The Eclogite Engine: Chemical geodynamics as
... overall picture. Eclogite can settle to various levels, depending on composition; the eclogite bodies that can sink to greater depths because of their density and size have low seismic velocities compared to other rocks with similar density. MORB-eclogite contains stishovite at high pressure and may ...
... overall picture. Eclogite can settle to various levels, depending on composition; the eclogite bodies that can sink to greater depths because of their density and size have low seismic velocities compared to other rocks with similar density. MORB-eclogite contains stishovite at high pressure and may ...
Lateral Density Inhomogeneities of the Continental and Oceanic
... which are close to those of the continental platforms. Thus, the FMS depth in stable continental and oceanic tectonic structures is within 4.5–5.5 km. Continental and oceanic rift zones are characterized by a shallower FMS depth owing to the elevated heat flow. The subduction zones of the Pacific co ...
... which are close to those of the continental platforms. Thus, the FMS depth in stable continental and oceanic tectonic structures is within 4.5–5.5 km. Continental and oceanic rift zones are characterized by a shallower FMS depth owing to the elevated heat flow. The subduction zones of the Pacific co ...
Anderson and Natland, 2005
... same data can be, and have been, used in support of other mechanisms, such as propagating fractures, membrane stresses, and sequential volcanic loading, they will likewise not be discussed. Age-progressive volcanism is not uniquely diagnostic of a plume. Clague and Dalrymple (1987, 1989), Koppers et ...
... same data can be, and have been, used in support of other mechanisms, such as propagating fractures, membrane stresses, and sequential volcanic loading, they will likewise not be discussed. Age-progressive volcanism is not uniquely diagnostic of a plume. Clague and Dalrymple (1987, 1989), Koppers et ...
Crustal structure of the Hatton and the conjugate east Greenland
... 2007]. In this paper we report recent, detailed studies of the Hatton margin and then examine the nature of this asymmetry with the conjugate margin and discuss possible causes for it. [4] When volcanic continental margins were first studied in detail, it became apparent that the widespread extrusiv ...
... 2007]. In this paper we report recent, detailed studies of the Hatton margin and then examine the nature of this asymmetry with the conjugate margin and discuss possible causes for it. [4] When volcanic continental margins were first studied in detail, it became apparent that the widespread extrusiv ...
Text
... Hastie et al. (2010a) described a suite of Early Eocene rhyodacites from Jamaica (Fig. 1), called the Newcastle Volcanics, which have very similar compositions to Eoarchaean TTG suites. Data suggested that the Newcastle Volcanics were generated by partial melting of a subducting portion of an oceani ...
... Hastie et al. (2010a) described a suite of Early Eocene rhyodacites from Jamaica (Fig. 1), called the Newcastle Volcanics, which have very similar compositions to Eoarchaean TTG suites. Data suggested that the Newcastle Volcanics were generated by partial melting of a subducting portion of an oceani ...
Fulltext - ETH E
... along the Eurasia-Africa suture zone is characterized by high-velocity material representing subducted oceanic lithosphere. This signature can be followed to as deep as 300-600 km, depending on the region and/or resolution. A high velocity body, possibly representing a fragment of subducted lithosph ...
... along the Eurasia-Africa suture zone is characterized by high-velocity material representing subducted oceanic lithosphere. This signature can be followed to as deep as 300-600 km, depending on the region and/or resolution. A high velocity body, possibly representing a fragment of subducted lithosph ...
Ringwood Phase transformations and their bearing on the
... petrological differentia~on of pyrolite at mid-ocean spreading centres to form new oceanic lithosphere. The MORB basaltic crust is underlain by a layer of harzburgite. During subduction, these lithologies each respond to sequential phase transformations in a different manner, so that at any given de ...
... petrological differentia~on of pyrolite at mid-ocean spreading centres to form new oceanic lithosphere. The MORB basaltic crust is underlain by a layer of harzburgite. During subduction, these lithologies each respond to sequential phase transformations in a different manner, so that at any given de ...
Chapter 4 Intrusive Igneous Rocks
... The Ma Wan Granite is typically equigranularand fme- to medium-grainedin texture but may sometimes display inequigranulartexture. Fine-grainedgranite generally intrudes the fme- to medium-grained lithologies forming the roof of the pluton. Dykes of fine-grainedgranitealso intrude the LantauGranite f ...
... The Ma Wan Granite is typically equigranularand fme- to medium-grainedin texture but may sometimes display inequigranulartexture. Fine-grainedgranite generally intrudes the fme- to medium-grained lithologies forming the roof of the pluton. Dykes of fine-grainedgranitealso intrude the LantauGranite f ...
Geochemical evidence for interaction between oceanic crust and
... Cenozoic basalts are widely distributed along the coastal provinces and adjacent offshore shelf from the northernmost in Heilongjiang province to the southernmost in Hainan island, and constitute the eastern China volcanic belt. A close spatial relationship between Paleogene basalts and sedimentary ...
... Cenozoic basalts are widely distributed along the coastal provinces and adjacent offshore shelf from the northernmost in Heilongjiang province to the southernmost in Hainan island, and constitute the eastern China volcanic belt. A close spatial relationship between Paleogene basalts and sedimentary ...
Early Paleozoic Tectonic and Thermomechanical
... UHP metamorphic rocks was a mixture of continental and mafic/ultramafic materials, derived either from oceanic mélanges or pieces of a rifted continental margin tectonically incorporated into an oceanic subduction channel. These observations require that the North Qaidam UHP metamorphic rocks origin ...
... UHP metamorphic rocks was a mixture of continental and mafic/ultramafic materials, derived either from oceanic mélanges or pieces of a rifted continental margin tectonically incorporated into an oceanic subduction channel. These observations require that the North Qaidam UHP metamorphic rocks origin ...
Supercontinents, mantle dynamics and plate
... predict that superdownwelling along multiple subduction zones might provide an effective mechanism to pull together dispersed continental fragments into a closely packed assembly. The recycled subducted material that accumulates at the mantle transition zone and sinks down into the core–mantle bound ...
... predict that superdownwelling along multiple subduction zones might provide an effective mechanism to pull together dispersed continental fragments into a closely packed assembly. The recycled subducted material that accumulates at the mantle transition zone and sinks down into the core–mantle bound ...
Physics and Chemistry of Deep Continental Crust
... in Mongolia, both far from plate boundaries) as well as the magmatism and enhanced surface heat flow often associated with these anomalous uplifts. Bird (1979) may have been the first to highlight that these nonplate tectonic geologic phenomena may result from the growth of small-scale density insta ...
... in Mongolia, both far from plate boundaries) as well as the magmatism and enhanced surface heat flow often associated with these anomalous uplifts. Bird (1979) may have been the first to highlight that these nonplate tectonic geologic phenomena may result from the growth of small-scale density insta ...
Downdip landward limit of Cascadia great earthquake rupture
... of fully seismic rupture is expected to be somewhat seaward of the limit for the modeled interseismic locked zone because some release of the locked zone strain buildup, especially the deep part, is in postseismic slip [e.g., Wang, 2007; Hu and Wang, 2012; Wang et al., 2012], so the limit from the g ...
... of fully seismic rupture is expected to be somewhat seaward of the limit for the modeled interseismic locked zone because some release of the locked zone strain buildup, especially the deep part, is in postseismic slip [e.g., Wang, 2007; Hu and Wang, 2012; Wang et al., 2012], so the limit from the g ...
The Caribbean-North America-Cocos Triple Junction
... Mann, 2007]. Numerical modeling, based on seismic tensors and GPS velocity fields [Álvarez‐Gómez et al., 2008; Rodriguez et al., 2009], assigns an important role to the fore‐arc sliver and the arcuate shape of the transform boundary. In this model the western edge of the Chortís block is regarded as ...
... Mann, 2007]. Numerical modeling, based on seismic tensors and GPS velocity fields [Álvarez‐Gómez et al., 2008; Rodriguez et al., 2009], assigns an important role to the fore‐arc sliver and the arcuate shape of the transform boundary. In this model the western edge of the Chortís block is regarded as ...
Thermal, Density, Seismological, and Rheological Structure of the
... This thesis presents a first-of-its-kind combined geophysical-petrological methodology to study the thermal, compositional, density, rheological, and seismological structure of different lithospheric domains. The methodology is incorporated in a finite-element code (LitMod) that solves simultaneousl ...
... This thesis presents a first-of-its-kind combined geophysical-petrological methodology to study the thermal, compositional, density, rheological, and seismological structure of different lithospheric domains. The methodology is incorporated in a finite-element code (LitMod) that solves simultaneousl ...
Flow and melting of a heterogeneous mantle
... compositions in islands formed on relatively old seafloor (N~16 m.y.). The compositions of hotspot islands erupting on younger seafloor are less variable and overlap more appreciably with common MORB compositions. Models predict these observations to result from the effect of lithospheric thickness ...
... compositions in islands formed on relatively old seafloor (N~16 m.y.). The compositions of hotspot islands erupting on younger seafloor are less variable and overlap more appreciably with common MORB compositions. Models predict these observations to result from the effect of lithospheric thickness ...
Magma genesis, plate tectonics, and chemical
... oceanicplates, and (4) continental plates.These may be subdiMAGMA GENESIS AND PLATE TECTONICS vided. Divergent plate boundariesinclude (1A) oceanic ridges The main variables to be consideredin magma genesisare and (lB) continental rift systems.Convergent plate boundaries (1) the compositionsof mater ...
... oceanicplates, and (4) continental plates.These may be subdiMAGMA GENESIS AND PLATE TECTONICS vided. Divergent plate boundariesinclude (1A) oceanic ridges The main variables to be consideredin magma genesisare and (lB) continental rift systems.Convergent plate boundaries (1) the compositionsof mater ...
DEEP SEA. WASTE DISPOSAL
... of elements. In addition to making a useful contribution to an international effort, the combined programmes should also meet the domestic requirement for the range of skills needed for participation in decision making at all levels and for knowledge about particular disposal areas of practical inte ...
... of elements. In addition to making a useful contribution to an international effort, the combined programmes should also meet the domestic requirement for the range of skills needed for participation in decision making at all levels and for knowledge about particular disposal areas of practical inte ...
Isostasy, dynamic topography, and the elevation of the Apennines of
... quantify the relative contribution of isostatic and dynamic components, providing new insights on the range of subduction processes contributing to the topography and vertical motion of the Apennines mountain belt. 2. Isostasy, elevation and uplift rate The elevation of a mountain belt and rate of s ...
... quantify the relative contribution of isostatic and dynamic components, providing new insights on the range of subduction processes contributing to the topography and vertical motion of the Apennines mountain belt. 2. Isostasy, elevation and uplift rate The elevation of a mountain belt and rate of s ...
Petrological models of magma evolution and deep crustal structure
... overburden pressure acting in the source region [271. The overburden pressure depends on the thickness of the crust and on the depth of the source. For a dike to advance upwards the fluid pressure at the top of the column must exceed the lithostatic pressure. If the melt is present in continuous con ...
... overburden pressure acting in the source region [271. The overburden pressure depends on the thickness of the crust and on the depth of the source. For a dike to advance upwards the fluid pressure at the top of the column must exceed the lithostatic pressure. If the melt is present in continuous con ...
Mechanical (de-)coupling of the lithosphere in the Valencia Trough
... horizontal decoupling. Other authors have studied decoupling as the possibility of two layers to move independently of each other in the vertical sense (e.g. [23], see Fig. 1c). In this view, stresses exerted by the bounding brittle layers would not be transmitted vertically. In contrast, they would ...
... horizontal decoupling. Other authors have studied decoupling as the possibility of two layers to move independently of each other in the vertical sense (e.g. [23], see Fig. 1c). In this view, stresses exerted by the bounding brittle layers would not be transmitted vertically. In contrast, they would ...
40. Neogene Controls on Hydrothermal Activity and
... the cruise was to recover sediments and rocks that would reveal the geologic history of seafloor hydrothermal activity as determined by the geochemistry and sedimentation history of hydrothermal material, the advection of sediment pore waters, the nature and history of alteration of seafloor basalt, ...
... the cruise was to recover sediments and rocks that would reveal the geologic history of seafloor hydrothermal activity as determined by the geochemistry and sedimentation history of hydrothermal material, the advection of sediment pore waters, the nature and history of alteration of seafloor basalt, ...
The Statistical Upper Mantle Assemblage, Earth
... The geochemical diversity of mid-ocean ridge basalt (MORB) and oceanic island basalt (OIB) has traditionally been attributed to the existence of large-scale mantle heterogeneity, in particular to accessible reservoirs at various depths. However, reconciling the geochemical constraints for isolated, ...
... The geochemical diversity of mid-ocean ridge basalt (MORB) and oceanic island basalt (OIB) has traditionally been attributed to the existence of large-scale mantle heterogeneity, in particular to accessible reservoirs at various depths. However, reconciling the geochemical constraints for isolated, ...
Softening of the subcontinental lithospheric mantle by
... The thermal and rheological consequences of thermomechanical erosion are explored by modelling the temperature and rheological properties of the thinned lithosphere as a function of thickness of ALM and time since asthenospherization (i.e., since the beginning of thermal relaxation). Results are giv ...
... The thermal and rheological consequences of thermomechanical erosion are explored by modelling the temperature and rheological properties of the thinned lithosphere as a function of thickness of ALM and time since asthenospherization (i.e., since the beginning of thermal relaxation). Results are giv ...
Chapter 16. Noble Gas Isotopes
... these to get global estimates of OIB statistics. The statistics and the distribution of helium in mantle magmas show that there is no statistical difference in 3 Hej 4 He (R) ratios between the available data for midoceanic ridge basalts (MOREs) and ocean island basalts (OIBs). It is usually assumed ...
... these to get global estimates of OIB statistics. The statistics and the distribution of helium in mantle magmas show that there is no statistical difference in 3 Hej 4 He (R) ratios between the available data for midoceanic ridge basalts (MOREs) and ocean island basalts (OIBs). It is usually assumed ...
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.