HR: 0800h
AN: V31E-0714    [Abstracts]
TI:
AU: * Kilinc, A I
EM: Kilinc@email.Uc.edu
AF: Department of Geology, University of Cincinnati, 500 Geology-Physics Bldg, Cincinnati, OH 45221-0013, United States
AB: The initial state of the system and the thermodynamic constraints under which the calc-alkaline Erciyes Volcano in Central Turkey evolved has been modeled using the MELTS algorithm. Results of MELTS simulations show that basaltic andesite magma with 3 wt% water and fO₂=QFM+3 at 1 GPa pressure evolved by closed system fractional crystallization to produce 63 Km³ of dacitic and rhyolitic Plinian fall and pumice deposits (Sen et al., 2003). In order to determine the initial state of the system simulations of fractional crystallization of the most primitive basaltic andesite magma were carried out in the pressure range of 0.0001 to 1 GPa, fO₂ range of QFM-3 to QFM+3 and at H20 ranging from zero to 4 wt%. The phase equilibria calculations that gave the best fit to natural rock compositions are P= 0.1 GPa, fO₂=QFM+3 and H₂O=3 wt%. Using these system parameters "parental" basaltic andesite magma was allowed to fractionate under closed system conditions starting at the liquidus temperature of 1107 C. MELTS calculations showed that water began to separate from the melt at 1027 C and the volume faction of water increased from 0.0049 at 1027 C to 0.69 at 767 C. Below this temperature the volume fraction of water increased to 5.4 and both physical and chemical conditions of the magma changed drastically, marking the explosive eruption of the volcano.
DE: 1009 Geochemical modeling (3610, 8410)
DE: 3610 Geochemical modeling (1009, 8410)
DE: 8410 Geochemical modeling (1009, 3610)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting