Mantle Mixing - Earth and Environmental Sciences
... A separate requirement for some form of compositional stratification in the mantle comes from consideration of Earth’s heat loss and its radiogenic heat budget. Expressed in terms of the present day heat production, the BSE budget of U, Th and K generates 19 TW (Van Schmus 1995). About 6-8 TW can be ...
... A separate requirement for some form of compositional stratification in the mantle comes from consideration of Earth’s heat loss and its radiogenic heat budget. Expressed in terms of the present day heat production, the BSE budget of U, Th and K generates 19 TW (Van Schmus 1995). About 6-8 TW can be ...
MANTLE MIXING - Earth and Environmental Sciences
... gives a MORB source mantle He concentration of 1.3 × 109 atoms 3He/g. O’Nions & Oxburgh (1983) noted that the rate of outgassing of the associated radiogenic 4He was similar to the amount produced in the MORB-source above 670 km. This flux is far lower than that predicted from the surface heat flow ...
... gives a MORB source mantle He concentration of 1.3 × 109 atoms 3He/g. O’Nions & Oxburgh (1983) noted that the rate of outgassing of the associated radiogenic 4He was similar to the amount produced in the MORB-source above 670 km. This flux is far lower than that predicted from the surface heat flow ...
The Earth`s mantle
... that were smaller than 10 km in size, and whose wave speeds varied by 1% or more from that of the ambient mantle. In the few cases where individual scatterers were identi®able, they had seismic velocities at least 4% slower than their surroundings48 and arrayed themselves in linear structures resemb ...
... that were smaller than 10 km in size, and whose wave speeds varied by 1% or more from that of the ambient mantle. In the few cases where individual scatterers were identi®able, they had seismic velocities at least 4% slower than their surroundings48 and arrayed themselves in linear structures resemb ...
Chapter 7. Radiogenic Isotope Geochemistry of the Crust and Oceans
... Rizo et al. (2011) subsequently reported 142Nd deficits in the 3.4 Ga mafic Amerlik dikes, which intrude the early Archean Isua supracrustals and surrounding gneisses. They argue these magmas were derived from a low Sm/Nd reservoir that formed before 4.47 Ga either as a result of crystallization of ...
... Rizo et al. (2011) subsequently reported 142Nd deficits in the 3.4 Ga mafic Amerlik dikes, which intrude the early Archean Isua supracrustals and surrounding gneisses. They argue these magmas were derived from a low Sm/Nd reservoir that formed before 4.47 Ga either as a result of crystallization of ...
PDF
... most stations the polarization remains stable during the deployment, being dominated by signals arriving from one or two azimuthal directions. These azimuths do not align to a common location, again suggesting the presence of distinct source regions near each station (Figure 3). ...
... most stations the polarization remains stable during the deployment, being dominated by signals arriving from one or two azimuthal directions. These azimuths do not align to a common location, again suggesting the presence of distinct source regions near each station (Figure 3). ...
Thermal history of the Earth and its petrological expression
... mantle convection in the past. We infer that the mantle was warming in deep Archean–Hadean time because internal heating exceeded surface heat loss, and it has been cooling from 2.5 to 3.0 Ga to the present. Non-arc Precambrian basalts are likely to be similar to those that formed oceanic crust and ...
... mantle convection in the past. We infer that the mantle was warming in deep Archean–Hadean time because internal heating exceeded surface heat loss, and it has been cooling from 2.5 to 3.0 Ga to the present. Non-arc Precambrian basalts are likely to be similar to those that formed oceanic crust and ...
Geodynamics: Surviving mantle convection
... seismic shear-wave velocity at the bottom of the mantle that are likely to be chemically distinct from surrounding mantle material2,6. Another hint may be provided by the observation that some pieces of the oceanic crust that subduct from the Earth’s surface do not sink deep into the mantle but stac ...
... seismic shear-wave velocity at the bottom of the mantle that are likely to be chemically distinct from surrounding mantle material2,6. Another hint may be provided by the observation that some pieces of the oceanic crust that subduct from the Earth’s surface do not sink deep into the mantle but stac ...
A model to explain the various paradoxes associated with mantle
... are intimately related to ‘‘primordial’’ components (11). It also explains the range of R found on oceanic islands and the temporal evolution toward MORB values (16). Ocean island basalts should have lower helium abundances than MORB or than gas-rich mantle xenoliths, as observed. ...
... are intimately related to ‘‘primordial’’ components (11). It also explains the range of R found on oceanic islands and the temporal evolution toward MORB values (16). Ocean island basalts should have lower helium abundances than MORB or than gas-rich mantle xenoliths, as observed. ...
M. Koch
... horizontal (Moho) or vertical (faults) boundaries, and of the data (station) coverage. Parametrization possible with a) blocks (no a priori smoothing) (ACH-method, SSH- method of the author, see References by the author M. Koch ) smoothing may occur a posteriori during the regularization (damping) o ...
... horizontal (Moho) or vertical (faults) boundaries, and of the data (station) coverage. Parametrization possible with a) blocks (no a priori smoothing) (ACH-method, SSH- method of the author, see References by the author M. Koch ) smoothing may occur a posteriori during the regularization (damping) o ...
The seismic Travel Time Problem as applied to Tomography of the
... horizontal (Moho) or vertical (faults) boundaries, and of the data (station) coverage. Parametrization possible with a) blocks (no a priori smoothing) (ACH-method, SSH- method of the author, see References by the author M. Koch ) smoothing may occur a posteriori during the regularization (damping) o ...
... horizontal (Moho) or vertical (faults) boundaries, and of the data (station) coverage. Parametrization possible with a) blocks (no a priori smoothing) (ACH-method, SSH- method of the author, see References by the author M. Koch ) smoothing may occur a posteriori during the regularization (damping) o ...
Recent Refinements in Geophysical Constraints on Lunar Origin
... S- and X-band Doppler tracking of orbiting spacecraft, principally the Lunar Orbiters, Apollo Command modules and subsatellites, and the Clementine and Lunar Prospector spacecraft. The Lunar Orbiters were typically in elliptical orbits with periapses of 50–100 km above the lunar surface, while the A ...
... S- and X-band Doppler tracking of orbiting spacecraft, principally the Lunar Orbiters, Apollo Command modules and subsatellites, and the Clementine and Lunar Prospector spacecraft. The Lunar Orbiters were typically in elliptical orbits with periapses of 50–100 km above the lunar surface, while the A ...
Geo-neutrinos and Earth`s interior
... solar photosphere points towards considering CI representatives of the material available in the pre-solar nebula and the basic material from which our planet has been formed. Some authors, however, have argued for a genetic relationship of our planet with other chondrites, such as enstatite chondri ...
... solar photosphere points towards considering CI representatives of the material available in the pre-solar nebula and the basic material from which our planet has been formed. Some authors, however, have argued for a genetic relationship of our planet with other chondrites, such as enstatite chondri ...
Are the Earth and the Moon compositionally alike? Inferences on
... both to the Earth and to CI. How much of the depletion of the volatile elements was due to early nebular processes and how much has resulted from the Moon-forming collision is problematic [Taylor, 2001]. There has been a longstanding controversy over the question whether the Moon is significantly en ...
... both to the Earth and to CI. How much of the depletion of the volatile elements was due to early nebular processes and how much has resulted from the Moon-forming collision is problematic [Taylor, 2001]. There has been a longstanding controversy over the question whether the Moon is significantly en ...
Short-term episodicity of Archaean plate tectonics
... marker; while the genesis of part of the TTG group (with very high La/Yb and low HFSE) does require high-pressure melting, at 20 kbar or more (Halla et al., 2009; Moyen, 2011), and can therefore be regarded as a subduction indicator, it is equally possible to form TTG(-like) rocks at much lower pres ...
... marker; while the genesis of part of the TTG group (with very high La/Yb and low HFSE) does require high-pressure melting, at 20 kbar or more (Halla et al., 2009; Moyen, 2011), and can therefore be regarded as a subduction indicator, it is equally possible to form TTG(-like) rocks at much lower pres ...
Short-term episodicity of Archaean plate tectonics
... marker; while the genesis of part of the TTG group (with very high La/Yb and low HFSE) does require high-pressure melting, at 20 kbar or more (Halla et al., 2009; Moyen, 2011), and can therefore be regarded as a subduction indicator, it is equally possible to form TTG(-like) rocks at much lower pres ...
... marker; while the genesis of part of the TTG group (with very high La/Yb and low HFSE) does require high-pressure melting, at 20 kbar or more (Halla et al., 2009; Moyen, 2011), and can therefore be regarded as a subduction indicator, it is equally possible to form TTG(-like) rocks at much lower pres ...
Seismic constraints on Ear th`s small-sc
... ers (Thorne and Garnero 2007). One puzzling aspect of ULVZs is their distribution at the CMB. Seismic studies detect areas of the CMB that are apparently devoid of ULVZ structure in close proximity to clear ULVZ detections (Thorne et al. 2004, Rost et al. 2005). There seems to be no ubiquitous ULVZ ...
... ers (Thorne and Garnero 2007). One puzzling aspect of ULVZs is their distribution at the CMB. Seismic studies detect areas of the CMB that are apparently devoid of ULVZ structure in close proximity to clear ULVZ detections (Thorne et al. 2004, Rost et al. 2005). There seems to be no ubiquitous ULVZ ...
Precision laser metrology for the modern Accelerators Colliders
... atmospheric air were discussed, showing that the combination of: Single mode laser associated with a fiber beam coupler for the light emitting point An optimal laser ray focusing collimation An intermediate sensor having no impact on the straightness of the beam The calibration of each senso ...
... atmospheric air were discussed, showing that the combination of: Single mode laser associated with a fiber beam coupler for the light emitting point An optimal laser ray focusing collimation An intermediate sensor having no impact on the straightness of the beam The calibration of each senso ...
Thermal, electrical and elastic properties of the Moon
... (2004) used the lunar tidal deformation measured by the lunar laser ranging method and the lunar prospector probe to give constraits on the size and the ...
... (2004) used the lunar tidal deformation measured by the lunar laser ranging method and the lunar prospector probe to give constraits on the size and the ...
Earthly Waves - Columbus City Schools
... data and conclusions of others while avoiding plagiarism and following a standard format for citation. *For more information: http://www.corestandards.org/assets/CCSSI_ELA%20Standards.pdf ...
... data and conclusions of others while avoiding plagiarism and following a standard format for citation. *For more information: http://www.corestandards.org/assets/CCSSI_ELA%20Standards.pdf ...
Draft 2.5 - posted 15 June 2014 /2500k
... mean poles and has averaged about 15 cm/yr since 1890. The speed and direction of polar drift can vary considerably in just a few years. Polar wander is the large amplitude geographic motion of polar drift on the geologic timescale. Polar drift and polar wander are reasoned to be caused mainly by sl ...
... mean poles and has averaged about 15 cm/yr since 1890. The speed and direction of polar drift can vary considerably in just a few years. Polar wander is the large amplitude geographic motion of polar drift on the geologic timescale. Polar drift and polar wander are reasoned to be caused mainly by sl ...
Tidal acceleration
Tidal acceleration is an effect of the tidal forces between an orbiting natural satellite (e.g. the Moon), and the primary planet that it orbits (e.g. Earth). The acceleration causes a gradual recession of a satellite in a prograde orbit away from the primary, and a corresponding slowdown of the primary's rotation. The process eventually leads to tidal locking of the smaller first, and later the larger body. The Earth–Moon system is the best studied case.The similar process of tidal deceleration occurs for satellites that have an orbital period that is shorter than the primary's rotational period, or that orbit in a retrograde direction.The naming is somewhat confusing, because the speed of the satellite relative to the body it orbits is decreased as a result of tidal acceleration, and increased as a result of tidal deceleration.