HR: 14:45h
AN: V33F-04    [Abstracts]
TI: Role of KCl-NaCl and CaCl2 Fluids in Igneous and Ore-Forming Processes
AU: * Kilinc, A I
EM: Attila.Kilinc@uc.edu
AB: Experiments from two to nine Kilobars with KCl-NaCl and NaCl-CaCl2 fluids reveal that chloride partitions strongly in favor of the fluid phase up to six Kilobars and its partition in favor of a melt slightly increases above six Kilobars. KCl/NaCl ratio in the fluid phase in equilibrium with a granitic melt increases with increasing pressure while the KCl/NaCl ratio in the coexisting melt decreases at 700 C. KCl/NaCl ratio both in the fluid phase and the melt, however, becomes pressure independent at 750 C. At a given pressure KCl/NaCl ratio in a fluid phase coexisting in equilibrium with a granitic melt increases with increasing temperature between 650 and 750 C. This explains the K/Na zoning typically seen in granitic pegmatites. CaCl2/FeCl2 ratio in silica-rich melts and coexisting aqueous phase decreases with decreasing pressure making the fluids very rich in iron. This experimental data on the partitioning of iron at moderately low pressures supports the general conclusion that the source for iron in most contact metasomatic deposits is the intrusive and the chloride-bearing aqueous solutions contain appreciable amounts of iron, which in turn, could precipitate in reactive rocks such as carbonates.
DE: 3665 Mineral occurrences and deposits
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting