The role of crustal quartz in controlling Cordilleran
... Large-scale deformation of continents remains poorly understood more than 40 years after the plate tectonic revolution1. Rock flow strength and mass density variations both contribute to stress, so both are certain to be important, but these depend (somewhat nebulously) on rock type, temperature and ...
... Large-scale deformation of continents remains poorly understood more than 40 years after the plate tectonic revolution1. Rock flow strength and mass density variations both contribute to stress, so both are certain to be important, but these depend (somewhat nebulously) on rock type, temperature and ...
Tomography of the 2011 Iwaki earthquake (M 7.0) and Fukushima
... so can migrate upward. In the forearc region, the fluids can move up to the overlying crust. When the fluids enter an active fault (such as the Idosawa fault) in the crust, fault-zone frictions will decrease. This process, together with the exertion of horizontally extensional stress regime, induced ...
... so can migrate upward. In the forearc region, the fluids can move up to the overlying crust. When the fluids enter an active fault (such as the Idosawa fault) in the crust, fault-zone frictions will decrease. This process, together with the exertion of horizontally extensional stress regime, induced ...
Thermo-rheological, shear heating model for leucogranite
... garnet growth at the current erosion level; it is, however, insufficient to produce staurolite, and melting can occur only in the deepest parts of the crust; (3) temperatures in crust with stable 70 km thickness for 40 Ma and 35 km drop-off length for heat production could become sufficient to pro ...
... garnet growth at the current erosion level; it is, however, insufficient to produce staurolite, and melting can occur only in the deepest parts of the crust; (3) temperatures in crust with stable 70 km thickness for 40 Ma and 35 km drop-off length for heat production could become sufficient to pro ...
High School - Tsunami Awareness Program
... (Tokyo, Japan; Lima, Peru). Earthquakes are as inescapable as the weather. Even Mars and the Moon have them. Here on Earth, seismologists report that every year there are a couple of million earthquakes strong enough to be felt, a thousand or so that can bring down chimneys, and about a dozen capabl ...
... (Tokyo, Japan; Lima, Peru). Earthquakes are as inescapable as the weather. Even Mars and the Moon have them. Here on Earth, seismologists report that every year there are a couple of million earthquakes strong enough to be felt, a thousand or so that can bring down chimneys, and about a dozen capabl ...
Minerals and Rocks
... solid, coherent layers of rock. There are three major categories of sedimentary rocks: clastic, organic, and chemical precipitates. Broken fragments of solids are called clasts (from Latin: clastus, broken). In order of increasing size, clasts may range from clay, silt, and sand (see again Fig. 12.7 ...
... solid, coherent layers of rock. There are three major categories of sedimentary rocks: clastic, organic, and chemical precipitates. Broken fragments of solids are called clasts (from Latin: clastus, broken). In order of increasing size, clasts may range from clay, silt, and sand (see again Fig. 12.7 ...
View - GFZpublic
... & Evans 1979; Brace & Kohlstedt 1980). The 1-D strength envelope approach commonly divides the continental lithosphere into two or three rheological layers (upper crust, lower crust, mantle) and applies a simple rheological model that assumes that the deformation mechanisms within each layer are con ...
... & Evans 1979; Brace & Kohlstedt 1980). The 1-D strength envelope approach commonly divides the continental lithosphere into two or three rheological layers (upper crust, lower crust, mantle) and applies a simple rheological model that assumes that the deformation mechanisms within each layer are con ...
the granulite belt of lapland and the belomorides
... Gibb 1983). It is now speculated that the transition to the present-day plate tectonic regime was » influenced by changes in crustal growth processes; interpretations consistent with plate tectonics have therefore been proposed (Hargraves 1981). Furthermore, a model based on the stability of the oce ...
... Gibb 1983). It is now speculated that the transition to the present-day plate tectonic regime was » influenced by changes in crustal growth processes; interpretations consistent with plate tectonics have therefore been proposed (Hargraves 1981). Furthermore, a model based on the stability of the oce ...
Static and dynamic support of western United States topography
... was suggested, for example, that a mantle upwelling may be the source of large-scale uplift in the Cordillera, perhaps associated with the Yellowstone plume (Crough and Thompson, 1977; Parsons et al., 1994). The Basin and Range region would then be expected to sit anomalously high compared to its cr ...
... was suggested, for example, that a mantle upwelling may be the source of large-scale uplift in the Cordillera, perhaps associated with the Yellowstone plume (Crough and Thompson, 1977; Parsons et al., 1994). The Basin and Range region would then be expected to sit anomalously high compared to its cr ...
Gabbro
... have a "basaltic" composition. However; only a thin surface veneer of oceanic crust is basalt. The deeper rocks of the oceanic crust are generally coarser-grained gabbro. Basalt occurs at the surface of the crust because the rocks there have cooled quickly. At greater depth the cooling rate is slowe ...
... have a "basaltic" composition. However; only a thin surface veneer of oceanic crust is basalt. The deeper rocks of the oceanic crust are generally coarser-grained gabbro. Basalt occurs at the surface of the crust because the rocks there have cooled quickly. At greater depth the cooling rate is slowe ...
Primary magmas and mantle temperatures
... asthenosphere, which is inferred to have a potential temperature of 1280°C and adiabatic temperature distribution with depth. The asthenosphere composition is inferred to be a reasonably wellmixed and slightly residual lherzolite evolved from the silicate component of the primitive Earth by separati ...
... asthenosphere, which is inferred to have a potential temperature of 1280°C and adiabatic temperature distribution with depth. The asthenosphere composition is inferred to be a reasonably wellmixed and slightly residual lherzolite evolved from the silicate component of the primitive Earth by separati ...
Anisotropic Pn tomography of Turkey and adjacent regions
... Accepted 2011 September 17. Received 2011 September 17; in original form 2011 February 11 ...
... Accepted 2011 September 17. Received 2011 September 17; in original form 2011 February 11 ...
seismotectonics of the northern andes (colombia)
... lithospheric plates (Figure 1): The Nazca oceanic plate is converging eastward relative to the northwestern South America at 6 cm/yr and the Caribbean plate is moving 1-2 cm/yr to the E-SE relative to the South American plate (Freymueller et. al., 1993; Kellogg and Vega, 1995). The convergence of th ...
... lithospheric plates (Figure 1): The Nazca oceanic plate is converging eastward relative to the northwestern South America at 6 cm/yr and the Caribbean plate is moving 1-2 cm/yr to the E-SE relative to the South American plate (Freymueller et. al., 1993; Kellogg and Vega, 1995). The convergence of th ...
The Origin, Evolution and Present State of Subcontinental Lithosphere
... lithosphere. Because (1) the lithosphere thinning is the largest in scale in a global context, (2) the genetically-related Mesozoic-Cenozoic volcanism is wide-spread with abundant mantle materials (xenoliths), and (3) there are also abundant geophysical data (seismic, heat flow, gravity etc.) availa ...
... lithosphere. Because (1) the lithosphere thinning is the largest in scale in a global context, (2) the genetically-related Mesozoic-Cenozoic volcanism is wide-spread with abundant mantle materials (xenoliths), and (3) there are also abundant geophysical data (seismic, heat flow, gravity etc.) availa ...
Continent-sized anomalous zones with low
... At present, the degree of correlation between lowermost mantle P-wave velocity heterogeneity (δVP) and δVS in LLSVP regions varies between models. Comparisons of δVS and δVP models show qualitative agreement between LLSVPs and large low δVP zones, but the small-to-intermediate-scale structure differ ...
... At present, the degree of correlation between lowermost mantle P-wave velocity heterogeneity (δVP) and δVS in LLSVP regions varies between models. Comparisons of δVS and δVP models show qualitative agreement between LLSVPs and large low δVP zones, but the small-to-intermediate-scale structure differ ...
Chapter 17. The Other Isotopes
... can also be used to fingerprint different sources of magma . In addition, they can constrain timing of events. Isotopes are less useful in constraining the locations or depths of mantle components or reservoirs. Just about every radiogenic, nucleogenic or cosmogenic isotope has been used at one time ...
... can also be used to fingerprint different sources of magma . In addition, they can constrain timing of events. Isotopes are less useful in constraining the locations or depths of mantle components or reservoirs. Just about every radiogenic, nucleogenic or cosmogenic isotope has been used at one time ...
Upper Mantle Seismic Anisotropy Beneath the West Antarctic Rift
... both hotspot and no-net-rotation frameworks, showing that the anisotropy does not result from shear due to plate motion over the mantle. Further, the West Antarctic directions are substantially different from those of East Antarctica, indicating that anisotropy across the continent reflects multiple ...
... both hotspot and no-net-rotation frameworks, showing that the anisotropy does not result from shear due to plate motion over the mantle. Further, the West Antarctic directions are substantially different from those of East Antarctica, indicating that anisotropy across the continent reflects multiple ...
Seismic attenuation in the Carpathian bend zone and surroundings
... nental margin, and mantle xenoliths in the basalts show no sign of crustal contamination [32]. The age progression of the calk-alkaline volcanics and the presence of the Persani basalts are difficult to reconcile with simple subduction beneath the Transylvanian basin. However, the volume of the volc ...
... nental margin, and mantle xenoliths in the basalts show no sign of crustal contamination [32]. The age progression of the calk-alkaline volcanics and the presence of the Persani basalts are difficult to reconcile with simple subduction beneath the Transylvanian basin. However, the volume of the volc ...
Results of the CEMES project.
... institutes from different countries in the region. The main objective of CEMES was to provide reliable estimates of the distribution of electrical conductance in the upper mantle beneath the region, based on a joint interpretation of long-period magnetotelluric (MT) data with already available deep ...
... institutes from different countries in the region. The main objective of CEMES was to provide reliable estimates of the distribution of electrical conductance in the upper mantle beneath the region, based on a joint interpretation of long-period magnetotelluric (MT) data with already available deep ...
20 Transform Plate Boundaries - North Coast Distance Education
... Transform plate boundaries in the ocean basins are prominent linear features that are perpendicular to the midocean ridges. They are the short, active parts of fracture zones that may be several kilometers wide and thousands of kilometers long. The characteristics of oceanic fracture zones depend on ...
... Transform plate boundaries in the ocean basins are prominent linear features that are perpendicular to the midocean ridges. They are the short, active parts of fracture zones that may be several kilometers wide and thousands of kilometers long. The characteristics of oceanic fracture zones depend on ...
Field Trip to the Fall Zone, Cape Fear River, Raven Rock State Park
... and eustatic sea level changes. Patterns of erosion, transport and deposition evolve through time in response to diverse physical and chemical processes. Gravity-driven sediment transport (e.g., landslides and turbidity flows) destabilize the slope and carry sediment to the deep sea where it may be ...
... and eustatic sea level changes. Patterns of erosion, transport and deposition evolve through time in response to diverse physical and chemical processes. Gravity-driven sediment transport (e.g., landslides and turbidity flows) destabilize the slope and carry sediment to the deep sea where it may be ...
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.