Table S1: Compositions of glass and mineral standards

Standard						Formula					d18OVSMOW*
San Carlos Olivine				Mg1.86Fe0.14SiO4			5.35
Orthopyroxene					Mg0.87Fe0.13SiO3			9.2
Albite glass					Na0.98K0.02AlSi3O8			10.8
Anorthite glass				CaAl2Si2O8				8.3
Orthoclase glass				KAlSi3O8					10.3
Silica glass					SiO2						10.8
Hydrous albite glass (1 wt. %)	(NaAlSi3O8)0.87(H2O)0.13		5.1
Hydrous albite glass (3 wt. %)	(NaAlSi3O8)0.69(H2O)0.31		4.7
Hydrous albite glass (7 wt. %)	(NaAlSi3O8)0.48(H2O)0.52		3.1

* Measured by laser fluorination of ~ 2mg aliquots at the University of Wisconsin