This paper presents a biotite-calcic hornblende geothermometer which wasempirically calibrated based on the garnet-biotite geothermometer and thegarnet-plagioclase-hornblende-quartz geobarometer, in the ranges of 560-...This paper presents a biotite-calcic hornblende geothermometer which wasempirically calibrated based on the garnet-biotite geothermometer and thegarnet-plagioclase-hornblende-quartz geobarometer, in the ranges of 560-800 deg C (T) and 0.26-l.4GPa (P) using the data of metadolerite, amphibolite, metagabbro, and metapelite collected from theliterature. Biotite was treated as symmetric Fe-Mg-Al^VI-Ti quaternary solid solution, and calcichornblende was simplified as symmetric Fe-Mg binary solid solution. The resulting thermometer mayrebuild the input garnet-biotite temperatures well within an uncertainty of + - 50 deg C. Errors of+- 0.2 GPa for input pressure, along with analytical errors of = - 5 percent for the relevantmineral compositions, may lead to a random error of + - 16 deg C for this thermometer, so that thethermometer is almost independent of pressure estimates. The thermometer may clearly discriminatedifferent rocks of lower amphibolite, upper amphibolite and granulite facies on a high confidencelevel. It is assumed that there is a ferric iron content of 11.6 percent in biotite, and that theiron content in calcic hornblende may be calculated according to the method of Dale et al. (2000).This thermometer can be used for medium- to high-grade metabasites and metapelites.展开更多
基金the China National Natural Science Foundation(grants40002017 , 40074022) wasalso under the auspices of the National Key Project for Basic Research +1 种基金 CAS Project for the Tibetan Research Project(KZ.-951-A1-204 , KZ95T-06) a China Geological Survey grant(J2.1.4).
文摘This paper presents a biotite-calcic hornblende geothermometer which wasempirically calibrated based on the garnet-biotite geothermometer and thegarnet-plagioclase-hornblende-quartz geobarometer, in the ranges of 560-800 deg C (T) and 0.26-l.4GPa (P) using the data of metadolerite, amphibolite, metagabbro, and metapelite collected from theliterature. Biotite was treated as symmetric Fe-Mg-Al^VI-Ti quaternary solid solution, and calcichornblende was simplified as symmetric Fe-Mg binary solid solution. The resulting thermometer mayrebuild the input garnet-biotite temperatures well within an uncertainty of + - 50 deg C. Errors of+- 0.2 GPa for input pressure, along with analytical errors of = - 5 percent for the relevantmineral compositions, may lead to a random error of + - 16 deg C for this thermometer, so that thethermometer is almost independent of pressure estimates. The thermometer may clearly discriminatedifferent rocks of lower amphibolite, upper amphibolite and granulite facies on a high confidencelevel. It is assumed that there is a ferric iron content of 11.6 percent in biotite, and that theiron content in calcic hornblende may be calculated according to the method of Dale et al. (2000).This thermometer can be used for medium- to high-grade metabasites and metapelites.
