Non-hotspot volcano chains from small
... created by a mechanism similar to that proposed by Anderson (1998) for oceanic regions. The Michigan Basin, which is located within the ancient North American craton (∼1.1 - >2.5 Ga), lies on a very thick, U-Th-K depleted SCLM, which is refractory and buoyant relative to the asthenosphere, thus, pos ...
... created by a mechanism similar to that proposed by Anderson (1998) for oceanic regions. The Michigan Basin, which is located within the ancient North American craton (∼1.1 - >2.5 Ga), lies on a very thick, U-Th-K depleted SCLM, which is refractory and buoyant relative to the asthenosphere, thus, pos ...
TTGs and adakites: are they both slab melts?
... Atherton, 1996). Well-documented adakites are associated with the Chilean triple junction where the Chile rise is being subducted beneath the Andes in ...
... Atherton, 1996). Well-documented adakites are associated with the Chilean triple junction where the Chile rise is being subducted beneath the Andes in ...
Origin of the Newberry Hotspot Track: Evidence from
... signature, which are characteristic of many hotspots. Yet, despite these features, evidence for an upwelling conduit through the upper mantle beneath Yellowstone remains unclear and the debate continues as to whether a mantle plume is the origin [3,10–15]. The Newberry hotspot is far less studied th ...
... signature, which are characteristic of many hotspots. Yet, despite these features, evidence for an upwelling conduit through the upper mantle beneath Yellowstone remains unclear and the debate continues as to whether a mantle plume is the origin [3,10–15]. The Newberry hotspot is far less studied th ...
EENS 2120 Petrology Prof. Stephen A. Nelson Igneous Rocks of the
... Since Cpx would be the first solid phase to disappear during melting, further melting of peridotite at any of these pressure would produce liquids with compositions that lie along the Ol - Opx boundary curve at each pressure. Let's imagine that a liquid is produced at a pressure of 20 kb by partial ...
... Since Cpx would be the first solid phase to disappear during melting, further melting of peridotite at any of these pressure would produce liquids with compositions that lie along the Ol - Opx boundary curve at each pressure. Let's imagine that a liquid is produced at a pressure of 20 kb by partial ...
Snacktectonics
... Purpose of Activity: To model the interactions of Earth’s lithosphere (tectonic plates) as they slowly move on the Earth’s mantle (asthenosphere), through the use of snack foods. Background for Activity: The theory of plate tectonics says that the crust of the Earth is composed of separate plates wh ...
... Purpose of Activity: To model the interactions of Earth’s lithosphere (tectonic plates) as they slowly move on the Earth’s mantle (asthenosphere), through the use of snack foods. Background for Activity: The theory of plate tectonics says that the crust of the Earth is composed of separate plates wh ...
PDF 51 - The Open University
... 1937 South African geologist Alexander du Toit provided support through the years of controversy by drawing maps illustrating a northern supercontinent called Laurasia (i.e. the assembled land mass of what was to become North America, Greenland, Europe and Asia). The idea of the Laurasian continent ...
... 1937 South African geologist Alexander du Toit provided support through the years of controversy by drawing maps illustrating a northern supercontinent called Laurasia (i.e. the assembled land mass of what was to become North America, Greenland, Europe and Asia). The idea of the Laurasian continent ...
A new look at the causes and consequences of the Icelandic hot
... Geoid highs over hot-spots such as Iceland have been variously attributed to pressure variations associated with upper mantle convection (Sclater et al. 1975), to deep isostatic compensation of the associated topographic swell by hot, low density asthenosphere (Cochran & Talwani 1978) and to lateral ...
... Geoid highs over hot-spots such as Iceland have been variously attributed to pressure variations associated with upper mantle convection (Sclater et al. 1975), to deep isostatic compensation of the associated topographic swell by hot, low density asthenosphere (Cochran & Talwani 1978) and to lateral ...
Plate Tectonics as a Far- From- Equilibrium Self
... definition of plate tectonics. Plate tectonics is usually supposed to be the surface manifestation of mantle convection. However, a fluid cooled from above or heated from within is driven by the unstable surface boundary layer and there are no active convective upwellings. The dense surface layer is ...
... definition of plate tectonics. Plate tectonics is usually supposed to be the surface manifestation of mantle convection. However, a fluid cooled from above or heated from within is driven by the unstable surface boundary layer and there are no active convective upwellings. The dense surface layer is ...
CONTINENTAL SHELF SURVEY PROJECT OF JAPAN
... the outer edge of the continental margin does not extend up to that distance. In a case where the margin extends beyond 200 nautical miles, the outer edge of the continental margin shall be established on the basis of top ograp h ical and geological conditions. The definition of the continental shel ...
... the outer edge of the continental margin does not extend up to that distance. In a case where the margin extends beyond 200 nautical miles, the outer edge of the continental margin shall be established on the basis of top ograp h ical and geological conditions. The definition of the continental shel ...
Cascadia subducting plate fluids channelled to fore
... serpentinite based on seismic velocity data [e.g., Carlson and Miller, 1997; Christensen, 1972], it may be significant based on ocean drilling results [e.g., Juteau et al., 1990]. In addition to serpentinite formed at ridges and ocean basin fault zones, the upper mantle may be substantially serpentin ...
... serpentinite based on seismic velocity data [e.g., Carlson and Miller, 1997; Christensen, 1972], it may be significant based on ocean drilling results [e.g., Juteau et al., 1990]. In addition to serpentinite formed at ridges and ocean basin fault zones, the upper mantle may be substantially serpentin ...
Discovering Plate Boundaries
... This is an example of a Convergent (subducting) plate boundary in which oceanic crust (Nazca and Antarctic Plates) is being subducted beneath continental crust (South American Plate). Note that at such a boundary, it will always be the oceanic plate as the down-going plate and the continental plate ...
... This is an example of a Convergent (subducting) plate boundary in which oceanic crust (Nazca and Antarctic Plates) is being subducted beneath continental crust (South American Plate). Note that at such a boundary, it will always be the oceanic plate as the down-going plate and the continental plate ...
Plate Tectonics Questions
... Southern Hemisphere and the inferred tectonic movement of the continent of Australia over geologic time. The arrows between the dots show the relative movement of the center of the continent of Australia. The parallels of latitude from 0° to 90° south are labeled. ...
... Southern Hemisphere and the inferred tectonic movement of the continent of Australia over geologic time. The arrows between the dots show the relative movement of the center of the continent of Australia. The parallels of latitude from 0° to 90° south are labeled. ...
Computation of phase equilibria by linear programming
... Mapping phase relations by iterative application of a free-energy minimization is but one, and the crudest, of a variety of methods used in the geosciences [23]. The advantages of mapping strategies are that they are general with respect to the choice of mapping variables and that the resolution of ...
... Mapping phase relations by iterative application of a free-energy minimization is but one, and the crudest, of a variety of methods used in the geosciences [23]. The advantages of mapping strategies are that they are general with respect to the choice of mapping variables and that the resolution of ...
Subduction versus accretion of intra
... opening). With the onset of continental margin subduction, the convergence system enters into a compressional regime : extension in the back-arc basin ceases and is then changed by compression. Increasing compression causes failure of the overriding plate in the vicinity of the extinct back-arc spre ...
... opening). With the onset of continental margin subduction, the convergence system enters into a compressional regime : extension in the back-arc basin ceases and is then changed by compression. Increasing compression causes failure of the overriding plate in the vicinity of the extinct back-arc spre ...
Geophysical insights into the Transition fault debate: Propagating
... New Hampshire 03824, USA ABSTRACT On the basis of faulting mapped on seismic reflection and bathymetric data, seismicity, current plate motions, and evidence that the Yakutat block may be anomalously thick, we propose a tectonic model for Yakutat-Pacific interactions, including the often-debated Tra ...
... New Hampshire 03824, USA ABSTRACT On the basis of faulting mapped on seismic reflection and bathymetric data, seismicity, current plate motions, and evidence that the Yakutat block may be anomalously thick, we propose a tectonic model for Yakutat-Pacific interactions, including the often-debated Tra ...
Geodynpub_files/Boutelier, Chemenda, 2011
... characterized by high or low interplate pressure and associated with high or low-compression tectonic regime, are also obtained in the purely mechanical laboratory experiments of this process (Chemenda et al. 1995, 1996). As for oceanic subduction, the regime of continental subduction is mainly cont ...
... characterized by high or low interplate pressure and associated with high or low-compression tectonic regime, are also obtained in the purely mechanical laboratory experiments of this process (Chemenda et al. 1995, 1996). As for oceanic subduction, the regime of continental subduction is mainly cont ...
The viscosity of Earthв€™s lower mantle inferred from sinking speed
... In the Earth’s mantle, solid-state creep facilitates buoyancy driven material flow on the scale of centimeters per year across the entire mantle. Viscosity characterizes the internal friction of the flow and is one of the key quantities determining the mechanical behavior of the mantle. The latter gov ...
... In the Earth’s mantle, solid-state creep facilitates buoyancy driven material flow on the scale of centimeters per year across the entire mantle. Viscosity characterizes the internal friction of the flow and is one of the key quantities determining the mechanical behavior of the mantle. The latter gov ...
Role of the subducted slab, mantle wedge and
... Regional geology and tectonics The volcanoes of the AVZ result from the subduction of young (12–24 Ma) Antarctic plate below southernmost South America at low convergence velocities of 2 cmyyear (Fig. 1; Cande and Leslie l986). The AVZ is separated from the Andean Southern Volcanic Zone (SVZ) by a g ...
... Regional geology and tectonics The volcanoes of the AVZ result from the subduction of young (12–24 Ma) Antarctic plate below southernmost South America at low convergence velocities of 2 cmyyear (Fig. 1; Cande and Leslie l986). The AVZ is separated from the Andean Southern Volcanic Zone (SVZ) by a g ...
Ophiolites: Figments of Oceanic Lithosphere? Geological Society
... Sea margins are marked by discontinuous zones of basic igneous rocks up to about 200 km from the present continent-ocean crust boundary which were formed at the same time as ocean crust in the main ocean. These zones are often referred to as 'failed rifts', an unfortunate term since it implies that ...
... Sea margins are marked by discontinuous zones of basic igneous rocks up to about 200 km from the present continent-ocean crust boundary which were formed at the same time as ocean crust in the main ocean. These zones are often referred to as 'failed rifts', an unfortunate term since it implies that ...
Magnesium isotopic composition of the lower continental crust
... The large isotope fractionation during low-temperature waterrock interactions and limited fractionation during igneous differentiation make Mg isotopes a potentially powerful tracer of the influence of chemical weathering on the continental crust composition. Magnesium isotopic composition of the up ...
... The large isotope fractionation during low-temperature waterrock interactions and limited fractionation during igneous differentiation make Mg isotopes a potentially powerful tracer of the influence of chemical weathering on the continental crust composition. Magnesium isotopic composition of the up ...
One rift, two models
... narrower pressure range and shallower depths. Therefore, lithosphere beneath the Vitim field was thicker in Miocene than in Quaternary time, and the thinning was estimated as ~ 15 km for 13 myr. The boundary between the crystallization depths of garnet and spinel, two indicator ...
... narrower pressure range and shallower depths. Therefore, lithosphere beneath the Vitim field was thicker in Miocene than in Quaternary time, and the thinning was estimated as ~ 15 km for 13 myr. The boundary between the crystallization depths of garnet and spinel, two indicator ...
Laramide crustal thickening event in the Rocky Mountain Foreland
... of transient high temperatures ...
... of transient high temperatures ...
Earth,Tests,Ch13
... 1) The west coast of South America and the east coast of North America have very different continental margins. Answer: TRUE Diff: 1 ...
... 1) The west coast of South America and the east coast of North America have very different continental margins. Answer: TRUE Diff: 1 ...
Morphology and magnetic survey of the Rivera
... the western margin of the North American Plate has been recorded along the continental margin of North America from Alaska to Mexico (e.g. Atwater, 1989). The most recent collision appears off Manzanillo, Mexico (Figure 1), in the area located between the northern end of the PacificCocos segment of ...
... the western margin of the North American Plate has been recorded along the continental margin of North America from Alaska to Mexico (e.g. Atwater, 1989). The most recent collision appears off Manzanillo, Mexico (Figure 1), in the area located between the northern end of the PacificCocos segment of ...
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.