The key role of global solid-Earth processes in
... the lithosphere in East Greenland (Fig. 1C and Data S1) is much thinner – perhaps less than 100 km – and hence can be more effectively uplifted by hot material in the upper mantle beneath. A reconstruction of tectonic plates relative to the mantle (Doubrovine et al., 2012) offers a possible explanat ...
... the lithosphere in East Greenland (Fig. 1C and Data S1) is much thinner – perhaps less than 100 km – and hence can be more effectively uplifted by hot material in the upper mantle beneath. A reconstruction of tectonic plates relative to the mantle (Doubrovine et al., 2012) offers a possible explanat ...
PDF
... of anisotropy with a rift-parallel fast direction is along-rift active asthenospheric flow (Sandvol et al., 1992). For the southern Oklahoma aulacogen, which is a failed rift, this model requires that the lattice-preferred orientation in the asthenosphere has survived the 540 m.y. since the rift bec ...
... of anisotropy with a rift-parallel fast direction is along-rift active asthenospheric flow (Sandvol et al., 1992). For the southern Oklahoma aulacogen, which is a failed rift, this model requires that the lattice-preferred orientation in the asthenosphere has survived the 540 m.y. since the rift bec ...
Constraints on asthenospheric flow from the depths of oceanic
... spreading centers. Its average depth along the 5000 km length is 3100 m, while the mean depth along the adjacent, slower spreading Pacific-Antarctic Rise (PAR) is 2700 m. The deepest spreading center is the 4000 m deep, 1000 km long Australian Antarctic Discordance (AAD). Analytic and numerical ...
... spreading centers. Its average depth along the 5000 km length is 3100 m, while the mean depth along the adjacent, slower spreading Pacific-Antarctic Rise (PAR) is 2700 m. The deepest spreading center is the 4000 m deep, 1000 km long Australian Antarctic Discordance (AAD). Analytic and numerical ...
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 ...
Linking continental drift, plate tectonics and the thermal state of the
... Continents slowly drift at the top of the mantle, sometimes colliding, splitting and aggregating. The evolutions of the continent configuration, as well as oceanic plate tectonics, are surface expressions of mantle convection and closely linked to the thermal state of the mantle; however, quantitativ ...
... Continents slowly drift at the top of the mantle, sometimes colliding, splitting and aggregating. The evolutions of the continent configuration, as well as oceanic plate tectonics, are surface expressions of mantle convection and closely linked to the thermal state of the mantle; however, quantitativ ...
The Earth`s mantle
... chemical rather than thermal heterogeneities because they are too small (assuming thermal diffusivity of 1 ´ 10-6 m2 s-1; ref. 52) to maintain a temperature difference from the mantle for longer than about 200,000 years. Given the tomographic evidence for deep subduction, the most likely explanation ...
... chemical rather than thermal heterogeneities because they are too small (assuming thermal diffusivity of 1 ´ 10-6 m2 s-1; ref. 52) to maintain a temperature difference from the mantle for longer than about 200,000 years. Given the tomographic evidence for deep subduction, the most likely explanation ...
thrust systems - The Web site cannot be found
... orogeny. Erosion levelled ancient orogens to flatlands in the relatively inactive interior of continents. In addition, the structurally challenging parts of recent and growing orogens may not lie in the visible mountains; instead, they may be 10 or even 100 km below the Earth’s surface. The geometri ...
... orogeny. Erosion levelled ancient orogens to flatlands in the relatively inactive interior of continents. In addition, the structurally challenging parts of recent and growing orogens may not lie in the visible mountains; instead, they may be 10 or even 100 km below the Earth’s surface. The geometri ...
Seismic imaging of a hot upwelling beneath the British Isles
... The Iceland plume has had an important influence on vertical motions in the North Atlantic. The convecting mantle in this region contains a large-scale low-velocity seismic anomaly, which correlates with a long-wavelength gravity high and bathymetric feature. This suggests that an arm of plume mater ...
... The Iceland plume has had an important influence on vertical motions in the North Atlantic. The convecting mantle in this region contains a large-scale low-velocity seismic anomaly, which correlates with a long-wavelength gravity high and bathymetric feature. This suggests that an arm of plume mater ...
Rudnick and Lee.fm - Cin
... by the melt. Importantly, because of the one to two orders of magnitude higher concentration of Os in residual peridotites compared to melts, Os isotopic compositions of peridotite residues are difficult to overprint by later processes, such as melt infiltration, which have such dramatic effects on ...
... by the melt. Importantly, because of the one to two orders of magnitude higher concentration of Os in residual peridotites compared to melts, Os isotopic compositions of peridotite residues are difficult to overprint by later processes, such as melt infiltration, which have such dramatic effects on ...
Australian Journal of Earth Sciences - ePIC
... et al. (2004) and Walcott (1998) argued that the lack of geological evidence for large Cenozoic faults does not support large-magnitude, regional extension in much of the region. According to Rocchi et al. (2003) and Wilson (1995), the Transantarctic Mountains front, as well as offshore faults and f ...
... et al. (2004) and Walcott (1998) argued that the lack of geological evidence for large Cenozoic faults does not support large-magnitude, regional extension in much of the region. According to Rocchi et al. (2003) and Wilson (1995), the Transantarctic Mountains front, as well as offshore faults and f ...
Origin of Archean subcontinental lithospheric mantle: Some
... the low-density, gravitationally stable, high viscosity material that assures its long-term stability of the lithosphere. Lee (2006) criticized two aspects of the model. First he notes that melting at depth in the lower part of the melting column leaves garnet in the residue. Through his quantitativ ...
... the low-density, gravitationally stable, high viscosity material that assures its long-term stability of the lithosphere. Lee (2006) criticized two aspects of the model. First he notes that melting at depth in the lower part of the melting column leaves garnet in the residue. Through his quantitativ ...
Lithospheric deformation during the early stages of continental
... Incorporating the ability of the model to self-consistently strain soften and to localize strain may be an important agent for initializing and sustaining deformation during the collision of rigid lithospheric plates (e.g., Pysklywec et al., 2000; see results below). A small block of weak material ( ...
... Incorporating the ability of the model to self-consistently strain soften and to localize strain may be an important agent for initializing and sustaining deformation during the collision of rigid lithospheric plates (e.g., Pysklywec et al., 2000; see results below). A small block of weak material ( ...
Strength of the lithosphere and strain localisation in the Baikal rift
... above referenced values. These values were chosen also because they provide prediction for Moho and LAB depths that are in a good agreement with the previously published data such as deep seismic soundings, tomography models or xenolith data (e.g.,; Gao et al., 2004; Ionov, 2002; Pavlenkova et al., ...
... above referenced values. These values were chosen also because they provide prediction for Moho and LAB depths that are in a good agreement with the previously published data such as deep seismic soundings, tomography models or xenolith data (e.g.,; Gao et al., 2004; Ionov, 2002; Pavlenkova et al., ...
Temporal evolution of continental lithospheric strength in actively
... abruptly with compositional change at the Moho before subsequently decaying rapidly with depth in the upper mantle. Work in the 1980s and 1990s provided support for the conventional strength profile for continental lithosphere but also raised troubling questions. The apparent location of earthquake ...
... abruptly with compositional change at the Moho before subsequently decaying rapidly with depth in the upper mantle. Work in the 1980s and 1990s provided support for the conventional strength profile for continental lithosphere but also raised troubling questions. The apparent location of earthquake ...
Mechanisms of continental subduction and exhumation of HP and
... Large-scale nappes folding and other complex deformation processes occurring at subduction interface largely distort kinematic imprint of subduction (e.g. Diez Fernández et al., 2012; Tirel et al., submitted for publication), hence justifying a numerical modeling approach for decrypting and matching ...
... Large-scale nappes folding and other complex deformation processes occurring at subduction interface largely distort kinematic imprint of subduction (e.g. Diez Fernández et al., 2012; Tirel et al., submitted for publication), hence justifying a numerical modeling approach for decrypting and matching ...
Shear wave anisotropy beneath the Cascadia subduction zone and
... directions are approximately parallel to the direction of absolute plate motion of the main Juan de Fuca Plate (∼N70◦ E). Delay times of 1.0 to 1.5 s indicate a mantle source for the anisotropy, most likely strain-induced lattice-preferred orientation of anisotropic mantle minerals. The anisotropy m ...
... directions are approximately parallel to the direction of absolute plate motion of the main Juan de Fuca Plate (∼N70◦ E). Delay times of 1.0 to 1.5 s indicate a mantle source for the anisotropy, most likely strain-induced lattice-preferred orientation of anisotropic mantle minerals. The anisotropy m ...
Ultraslow, slow, or fast spreading ridges
... Oceanic spreading rates are highly variable, and these variations are known to correlate to a variety of surface observables, like magmatic production, heat flow or bathymetry. This correlation lead to classify ridges into fast and slow spreading ridges, but also into the more peculiar ultraslow spre ...
... Oceanic spreading rates are highly variable, and these variations are known to correlate to a variety of surface observables, like magmatic production, heat flow or bathymetry. This correlation lead to classify ridges into fast and slow spreading ridges, but also into the more peculiar ultraslow spre ...
View/Open - Earth
... Bathymetry was acquired with a RESON SeaBat 8160 multibeam, DGPS positioning, and TSS MAHRS MRU and gyrocompass (Fig. 2a). Data, processed by the Kongsberg Neptune package, produced Digital Terrain Models of Thetis and Nereus Deeps with up to 25 m of grid resolution. Topography of the northern cent ...
... Bathymetry was acquired with a RESON SeaBat 8160 multibeam, DGPS positioning, and TSS MAHRS MRU and gyrocompass (Fig. 2a). Data, processed by the Kongsberg Neptune package, produced Digital Terrain Models of Thetis and Nereus Deeps with up to 25 m of grid resolution. Topography of the northern cent ...
(Neoproterozoic-Paleozoic) and plate reconstructions
... specialized software products that use standard techniques for component analysis (Butler, 1992); and various modifications of the fold test (McFadden, 1990; Watson and Enkin, 1993, Enkin, 2003) and reversal test (McFadden and McElhinny, 1990) for dating the magnetization components. The sample coll ...
... specialized software products that use standard techniques for component analysis (Butler, 1992); and various modifications of the fold test (McFadden, 1990; Watson and Enkin, 1993, Enkin, 2003) and reversal test (McFadden and McElhinny, 1990) for dating the magnetization components. The sample coll ...
Review of the Lithium Isotope System as a Geochemical Tracer
... heavier isotopic ratios, in keeping with other stable isotope systems. Measurements reported as δ6Li can be readily converted to δ7Li, yielding a value that generally closely approximates the corresponding δ7Li. Mass spectrometric techniques for Li isotopic measurement in geological materials have b ...
... heavier isotopic ratios, in keeping with other stable isotope systems. Measurements reported as δ6Li can be readily converted to δ7Li, yielding a value that generally closely approximates the corresponding δ7Li. Mass spectrometric techniques for Li isotopic measurement in geological materials have b ...
compositional and thermal differences between lithospheric and
... Institute of the Earth’s Crust, Siberian Branch of RAS, Irkutsk, Russia Abstract: The lower part of lithosphere in collisional orogens may delaminate due to density inversion between the asthenosphere and the cold thickened lithospheric mantle. Generally, standard delamination models have neglected ...
... Institute of the Earth’s Crust, Siberian Branch of RAS, Irkutsk, Russia Abstract: The lower part of lithosphere in collisional orogens may delaminate due to density inversion between the asthenosphere and the cold thickened lithospheric mantle. Generally, standard delamination models have neglected ...
PDF
... do not, analogous to the way that some continental rifts evolve into ocean basins and others become extinct before they do. Regardless of its ultimate fate, if a suprasubduction zone extensional basin does not have seafloor spreading, then it must be regarded as an IAB. Active BABs and IABs today ar ...
... do not, analogous to the way that some continental rifts evolve into ocean basins and others become extinct before they do. Regardless of its ultimate fate, if a suprasubduction zone extensional basin does not have seafloor spreading, then it must be regarded as an IAB. Active BABs and IABs today ar ...
A Dynamic Model of Rifting Between Galicia Bank and Flemish Cap
... 2001a; Russell and Whitmarsh, 2003). Assuming symmetric spreading, this corresponds to a whole-extension rate of 20 mm/yr during rifting. This is consistent with area balancing of the cross section in Fig. 2. Restoration of the cross section to a uniform crust thickness of 32 km requires an extensi ...
... 2001a; Russell and Whitmarsh, 2003). Assuming symmetric spreading, this corresponds to a whole-extension rate of 20 mm/yr during rifting. This is consistent with area balancing of the cross section in Fig. 2. Restoration of the cross section to a uniform crust thickness of 32 km requires an extensi ...
Subduction cycles under western North America during the
... An extensive review of geologic and tectonic features of western North America suggests that the interaction of oceanic plates with the continent follows a broad cyclical pattern. In a typical cycle, periods of rapid subduction (7-15 c d y r ) , andesitic volcanism, and trench-normal contraction are ...
... An extensive review of geologic and tectonic features of western North America suggests that the interaction of oceanic plates with the continent follows a broad cyclical pattern. In a typical cycle, periods of rapid subduction (7-15 c d y r ) , andesitic volcanism, and trench-normal contraction are ...
Rheological heterogeneity, mechanical anisotropy
... composition and rheological parameters over its entire thickness (Fig. 1). The strength of rocks at a given depth D depends on temperature .TD /, pressure .PD /, deformation mechanism dominant at TD and PD , and strain rate. In a simplified approach, two main mechanisms are competing: brittle failur ...
... composition and rheological parameters over its entire thickness (Fig. 1). The strength of rocks at a given depth D depends on temperature .TD /, pressure .PD /, deformation mechanism dominant at TD and PD , and strain rate. In a simplified approach, two main mechanisms are competing: brittle failur ...
Oceanic trench
The oceanic trenches are hemispheric-scale long but narrow topographic depressions of the sea floor. They are also the deepest parts of the ocean floor. Oceanic trenches are a distinctive morphological feature of convergent plate boundaries, along which lithospheric plates move towards each other at rates that vary from a few mm to over ten cm per year. A trench marks the position at which the flexed, subducting slab begins to descend beneath another lithospheric slab. Trenches are generally parallel to a volcanic island arc, and about 200 km (120 mi) from a volcanic arc. Oceanic trenches typically extend 3 to 4 km (1.9 to 2.5 mi) below the level of the surrounding oceanic floor. The greatest ocean depth to be sounded is in the Challenger Deep of the Mariana Trench, at a depth of 11,034 m (36,201 ft) below sea level. Oceanic lithosphere moves into trenches at a global rate of about 3 km2/yr.