Výsledky vyhledávání - "Reidar G. Trønnes"

Akademický článek

Seismological expression of the iron spin crossover in ferropericlase in the Earth’s lower mantle

Autor: Grace E. Shephard, Christine Houser, John W. Hernlund, Juan J. Valencia-Cardona, Reidar G. Trønnes, Renata M. Wentzcovitch

Publikováno v: Nature Communications, Vol 12, Iss 1, Pp 1-11 (2021)

This study identifies the predicted seismic expression of the high-to-low iron spin crossover in the deep Earth mineral ferropericlase. A depth-dependent signal is detected in the fastest and slowest regions, related to lateral temperature variations

Externí odkaz: https://doaj.org/article/6e36326334c346a180cffbc204e410e9

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High-pressure silica phase transitions: Implications for deep mantle dynamics and silica crystallization in the protocore

Autor: John P. Brodholt, Pratik Kumar Das, Reidar G. Trønnes, Chris E. Mohn

Publikováno v: American Mineralogist. 105:1014-1020

The subsolidus phase diagram of silica in the 80–220 GPa pressure range was determined by density functional theory (DFT). The transition pressures calculated using the generalized gradient approximation (GGA) in the static limit (at 0 K, without z

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::6557eb061386b64a8ee6ce9627f41944
https://doi.org/10.2138/am-2020-7299

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Seismological expression of the iron spin crossover in ferropericlase in the Earth’s lower mantle

Autor: John Hernlund, Reidar G. Trønnes, Christine Houser, Grace E. Shephard, Juan Valencia-Cardona, Renata M. Wentzcovitch

Publikováno v: Nature Communications, Vol 12, Iss 1, Pp 1-11 (2021)
Nature Communications

The two most abundant minerals in the Earth’s lower mantle are bridgmanite and ferropericlase. The bulk modulus of ferropericlase (Fp) softens as iron d-electrons transition from a high-spin to low-spin state, affecting the seismic compressional ve

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e88024af52e47c23d6a53d9f0ebb6963
https://doi.org/10.1038/s41467-021-26115-z

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Spatiotemporal Variations in Surface Heat Loss Imply a Heterogeneous Mantle Cooling History

Autor: Krister Stræte Karlsen, Mathew Domeier, Reidar G. Trønnes, Clinton P. Conrad

Earth's heat budget is strongly influenced by spatial and temporal variations in surface heat flow caused by plate tectonic cycles. Here, we use a novel set of paleo‐seafloor age grids extending back to the mid‐Paleozoic to infer spatiotemporal v

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fb6e1e6f51376f382106ea499e03c292
http://hdl.handle.net/10852/85815

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How Thermochemical Piles Can (Periodically) Generate Plumes at Their Edges

Autor: Reidar G. Trønnes, Björn Heyn, Clinton P. Conrad

Publikováno v: Journal of Geophysical Research: Solid Earth. 125

Deep-rooted mantle plumes are thought to originate from the margins of the Large Low Shear Velocity Provinces (LLSVPs) at the base of the mantle. Visible in seismic tomography, the LLSVPs are usually interpreted to be intrinsically dense thermochemic

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6d299971ab7aa903a24e41ab6567c214
https://doi.org/10.1029/2019jb018726

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Ambient lower mantle structure and composition inferred from seismic tomography, convection models, and geochemistry

Autor: John Hernlund, Grace E. Shephard, Christine Houser, Reidar G. Trønnes, Fabio Crameri

The lower mantle can be grouped into high, low, and average (i.e., ambient) seismic velocity domains at each depth, based on the amplitude and polarity of wavespeed perturbations (% δlnVs, % δlnVp). Many studies focus on elucidating the thermo-chem

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::4013b9cfc4df458ab05984ac9215e98e
https://doi.org/10.5194/egusphere-egu2020-11806

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How thermochemical piles initiate plumes at their edges

Autor: Reidar G. Trønnes, Clinton P. Conrad, Björn Heyn

Deep-rooted mantle plumes are thought to originate from the margins of the Large Low Shear Velocity Provinces (LLSVPs) at the base of the mantle. Visible in seismic tomography, the LLSVPs are often numerically modeled as dense and viscous thermochemi

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::611ad63d58a29d65e021d9f61a586f89
https://doi.org/10.5194/egusphere-egu2020-5577

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Stabilizing Effect of Compositional Viscosity Contrasts on Thermochemical Piles

Autor: Björn Heyn, Reidar G. Trønnes, Clinton P. Conrad

Publikováno v: Geophysical Research Letters. 45:7523-7532

The large low shear velocity provinces (LLSVPs) observed in the lowermost mantle are widely accepted as chemically distinct thermochemical 'piles', but their origin and long-term evolution remain poorly understood. The survival time and shape of the

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::fb6af7906e81dbebe0b8a3a95d2d1155
https://doi.org/10.1029/2018gl078799

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Experimental constraints on melting temperatures in the MgO–SiO2 system at lower mantle pressures

Autor: Weiwei Wang, Michael J. Walter, M. A. Baron, Reidar G. Trønnes, Robert Myhill, Oliver T. Lord, Andrew Thomson

Publikováno v: Baron, M A, Lord, O T, Myhill, R, Thomson, A R, Wang, W, Trønnes, R G & Walter, M J 2017, ' Experimental constraints on melting temperatures in the MgO–SiO2 system at lower mantle pressures ', Earth and Planetary Science Letters, vol. 472, pp. 186-196 . https://doi.org/10.1016/j.epsl.2017.05.020

Eutectic melting curves in the system MgO–SiO2 have been experimentally determined at lower mantle pressures using laser-heated diamond anvil cell (LH-DAC) techniques. We investigated eutectic melting of bridgmanite plus periclase in the MgO–MgSi

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1452312b0ba7ec64a18d93711f34e524
https://doi.org/10.1016/j.epsl.2017.05.020

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Donwilhelmsite, [CaAl4Si2O11], a new lunar high-pressure Ca-Al-silicate with relevance for subducted terrestrial sediments

Autor: Ludovic Ferrière, Reidar G. Trønnes, Richard Wirth, Mariana Klementová, A. Greshake, Lukáš Palatinus, Ute Böttger, Vera A. Fernandes, Jörg Fritz

Publikováno v: American Mineralogist
Fritz, J, Greshake, A, Klementova, M, Wirth, R, Palatinus, L, Trønnes, R G, A. Fernandes, V, Böttger, U & Ferrière, L 2020, ' Donwilhelmsite, [CaAl4Si2O11], a new lunar high-pressure Ca-Al-silicate with relevance for subducted terrestrial sediments ', American Mineralogist . https://doi.org/10.2138/am-2020-7393

We report on the occurrence of a new high-pressure Ca-Al-silicate in localized shock melt pockets found in the feldspatic lunar meteorite Oued Awlitis 001 and discuss the implications of our discovery. The new mineral crystallized as tiny, micrometer

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0392e6e94524dbb2aa0f81b325a79502
https://gfzpublic.gfz-potsdam.de/pubman/item/item_5004273

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