K-Ar ages of igneous rocks and mineralization in part of the Bolivian tin belt Grant, J. N. ; Halls, C. ; Avila Salinas, W. ; Snelling, N. J. Abstract Publication: Economic Geology Pub Date: July 1979 DOI: 10.2113/gsecongeo.74.4.838 Bibcode: 1979EcGeo..74..838G