Effect of fluorine on near-liquidus phase equilibria of an Fe–Mg rich basalt
Treiman, Allan H.
MetadataShow full item record
KeywordHalogens; Martian meteorites; Alkali basalts; Basalt crystallization; Phase equilibria; Fluorine
Volatile species (H2O, CO2, F, Cl, etc) have important effects on the formation and crystallization history of basaltic magmas. Here, we have experimentally investigated the effects of F on phase equilibria of Fe-Mg-rich basalt. Our results show that fluorine has large effects on the liquidus temperature and the chemistry of crystallizing minerals. Compared to the F-free system, addition of ~2 wt.% F moves the olivine-pigeonite liquidus point down ~2 kbar and 95 °C (from 12 kbar, 1375 °C to 10 kbar, 1280 °C). With increasing fluorine concentrations, dramatically increases for both pyroxene and olivine, suggesting that fluorine in basaltic magmas complexes primarily with MgO. Complexing with MgO in the melt decreases its MgO activity, and forces the crystallizing minerals to greater Fe/Mg, and so increases . Models of basalt generation, where the magma is fluorine-rich, need to include the effect of not only water but fluorine on liquidus depression and minerals crystallizing/melting. Our results suggest that fluorine may significantly aid in the petrogenesis of silica-poor, alkali-rich magmas in the Earth and Mars.
Author Posting. © The Author(s), 2012. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Chemical Geology 312-313 (2012): 118-126, doi:10.1016/j.chemgeo.2012.04.015.
Showing items related by title, author, creator and subject.
Kinetics of H2–O2–H2O redox equilibria and formation of metastable H2O2 under low temperature hydrothermal conditions Foustoukos, Dionysis I.; Houghton, Jennifer L.; Seyfried, William E.; Sievert, Stefan M.; Cody, George D. (2010-07-23)Hydrothermal experiments were conducted to evaluate the kinetics of H2(aq) oxidation in the homogeneous H2-O2-H2O system at conditions reflecting subsurface/near-seafloor hydrothermal environments (55-250 oC and 242-497 ...
Primeau, Francois W. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1998-06)The steady states of two models of the double-gyre wind-driven ocean circulation are studied. The link between the steady state solutions of the models and their time-mean and low-frequency variability is explored to ...
pH dependent isotropic to nematic phase transitions in graphene oxide dispersions reveal droplet liquid crystalline phases Tkacz, Rachel; Oldenbourg, Rudolf; Mehta, Shalin B.; Miansari, Morteza; Verma, Amitabh; Majumder, Mainak (2014-05)Size fractionation, amplified by the surface charge density of graphene oxide (GO) sheets, broadens the pH dependent isotropic (I) to nematic (N) phase transition in aqueous dispersions of graphene oxide (GO). In this ...