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Widespread seismic anisotropy in Earth’s lowermost mantle beneath the Atlantic and Siberia

Grund, Michael; Ritter, Joachim R.R.

Abstract:
Deep inside the Earth, just above the core-mantle boundary at around 2,700 km depth, large-scale mantle structures are assumed to play a key role for global geodynamic processes. While unusual hot regions are attributed to feed rising mantle plumes and volcanic hotspots, the accumulation of subducted lithospheric plates is associated with colder than average features. In both environments the appearance of dynamic-driven processes such as deformation and mantle flow can directly be inferred by the presence of seismic anisotropy. However, the geometries as well as the interactions of these massive anomalous structures with the surrounding mantle material are still under debate. Based on new seismic data from a dense and large-aperture recording network in Scandinavia we characterize the anisotropic signatures of two so far unexplored regions in the lowermost mantle by using observations of clearly discrepant SKS-SKKS shear wave splitting measurements. Thereby we can demonstrate that anisotropy is located along the northern edges of the Large Low Shear Velocity Province beneath Africa. Furthermore, we recover an anisotropic structure in a region of fast seismic velocity underneath Siberia which provides additional evidence for widespread deformation caused by a deeply subducted slab.

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Postprint §
DOI: 10.5445/IR/1000090923
Veröffentlicht am 01.01.2020
Coverbild
Zugehörige Institution(en) am KIT Geophysikalisches Institut (GPI)
Publikationstyp Zeitschriftenaufsatz
Jahr 2019
Sprache Englisch
Identifikator ISSN: 0091-7613
KITopen-ID: 1000090923
Erschienen in Geology
Band 47
Heft 2
Seiten 123–126
Vorab online veröffentlicht am 31.12.2018
Nachgewiesen in Web of Science
Scopus
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