http://serc.carleton.edu/NAGTWorkshops/petrology/discussion/17875.html#discussion http://serc.carleton.edu/NAGTWorkshops/petrology/discussion/17875.html#post1271 Lorenzo Lazzarini 1176977460 http://serc.carleton.edu/NAGTWorkshops/petrology/discussion/17875.html#post1271