gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1994.58A.2.122 The Role of Hydrogen Fugacity in Controlling Ferric-Ferrous Ratio and Volatile Content of Kaersutitic Amphibole: An Experimental Study Popp R. K. Department of Geology, Texas A&M, College Station, TX, 77843, and Center for High Pressure Research USA Virgo D. Geophysical Laboratory and Center for High Pressure Research, 5251 Broad Branch Rd. NW, Washington D.C. 20015 Yoder H. S. Jr. Hoering T. C. Geophysical Laboratory, 5251 Broad Branch Rd. NW, Washington D.C. 20015 Phillips M. W. Department of Geology, University of Toledo, Toledo, OH, 43606, USA August–September 1994 58A 2 740 741 Copyright © 1994, The Mineralogical Society 1994