Redalyc.Foundations of Gulf of Mexico and Caribbean evolution
... that no significant motions occurred along the reconstructed Equatorial Atlantic rifted margins prior to the time represented by our Fig. 2B reconstruction. But how valid is this assumption, and what error limits can be placed on it? Pre-Aptian ages on basalts from the Equatorial Atlantic margins ha ...
... that no significant motions occurred along the reconstructed Equatorial Atlantic rifted margins prior to the time represented by our Fig. 2B reconstruction. But how valid is this assumption, and what error limits can be placed on it? Pre-Aptian ages on basalts from the Equatorial Atlantic margins ha ...
Plate generation and two-phase damage theory in a model of
... Two-phase dynamics has been richly studied in geophysics, with many people considering its application to problems in meltdynamics (McKenzie 1984; Spiegelman 1993a,b; Katz et al. 2006). Two-phase damage theory was developed in order to take a firstprinciples approach to studying the partitioning of ...
... Two-phase dynamics has been richly studied in geophysics, with many people considering its application to problems in meltdynamics (McKenzie 1984; Spiegelman 1993a,b; Katz et al. 2006). Two-phase damage theory was developed in order to take a firstprinciples approach to studying the partitioning of ...
Tectonics of the lower mantle
... melt alignment as a cause of transverse isotropy in D″. Using effective-medium modelling they showed that very small volume fractions of melt, if highly aligned, will not affect the overall velocity of the region, but will generate significant amounts of shear-wave splitting. Infiltration of core ma ...
... melt alignment as a cause of transverse isotropy in D″. Using effective-medium modelling they showed that very small volume fractions of melt, if highly aligned, will not affect the overall velocity of the region, but will generate significant amounts of shear-wave splitting. Infiltration of core ma ...
Continental crust generated in oceanic arcs
... within older continental crust (for example, Andes, Cascades, New Zealand, Indonesia, Japan) to ensure that the locations evaluated in this study are forming from juvenile sources and not inheriting geochemical signatures from pre-existing continental material. Figure 4 shows that average compositio ...
... within older continental crust (for example, Andes, Cascades, New Zealand, Indonesia, Japan) to ensure that the locations evaluated in this study are forming from juvenile sources and not inheriting geochemical signatures from pre-existing continental material. Figure 4 shows that average compositio ...
Sierra Nevada uplift - University of Missouri
... velocity field, the top boundary is defined as the base of the brittle crust, and the flow rate within the brittle crust is set to zero. The left side is a far-distance boundary, the effects of which on the flow field are proven to be negligible. The model assumes local isostasy. The simulations sta ...
... velocity field, the top boundary is defined as the base of the brittle crust, and the flow rate within the brittle crust is set to zero. The left side is a far-distance boundary, the effects of which on the flow field are proven to be negligible. The model assumes local isostasy. The simulations sta ...
the Central Equatorial Pacific West of the East Pacific Rise
... prevents examination of the basement topography by seismic reflection. Where this is the case, it is impossible to determine whether the hole was placed in the right position to sample the oldest sediments in the area. Several configurations where this would not be the case are possible, including d ...
... prevents examination of the basement topography by seismic reflection. Where this is the case, it is impossible to determine whether the hole was placed in the right position to sample the oldest sediments in the area. Several configurations where this would not be the case are possible, including d ...
Document
... continental crust in the IBM upper plate, yet recent seismic studies of this arc reveal a thick middle crust layer with 6.0-6.8 km/s Vp that is hypothesized to be intermediate in composition. The primary goals of sampling the in situ arc crust through drilling are: (1) to identify the structure and ...
... continental crust in the IBM upper plate, yet recent seismic studies of this arc reveal a thick middle crust layer with 6.0-6.8 km/s Vp that is hypothesized to be intermediate in composition. The primary goals of sampling the in situ arc crust through drilling are: (1) to identify the structure and ...
Lecture 19: Mantle Plumes - Earth and Atmospheric Sciences
... lithosphere with a distinctive isotopic signature and geochemists with a means of identifying continental lithosphere. In an earlier section, we discussed the hypothesis of McKenzie and O’Nions t h a t subcontinental lithosphere can delaminate and sink to the bottom of the mantle where it is incorpo ...
... lithosphere with a distinctive isotopic signature and geochemists with a means of identifying continental lithosphere. In an earlier section, we discussed the hypothesis of McKenzie and O’Nions t h a t subcontinental lithosphere can delaminate and sink to the bottom of the mantle where it is incorpo ...
Evolution of the Earth as an andesite planet: water, plate tectonics
... (2008, 2014) and is schematically shown in Fig. 4. The compositions of the inferred crust/mantle components used here are listed in Table 1. A representative IBM basalt (basalt in Table 1), which was the initial material used in Tatsumi and Suzuki (2009), was assumed to form the initial arc crust. A ...
... (2008, 2014) and is schematically shown in Fig. 4. The compositions of the inferred crust/mantle components used here are listed in Table 1. A representative IBM basalt (basalt in Table 1), which was the initial material used in Tatsumi and Suzuki (2009), was assumed to form the initial arc crust. A ...
Science Article PDF - Geological Society of America
... mantle plume rooted in the lower mantle over which North America moves. Yet Yellowstone’s initiation and its association with the “backward” propagating Newberry hotspot across eastern Oregon pose difficult questions to those explaining Yellowstone as a simple consequence of a deep-seated plume. Tel ...
... mantle plume rooted in the lower mantle over which North America moves. Yet Yellowstone’s initiation and its association with the “backward” propagating Newberry hotspot across eastern Oregon pose difficult questions to those explaining Yellowstone as a simple consequence of a deep-seated plume. Tel ...
Plate dynamics, mantle structure and tectonic evolution of the
... Introduction1 1.1 Short overview of the tectonic history of the Caribbean plate The Caribbean plate (Figure 1.1) is an actively deforming region between two major subduction zones: the Lesser Antilles subduction zone in the east and the Central America subduction zone in the west. The northern bound ...
... Introduction1 1.1 Short overview of the tectonic history of the Caribbean plate The Caribbean plate (Figure 1.1) is an actively deforming region between two major subduction zones: the Lesser Antilles subduction zone in the east and the Central America subduction zone in the west. The northern bound ...
The Mantle and its Products
... Because it is impossible to obtain samples of the mantle directly, Earth scientists have to resort to a variety of methods to evaluate both its mineralogy and chemical composition. Using chemical data obtained from meteorites (especially the group of meteorites known as “chondrites”) it is possible ...
... Because it is impossible to obtain samples of the mantle directly, Earth scientists have to resort to a variety of methods to evaluate both its mineralogy and chemical composition. Using chemical data obtained from meteorites (especially the group of meteorites known as “chondrites”) it is possible ...
Subcontinental Lithosphere
... through deep recycling of oceanic crust (Figure 21.1). Partial melting at mid-ocean ridges creates oceanic crust that is less depleted in incompatible elements than the depleted upper mantle. The oceanic crust is apparently inevitably subducted as virtually none is preserved at the surface, so it cl ...
... through deep recycling of oceanic crust (Figure 21.1). Partial melting at mid-ocean ridges creates oceanic crust that is less depleted in incompatible elements than the depleted upper mantle. The oceanic crust is apparently inevitably subducted as virtually none is preserved at the surface, so it cl ...
Evolution of the Earth as an andesite planet: water
... (2008, 2014) and is schematically shown in Fig. 4. The compositions of the inferred crust/mantle components used here are listed in Table 1. A representative IBM basalt (basalt in Table 1), which was the initial material used in Tatsumi and Suzuki (2009), was assumed to form the initial arc crust. A ...
... (2008, 2014) and is schematically shown in Fig. 4. The compositions of the inferred crust/mantle components used here are listed in Table 1. A representative IBM basalt (basalt in Table 1), which was the initial material used in Tatsumi and Suzuki (2009), was assumed to form the initial arc crust. A ...
subduction to strike-slip transitions on plate boundaries
... explain the genesis of the older, north-trending faults observed in the study. During the Neogene the landward margin of the Ecuador trench may have also suffered net tectonic erosion, which is an alternative hypothesis to explain Neogene east-west extension recorded by the first generation of fault ...
... explain the genesis of the older, north-trending faults observed in the study. During the Neogene the landward margin of the Ecuador trench may have also suffered net tectonic erosion, which is an alternative hypothesis to explain Neogene east-west extension recorded by the first generation of fault ...
The Cretaceous and Cenozoic tectonic evolution of
... The 1970s also heralded the first regional plate reconstructions that incorporated the western Pacific plate boundaries (Hilde et al., 1977; Weissel et al., 1978) and the origin and evolution of the para-autochthonous Sula Spur (AudleyCharles et al., 1979; Norvick, 1979) interacting with the allocht ...
... The 1970s also heralded the first regional plate reconstructions that incorporated the western Pacific plate boundaries (Hilde et al., 1977; Weissel et al., 1978) and the origin and evolution of the para-autochthonous Sula Spur (AudleyCharles et al., 1979; Norvick, 1979) interacting with the allocht ...
Coupled evolution of Archean continental crust
... basalts are not necessarily formed in a plume setting are used to challenge the mantle plume model for the formation of the Archean SCLM. Petrological modeling suggests that, instead, the SCLM formed at a hot ocean ridge giving rise to dense, Fe-rich basaltic ocean crust and highly depleted thick oc ...
... basalts are not necessarily formed in a plume setting are used to challenge the mantle plume model for the formation of the Archean SCLM. Petrological modeling suggests that, instead, the SCLM formed at a hot ocean ridge giving rise to dense, Fe-rich basaltic ocean crust and highly depleted thick oc ...
Mid-Ocean Ridges: Mantle Convection and Formation
... circulation. This cooling generates a thermal boundary layer, which is rigid to convection and is the newly created edge of the tectonic plate. As the lithosphere moves away from the ridge, it thickens via additional cooling, becomes denser, and sinks deeper into the underlying ductile asthenosphere ...
... circulation. This cooling generates a thermal boundary layer, which is rigid to convection and is the newly created edge of the tectonic plate. As the lithosphere moves away from the ridge, it thickens via additional cooling, becomes denser, and sinks deeper into the underlying ductile asthenosphere ...
eastern european alpine system and the carpathian
... double looped trend of mountains. Structures within these two belts generally follow the two mountainous belts, and superficially the structures appear more or less continuous, but nothing could be further from the truth. Structures within the two belts have formed diachronously over a period of nea ...
... double looped trend of mountains. Structures within these two belts generally follow the two mountainous belts, and superficially the structures appear more or less continuous, but nothing could be further from the truth. Structures within the two belts have formed diachronously over a period of nea ...
PDF
... (VF) have elevated concentrations of large ion lithophile elements (LILEs), whereas rear‐arc (RA) lavas are rich in light rare earth elements (LREEs) and high field strength elements (HFSEs). VF lavas also have more radiogenic Pb, Nd, Sr, and Hf isotopic compositions. We have used the Arc Basalt Sim ...
... (VF) have elevated concentrations of large ion lithophile elements (LILEs), whereas rear‐arc (RA) lavas are rich in light rare earth elements (LREEs) and high field strength elements (HFSEs). VF lavas also have more radiogenic Pb, Nd, Sr, and Hf isotopic compositions. We have used the Arc Basalt Sim ...
Full Text
... this discrepancy comes from the more storied lifetime of continental lithosphere compared to its oceanic counterpart. Oceanic lithosphere is created at the mid-ocean ridges, from which it ages, cools, and thickens until it meets it demise at subduction zones. Continental lithosphere, on the other ha ...
... this discrepancy comes from the more storied lifetime of continental lithosphere compared to its oceanic counterpart. Oceanic lithosphere is created at the mid-ocean ridges, from which it ages, cools, and thickens until it meets it demise at subduction zones. Continental lithosphere, on the other ha ...
Thermal and petrophysical characterization of the lithospheric
... The geometry of the crust and lithosphere mantle is not so well constrained along the Algerian basin owing to scarcity of geophysical experiments. In the northwest part of the Algerian basin the available seismic refraction profile of Hinz (1972) shows that the crust is partly oceanic with a thicknes ...
... The geometry of the crust and lithosphere mantle is not so well constrained along the Algerian basin owing to scarcity of geophysical experiments. In the northwest part of the Algerian basin the available seismic refraction profile of Hinz (1972) shows that the crust is partly oceanic with a thicknes ...
EPSL94HokeHelium3Alt.. - University of Colorado Boulder
... We report results of a regional survey of helium isotopes measured in water and gas samples in volcanic sulfataras and geothermal springs from the Central Andes of northern Chile and Bolivia between the latitudes 15°S and 23°S. The highest 3 H e / 4 H e ratios (reported as R / R A ratios: R = sample ...
... We report results of a regional survey of helium isotopes measured in water and gas samples in volcanic sulfataras and geothermal springs from the Central Andes of northern Chile and Bolivia between the latitudes 15°S and 23°S. The highest 3 H e / 4 H e ratios (reported as R / R A ratios: R = sample ...
G. Heinson, Electromagnetic studies of the lithosphere and
... depths, the LVZs broaden, and at a depth of 250 km they are quite diffuse. At greater depths, the LVZs can still be identified with the mid-ocean ridges, but hot spots such as Hawaii and Tahiti also show a broad-scale anomaly which is almost circular. Beneath continental shields (for example western ...
... depths, the LVZs broaden, and at a depth of 250 km they are quite diffuse. At greater depths, the LVZs can still be identified with the mid-ocean ridges, but hot spots such as Hawaii and Tahiti also show a broad-scale anomaly which is almost circular. Beneath continental shields (for example western ...
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.