gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1998.62A.3.148 Long Magma Residence Times at an Island Arc Volcano (Soufriere, St. Vincent) in the Lesser Antilles: Evidence from ²³⁸U-²³⁰Th Isochron Dating Tumer S. P. Hawkesworth C. J. van Calsteren P. Department of Earth Sciences, The Open University, Milton Keynes MK7 6AA, UK Heath E. Macdonald R. Department of Environmental Sciences, Lancaster University, Lancaster LA1 4YQ, UK 1998 62A 3 1553 1554 Copyright © 1998, The Mineralogical Society 1998