Seismic low-velocity layer at the top of subducting slabs
... shape, a geometry that allows rapid and stable calculation of responses over wide frequency bands. The tests complement 2D finite-difference tests that have been recently conducted for the Andean slab geometry (Martin et al., 2003), which directly explore the effects of slab curvature. First-order e ...
... shape, a geometry that allows rapid and stable calculation of responses over wide frequency bands. The tests complement 2D finite-difference tests that have been recently conducted for the Andean slab geometry (Martin et al., 2003), which directly explore the effects of slab curvature. First-order e ...
Seismic evidence for a chemical heterogeneity in the midmantle: A
... models [van der Hilst et al., 1997; Grand et al., 1997; Fukao et al., 2001] around the mid-lower mantle scatterers. The interpretation of the seismic reflectors/scatterers is therefore still unknown, nor the physical mechanisms capable of producing these seismic structures. [4] A sequence of middle- ...
... models [van der Hilst et al., 1997; Grand et al., 1997; Fukao et al., 2001] around the mid-lower mantle scatterers. The interpretation of the seismic reflectors/scatterers is therefore still unknown, nor the physical mechanisms capable of producing these seismic structures. [4] A sequence of middle- ...
Infrasound/seismic observation of the Hayabusa reentry
... The Hayabusa, the world’s first sample-return (round trip) minor body explorer, returned to the Earth, and reentered the Earth’s atmosphere on June 13, 2010. In order to study bolide phenomena, ground-based observations of the reentry were carried out in WPA, Australia, as an extremely rare artifici ...
... The Hayabusa, the world’s first sample-return (round trip) minor body explorer, returned to the Earth, and reentered the Earth’s atmosphere on June 13, 2010. In order to study bolide phenomena, ground-based observations of the reentry were carried out in WPA, Australia, as an extremely rare artifici ...
A-Type Granites and Related Rocks Through Time
... granites in various tectonic settings through the geologic time. It is clear that no single mechanism can account for the wide range of petrotectonic associations registered by the A-type granites, and one prime aim of the project will be to comprehensively scrutinize petrogenetic scenarios, and whe ...
... granites in various tectonic settings through the geologic time. It is clear that no single mechanism can account for the wide range of petrotectonic associations registered by the A-type granites, and one prime aim of the project will be to comprehensively scrutinize petrogenetic scenarios, and whe ...
Deformation in the asthenospheric mantle beneath the Carpathian
... 80∘ N display a nearly normal distribution around an average value of 120∘ N. The majority of the measurements fall into this distribution, in the range of 85∘ N to 145∘ N, while there are a number of good quality measures showing fast azimuths less than 80∘ N. To represent the individual measuremen ...
... 80∘ N display a nearly normal distribution around an average value of 120∘ N. The majority of the measurements fall into this distribution, in the range of 85∘ N to 145∘ N, while there are a number of good quality measures showing fast azimuths less than 80∘ N. To represent the individual measuremen ...
Mantle hydration and Cl-rich fluids in the subduction forearc
... This ratio is not, therefore, a very good indicator of lithology, and absolute values of velocities are preferable. Notable trends are those of increasing velocities in the oceanic crust accompanying transition from hydrated gabbros to dry eclogites, and a similar trend of decreasing velocities acco ...
... This ratio is not, therefore, a very good indicator of lithology, and absolute values of velocities are preferable. Notable trends are those of increasing velocities in the oceanic crust accompanying transition from hydrated gabbros to dry eclogites, and a similar trend of decreasing velocities acco ...
Atmospheric K-feldspar as a potential climate modulating agent
... falls in flux). Modern landmasses are comparatively widespread across all latitudes. Terrestrial glaciation/deglaciation cycles in the past ~800 k.y. are shown to correlate with global dustiness variance by a factor of 50–100 (Fuhrer et al., 1999; Lambert et al., 2008; Vallelonga and Svensson, 2014) ...
... falls in flux). Modern landmasses are comparatively widespread across all latitudes. Terrestrial glaciation/deglaciation cycles in the past ~800 k.y. are shown to correlate with global dustiness variance by a factor of 50–100 (Fuhrer et al., 1999; Lambert et al., 2008; Vallelonga and Svensson, 2014) ...
Atmospheric K-feldspar as a potential climate modulating
... falls in flux). Modern landmasses are comparatively widespread across all latitudes. Terrestrial glaciation/deglaciation cycles in the past ~800 k.y. are shown to correlate with global dustiness variance by a factor of 50–100 (Fuhrer et al., 1999; Lambert et al., 2008; Vallelonga and Svensson, 2014) ...
... falls in flux). Modern landmasses are comparatively widespread across all latitudes. Terrestrial glaciation/deglaciation cycles in the past ~800 k.y. are shown to correlate with global dustiness variance by a factor of 50–100 (Fuhrer et al., 1999; Lambert et al., 2008; Vallelonga and Svensson, 2014) ...
Distinct crustal isostasy trends east and west of the Rocky Mountain
... crust thickness and elevation, but their crustal roots are disproportionately thick for their low modern elevations suggesting postorogenic increases in density [Fischer, 2002]. The lower crust to upper mantle density increase required for crustal isostasy in these settings is often ~0.1–0.2 g/cm3 [ ...
... crust thickness and elevation, but their crustal roots are disproportionately thick for their low modern elevations suggesting postorogenic increases in density [Fischer, 2002]. The lower crust to upper mantle density increase required for crustal isostasy in these settings is often ~0.1–0.2 g/cm3 [ ...
Quantum Monte Carlo computations of phase of high-pressure silica
... tions with QMC has shown great promise in studies of the electron gas, atoms, molecules, and simple solids (24, 25). Here we address the question of whether QMC is ready for accurate computations of complex minerals by studying silica. In QMC the only essential inputs are the trial wave function (we ...
... tions with QMC has shown great promise in studies of the electron gas, atoms, molecules, and simple solids (24, 25). Here we address the question of whether QMC is ready for accurate computations of complex minerals by studying silica. In QMC the only essential inputs are the trial wave function (we ...
gge_orals_nov8_2006 - Department of Earth and Planetary
... determination of relative travel times was expanded accordingly. Utilizing multiple 3D mantle models as a constraint on resolution of the upper mantle, the minimum distance found for consistent ray parameter measurement was estimated at 15°. The average ray parameter derived from the dataset is foun ...
... determination of relative travel times was expanded accordingly. Utilizing multiple 3D mantle models as a constraint on resolution of the upper mantle, the minimum distance found for consistent ray parameter measurement was estimated at 15°. The average ray parameter derived from the dataset is foun ...
Thermal history of the Earth and its petrological expression
... Precambrian basalts are likely to be similar to those that formed oceanic crust and erupted on continents. It is estimated that ∼ 25–35 km of oceanic crust formed in the ancient Earth by about 30% melting of hot ambient mantle. In contrast, komatiite parental magmas reveal TP that are higher than th ...
... Precambrian basalts are likely to be similar to those that formed oceanic crust and erupted on continents. It is estimated that ∼ 25–35 km of oceanic crust formed in the ancient Earth by about 30% melting of hot ambient mantle. In contrast, komatiite parental magmas reveal TP that are higher than th ...
History of geodesy
Geodesy (/dʒiːˈɒdɨsi/), also named geodetics, is the scientific discipline that deals with the measurement and representation of the Earth. The history of geodesy began in antiquity and blossomed during the Age of Enlightenment.Early ideas about the figure of the Earth held the Earth to be flat (see flat earth), and the heavens a physical dome spanning over it. Two early arguments for a spherical Earth were that lunar eclipses were seen as circular shadows which could only be caused by a spherical Earth, and that Polaris is seen lower in the sky as one travels South.