Papers by Barbara Romanowicz
Geophysical Journal International, Dec 9, 2013
Geophysical Journal International, Feb 27, 2018
HAL (Le Centre pour la Communication Scientifique Directe), Jun 6, 2016
Physics of the Earth and Planetary Interiors, Aug 1, 2018
Physics of the Earth and Planetary Interiors, Feb 1, 2020
Comptes Rendus Geoscience, Sep 1, 2011
Geophysical Journal International, Aug 1, 2005
Geophysical Journal International, Oct 14, 2017
HAL (Le Centre pour la Communication Scientifique Directe), Apr 27, 2014
Geophysical Research Letters, May 7, 2021
The existence of a thin, weak asthenospheric layer beneath Earth’s lithospheric plates is consist... more The existence of a thin, weak asthenospheric layer beneath Earth’s lithospheric plates is consistent with existing geological and geophysical constraints, including Pleistocene glacio-isostatic adjustment, modeling of gravity anomalies, studies of seismic anisotropy, and post-seismic rebound. Mantle convection models suggest that a pronounced weak zone beneath the upper thermal boundary layer (lithosphere) may be essential to the plate tectonic style of convection found on Earth. The asthenosphere is likely related to partial melting and the presence of water in the sub-lithospheric mantle, further implying that the long-term evolution of the Earth, including the apparently early onset and persistence of plate tectonics, may be controlled by thermal regulation and volatile recycling that maintain a geotherm that approaches the wet mantle solidus at asthenospheric depths.
Recent studies of seismic-wave receiver function data have detected a structural boundary under c... more Recent studies of seismic-wave receiver function data have detected a structural boundary under continental cratons at 100–140 km depths, which is too shallow to be consistent with the lithosphere–asthenosphere boundary, as inferred from seismic tomography and other geophysical studies. This leads to the conclusion that 1) the cratonic lithosphere may be thinner than expected, contradicting tomographic and other geophysical or geochemical inferences, or 2) that the receiver function studies detect a mid-lithospheric discontinuity rather than the LAB. On the other hand, several recent studies documented significant changes in the direction of azimuthal anisotropy with depth that suggest layering in the anisotropic structure of the stable part of the North American continent. In particular, Yuan and Romanowicz (2010) combined long period surface wave and overtone data with core refracted shear wave (SKS) splitting measurements in a joint tomographic inversion. A question that arises i...
The EGU General Assembly, 2017
The accurate imaging of localized geological structures inside the deep Earth is key to understan... more The accurate imaging of localized geological structures inside the deep Earth is key to understand our planet and its history. Since the introduction of the Preliminary Reference Earth Model, many generations of global tomographic models have been developed and give us access to the 3D structure of the Earth's interior. The latest generation of global tomographic models has emerged with the development of accurate numerical wavefield computations in a 3D earth combined with access to enhanced HPC capabilities. These models have sharpened up mantle images and unveiled relatively small scale structures that were blurred out in previous generation models. Fingerlike structures have been found at the base of the oceanic asthenosphere, and vertically oriented broad low velocity plume conduits [1] extend throughout the lower mantle beneath those major hotspots that are located within the perimeter of the deep mantle large low shear velocity provinces (LLSVPs). While providing new insi...
The presence of seismic anisotropy in the crust and upper mantle is well documented, with relativ... more The presence of seismic anisotropy in the crust and upper mantle is well documented, with relatively good consensus on its origins, owing to direct observations in the field and laboratory experiments on mineral crystal structure and deformation properties, in a range of pressures and temperatures that is readily accessible. The situation is much less clear for the deep mantle, due to poor sampling by seismic waves, contamination by upper mantle effects, and the difficulty for mineral physics deformation experiments to reach relevant physical conditions. However, in the last decade, there has been significant progress in both fields, and a new and promising approach has emerged, aiming at combining seismic observations of anisotropy in the deep Earth with knowledge from geodynamics modelling and constraints from mineral physics, towards understanding deformation patterns related to global mantle circulation. Here we review the present state of knowledge on deep mantle anisotropy in ...
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Papers by Barbara Romanowicz