Geology - Geostud
... adjusted from the velocity model used for the ray tracing; the eastward-dipping high-velocity slab, rooted under a zone with a Vp of 7.4 km/s, is added. The RF data require lower velocities in the uppermost crust as well as some local adjustments of Moho depths. A section through 73°N is shown in Fi ...
... adjusted from the velocity model used for the ray tracing; the eastward-dipping high-velocity slab, rooted under a zone with a Vp of 7.4 km/s, is added. The RF data require lower velocities in the uppermost crust as well as some local adjustments of Moho depths. A section through 73°N is shown in Fi ...
Buckling an orogen: The Cantabrian Orocline
... models were imaged using 3-D computer tomography (CT). Details of the experiments can be found in Pastor-Galán et al. (2012). The experimental set-up consisted of a 30 × 12 × 8 cm elongate model plate (crust and lithospheric mantle and its underlying asthenospheric mantle), which was shortened into ...
... models were imaged using 3-D computer tomography (CT). Details of the experiments can be found in Pastor-Galán et al. (2012). The experimental set-up consisted of a 30 × 12 × 8 cm elongate model plate (crust and lithospheric mantle and its underlying asthenospheric mantle), which was shortened into ...
Balancing the force budget of plate tectonics along the Nazca/South
... Buoyancy forces associated with subduction of cool, dense lithosphere at zones of plate convergence are thought to provide significant driving force, but the relative magnitudes of other driving and resisting forces are less clear, as are the main factors controlling long-term changes in plate motio ...
... Buoyancy forces associated with subduction of cool, dense lithosphere at zones of plate convergence are thought to provide significant driving force, but the relative magnitudes of other driving and resisting forces are less clear, as are the main factors controlling long-term changes in plate motio ...
+ t 1/2
... The lavas within many OIB suites define approximately linear arrays between two chemical and isotopic components, one relatively depleted and the other relatively enriched. Originally these were thought to correlate with the MORB source and primitive mantle respectively. However, it rapidly bec ...
... The lavas within many OIB suites define approximately linear arrays between two chemical and isotopic components, one relatively depleted and the other relatively enriched. Originally these were thought to correlate with the MORB source and primitive mantle respectively. However, it rapidly bec ...
Regional anomalies of sediment thickness, basement depth and
... in this study, but we also find evidence for three more localized and shorter-lived pulses of volcanism. These pulses formed conjugate structures comprising the Milne Seamounts and Azores-Biscay Rise (at f 75– 40 Ma), the Southeast Newfoundland Ridge and Madeira-Tore Rise ( f 130 – 110 Ma), and the ...
... in this study, but we also find evidence for three more localized and shorter-lived pulses of volcanism. These pulses formed conjugate structures comprising the Milne Seamounts and Azores-Biscay Rise (at f 75– 40 Ma), the Southeast Newfoundland Ridge and Madeira-Tore Rise ( f 130 – 110 Ma), and the ...
Plate Tectonics Guide - Visual Learning Systems
... business specializing in the production of quality educational science videos and materials. We have a long family tradition of education. Our grandmothers graduated from normal school in the 1920’s to become teachers. Brian’s mother was an elementary teacher and guidance counselor, and his father w ...
... business specializing in the production of quality educational science videos and materials. We have a long family tradition of education. Our grandmothers graduated from normal school in the 1920’s to become teachers. Brian’s mother was an elementary teacher and guidance counselor, and his father w ...
Plate Tectonics Guide
... business specializing in the production of quality educational science videos and materials. We have a long family tradition of education. Our grandmothers graduated from normal school in the 1920’s to become teachers. Brian’s mother was an elementary teacher and guidance counselor, and his father w ...
... business specializing in the production of quality educational science videos and materials. We have a long family tradition of education. Our grandmothers graduated from normal school in the 1920’s to become teachers. Brian’s mother was an elementary teacher and guidance counselor, and his father w ...
Physically Based Terrain Generation
... still continues to be, formed, deformed and destroyed around the planet. Factors under, inside and above the outermost shell have an effect on the resulting topography but of all these forces those that lie under the surface are the most meaningful. Thus in order to model plate tectonics at any dece ...
... still continues to be, formed, deformed and destroyed around the planet. Factors under, inside and above the outermost shell have an effect on the resulting topography but of all these forces those that lie under the surface are the most meaningful. Thus in order to model plate tectonics at any dece ...
Earth Sci Ch 14 ppt
... leads to the deep-ocean floor and marks the seaward edge of the continental shelf. • A submarine canyon is the seaward extension of a valley that was cut on the continental shelf during a time when sea level was lower—a canyon carved into the outer continental shelf, slope, and rise by turbidity cur ...
... leads to the deep-ocean floor and marks the seaward edge of the continental shelf. • A submarine canyon is the seaward extension of a valley that was cut on the continental shelf during a time when sea level was lower—a canyon carved into the outer continental shelf, slope, and rise by turbidity cur ...
Volcanoes and Igneous Activity Earth
... leads to the deep-ocean floor and marks the seaward edge of the continental shelf. • A submarine canyon is the seaward extension of a valley that was cut on the continental shelf during a time when sea level was lower—a canyon carved into the outer continental shelf, slope, and rise by turbidity cur ...
... leads to the deep-ocean floor and marks the seaward edge of the continental shelf. • A submarine canyon is the seaward extension of a valley that was cut on the continental shelf during a time when sea level was lower—a canyon carved into the outer continental shelf, slope, and rise by turbidity cur ...
Continental Margins 12.2 Ocean Floor Features
... leads to the deep-ocean floor and marks the seaward edge of the continental shelf. • A submarine canyon is the seaward extension of a valley that was cut on the continental shelf during a time when sea level was lower—a canyon carved into the outer continental shelf, slope, and rise by turbidity cur ...
... leads to the deep-ocean floor and marks the seaward edge of the continental shelf. • A submarine canyon is the seaward extension of a valley that was cut on the continental shelf during a time when sea level was lower—a canyon carved into the outer continental shelf, slope, and rise by turbidity cur ...
How does Earth`s continental crust form? Scientists have
... geochemical composition of the rock changed with abundant in lower continental crust. To determine the potential for relamination to produce lower increasing depth in the crust. They were able to continental crust, the scientists calculated the extract minerals that had recorded the pressure density ...
... geochemical composition of the rock changed with abundant in lower continental crust. To determine the potential for relamination to produce lower increasing depth in the crust. They were able to continental crust, the scientists calculated the extract minerals that had recorded the pressure density ...
Lecture 6 - Mantle and Basalts
... E-MORB’s are represented by plumes centered on mid-ocean ridges. Examples include Iceland and the Azores. They are thought to be derived from plumes generated near the 650 km discontinuity, from either a) a distinct lower mantle source, or b) boundary source enriched by subducted ocean crust trapp ...
... E-MORB’s are represented by plumes centered on mid-ocean ridges. Examples include Iceland and the Azores. They are thought to be derived from plumes generated near the 650 km discontinuity, from either a) a distinct lower mantle source, or b) boundary source enriched by subducted ocean crust trapp ...
Spherical shell models of mantle convection
... pattern emerges only with a non-Newtonian rheology. However, using the expected parameters for mantle rocks creep fails to yield signi¢cant toroidal kinetic energy. A most successful platelike behavior is obtained with an ad hoc `self-lubricating' rheology, especially in the description of strike^sl ...
... pattern emerges only with a non-Newtonian rheology. However, using the expected parameters for mantle rocks creep fails to yield signi¢cant toroidal kinetic energy. A most successful platelike behavior is obtained with an ad hoc `self-lubricating' rheology, especially in the description of strike^sl ...
A global-scale plate reorganization event at 105−100Ma
... A major plate reorganization is postulated to have occurred at approximately 100 Ma. However, this reorganization has received limited attention, despite being associated with the most prominent suite of fracture zone bends on the planet and many other geological events. We investigate tectonic even ...
... A major plate reorganization is postulated to have occurred at approximately 100 Ma. However, this reorganization has received limited attention, despite being associated with the most prominent suite of fracture zone bends on the planet and many other geological events. We investigate tectonic even ...
Ducea, M. N., Kidder, S. B., Chesley, J. T., and
... Downloaded By: [California Institute of Technology] At: 01:13 6 May 2009 ...
... Downloaded By: [California Institute of Technology] At: 01:13 6 May 2009 ...
Geological features and geophysical signatures of continental
... indispensable in earth sciences to explain the formation of rifted margins during continental breakup and subsequent formation of oceanic basins. The theory of plate tectonics states that the outer rigid layer (about 70-100 km thick) of the earth called lithosphere, is divided into number of segmen ...
... indispensable in earth sciences to explain the formation of rifted margins during continental breakup and subsequent formation of oceanic basins. The theory of plate tectonics states that the outer rigid layer (about 70-100 km thick) of the earth called lithosphere, is divided into number of segmen ...
Paper
... determine the BMC (Lonardi and Ewing, 1971, Piola and Rivas, 1997), which is a distinct characteristic of the Argentina Basin. Oceanographic configurations are clearly different North and South of the confluence. South of the BMC (see Figure 3, section B), where the CDS is located, the intermediate ...
... determine the BMC (Lonardi and Ewing, 1971, Piola and Rivas, 1997), which is a distinct characteristic of the Argentina Basin. Oceanographic configurations are clearly different North and South of the confluence. South of the BMC (see Figure 3, section B), where the CDS is located, the intermediate ...
The Lithosphere – Asthenosphere System: Nature of the Tectonic
... velocity variation at depth, the top of the radial anisotropy positive anomaly and from the changes in orientation of the fast axis of azimuthal anisotropy. The LAB depth determinations of the different proxies are basically consistent for each oceanic region. The estimates of the LAB depth based on ...
... velocity variation at depth, the top of the radial anisotropy positive anomaly and from the changes in orientation of the fast axis of azimuthal anisotropy. The LAB depth determinations of the different proxies are basically consistent for each oceanic region. The estimates of the LAB depth based on ...
Are lithospheres forever?
... terranes of both Archaean and Proterozoic age. Mapping based on garnet and chromite concentrates from >50 kimberlites along this trend shows that within-craton domains with distinctive mantle stratigraphy coincide with crustal terranes mapped at the surface (Griffin et al., 1998a), implying that ind ...
... terranes of both Archaean and Proterozoic age. Mapping based on garnet and chromite concentrates from >50 kimberlites along this trend shows that within-craton domains with distinctive mantle stratigraphy coincide with crustal terranes mapped at the surface (Griffin et al., 1998a), implying that ind ...
continental margin
... leads to the deep-ocean floor and marks the seaward edge of the continental shelf. • A submarine canyon is the seaward extension of a valley that was cut on the continental shelf during a time when sea level was lower—a canyon carved into the outer continental shelf, slope, and rise by turbidity cur ...
... leads to the deep-ocean floor and marks the seaward edge of the continental shelf. • A submarine canyon is the seaward extension of a valley that was cut on the continental shelf during a time when sea level was lower—a canyon carved into the outer continental shelf, slope, and rise by turbidity cur ...
- ResearchOnline@JCU
... seafloor-altered basalt and Fe – Ti basalt. All of the samples studied represent a single slice of oceanic crust interpreted to have formed in a back-arc or marginal basin setting. Examination of modern oceanic crust suggests that most subducting crust also contains a diverse range of mafic rock-typ ...
... seafloor-altered basalt and Fe – Ti basalt. All of the samples studied represent a single slice of oceanic crust interpreted to have formed in a back-arc or marginal basin setting. Examination of modern oceanic crust suggests that most subducting crust also contains a diverse range of mafic rock-typ ...
Plate Tectonics: This works as a result of hot mantle asthenosphere
... abundant lamellae above the Moho as in BIRPS SWAT 4, (b) bands of reflectors as in BIRPS WINCH 3, (c) hyperbola-like diffractions as in BIRPS SWAT 6-9, (d) "crocodile" diverging reflectors observed in old collision zones, but not so far in the UK, (e) "ramp and flat" stuctures as in BIRPS SWAT 4 2/3 ...
... abundant lamellae above the Moho as in BIRPS SWAT 4, (b) bands of reflectors as in BIRPS WINCH 3, (c) hyperbola-like diffractions as in BIRPS SWAT 6-9, (d) "crocodile" diverging reflectors observed in old collision zones, but not so far in the UK, (e) "ramp and flat" stuctures as in BIRPS SWAT 4 2/3 ...
Mechanism and timing of Pb transport from subducted oceanic crust
... upper mantle. High 207Pb/204Pb ratios in many arc lavas relative to midocean ridge basalts are generally thought to result from addition of subducted sediment (e.g. Woodhead, 1989; Elliott et al., 1997; Ewart et al., 1998). Unfortunately, it is much more difficult to estimate the relative contributio ...
... upper mantle. High 207Pb/204Pb ratios in many arc lavas relative to midocean ridge basalts are generally thought to result from addition of subducted sediment (e.g. Woodhead, 1989; Elliott et al., 1997; Ewart et al., 1998). Unfortunately, it is much more difficult to estimate the relative contributio ...
Unit 2 Exploring Plate Tectonics
... Pacific plate was moving in a north-northwest direction, then abruptly (in geologic time, anyway) changed to a more west-northwest direction. Other seamount chains in the Pacific show a similar pattern. Sudden changes in plate motion occur when two or more continents collide. Continental plates are ...
... Pacific plate was moving in a north-northwest direction, then abruptly (in geologic time, anyway) changed to a more west-northwest direction. Other seamount chains in the Pacific show a similar pattern. Sudden changes in plate motion occur when two or more continents collide. Continental plates are ...
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.