Results 121 to 130 of about 19,207 (163)

A Complex Pattern of Mantle Flow in the Lau Backarc

Science, 2001
Shear-wave splitting analysis of local events recorded on land and on the ocean floor in the Tonga arc and Lau backarc indicate a complex pattern of azimuthal anisotropy that cannot be explained by mantle flow coupled to the downgoing plate. These observations suggest that the direction of mantle flow rotates from convergence-parallel in the Fiji ...
G P, Smith, D A, Wiens, K M, Fischer, L M, Dorman, S C, Webb, J A, Hildebrand   +5 more
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Seismic Determination of Elastic Anisotropy and Mantle Flow

Science, 1993
When deformed, many rocks develop anisotropic elastic properties. On many seismic records, a long-period (100 to 250 seconds), "quasi-Love" wave with elliptical polarization arrives slightly after the Love wave but before the Rayleigh wave. Mantle anisotropy is sufficient to explain these observations qualitatively as long as the "fast" axis of ...
J, Park, Y, Yu
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What the mantle sees: The Effects of continents on mantle heat flow

2000
The effects of continents on mantle heat flow are explored through a synthesis of heat flow data analysis and theoretical modeling. The data employed are from the Canadian Shield and the Canadian Appalachians and consist of both surface heat flow measurements and measurements of crustal heat production. The combined data sets, together with gravity and
A. Lenardic, L. Guillou-Frottier, J.-C. Mareschal, C. Jaupart, L.-N. Moresi, W. M. Kaula   +5 more
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Seismic anisotropy and mantle flow

Journal of Geophysical Research: Solid Earth, 1989
Seismic anisotropy in the mantle is primarily due to deformation‐induced lattice preferred orientation (LPO) of olivine crystals. The aim of this paper is to better understand how such LPO is produced by flow, and to learn whether observations of seismic anisotropy can be used to infer the local direction of flow within the mantle.
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Chaotic topography, mantle flow and mantle migration in the Australian–Antarctic discordance

Nature, 1998
Oceanic crust formed over the past 30 million years at the Australian–Antarctic discordance (AAD) is characterized by chaotic sea-floor topography, reflecting a weak magma supply from an unusually cold underlying mantle. During the past 3–4 million years, however, a source of increased magma supply, coinciding with the known Indian–Pacific mantle ...
David M. Christie, Brian P. West, Douglas G. Pyle, Barry B. Hanan   +3 more
openaire   +1 more source

Isotopic portrayal of the Earth’s upper mantle flow field

Nature, 2007
It is now well established that oceanic plates sink into the lower mantle at subduction zones, but the reverse process of replacing lost upper-mantle material is not well constrained. Even whether the return flow is strongly localized as narrow upwellings or more broadly distributed remains uncertain.
Meyzen, Christine, Blichert-Toft, Janne, Ludden, John, Humler, Eric, Mevel, Catherine, Albarède, Francis   +5 more
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Upper mantle flow in the western Mediterranean

Earth and Planetary Science Letters, 2007
Two cross-sections of the western Mediterranean Neogene-to-present back-arc basin are presented, in which geological and geophysical data of the TRANSMED Project are tied to a new shear-wave tomography. Major results are i) the presence of a well stratified upper mantle beneath the older African continent, with a marked low-velocity layer between 130 ...
Giuliano F. Panza, Reneta B. Raykova, CARMINATI, Eugenio Ambrogio Maria, DOGLIONI, Carlo   +3 more
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Seismic Anisotropy and Flow in the Mantle

1997
Seismic anisotropy is a dependence of velocities of seismic waves on their polarizations and directions of propagation. Anisotropy of the uppermost mantle is caused mainly by lattice preferred orientation (LPO) of olivine, the most abundant and highly anisotropic mineral.
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Flow and Fluid Behaviour of the Mantle

2014
With Chap. 13, we move from the lithosphere to the underlying mantle. In fact, this chapter introduces the important theme of mantle dynamics, in particular thermal convection and asthenosphere currents. Navier-Stokes and energy balance equations are derived and discussed, along with the classic Boussinesq approximation.
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Constraining mantle heterogeneity and mantle flow using seismic and geodynamic data

2018
In this dissertation, I have developed new 3-D models of mantle heterogeneity using seismic and geodynamic data to better understand the thermo-chemical composition of the mantle and its dynamics. First, the effect of subducting slabs in global shear wave tomography has been evaluated.
Lu, Chang, 0000-0002-9067-7490
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