کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4699401 1637644 2012 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effect of fluorine on near-liquidus phase equilibria of an Fe–Mg rich basalt
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
Effect of fluorine on near-liquidus phase equilibria of an Fe–Mg rich basalt
چکیده انگلیسی

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, KdMineral-MeltFe − Mg 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 KdMineral-MeltFe − Mg. 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.


► We show that fluorine depresses the liquidus temperature of basalts significantly.
► Fluorine has a large effect on the chemistry of liquidus phases.
► Addition of 2 wt.% F moves the olivine-pigeonite liquidus point down ~ 2 kbar and 95 °C.
► With increasing melt F concentrations, KdOlivine-MeltFe − Mg and KdOpx-MeltFe − Mg increases.
► Fluorine in the basaltic magma appears to complex primarily with MgO.
► Fluorine may aid in the petrogenesis of alkali-rich magmas in the Earth and Mars.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Geology - Volumes 312–313, 18 June 2012, Pages 118–126
نویسندگان
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