Article
Article name INFLUENCE OF HEAT AND MASS TRANSFER ON COMPOSITION OF BASALTIC MELT IN THE MUSHROOM-SHAPED HEAD OF THERMOCHEMICAL PLUME
Authors Kirdyashkin A.. ,
Bibliographic description
Category Earth science
DOI 551.2+551.14+536.25
DOI 10.21209/2227-9245-2018-24-10-21-31
Article type scientific
Annotation A thermochemical plume originates at the core-mantle boundary and ascends (melts up) to the surface.The main research task is to evaluate the compositional changes of melt in the plume head, assuming that the initial composition of melt is basaltic. The evaluations are based on the analysis of heat and mass transfer in the melt of the plume head. The flow structure that developed in a meltof plume head as well as in plume conduit is represented on the basis of experimental and theoretical modeling. Basing on the phase diagram of the CaO-MgO-Al2O3-SiO2 model system, the authors have shown that melting in the two upper convection cells of the plume conduit proceeds according to eutectic equilibria L=Cpx+Opx+An+Sp and L=Fo+An+Cpx+Opx. In the case of the CaO-MgO-Al2O3-SiO2-Na2O system the crystallization differentiation proceeds as separation of plagioclase crystals (in the form of albite-anorthtite solid solutions). This leads to the enrichment of residual melt in silica and alkaline components. Basing on thermal and hydrodynamic structure of the plume head together with the chemical composition of basaltic melt, the autjors have estimated the possible compositional changes in the melt. The calculations were performed in two stages: 1) after settling of refractory minerals; 2) after settling of plagioclase in the melt resulting from the first stage. As a consequence of crystallization differentiation, SiO2 content in the residual melt is consistent with that of the crustal layer
Key words Key words: modeling; mantle plumes; free-convection flows; plume head; melt; settling time; normative composition; basalts; phase diagram; plagioclase; eutectic melting
Article information Kirdyashkin A., Kirddyashkin A., Surkov N. Influence of heat and mass transfer on composition of basaltic melt in the mushroom-shaped head of thermochemical plume // Transbaikal State University Journal, 2018, vol. 24, no. 10, pp.21-31
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Full articleINFLUENCE OF HEAT AND MASS TRANSFER ON COMPOSITION OF BASALTIC MELT IN THE MUSHROOM-SHAPED HEAD OF THERMOCHEMICAL PLUME