PDF 51 - The Open University
... book The Age of the Earth. Importantly, his second famous book Principles of Physical Geology did not follow the traditional viewpoints and concluded with a chapter describing continental drift. 1940-1960 The complexity of ocean floor topography was realised through improvements to sonar equipment d ...
... book The Age of the Earth. Importantly, his second famous book Principles of Physical Geology did not follow the traditional viewpoints and concluded with a chapter describing continental drift. 1940-1960 The complexity of ocean floor topography was realised through improvements to sonar equipment d ...
Imaging the lithosphere‐asthenosphere boundary
... RYCHERT AND SHEARER: IMAGING THE PACIFIC LAB USING SSLIP ...
... RYCHERT AND SHEARER: IMAGING THE PACIFIC LAB USING SSLIP ...
Primitive off-rift basalts from Iceland and Jan Mayen: Os
... the Iceland plume is clearly dispersed in the shallow upper mantle, as shown by the incompatible trace element (ITE) enriched signature of Atlantic mid-ocean ridge basalts (MORB) progressively decreasing away from Iceland along the MAR (e.g., Schilling, 1973). The geochemical signatures of Icelandic ...
... the Iceland plume is clearly dispersed in the shallow upper mantle, as shown by the incompatible trace element (ITE) enriched signature of Atlantic mid-ocean ridge basalts (MORB) progressively decreasing away from Iceland along the MAR (e.g., Schilling, 1973). The geochemical signatures of Icelandic ...
DEEP STRUCTURE AND GEOPHYSICAL PROCESSES BENEATH
... several hypotheses on the origin of island arc volcanism and intra-arc basins involve the consideration of processes secondary to subduction. The method of approach was well suited to the problems studied as the heat flow equation could be solved once the kinematics of subduction were known and sinc ...
... several hypotheses on the origin of island arc volcanism and intra-arc basins involve the consideration of processes secondary to subduction. The method of approach was well suited to the problems studied as the heat flow equation could be solved once the kinematics of subduction were known and sinc ...
Gravitational collapse of the continental crust: definition, regimes
... Between the late 1960s and the late 1970s, earth scientists focused their attention on testing the plate tectonics theory. In this context, the emphasis was redirected on horizontal compression and the role of gravity on crustal deformation was neglected. Nevertheless, during this period a few autho ...
... Between the late 1960s and the late 1970s, earth scientists focused their attention on testing the plate tectonics theory. In this context, the emphasis was redirected on horizontal compression and the role of gravity on crustal deformation was neglected. Nevertheless, during this period a few autho ...
Gravitational collapse of the continental crust: definition, regimes
... Between the late 1960s and the late 1970s, earth scientists focused their attention on testing the plate tectonics theory. In this context, the emphasis was redirected on horizontal compression and the role of gravity on crustal deformation was neglected. Nevertheless, during this period a few autho ...
... Between the late 1960s and the late 1970s, earth scientists focused their attention on testing the plate tectonics theory. In this context, the emphasis was redirected on horizontal compression and the role of gravity on crustal deformation was neglected. Nevertheless, during this period a few autho ...
Thinning of continental backarc lithosphere by flow
... compositional density, and hotter initial thermal structure. The numerical model results are in good agreement with a buoyancy stability analysis, which includes the vertical gradients in temperature and strain rate through the lithosphere. As both rheology and density depend on lithosphere composit ...
... compositional density, and hotter initial thermal structure. The numerical model results are in good agreement with a buoyancy stability analysis, which includes the vertical gradients in temperature and strain rate through the lithosphere. As both rheology and density depend on lithosphere composit ...
Tectonic fabric of the subcontinental lithosphere
... With this convergence in mind, this special issue brings together work on geophysical observations of anisotropy that share a common focus on the continental lithosphere. This collection of papers includes four contributions that address physical properties of electrically and mechanically anisotrop ...
... With this convergence in mind, this special issue brings together work on geophysical observations of anisotropy that share a common focus on the continental lithosphere. This collection of papers includes four contributions that address physical properties of electrically and mechanically anisotrop ...
Foundering of lower island-arc crust as an explanation for the origin
... A long-standing theory for the genesis of continental crust is that it is formed in subduction zones1. However, the observed seismic properties of lower crust and upper mantle in oceanic island arcs2,3 differ significantly from those in the continental crust4. Accordingly, significant modifications ...
... A long-standing theory for the genesis of continental crust is that it is formed in subduction zones1. However, the observed seismic properties of lower crust and upper mantle in oceanic island arcs2,3 differ significantly from those in the continental crust4. Accordingly, significant modifications ...
Capitanio et al. - Wiley Online Library
... 1988]. Continental tectonics during collision must ultimately relate to the subduction zones dynamics, where the fundamental tectonic forces originate. However, the observed complex patterns and evolution of continental tectonics are not easily reconciled with the reconstructed subduction histories, ...
... 1988]. Continental tectonics during collision must ultimately relate to the subduction zones dynamics, where the fundamental tectonic forces originate. However, the observed complex patterns and evolution of continental tectonics are not easily reconciled with the reconstructed subduction histories, ...
Lessons from the 2004 Sumatra–Andaman earthquake
... earthquake. Thus, in this case, the precursor cannot be used for a definitive earthquake prediction. Some large earthquakes were preceded by a distinct foreshock activity, but many earthquakes do not have distinct foreshocks. Also, a group of small earthquakes can occur without any major earthquake f ...
... earthquake. Thus, in this case, the precursor cannot be used for a definitive earthquake prediction. Some large earthquakes were preceded by a distinct foreshock activity, but many earthquakes do not have distinct foreshocks. Also, a group of small earthquakes can occur without any major earthquake f ...
Earthquake Mechanisms and Stress Field
... exposed to stress field in the Earth’s crust and lithosphere. If stress reaches a critical value exceeding strength of faults or fractures in rock, accumulated energy of elastic deformation is partially spent for anelastic deformations in the focal zone and partially released and radiated in the form ...
... exposed to stress field in the Earth’s crust and lithosphere. If stress reaches a critical value exceeding strength of faults or fractures in rock, accumulated energy of elastic deformation is partially spent for anelastic deformations in the focal zone and partially released and radiated in the form ...
Plate tectonics conserves angular momentum
... et al., 2000). Although the concept of plate tectonics was new, there was recognition that there exists a vast store of geologic information about past periods of mountain building and the changing patterns of Earth deformations. Thus it was broadly recognized that the present pattern of plate motio ...
... et al., 2000). Although the concept of plate tectonics was new, there was recognition that there exists a vast store of geologic information about past periods of mountain building and the changing patterns of Earth deformations. Thus it was broadly recognized that the present pattern of plate motio ...
Hawaii, Boundary Layers and Ambient
... of D’’ that have been quoted as arguments for it being a plausible geochemical reservoir, such as heterogeneity, anisotropy, possible presence of melt, and a high thermal gradient, also apply to the upper BL. D’’, however, has been assumed to have a higher potential temperature and to ...
... of D’’ that have been quoted as arguments for it being a plausible geochemical reservoir, such as heterogeneity, anisotropy, possible presence of melt, and a high thermal gradient, also apply to the upper BL. D’’, however, has been assumed to have a higher potential temperature and to ...
Depth distribution of Moho and tectonic framework in eastern Asian
... The main body of this region is the inland continent of China, which includes Pamir and the Tibetan Plateau (with the thickest crustal thickness of 74 km in the central area) in the western part. The region is separated from the Indian subcontinent by a gradient belt with a great variation of crusta ...
... The main body of this region is the inland continent of China, which includes Pamir and the Tibetan Plateau (with the thickest crustal thickness of 74 km in the central area) in the western part. The region is separated from the Indian subcontinent by a gradient belt with a great variation of crusta ...
Geophysical Evidence for Mid-crustal Magma Reservoirs in the
... mitigate volcanic risk for such a large population, we must first improve our understanding of the distribution of magma source regions within the mantle and crust, including where partial melts originate, and the means by which magma is transported from source region to the surface. The evolving na ...
... mitigate volcanic risk for such a large population, we must first improve our understanding of the distribution of magma source regions within the mantle and crust, including where partial melts originate, and the means by which magma is transported from source region to the surface. The evolving na ...
Figure 1 - ePrints Soton - University of Southampton
... comprise solely products of partial melting. The remarkable consistency of seismic velocities in layer 3, the lower oceanic crust, was apparent in early compilations of results from seismic refraction profiles (Raitt, 1963), and remains true even after the addition of many more seismic results, and ...
... comprise solely products of partial melting. The remarkable consistency of seismic velocities in layer 3, the lower oceanic crust, was apparent in early compilations of results from seismic refraction profiles (Raitt, 1963), and remains true even after the addition of many more seismic results, and ...
Initiation of Subduction Zones as a Consequence
... respect to the asthenosphere. Therefore, it would be physically optimal if one part of the lithosphere experienced a greater gravitational attraction than its adjacent neighbour before or during the initiation of a subduction zone. This requires the pre-existence of a density contrast within the lit ...
... respect to the asthenosphere. Therefore, it would be physically optimal if one part of the lithosphere experienced a greater gravitational attraction than its adjacent neighbour before or during the initiation of a subduction zone. This requires the pre-existence of a density contrast within the lit ...
Geochemistry of Jurassic Oceanic Crust beneath
... 1996; Thirlwall, 1997). Estimates of recycling ages are critically dependent on the effects of hydrothermal alteration near the ridge axis and the subduction process on the Pb isotope systematics of ocean crust. Ocean island basalts have long been considered to be one of the major means for evaluati ...
... 1996; Thirlwall, 1997). Estimates of recycling ages are critically dependent on the effects of hydrothermal alteration near the ridge axis and the subduction process on the Pb isotope systematics of ocean crust. Ocean island basalts have long been considered to be one of the major means for evaluati ...
Differentiation of the continental crust by relamination
... Crust extracted from the mantle in arcs is refined into continental crust in subduction zones. During sediment subduction, subduction erosion, arc subduction, and continent subduction, mafic rocks become eclogite and may sink into the mantle, whereas more silica-rich rocks are transformed into felsic ...
... Crust extracted from the mantle in arcs is refined into continental crust in subduction zones. During sediment subduction, subduction erosion, arc subduction, and continent subduction, mafic rocks become eclogite and may sink into the mantle, whereas more silica-rich rocks are transformed into felsic ...
Shear wave anisotropy beneath the Cascadia subduction zone and
... greater than 900 ◦ C, mantle minerals will develop LPO under moderate shear strain, and thus anisotropy can be actively produced by present-day mantle deformation. If the temperature is then decreased to less than 900 ◦ C, anisotropy may become ‘frozen in’, leading to fossil anisotropy. Present-day ...
... greater than 900 ◦ C, mantle minerals will develop LPO under moderate shear strain, and thus anisotropy can be actively produced by present-day mantle deformation. If the temperature is then decreased to less than 900 ◦ C, anisotropy may become ‘frozen in’, leading to fossil anisotropy. Present-day ...
Asymmetric plume-ridge interaction around Iceland: The Kolbeinsey
... sense at 68430N. Magnetic data show that this offset formed at 5.5 Ma and has propagated northward through time. Thus the southern Kolbeinsey Ridge has lengthened to the north at a rate of 100 mm/yr [Appelgate, 1997]. (This rate is similar to the southward propagation rate of the V-shaped anomali ...
... sense at 68430N. Magnetic data show that this offset formed at 5.5 Ma and has propagated northward through time. Thus the southern Kolbeinsey Ridge has lengthened to the north at a rate of 100 mm/yr [Appelgate, 1997]. (This rate is similar to the southward propagation rate of the V-shaped anomali ...
Origin of dipping structures in fast
... 39 800, Fig. 4) and Line 45 (CMP 32 100, Fig. 2a). Basement topography is substantially rougher for oceanic crust created at intermediate spreading rate, with variations of up to ∼800 m over distances of 1–14 km (Fig. 5a), similar to intermediate spreading crust elsewhere (e.g., Malinverno, 1991). F ...
... 39 800, Fig. 4) and Line 45 (CMP 32 100, Fig. 2a). Basement topography is substantially rougher for oceanic crust created at intermediate spreading rate, with variations of up to ∼800 m over distances of 1–14 km (Fig. 5a), similar to intermediate spreading crust elsewhere (e.g., Malinverno, 1991). F ...
TECTONIC ANALYSIS OF NORTHWESTERN SOUTH AMERICA
... includes a complex and dangerous mosaic of tectonic plates that have produced devastating earthquakes, tsunamis, volcanic eruptions and landslides in the last decades. The region’s economic development has also seriously suffered because the region is poorly explored for natural resources. To more e ...
... includes a complex and dangerous mosaic of tectonic plates that have produced devastating earthquakes, tsunamis, volcanic eruptions and landslides in the last decades. The region’s economic development has also seriously suffered because the region is poorly explored for natural resources. To more e ...
Crustal growth at active continental margins: Numerical
... 2D coupled petrological–thermomechanical numerical model of an oceanic-continental subduction zone. This model includes spontaneous slab retreat and bending, dehydration of subducted crust, aqueous fluid transport, partial melting, melt extraction and melt emplacement in form of extrusive volcanics a ...
... 2D coupled petrological–thermomechanical numerical model of an oceanic-continental subduction zone. This model includes spontaneous slab retreat and bending, dehydration of subducted crust, aqueous fluid transport, partial melting, melt extraction and melt emplacement in form of extrusive volcanics a ...
Post-glacial rebound
.jpg?width=300)
Post-glacial rebound (sometimes called continental rebound) is the rise of land masses that were depressed by the huge weight of ice sheets during the last glacial period, through a process known as isostatic depression. Post-glacial rebound and isostatic depression are different parts of a process known as either glacial isostasy, glacial isostatic adjustment, or glacioisostasy. Glacioisostasy is the solid Earth deformation associated with changes in ice mass distribution. The most obvious and direct affects of post-glacial rebound are readily apparent in northern Europe (especially Scotland, Estonia, Latvia, Fennoscandia, and northern Denmark), Siberia, Canada, the Great Lakes of Canada and the United States, the coastal region of the US state of Maine, parts of Patagonia, and Antarctica. However, through processes known as ocean siphoning and continental levering, the effects of post-glacial rebound on sea-level are felt globally far from the locations of current and former ice sheets.