gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1998.62A.2.284 Isotope Constraints on the Involvement of fluids in the San Andreas Fault System, California Pili E. Kennedy B. M. Conrad M. S. Center for Isotope Geochemistry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA Gratier J.-P. LGIT CNRS-Observatoire, IRIGM, BP 53X, F38041 Grenoble, France Poitrasson F. Laboratoire de Géochimie — UMR 5563 CNRS, Université Paul Sabatier, 38, rue des 36 Ponts, 31400 Toulouse, France 1998 62A 2 1182 1183 Copyright © 1998, The Mineralogical Society 1998