Older hydrothermal alteration in the Yellowstone Caldera, Wyoming Larson, P. B. ; Phillips, A. ; John, D. ; Cosca, M. ; Pritchard, C. ; Andersen, A. ; Manion, J. Abstract Publication: Geochimica et Cosmochimica Acta Supplement Pub Date: July 2008 Bibcode: 2008GeCAS..72Q.518L