The Geysers-Cobb Mountain Magma System , California ( Part 1 ) : UPb zircon ages of volcanic rocks , conditions of zircon crystallization and magma residence times

Combined U-Pb zircon and Ar/Ar sanidine data from volcanic rocks within or adjacent to the Geysers geothermal reservoir constrain the timing of episodic eruption events and the pre-eruptive magma history. Zircon U-Pb concordia intercept model ages (corrected for initial Th disequilibrium) decrease as predicted from stratigraphic and regional geological… (More)