Abstract
Near-liquidus phase relations of an andesite and the andesitic mixtures with Na2O, CaO, MgO, and iron oxide added to the andesite were determined under one-atmosphere, fO2-controlled conditions. The stability relation between clino- and orthopyroxene was determined, and pyroxenes, plagioclase and coexisting liquids (glasses) were analyzed. The liquidus temperature of plagioclase decreased and that of pyroxenes increased by the addition of Na2O, CaO and MgO, but they decreased by the addition of iron oxides. The effect of Na2O on the crystallization of minerals from andesitic melts is explained in relation to the chemical potential of wollastonite component in the liquid. The normative composition is useful to deduce the first appearance temperature of liquidus phase, and will be a satisfactory measure for the subliquidus phase if the composition of the liquidus phase is known.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
