Oceanic lithosphereasthenosphere boundary from surface wave
... the a posteriori covariance matrix, which is computationally too expensive. In this study, we use cluster analysis to match the upper limit of the path number that can be computed by the algorithm. The paths that have quasi similar source and receiver coordinates are gathered to produce a single pat ...
... the a posteriori covariance matrix, which is computationally too expensive. In this study, we use cluster analysis to match the upper limit of the path number that can be computed by the algorithm. The paths that have quasi similar source and receiver coordinates are gathered to produce a single pat ...
Biotic vs. abiotic Earth_ A model for mantle hydration
... and Moore, 1986), or may be stored in hydrous minerals formed during low-temperature metamorphism (e.g. Jarrard, 2003; Stern, 2002). Nevertheless, the permeability of the clay-rich sedimentary layer decreases with increasing lithostatic pressure and compaction. With increasing depth, the sedimentary ...
... and Moore, 1986), or may be stored in hydrous minerals formed during low-temperature metamorphism (e.g. Jarrard, 2003; Stern, 2002). Nevertheless, the permeability of the clay-rich sedimentary layer decreases with increasing lithostatic pressure and compaction. With increasing depth, the sedimentary ...
(2013) Porous fluid flow enables oceanic subduction initiation on
... 200 MPa to 0.60 at higher pressures [Brace and Kohlstedt, 1980; Byerlee, 1978] (Byerlee law). It is notably lower (0.15–0.45) [Escartin et al., 2001; Moore et al., 1996, 1997; Reinen et al., 1994] for serpentinized peridotites present at oceanic transform plate boundaries [Gregg et al., 2007; Planer ...
... 200 MPa to 0.60 at higher pressures [Brace and Kohlstedt, 1980; Byerlee, 1978] (Byerlee law). It is notably lower (0.15–0.45) [Escartin et al., 2001; Moore et al., 1996, 1997; Reinen et al., 1994] for serpentinized peridotites present at oceanic transform plate boundaries [Gregg et al., 2007; Planer ...
The Bouguer gravity map of the Mediterranean Sea
... sub-basins characterized by bathymetric depressions and gravity highs. The eastern part is dominated by an elongated NE-SW trending depression, known as the Herodotus Abyssal Plain, with a Bouguer gravity maximum of approximately 220 mGal. The anomalies shoal to the east, and are separated from the ...
... sub-basins characterized by bathymetric depressions and gravity highs. The eastern part is dominated by an elongated NE-SW trending depression, known as the Herodotus Abyssal Plain, with a Bouguer gravity maximum of approximately 220 mGal. The anomalies shoal to the east, and are separated from the ...
Buoyancy frequency profiles and internal semidiurnal tide turning
... between 1990 and 1998; in addition, data from as early as 1985 have been incorporated into the database. The goal was to obtain a snapshot o f the state o f the ocean within a single decade. In situ measurements included CTD (conductivity, temperature, depth), sea level, and current (determined with ...
... between 1990 and 1998; in addition, data from as early as 1985 have been incorporated into the database. The goal was to obtain a snapshot o f the state o f the ocean within a single decade. In situ measurements included CTD (conductivity, temperature, depth), sea level, and current (determined with ...
From Local Network Data' Evidence for a Seismogenic Lower Crust
... zones. To select well-located shallow events, we applied is greater than its epicentral distance typically has the severalcriteria,describedbelow, producinga subsetof 575 depth determinedas well as an event inside the network. In events. These events were located with two crustal velocity cross sect ...
... zones. To select well-located shallow events, we applied is greater than its epicentral distance typically has the severalcriteria,describedbelow, producinga subsetof 575 depth determinedas well as an event inside the network. In events. These events were located with two crustal velocity cross sect ...
Intermediate-Depth Earthquakes in a Region of Continental
... are usually attributed to cooler-than-average environments in which geotherms are depressed (Chen and Molnar, 1983; Allis and Shi, 1995). The spatial patterns in the South Island, New Zealand, mantle earthquake hypocenters relative to regional tomographic P-wave velocity images (Kohler and Eberhart- ...
... are usually attributed to cooler-than-average environments in which geotherms are depressed (Chen and Molnar, 1983; Allis and Shi, 1995). The spatial patterns in the South Island, New Zealand, mantle earthquake hypocenters relative to regional tomographic P-wave velocity images (Kohler and Eberhart- ...
Chapter 9 Convergent margin tectonics: A marine perspective
... erosional would yield insights greater than those derived from studies of either margin type alone. In contrast to the accretionary Guatemalan margin, the southwestern Mexico margin appeared to have no older accreted mass because Mesozoic rock crops out along the coast as observed along the Chilean ...
... erosional would yield insights greater than those derived from studies of either margin type alone. In contrast to the accretionary Guatemalan margin, the southwestern Mexico margin appeared to have no older accreted mass because Mesozoic rock crops out along the coast as observed along the Chilean ...
Explicitly resolved vs parameterized mesoscale processes
... Labrador Sea and extending in Irminger Sea; south of 55°N the MLD is reduced due to the presence of the 3000m. Purple isoline depicts the sea-ice bound (5%). Red boxes for areas where times series are Northwest corner with warm/salty waters advected by the North Atlantic Current into the subpolar gy ...
... Labrador Sea and extending in Irminger Sea; south of 55°N the MLD is reduced due to the presence of the 3000m. Purple isoline depicts the sea-ice bound (5%). Red boxes for areas where times series are Northwest corner with warm/salty waters advected by the North Atlantic Current into the subpolar gy ...
The Ocean Acidification Initiative Goal: $2.5 million
... for proposals, the Institutes play a critical role in our research community by awarding seed funding to new high-risk, high-reward projects each year; many of those projects go on to leverage that seed-funding into millions of dollars in federal support. ...
... for proposals, the Institutes play a critical role in our research community by awarding seed funding to new high-risk, high-reward projects each year; many of those projects go on to leverage that seed-funding into millions of dollars in federal support. ...
Spreading-rate dependence of melt extraction at mid
... concentrations observed in basalts from very-slow-spreading ridges have been interpreted to indicate deeper melting with nearly complete melt extraction at these ridges3. Numerical models suggest that this REE enrichment might also be expected in a passively driven system where the off-axis portion ...
... concentrations observed in basalts from very-slow-spreading ridges have been interpreted to indicate deeper melting with nearly complete melt extraction at these ridges3. Numerical models suggest that this REE enrichment might also be expected in a passively driven system where the off-axis portion ...
pdf - Wiley Online Library
... (M2) tidal frequency, wM2. Profiles of N2(z) (the quantity in the equations of motion) are computed using conductivity, temperature, and depth data obtained in the World Ocean Circulation Experiment (WOCE). Values for N2(z) computed using Gibbs SeaWater routines in two thermodynamically equivalent e ...
... (M2) tidal frequency, wM2. Profiles of N2(z) (the quantity in the equations of motion) are computed using conductivity, temperature, and depth data obtained in the World Ocean Circulation Experiment (WOCE). Values for N2(z) computed using Gibbs SeaWater routines in two thermodynamically equivalent e ...
Chapter 17 – Plate Tectonics
... 2. How do glacial deposits in Africa, India, Australia, and South America support the idea of continental drift? 3. THINKING CRITICALLY: Why are the magnetic bands in the eastern Pacific Ocean so far apart compared to the magnetic bands along the Mid-Atlantic Ridge? ...
... 2. How do glacial deposits in Africa, India, Australia, and South America support the idea of continental drift? 3. THINKING CRITICALLY: Why are the magnetic bands in the eastern Pacific Ocean so far apart compared to the magnetic bands along the Mid-Atlantic Ridge? ...
Collision of continental corner from 3
... precluded by numerical limitations of the multigrid solver convergence. Indeed, the large viscosity contrast caused by this lowviscosity boundary layer minimizes shear stresses (<105 Pa) at the top of the solid portion of the model (Burg and Gerya, 2005). For simplicity, surface erosion and sediment ...
... precluded by numerical limitations of the multigrid solver convergence. Indeed, the large viscosity contrast caused by this lowviscosity boundary layer minimizes shear stresses (<105 Pa) at the top of the solid portion of the model (Burg and Gerya, 2005). For simplicity, surface erosion and sediment ...
Foraminifera and Nannoplankton in Palaeoceanography
... Sediments of core MD95-2040 were studied in high-resolution to reveal changes in the hydrographic conditions during glacial stage 6. The multi-proxy approach includes various planktonic foraminifera-based proxy records and the distribution of Coccolithus pelagicus. The influence of northern Atlantic ...
... Sediments of core MD95-2040 were studied in high-resolution to reveal changes in the hydrographic conditions during glacial stage 6. The multi-proxy approach includes various planktonic foraminifera-based proxy records and the distribution of Coccolithus pelagicus. The influence of northern Atlantic ...
the long-term strength of continental lithosphere
... In oceanic regions, forward and inverse models do yield similar Te values. This is exemplified along the Hawaiian-Emperor seamount chain in the Pacific Ocean. Forward modeling reveals a mean Te of 25 ± 9 km, while inverse (spectral) modeling using a free-air admittance method obtains 20–30 km (Watts ...
... In oceanic regions, forward and inverse models do yield similar Te values. This is exemplified along the Hawaiian-Emperor seamount chain in the Pacific Ocean. Forward modeling reveals a mean Te of 25 ± 9 km, while inverse (spectral) modeling using a free-air admittance method obtains 20–30 km (Watts ...
Evolution of young oceanic lithosphere and the meaning of seafloor
... are not negatively buoyant [e.g., Hynes, 2005; Valencia and O’Connell, 2009], and because plate tectonics is nonetheless happening, the initiation of subduction may be controlled by other factors such as external compression [e.g., Gurnis et al., 2004]. Such external forcing depends on the evolving ...
... are not negatively buoyant [e.g., Hynes, 2005; Valencia and O’Connell, 2009], and because plate tectonics is nonetheless happening, the initiation of subduction may be controlled by other factors such as external compression [e.g., Gurnis et al., 2004]. Such external forcing depends on the evolving ...
Oceanography and Atmospheric Sciences: 1959–2009
... Early studies focus on Oregon’s coastal morphology, beach sand composition and littoral transport, and distribution of estuarine deposits related to hydrography. ...
... Early studies focus on Oregon’s coastal morphology, beach sand composition and littoral transport, and distribution of estuarine deposits related to hydrography. ...
An Overview of the Bathymetry and Geomorphology of the Tanzania
... EEZ using data extracted from the GDA. The Tanzania EEZ appears to be gently inclined northeastward. The Tanzania EEZ seafloor can be divided into three bathymetrical zones: (i) steep seafloor with depths between 0 and 500 m, (ii) moderately steep seafloor with depths between 500 and 3500 m, and (ii ...
... EEZ using data extracted from the GDA. The Tanzania EEZ appears to be gently inclined northeastward. The Tanzania EEZ seafloor can be divided into three bathymetrical zones: (i) steep seafloor with depths between 0 and 500 m, (ii) moderately steep seafloor with depths between 500 and 3500 m, and (ii ...
Oceanic lithosphere-asthenosphere boundary from - HAL
... the a posteriori covariance matrix, which is computationally too expensive. In this study, we use cluster analysis to match the upper limit of the path number that can be computed by the algorithm. The paths that have quasi similar source and receiver coordinates are gathered to produce a single pat ...
... the a posteriori covariance matrix, which is computationally too expensive. In this study, we use cluster analysis to match the upper limit of the path number that can be computed by the algorithm. The paths that have quasi similar source and receiver coordinates are gathered to produce a single pat ...
Towards absolute plate motions constrained by lower
... convergence zones, often comprising the remnants of a volcanic arc. Studies comparing the amount of Tethyan subducted material predicted by geological reconstructions with volumes of subducted lithosphere imaged in the mantle by seismic tomography11,12 suggest a first-order correlation between the o ...
... convergence zones, often comprising the remnants of a volcanic arc. Studies comparing the amount of Tethyan subducted material predicted by geological reconstructions with volumes of subducted lithosphere imaged in the mantle by seismic tomography11,12 suggest a first-order correlation between the o ...
The long-term strength of continental lithosphere: “jelly sandwich” or
... In oceanic regions, forward and inverse models do yield similar Te values. This is exemplified along the Hawaiian-Emperor seamount chain in the Pacific Ocean. Forward modeling reveals a mean Te of 25 ± 9 km, while inverse (spectral) modeling using a free-air admittance method obtains 20–30 km (Watts ...
... In oceanic regions, forward and inverse models do yield similar Te values. This is exemplified along the Hawaiian-Emperor seamount chain in the Pacific Ocean. Forward modeling reveals a mean Te of 25 ± 9 km, while inverse (spectral) modeling using a free-air admittance method obtains 20–30 km (Watts ...
Beyond Plate Tectonics: “Plate” Dynamics
... Eighty years ago, we learned about the existence of the MidAtlantic Ridge from the Meteor expedition.1 Then it became possible to determine that in the center of the Atlantic Ocean there was an elevated mountain belt with fresh basalts exposed at the surface. Mountains sloped downhill towards the co ...
... Eighty years ago, we learned about the existence of the MidAtlantic Ridge from the Meteor expedition.1 Then it became possible to determine that in the center of the Atlantic Ocean there was an elevated mountain belt with fresh basalts exposed at the surface. Mountains sloped downhill towards the co ...
2.isca-irjes-2014-01.. - International Science Congress Association
... development during continental collision has been studied in both numerical and physical modelling studies10,11,27,28. In most models the plate contact was represented by a predefined weak zone dipping 45° with respect to direction of shortening10,12,2932 .The implementation of a weak interface sepa ...
... development during continental collision has been studied in both numerical and physical modelling studies10,11,27,28. In most models the plate contact was represented by a predefined weak zone dipping 45° with respect to direction of shortening10,12,2932 .The implementation of a weak interface sepa ...
Plate Tectonics
... deformation, most of these are associated with (adjacent to ) plate boundaries and are areas of high earthquake ...
... deformation, most of these are associated with (adjacent to ) plate boundaries and are areas of high earthquake ...
Abyssal plain
An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 m. Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth’s surface. They are among the flattest, smoothest and least explored regions on Earth. Abyssal plains are key geologic elements of oceanic basins (the other elements being an elevated mid-ocean ridge and flanking abyssal hills). In addition to these elements, active oceanic basins (those that are associated with a moving plate tectonic boundary) also typically include an oceanic trench and a subduction zone.Abyssal plains were not recognized as distinct physiographic features of the sea floor until the late 1940s and, until very recently, none had been studied on a systematic basis. They are poorly preserved in the sedimentary record, because they tend to be consumed by the subduction process. The creation of the abyssal plain is the end result of spreading of the seafloor (plate tectonics) and melting of the lower oceanic crust. Magma rises from above the asthenosphere (a layer of the upper mantle) and as this basaltic material reaches the surface at mid-ocean ridges it forms new oceanic crust. This is constantly pulled sideways by spreading of the seafloor. Abyssal plains result from the blanketing of an originally uneven surface of oceanic crust by fine-grained sediments, mainly clay and silt. Much of this sediment is deposited by turbidity currents that have been channelled from the continental margins along submarine canyons down into deeper water. The remainder of the sediment is composed chiefly of pelagic sediments. Metallic nodules are common in some areas of the plains, with varying concentrations of metals, including manganese, iron, nickel, cobalt, and copper. These nodules may provide a significant resource for future mining ventures.Owing in part to their vast size, abyssal plains are currently believed to be a major reservoir of biodiversity. The abyss also exerts significant influence upon ocean carbon cycling, dissolution of calcium carbonate, and atmospheric CO2 concentrations over timescales of 100–1000 years. The structure and function of abyssal ecosystems are strongly influenced by the rate of flux of food to the seafloor and the composition of the material that settles. Factors such as climate change, fishing practices, and ocean fertilization are expected to have a substantial effect on patterns of primary production in the euphotic zone. This will undoubtedly impact the flux of organic material to the abyss in a similar manner and thus have a profound effect on the structure, function and diversity of abyssal ecosystems.