The Model of Oceanic Crust Expansion
... In the formula, V refers to the incremental quantity of the volume of the earth’s mantle in the phase of expansion; Tv refers to the state variant of the solid matters within the earth in the phase of expansion; 0.097 refers to the comprehensive volume changing coefficient of the earth’s matters (15 ...
... In the formula, V refers to the incremental quantity of the volume of the earth’s mantle in the phase of expansion; Tv refers to the state variant of the solid matters within the earth in the phase of expansion; 0.097 refers to the comprehensive volume changing coefficient of the earth’s matters (15 ...
evidence from Th, Sr and Pb isotope data for Tonga
... are produced when these fluids reach mantle that is hot enough to melt. However, the rate at which these processes occur are not well understood. Recent ...
... are produced when these fluids reach mantle that is hot enough to melt. However, the rate at which these processes occur are not well understood. Recent ...
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 ...
The anatomy and ontogeny of modern intra
... 20–35 km thick; a more useful definition is that IOASs occur as chains of small islands, generally just the tops of the largest volcanoes. A very small fraction of IOASs lie above sea level, but advancing marine technologies allow their most important features to be defined. Modern IOASs subduct old ...
... 20–35 km thick; a more useful definition is that IOASs occur as chains of small islands, generally just the tops of the largest volcanoes. A very small fraction of IOASs lie above sea level, but advancing marine technologies allow their most important features to be defined. Modern IOASs subduct old ...
Plate Tectonics - The Open University
... supercontinent that he named Pangaea, meaning 'all Earth'. He drew maps showing how the continents have since moved to today's positions. He proposed that Pangaea began to break apart just after the beginning of the Mesozoic Era, about 200 Ma ago, and that the continents then slowly drifted into the ...
... supercontinent that he named Pangaea, meaning 'all Earth'. He drew maps showing how the continents have since moved to today's positions. He proposed that Pangaea began to break apart just after the beginning of the Mesozoic Era, about 200 Ma ago, and that the continents then slowly drifted into the ...
The three-dimensional thermo-mechanical signature of
... transpressive deformation with a different sense of shear as the other side of the slab window. Immediately above the slab window, the velocity vectors should be divergent, and may lead to the development of extensional structures. However, if both plates are transpressive in the same direction, but ...
... transpressive deformation with a different sense of shear as the other side of the slab window. Immediately above the slab window, the velocity vectors should be divergent, and may lead to the development of extensional structures. However, if both plates are transpressive in the same direction, but ...
Generation of new continental crust by sublithospheric silicic
... has been questioned. This was one of the most important handicaps to accept the andesite model in the past. This point is analyzed below. The andesite model was a paradigm and inspired experimental studies aimed to produce andesite primary magmas in relation to subduction (Green and Ringwood, 1966, ...
... has been questioned. This was one of the most important handicaps to accept the andesite model in the past. This point is analyzed below. The andesite model was a paradigm and inspired experimental studies aimed to produce andesite primary magmas in relation to subduction (Green and Ringwood, 1966, ...
Bulletin of the Geological Society of Denmark, Vol. 29/1-2, pp. 77-101
... molasse sedimentation and Mesozoic rifting, and a southern area which apparently formed a cratonic block from the Early Proterozoic to the Middle Cretaceous. The whole margin was finally separated from the NW Eiu'opean margin by sea floor spreading in the latest Paleocene to earliest Eocene and now ...
... molasse sedimentation and Mesozoic rifting, and a southern area which apparently formed a cratonic block from the Early Proterozoic to the Middle Cretaceous. The whole margin was finally separated from the NW Eiu'opean margin by sea floor spreading in the latest Paleocene to earliest Eocene and now ...
Melting of the Uppermost Metasomatized Asthenosphere Triggered
... mantle upwelling, to constrain the melting processes in the mantle. However, the relatively differentiated compositions of the Changbaishan volcanic rocks prevented Kuritani et al. from discussing the melting process in detail. The Quaternary Chugaryeong volcano, located in the centre of the Korean ...
... mantle upwelling, to constrain the melting processes in the mantle. However, the relatively differentiated compositions of the Changbaishan volcanic rocks prevented Kuritani et al. from discussing the melting process in detail. The Quaternary Chugaryeong volcano, located in the centre of the Korean ...
On subducting slab entrainment of buoyant asthenosphere
... the Basin and Range (Goes and van der Lee, 2002) in the western U.S. However, beneath stable continental regions such as the Archaean shields in W. Australia (Gaherty et al., 1999) and N. America (Goes and van der Lee, 2002) seismic wavespeeds are significantly faster, implying the presence of much s ...
... the Basin and Range (Goes and van der Lee, 2002) in the western U.S. However, beneath stable continental regions such as the Archaean shields in W. Australia (Gaherty et al., 1999) and N. America (Goes and van der Lee, 2002) seismic wavespeeds are significantly faster, implying the presence of much s ...
Doglioni et al Mantle wedge asymmetries and geochemical
... flow anomalies, seismicity and slab dip. Therefore, there is a long list of parameters, which are relevant to the geometry and evolution of each particular subduction zone. However, since the lithosphere has a netrotation relative to the mantle (the so-called “westward” drift, e.g., Le Pichon, 1968; ...
... flow anomalies, seismicity and slab dip. Therefore, there is a long list of parameters, which are relevant to the geometry and evolution of each particular subduction zone. However, since the lithosphere has a netrotation relative to the mantle (the so-called “westward” drift, e.g., Le Pichon, 1968; ...
Formation and Exhumation of Ultrahigh
... detached from the subducting lithosphere at a depth of ~100 km and is rapidly exhumed up the subduction zone during continued convergence (FIG. 1). The requirement to have continental rocks reach mantle depths has led to the assumption that most UHP terranes formed where continental margins were sub ...
... detached from the subducting lithosphere at a depth of ~100 km and is rapidly exhumed up the subduction zone during continued convergence (FIG. 1). The requirement to have continental rocks reach mantle depths has led to the assumption that most UHP terranes formed where continental margins were sub ...
The lithosphere and asthenosphere of the
... horizontally (SH) from dispersed Rayleigh and Love surface waves. These had been recorded in Iceland by the ICEMELT broad-band seismic network, with about half of the waves coming from near-distance earthquakes (≤1000 km). The analysis included unusually short periods, as brief as 5.0 s, and periods ...
... horizontally (SH) from dispersed Rayleigh and Love surface waves. These had been recorded in Iceland by the ICEMELT broad-band seismic network, with about half of the waves coming from near-distance earthquakes (≤1000 km). The analysis included unusually short periods, as brief as 5.0 s, and periods ...
The lithosphere and asthenosphere of the Iceland hotspot from
... horizontally (SH) from dispersed Rayleigh and Love surface waves. These had been recorded in Iceland by the ICEMELT broad-band seismic network, with about half of the waves coming from near-distance earthquakes (≤1000 km). The analysis included unusually short periods, as brief as 5.0 s, and periods ...
... horizontally (SH) from dispersed Rayleigh and Love surface waves. These had been recorded in Iceland by the ICEMELT broad-band seismic network, with about half of the waves coming from near-distance earthquakes (≤1000 km). The analysis included unusually short periods, as brief as 5.0 s, and periods ...
Geodynamics of the Yellowstone hotspot and mantle plume: Seismic
... or other direct methods. Practical limitations have been related to the lateral extent and density of seismic stations and the frequency content of seismic data required for tomographic inversion, which have prevented the resolution required to resolve anomalous low-wavevelocity bodies deeper than ~ ...
... or other direct methods. Practical limitations have been related to the lateral extent and density of seismic stations and the frequency content of seismic data required for tomographic inversion, which have prevented the resolution required to resolve anomalous low-wavevelocity bodies deeper than ~ ...
Layered Mantle Lithosphere in the Lac de Gras
... spectra. Quantitative concentration data are extracted from these spectra as described by Ryan et al. (1990b). Normalization to EMP values for Fe is used to correct for differences in sample conductivity; otherwise the method is independent of standards. Typical analytical precision and accuracy are ...
... spectra. Quantitative concentration data are extracted from these spectra as described by Ryan et al. (1990b). Normalization to EMP values for Fe is used to correct for differences in sample conductivity; otherwise the method is independent of standards. Typical analytical precision and accuracy are ...
Geology - Archean Environment: The habitat of early life.
... data are abundant, and between the preNeoproterozoic, where UHP metamorphism does not occur, and Neoproterozoic and younger belts, where UHP metamorphism is common. These observations are inconsistent with a progressively degraded record with increasing age. However, it is likely that some Phanerozo ...
... data are abundant, and between the preNeoproterozoic, where UHP metamorphism does not occur, and Neoproterozoic and younger belts, where UHP metamorphism is common. These observations are inconsistent with a progressively degraded record with increasing age. However, it is likely that some Phanerozo ...
guide to the geology trail - The Sleeping Giant Park Association
... sediments into the basin from the highlands on either side. As layer upon layer of sediment accumulated, natural processes gradually cemented them together to form the red, tan, and gray sandstone and conglomerate that can be found across central Connecticut. Eventually, the mountainous highlands we ...
... sediments into the basin from the highlands on either side. As layer upon layer of sediment accumulated, natural processes gradually cemented them together to form the red, tan, and gray sandstone and conglomerate that can be found across central Connecticut. Eventually, the mountainous highlands we ...
MANTLE GEOPHYSICAL OBSERVATIONS AND MANTLE DYNAMICS and the
... During the time that seafloor spreading was being recognized as the surface expression of a convecting Earth, hotspots were also being attributed to mantle processes, separate from, but consistent with, the plate tectonic paradigm. Wilson [1963] introduced the concept that the age progression along ...
... During the time that seafloor spreading was being recognized as the surface expression of a convecting Earth, hotspots were also being attributed to mantle processes, separate from, but consistent with, the plate tectonic paradigm. Wilson [1963] introduced the concept that the age progression along ...
Origin of the Bermuda volcanoes and Bermuda
... negligible, averaging only about .004 mm/a. At least under parts of Bermuda, the sequence of limestones and interglacial soils is underlain by a lateritic clay horizon (“Primary Red Clay”) derived from subaerial weathering of the volcanic basement in a humid tropical or semi-tropical environment (Mo ...
... negligible, averaging only about .004 mm/a. At least under parts of Bermuda, the sequence of limestones and interglacial soils is underlain by a lateritic clay horizon (“Primary Red Clay”) derived from subaerial weathering of the volcanic basement in a humid tropical or semi-tropical environment (Mo ...
Crustal structure of the Hatton and the conjugate east Greenland
... margins is unhelpful because there is some igneous activity on all rifted margins; indeed, by the time that seafloor spreading has started, the crust adjacent to all rifted margins is 100% igneous, as it generates oceanic crust. But the volcanic versus nonvolcanic distinction remains useful in place ...
... margins is unhelpful because there is some igneous activity on all rifted margins; indeed, by the time that seafloor spreading has started, the crust adjacent to all rifted margins is 100% igneous, as it generates oceanic crust. But the volcanic versus nonvolcanic distinction remains useful in place ...
Wilson cycle
... Oceanic basin is created by 2 boundaries, the other fails. Many examples in the Atlantic margins, and also in the continental interior, from the Precambrian to present day. ...
... Oceanic basin is created by 2 boundaries, the other fails. Many examples in the Atlantic margins, and also in the continental interior, from the Precambrian to present day. ...
Journal of Volcanology and Geothermal Research
... or other direct methods. Practical limitations have been related to the lateral extent and density of seismic stations and the frequency content of seismic data required for tomographic inversion, which have prevented the resolution required to resolve anomalous low-wavevelocity bodies deeper than ~ ...
... or other direct methods. Practical limitations have been related to the lateral extent and density of seismic stations and the frequency content of seismic data required for tomographic inversion, which have prevented the resolution required to resolve anomalous low-wavevelocity bodies deeper than ~ ...
Magmatic processes at slow spreading ridges
... spreading centres themselves; for example, whether the axes are marked by topographic highs or by median valleys. Early explanations (e.g. Cann 1974) for the composition and layering of oceanic crust drew heavily on observations of ophiolites, and postulated the existence of large crustal magma cham ...
... spreading centres themselves; for example, whether the axes are marked by topographic highs or by median valleys. Early explanations (e.g. Cann 1974) for the composition and layering of oceanic crust drew heavily on observations of ophiolites, and postulated the existence of large crustal magma cham ...
Cenozoic geological and plate tectonic evolution of SE Asia and the
... episodes of extension, forming ocean basins and causing subsidence within continental regions, probably driven by subduction. Within eastern Indonesia, New Guinea and the Melanesian arcs, there are multiple Cenozoic sutures, with very short histories compared to most well-known older orogenic belts. ...
... episodes of extension, forming ocean basins and causing subsidence within continental regions, probably driven by subduction. Within eastern Indonesia, New Guinea and the Melanesian arcs, there are multiple Cenozoic sutures, with very short histories compared to most well-known older orogenic belts. ...
Post-glacial rebound
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Post-glacial rebound (sometimes called continental rebound) is the rise of land masses that were depressed by the huge weight of ice sheets during the last glacial period, through a process known as isostatic depression. Post-glacial rebound and isostatic depression are different parts of a process known as either glacial isostasy, glacial isostatic adjustment, or glacioisostasy. Glacioisostasy is the solid Earth deformation associated with changes in ice mass distribution. The most obvious and direct affects of post-glacial rebound are readily apparent in northern Europe (especially Scotland, Estonia, Latvia, Fennoscandia, and northern Denmark), Siberia, Canada, the Great Lakes of Canada and the United States, the coastal region of the US state of Maine, parts of Patagonia, and Antarctica. However, through processes known as ocean siphoning and continental levering, the effects of post-glacial rebound on sea-level are felt globally far from the locations of current and former ice sheets.