caa a22 4500 46579081X CHVBK 20180323112024.0 cr unu---uuuuu 170327e19901101xx s 000 0 eng 10.1007/BF01167289 doi (NATIONALLICENCE)springer-10.1007/BF01167289 Experimental and major element constraints on the evolution of lavas from Lihir Island, Papua New Guinea [Elektronische Daten] [A. Kennedy, T. Grove, R. Johnson] The major element chemistry of SiO2-undersaturated arc lavas from Lihir Island, Papua New Guinea, and 1 atmosphere experiments on an alkali basalt from this island show complex polybaric fractionation affected this suite of lavas. Low Ni and MgO are typical of these arc lavas and result from olivine fractionation, probably at high pressure. Fractionation at low pressure (<5 kb) produces two evolutionary trends. Separation of clinopyroxene, plagioclase and minor olivine from the primitive lavas results in increasing normative nepheline contents and major element trends similar to those of the experiments. In contrast, addition of magnetite and amphibole to the fractionating assemblage in the evolved lavas results in decreasing normative nepheline and major element trends which are markedly different from those of the experiments. The composition of experimental glasses and 1 atmosphere liquid lines of descent, derived from anhydrous melting experiments run at the fayalite-magnetite-quartz (FMQ) buffer and at higher oxygen fugacities, are displaced from the lavas on oxide-oxide plots. HighfO2 produces high Fe3+/Fe2+ and the early crystallization of abundant magnetite, and high H2O contents are responsible for crystallization of amphibole. Crystal fractionation of these phases and the high Fe3+/Fe2+ are responsible for the displacement of the lavas and experimental glasses in mineral projection schemes from the 1 atmosphere olivine-clinopyroxene-plagioclase saturation boundary of Sack et al. (1987). Springer-Verlag, 1990 Kennedy A. Department of Earth Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 02139, Cambridge, MA, USA aut Grove T. Department of Earth Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 02139, Cambridge, MA, USA aut Johnson R. Bureau of Mineral Resources, G.P.O. Box 378, 2601, Canberra, A.C.T., Australia aut Contributions to Mineralogy and Petrology Springer-Verlag 104/6(1990-11-01), 722-734 0010-7999 104:6<722 1990 104 410 https://doi.org/10.1007/BF01167289 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01167289 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kennedy A. Department of Earth Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 02139, Cambridge, MA, USA aut NATIONALLICENCE 700 1- Grove T. Department of Earth Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 02139, Cambridge, MA, USA aut NATIONALLICENCE 700 1- Johnson R. Bureau of Mineral Resources, G.P.O. Box 378, 2601, Canberra, A.C.T., Australia aut NATIONALLICENCE 773 0- Contributions to Mineralogy and Petrology Springer-Verlag 104/6(1990-11-01), 722-734 0010-7999 104:6<722 1990 104 410 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer