Viscosity of mafic magmas at high pressures

Autor: Chrystèle Sanloup, Yoshio Kono, B. Cochain, C. Leroy
Přispěvatelé: Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Scottish Universities Physics Alliance (SUPA), Pétrologie, géochimie, minéralogie magmatiques (PGM2), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), Geophysical Laboratory [Carnegie Institution], Carnegie Institution for Science [Washington], ANR-11-IDEX-0004,SUPER,Sorbonne Universités à Paris pour l'Enseignement et la Recherche(2011), Carnegie Institution for Science
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Geophysical Research Letters
Geophysical Research Letters, American Geophysical Union, 2017, 44 (2), pp.818-826 ⟨10.1002/2016GL071600⟩
Geophysical Research Letters, 2017, 44 (2), pp.818-826 ⟨10.1002/2016GL071600⟩
ISSN: 0094-8276
1944-8007
DOI: 10.1002/2016GL071600⟩
Popis: International audience; While it is accepted that silica-rich melts behave anomalously with a decrease of their viscosity at increased pressures (P), the viscosity of silica-poor melts is much less constrained. However, modeling of mantle melts dynamics throughout Earth's history, including the magma ocean era, requires precise knowledge of the viscous properties of silica-poor magmas. We extend here our previous measurements on fayalite melt to natural end-members pyroxenite melts (MgSiO 3 and CaSiO 3) using in situ X-ray radiography up to 8 GPa. For all compositions, viscosity decreases with P, rapidly below 5 GPa and slowly above. The magnitude of the viscosity decrease is larger for pyroxene melts than for fayalite melt and larger for the Ca end-member within pyroxene melts. The anomalous viscosity decrease appears to be a universal behavior for magmas up to 13 GPa, while the P dependence of viscosity beyond this remains to be measured. These results imply that mantle melts are very pervasive at depth.
Databáze: OpenAIRE
Externí odkaz: