The　Zhaiping　Ag-Pb-Zn　vein　deposit　in　the　Coastal　Volcanic　Belt　of　southeastern　China,　which　resulted　from　subduction　of　the　paleo-Pacific　oceanic　lithosphere　beneath　the　South　China　Block,　is　hosted　by　Early　Cretaceous　sub-volcanic　rocks　(rhyolite　porphyry)　and　younger　granite　porphyry　and　quartz　porphyry.　Three　generations　of　veins　have　been　recognized:　(i)　pre-ore　quartz　+　pyrite,　(ii)　syn-ore　silver　+　pyrite　+　pyrrhotite　+　base　metal　sulfides　+　quartz　+　sericite,　and　(iii)　post-ore　quartz　+　calcite　+　fluorite　veins.　Rubidium-Sr　dating　of　syn-ore　pyrite　yielded　an　isochron　age　of　132.2　+/-　2.1　Ma　(2　sigma,　MSWD　=　2.0,　n　=　4),　which　is　roughly　coincidental　with　the　age　of　the　granite　porphyry　and　quartz　porphyry　(zircon　U-Pb　age:　ca.　133　Ma).　The　age　data,　together　with　Pb,　S,　H,　and　O　isotopic　compositions,　indicate　a　close　temporal　and　possibly　genetic　relationship　between　mineralization　and　porphyry　magmatism　at　Zhaiping.　Geochemical　and　isotope　data　demonstrate　that　the　Zhaiping　sub-volcanic　rocks　were　derived　from　partial　melting　of　Proterozoic　crustal　sources　and　underwent　fractionation　of　feldspars,　monazite,　and/or　allanite.　The　Sr-87/Sr-86　ratios　of　pre-ore　(Ap(h1))　and　syn-ore　(Ap(h2))　stage　apatite　are　in　the　ranges　of　0.71350　to　0.71441　and　0.71260　to　0.71328,　respectively,　which　are　distinct　from　those　of　the　sub-volcanic　intrusive　rocks　(0.7119-0.7125).　The　Sr　isotope　signature,　together　with　lower　fluid　temperatures　(＜　360　degrees　C)　relative　to　typical　magmatic　fluid,　points　at　addition　of　an　external　fluid.　It　is　suggested　that　the　sub-volcanic　intrusion　acted　as　a　heat　source　that　drove　the　dehydration　of,　and　subsequent　fluid　circulation　within,　the　host　rocks.　Lower　Sr-87/Sr-86　ratio　but　higher　Sr　content　of　Ap(h2)　relative　to　Ap(h1)　possibly　indicates　continuous　fluid-rock　interaction　and　progressive　decomposition　of　feldspar　in　the　host　rocks,　thus　supplying　large　amounts　of　Sr　and　probably　Pb　to　the　ore　fluid.