ASSESSMENT OF THE GARNET-CLINOPYROXENE THERMOMETER

thermometer based on the MgFe-1 exchange equilibrium between garnet an d clinopyroxene is formulated by using new experimental data measured at 600 degrees to 950 degrees C, 0.8 to 3.0 GPa, and f(O-2) defined by the fayalite-quartz-magnetite buffer in the basalt-H2O system. The ne w formulation is T = 3820/1.828 + In K-D (1 + a(2.2 - P)), where T is temperature (K), P is pressure (GPa), K-D is the Fe-Mg partition coeff icient between garnet and clinopyroxene, defined as K-D = (Fe2+/Mg)(ga rnet)/(Fe2+/Mg)(clinopyroxene), and a = 132/T. Application of the ther mometer to rocks in amphibolite, granulite, and eclogite terranes yiel ds temperatures that are in reasonable agreement with other well-calib rated thermometers and the experimental calibrations by Ellis and Gree n (1979) and Pattison and Newton (1989).