%0 Journal Article %T Fluorite stability in silicic magmas. %+ Institut des Sciences de la Terre d'Orléans (ISTO) %+ Environment Centre (ENVIRONMENT CENTRE) %A Scaillet, Bruno %A Macdonald, Ray %< avec comité de lecture %@ 0010-7999 %J Contributions to Mineralogy and Petrology %I Springer Verlag %V 147 %P 319-329 %8 2004 %D 2004 %R 10.1007/s00410-004-0559-1 %Z Sciences of the Universe [physics]/Earth Sciences/VolcanologyJournal articles %X Recent experimental evidence is used to assess the conditions under which fluorite forms an early crystallising phase in silicic magmas. Fluorite solubility primarily depends on the (Na + K)/Al balance in the coexisting silicic melt, reaching a minimum in metaluminous melts. It can display reaction relationships with topaz and titanite, depending on changes in melt composition during crystallisation. An empirical model of fluorite stability in Ca-poor peralkaline rhyolite melts is derived and applied to selected rocks: $$ {\text{F}}_{{{\text{melt}}}} {\left( {{\text{wt}}\% } \right)} = {\left[ {{\left( {{\text{Na}} + {\text{K}}/{\text{Al}}} \right)}{\left\{ {2.1110^{{ - 3}} {\text{T}}{\left( {^\circ C} \right)} + 1.5778} \right\}}} \right]} - 2.789 $$ At the F contents preserved in most silicic rocks, fluorite should normally appear late in the crystallisation sequence, in agreement with petrographic observations. During fluid-absent crustal anatexis, fluorite should melt at a relatively early stage and restitic fluorite is unlikely to persist during prolonged melting. Fluorite may, however, exert a decisive control on the alkali/alumina balance of sub-aluminous anatectic melts and it can affect the liquid line of descent of silicic magmas once extracted from source. %G English %2 https://insu.hal.science/hal-00023899/document %2 https://insu.hal.science/hal-00023899/file/scaillet-contrib.pdf %L hal-00023899 %U https://insu.hal.science/hal-00023899 %~ INSU %~ CNRS %~ UNIV-ORLEANS %~ ISTO %~ OSUC