Experimental calibration of hornblende as a proposed emprical geobarometer



The recent Eos report by Anderson [1987] reviewed prospects for using dated granitoid plutons as crustal nails in the reconstruction of descent or ascent of deformed crust during orogenic processes, if suitable geobarometers could be established. Hammarstrom and Zen [1986] and Hollister et al [1987] have proposed an empirical geobarometer for calcalkaline plutonic rocks of tonalite and granodiorite composition based on the total Al content (Air) of calcic hornblendes. This proposition has generated considerable interest.