Ridge subduction and porphyry copper
... Cu and Au are moderately incompatible elements, oceanic crust has much higher Cu-Au concentrations than the mantle and the continental crust, and thus slab melts with their diagnostic adakitic chemistry have systematically higher Cu and Au, which is favorable for mineralization. Considering the geot ...
... Cu and Au are moderately incompatible elements, oceanic crust has much higher Cu-Au concentrations than the mantle and the continental crust, and thus slab melts with their diagnostic adakitic chemistry have systematically higher Cu and Au, which is favorable for mineralization. Considering the geot ...
PDF (Chapter 23. The Upper Mantle)
... subsequently found to contain a high-velocity lid and a low-velocity zone (LVZ), generally associated with the asthenosphere. Region C, the mantle transition region (TR), was subsequently found to contain two abrupt seismic discontinuities near the depths of 410 and 650 km, and a region of high and ...
... subsequently found to contain a high-velocity lid and a low-velocity zone (LVZ), generally associated with the asthenosphere. Region C, the mantle transition region (TR), was subsequently found to contain two abrupt seismic discontinuities near the depths of 410 and 650 km, and a region of high and ...
Evolutionary cycles during the Andean orogeny
... Trumbull et al., 1999). This correlation is attributed to upper crustal contamination during low-pressure differentiation. Such evolutionary Andean series correlating with crustal thickening are reported through time from late Oligocene to late Miocene lavas in the Maricunga belt (26–28!S, Kay et al ...
... Trumbull et al., 1999). This correlation is attributed to upper crustal contamination during low-pressure differentiation. Such evolutionary Andean series correlating with crustal thickening are reported through time from late Oligocene to late Miocene lavas in the Maricunga belt (26–28!S, Kay et al ...
Crustal flow in Tibet: geophysical evidence for the physical state of
... their efforts along the NNE-trending LhasaGolmud highway and areas accessible from it, at ~88–95°E, leading to a strong concentration of data-sets in eastern Tibet (Fig. 1). However, although reflection and refraction experiments typically obtain data only directly beneath the seismic array, shear-w ...
... their efforts along the NNE-trending LhasaGolmud highway and areas accessible from it, at ~88–95°E, leading to a strong concentration of data-sets in eastern Tibet (Fig. 1). However, although reflection and refraction experiments typically obtain data only directly beneath the seismic array, shear-w ...
The effect of the large-scale mantle flow field on the Iceland hotspot
... based on surface plate velocities and mantle density anomalies derived from seismic tomography. • The model uses detailed time-dependent relative plate motion history and ridge geometry, based on marine magnetic anomalies, and lithospheric thickness variations based on it. • Location of the plume re ...
... based on surface plate velocities and mantle density anomalies derived from seismic tomography. • The model uses detailed time-dependent relative plate motion history and ridge geometry, based on marine magnetic anomalies, and lithospheric thickness variations based on it. • Location of the plume re ...
Mantle structure and tectonic history of SE Asia
... the positive velocity anomaly can be traced well into the lower mantle to depths of c. 1500 km (Fukao et al., 1992; Puspito and Shimazaki, 1995; Widiyantoro and van der Hilst, 1997). This is not an artefact of tomographic methodology and we consider it to be lithosphere that was subducted before the ...
... the positive velocity anomaly can be traced well into the lower mantle to depths of c. 1500 km (Fukao et al., 1992; Puspito and Shimazaki, 1995; Widiyantoro and van der Hilst, 1997). This is not an artefact of tomographic methodology and we consider it to be lithosphere that was subducted before the ...
Antipodal hotspots and bipolar catastrophes: Were oceanic large
... been attributed to deep-mantle plumes [7]. During that time the dstandardT plume model of narrow upwellings from the core–mantle boundary has undergone an increasing number of modifications in response to incompatible observations [8], and more recently has been rejected altogether by some authors [ ...
... been attributed to deep-mantle plumes [7]. During that time the dstandardT plume model of narrow upwellings from the core–mantle boundary has undergone an increasing number of modifications in response to incompatible observations [8], and more recently has been rejected altogether by some authors [ ...
Geodynpub_files/Taiwan, 1997
... the lithosphere. The opposing Luzon and Ryukyu subduction zones are initiated by inclined cuts made within the PSP. The subduction/collision is driven by a piston. Pre-collisional intraoceanic subduction along the Luzon and Ryukyu boundaries results in the formation of a transform zone between them, ...
... the lithosphere. The opposing Luzon and Ryukyu subduction zones are initiated by inclined cuts made within the PSP. The subduction/collision is driven by a piston. Pre-collisional intraoceanic subduction along the Luzon and Ryukyu boundaries results in the formation of a transform zone between them, ...
Activity 1 Where are the Volcanoes?
... down beneath the continents. Look at Figure 2 to see an example.The Nazca Plate, moving eastward from the East Pacific Ridge, slides down beneath the west coast of South America.The plate is heated as it sinks into the much hotter rocks of the deep Earth.The heat causes fluids, especially water, to ...
... down beneath the continents. Look at Figure 2 to see an example.The Nazca Plate, moving eastward from the East Pacific Ridge, slides down beneath the west coast of South America.The plate is heated as it sinks into the much hotter rocks of the deep Earth.The heat causes fluids, especially water, to ...
A Three-Dimensional Model of the Lithosphere Dynamics
... thereby attracts the attention of both scientists and statesmen. This region is characterized by a very high geodynamic and seismic activity, which makes it seismically hazardous. The strongest earthquakes with magnitudes of 8.0 and higher are known to have occurred on the southern, western, and eas ...
... thereby attracts the attention of both scientists and statesmen. This region is characterized by a very high geodynamic and seismic activity, which makes it seismically hazardous. The strongest earthquakes with magnitudes of 8.0 and higher are known to have occurred on the southern, western, and eas ...
Earth`s Structure
... Harlow collects these diamonds from places such as Australia, Africa, and Thailand. Back in the lab, Harlow and his colleagues remove inclusions from diamonds. First, they break open a diamond with a tool similar to a nutcracker. Then they use a microscope and a pinlike tool to sift through the diam ...
... Harlow collects these diamonds from places such as Australia, Africa, and Thailand. Back in the lab, Harlow and his colleagues remove inclusions from diamonds. First, they break open a diamond with a tool similar to a nutcracker. Then they use a microscope and a pinlike tool to sift through the diam ...
3-D multiobservable probabilistic inversion for the compositional
... Significant controversy also exists regarding the causes for the contrasting tectonomagmatic activity and epirogenesis experienced by the CP and surrounding provinces. In the case of the CP high topography and stability, most early, and some recent, ideas favor lithospheric features/processes as the ...
... Significant controversy also exists regarding the causes for the contrasting tectonomagmatic activity and epirogenesis experienced by the CP and surrounding provinces. In the case of the CP high topography and stability, most early, and some recent, ideas favor lithospheric features/processes as the ...
Mechanisms of continental subduction and exhumation of HP and
... mechanisms of weakening of the subduction interface and to the preservation of slab strength during subduction. The former seem to be ultimately related to the metamorphic processes. In oceans, it is already generally agreed that the subduction interface is lubricated due to the presence of serpenti ...
... mechanisms of weakening of the subduction interface and to the preservation of slab strength during subduction. The former seem to be ultimately related to the metamorphic processes. In oceans, it is already generally agreed that the subduction interface is lubricated due to the presence of serpenti ...
Crustal-Scale Cross-Section of the US Cordillera
... mostly by consideration of a cross-section of California (south of the Klamath Mountains) and neighboring Nevada, we recognize that strike-slip motion has affected and continues to affect the western part of the United States. In addition, we present a re-eval- ...
... mostly by consideration of a cross-section of California (south of the Klamath Mountains) and neighboring Nevada, we recognize that strike-slip motion has affected and continues to affect the western part of the United States. In addition, we present a re-eval- ...
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... The thrusting of the Tarim plate under the southern Tien Shan results in the shortening of the upper crust at rates of <1015 mm/yr, whereas India moves northward at 50 mm/yr (Abdrakhmatov et al. 2001). A part of the strain may have been accommodated within viscoelastic layers in the middle crust of ...
... The thrusting of the Tarim plate under the southern Tien Shan results in the shortening of the upper crust at rates of <1015 mm/yr, whereas India moves northward at 50 mm/yr (Abdrakhmatov et al. 2001). A part of the strain may have been accommodated within viscoelastic layers in the middle crust of ...
Geological Society of America Bulletin
... Himalayan, Appalachian) and accretionary-type (i.e., North American Cordilleran) orogenic belts (Fig. 1) that mark major boundaries between amalgamated plates or accreted terranes (Lister and Forster, 2009). The geological record of the evolution of ocean basins from the rift-drift and seafloor spre ...
... Himalayan, Appalachian) and accretionary-type (i.e., North American Cordilleran) orogenic belts (Fig. 1) that mark major boundaries between amalgamated plates or accreted terranes (Lister and Forster, 2009). The geological record of the evolution of ocean basins from the rift-drift and seafloor spre ...
The strength of faults in the crust in the western
... element code instead of a flat-Earth one in order to avoid unphysical boundary conditions at the edges of our area of interest. A global code has never been used before to model the behavior of a regional area in such detail, therefore our work is as much an investigation of fault strength as it is a ...
... element code instead of a flat-Earth one in order to avoid unphysical boundary conditions at the edges of our area of interest. A global code has never been used before to model the behavior of a regional area in such detail, therefore our work is as much an investigation of fault strength as it is a ...
Zuni–Bandera volcanism, Rio Grande, USA — Melt formation in
... the mantle leads to development of melt columns (Klein and Langmuir, 1987) where normal potential temperature (1300 °C) convecting sub-lithospheric mantle begins to replace thinned lithosphere. With advanced lithospheric extension, decompression of the continental lithosphere and input of heat from ...
... the mantle leads to development of melt columns (Klein and Langmuir, 1987) where normal potential temperature (1300 °C) convecting sub-lithospheric mantle begins to replace thinned lithosphere. With advanced lithospheric extension, decompression of the continental lithosphere and input of heat from ...
Ambient seismic noise tomography of the southern East Sea (Japan
... other places. A similar pattern is observed in our group velocity map for the 5 s period (Fig 3a). ...
... other places. A similar pattern is observed in our group velocity map for the 5 s period (Fig 3a). ...
Crustal evaluation of the northern Red Sea rift and Gulf of Suez
... well logs and geological cross-sections. The combination of gravity and magnetic data has improved the geometry and the density distribution in the 3-D calculated profiles. Results of the current work reveal possible crustal thickness and density distribution between the sedimentary cover and the upp ...
... well logs and geological cross-sections. The combination of gravity and magnetic data has improved the geometry and the density distribution in the 3-D calculated profiles. Results of the current work reveal possible crustal thickness and density distribution between the sedimentary cover and the upp ...
Positive geothermal anomalies in oceanic crust of
... clude – also in conjunction with the measured λ-values of of warm surface waters. Three recordings in the western sec∼0.85 Wm−1 K−1 in area 14 – that soft sediments were entor of area 13, however, showed an unusual T -curve (see, countered in latter area at all points of measurement. Direct e.g. T - ...
... clude – also in conjunction with the measured λ-values of of warm surface waters. Three recordings in the western sec∼0.85 Wm−1 K−1 in area 14 – that soft sediments were entor of area 13, however, showed an unusual T -curve (see, countered in latter area at all points of measurement. Direct e.g. T - ...
Insights into the lithospheric structure and tectonic setting of the
... structure of the crust, not just basement geometry. For the crust, this compilation includes an intracrustal horizon inferred mainly on the basis of velocity models and 2-D gravity modelling because crustal reflectivity does not allow clear imaging from seismic data alone (e.g. Breivik et al. 2005). ...
... structure of the crust, not just basement geometry. For the crust, this compilation includes an intracrustal horizon inferred mainly on the basis of velocity models and 2-D gravity modelling because crustal reflectivity does not allow clear imaging from seismic data alone (e.g. Breivik et al. 2005). ...
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.