Study on the structural-magmatic events and the formation of ore deposits in the Sanshui basin, central Guangdong Province

Abstract：Zircon LA-ICP-MS U-Pb age of the Cenozoic silver-bearing trachytic tuff from the Sanshui basin ranges from 90 to 3175 Ma. The zircon age of the Cenozoic volcanic rocks indicates that the zircon grains were captured during the formation and ascending of the volcanic melts. The occurrence of zircon grains with ages (2489 Ma±30 Ma,3175 Ma±38 Ma shows that the basement of the Shanshui basin contains the Archean relict zircon. The occurrence of zircon grains in Proterozoic age indicates that the Proterozoic basement of the Cathaysian block underwent structural-magmaic activities (955~1148 Ma) at the same period as the Grenville orogeny and the Neoproterozoic structural-magmatic activities (798 Ma±12 Ma, 883 Ma±10 Ma). The region of the Sanshui basin underwent Caledonian (438.0 Ma±6.8 Ma), early Yanshanian (~160 Ma), late Yanshanian(±98.2±1.1Ma), and Himalayan structural-magmatic events. The multi-structural magmatic events correlate well with the formation of deposits occurred in the southwestern rim of the Sanshui basin. It is concluded that the multi-structural-magmatic events are the key factors controlling the formation of the deposits in the southwestern rim of the Sanshui basin. The South China Fold belt underwent Himalayan ore-forming event and the rim regions of the faulted basins in the South China Fold Belt that underwent multi-structural-magmatic activities are favorable target area for mineral prospecting.