocene collision of the Ontong-Java Plateau with the Solomon arc (Mann and Taira, 2004). Cont ...
Constraints on mantle melting and composition and nature of slab
... parental magmas and mantle sources, 2) to constrain thermal conditions of mantle melting, and 3) to estimate the composition of slabderived components. We demonstrate that typical Kamchatkan arc-type magmas originate through 5–14% melting of sources similar or slightly more depleted in HFSE (with up ...
... parental magmas and mantle sources, 2) to constrain thermal conditions of mantle melting, and 3) to estimate the composition of slabderived components. We demonstrate that typical Kamchatkan arc-type magmas originate through 5–14% melting of sources similar or slightly more depleted in HFSE (with up ...
Slide 1
... HREE depletion, where both LREE and HREE abundances decrease with increasing SiO2. They are also depleted in Y and enriched in Sr. The more felsic members of this group generally exhibit concave-up patterns of HREE depletion. Most exhumed arcs show one or the other of these trends, but some, includi ...
... HREE depletion, where both LREE and HREE abundances decrease with increasing SiO2. They are also depleted in Y and enriched in Sr. The more felsic members of this group generally exhibit concave-up patterns of HREE depletion. Most exhumed arcs show one or the other of these trends, but some, includi ...
Plume mantle source heterogeneity through time: Insights from the
... high pressures are consistent with low-velocity anomalies obtained by geophysical tomographic techniques, which have yielded, for instance, high-resolution images of Atlantic mantle plumes, as found in Iceland, Azores and Eifel, down to 400 km depth [Pilidou et al., 2005]. [3] To account for the ran ...
... high pressures are consistent with low-velocity anomalies obtained by geophysical tomographic techniques, which have yielded, for instance, high-resolution images of Atlantic mantle plumes, as found in Iceland, Azores and Eifel, down to 400 km depth [Pilidou et al., 2005]. [3] To account for the ran ...
54. Regional Geology of the Goban Spur Continental Margin
... phase had a duration of about 15 m.y. However, the age of the rifting-to-spreading transition derived from Site 549 is between 2 and 4 m.y. greater than the age derived from Site 550, drilled on the ocean crust. A possible explanation is that extension within the upper continental crust was taken up ...
... phase had a duration of about 15 m.y. However, the age of the rifting-to-spreading transition derived from Site 549 is between 2 and 4 m.y. greater than the age derived from Site 550, drilled on the ocean crust. A possible explanation is that extension within the upper continental crust was taken up ...
Lower Continental Crust. - UCSB Earth Science
... To characterize the composition of continental granulite-facies terrains, Rudnick & Presper (1990) assembled a database of rock compositions from Archean and post-Archean terrains recrystallized at >0.6 GPa. Huang et al. (2013) updated this database and added a compilation of amphibolite-facies samp ...
... To characterize the composition of continental granulite-facies terrains, Rudnick & Presper (1990) assembled a database of rock compositions from Archean and post-Archean terrains recrystallized at >0.6 GPa. Huang et al. (2013) updated this database and added a compilation of amphibolite-facies samp ...
Mantle Discontinuities - Northwestern University
... upper 100 km of oceanic and tectonically active regions, but he finds no evidence for a sharp (less than 56 km depth-extent) base to the low velocity zone. The 410 krn Discontinuity Shearer's [I9901 global stacking study yields a bestfitting depth of 410 km for the "400 km discontinuity", with topo ...
... upper 100 km of oceanic and tectonically active regions, but he finds no evidence for a sharp (less than 56 km depth-extent) base to the low velocity zone. The 410 krn Discontinuity Shearer's [I9901 global stacking study yields a bestfitting depth of 410 km for the "400 km discontinuity", with topo ...
Mantle Influence, Rifting and Magmatism in the East African Rift
... The most energetic hydrothermal features in Africa occur in the EARS region. EARS development is controlled by the magnitude of the in-field extensive stresses, the fabrics of rifting terrains and, during its later stages, by mantle plume impact. The African Superplume has installed an anomalously h ...
... The most energetic hydrothermal features in Africa occur in the EARS region. EARS development is controlled by the magnitude of the in-field extensive stresses, the fabrics of rifting terrains and, during its later stages, by mantle plume impact. The African Superplume has installed an anomalously h ...
short and long-term folding and faulting of the lithosphere under
... As we want to study how the lithosphere responds when subjected to a force, in our case a compression, it is important to introduce two important concepts on the field of geodynamics: stress and strain. Stress can be defined as the internal distribution and intensity of a force acting at any point w ...
... As we want to study how the lithosphere responds when subjected to a force, in our case a compression, it is important to introduce two important concepts on the field of geodynamics: stress and strain. Stress can be defined as the internal distribution and intensity of a force acting at any point w ...
Composition of the depleted mantle
... has been constant over the history of the Earth the total amount of oceanic crust (density 3 gr/cm3) produced equals 8% of Earth’s mantle. If we assume further that the oceanic crust represents an average of 10% melt, then roughly the equivalent of 80% of the total volume of the mantle could have be ...
... has been constant over the history of the Earth the total amount of oceanic crust (density 3 gr/cm3) produced equals 8% of Earth’s mantle. If we assume further that the oceanic crust represents an average of 10% melt, then roughly the equivalent of 80% of the total volume of the mantle could have be ...
Review of Late Jurassic-early Miocene sedimentation and plate
... would have produced an ophiolitic basement younger than the rifted apron of terrigenous sediments. Because this mafic crust is actually *25 Myr older than the basal GVG sediments (e.g., Stern 2004; Stern et al. 2012; Shervais and Choi 2012), the postulated plate-junction step-out stranding pre-exist ...
... would have produced an ophiolitic basement younger than the rifted apron of terrigenous sediments. Because this mafic crust is actually *25 Myr older than the basal GVG sediments (e.g., Stern 2004; Stern et al. 2012; Shervais and Choi 2012), the postulated plate-junction step-out stranding pre-exist ...
GUIDE TO PLATE TECTONICS AND EARTHQUAKES
... with links to teaching resources tailored for a middle school audience. We recommend that first-time users download and view this presentation to understand the logical sequence of the subtopics below. This PDF guide is an outline of the PowerPoint presentation with links to resources posted on the ...
... with links to teaching resources tailored for a middle school audience. We recommend that first-time users download and view this presentation to understand the logical sequence of the subtopics below. This PDF guide is an outline of the PowerPoint presentation with links to resources posted on the ...
Plate tectonics
Plate tectonics (from the Late Latin tectonicus, from the Greek: τεκτονικός ""pertaining to building"") is a scientific theory that describes the large-scale motion of Earth's lithosphere. This theoretical model builds on the concept of continental drift which was developed during the first few decades of the 20th century. The geoscientific community accepted the theory after the concepts of seafloor spreading were later developed in the late 1950s and early 1960s.The lithosphere, which is the rigid outermost shell of a planet (on Earth, the crust and upper mantle), is broken up into tectonic plates. On Earth, there are seven or eight major plates (depending on how they are defined) and many minor plates. Where plates meet, their relative motion determines the type of boundary; convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries. The lateral relative movement of the plates typically varies from zero to 100 mm annually.Tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle; the material lost is roughly balanced by the formation of new (oceanic) crust along divergent margins by seafloor spreading. In this way, the total surface of the globe remains the same. This prediction of plate tectonics is also referred to as the conveyor belt principle. Earlier theories (that still have some supporters) propose gradual shrinking (contraction) or gradual expansion of the globe.Tectonic plates are able to move because the Earth's lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the mantle result in convection. Plate movement is thought to be driven by a combination of the motion of the seafloor away from the spreading ridge (due to variations in topography and density of the crust, which result in differences in gravitational forces) and drag, with downward suction, at the subduction zones. Another explanation lies in the different forces generated by the rotation of the globe and the tidal forces of the Sun and Moon. The relative importance of each of these factors and their relationship to each other is unclear, and still the subject of much debate.