Abstract:Fluorite, barite and lead-zinc (mercury) minerals are widely distributed in northeastern Guizhou (Yanhe)-southeastern Chongqing (Youyang) area; nevertheless, there has been no direct isotope age evidence about the mineralization age. The Dazhuyuan fluorite deposit in the northeast of Guizhou is located at the southeast edge of the upper Yangtze block, the orebodies are hosted in the Lower Ordovician carbonate of Tongzi and Honghuayuan formations, controlled by NW-trending faults,and the deposit is the representative in the hydrothermal vein type fluorite deposits of this area. Therefore, the authors selected the deposit to carry out the dating of the mineralization by using the monomineral Sm-Nd isochron method and obtained the Sm-Nd isochron age of fluorite of 436±15 Ma (MSWD=0.85), and the age of associated calcite and fluorite assemblage of 430±13 Ma (MSWD=1.02); the two ages are consistent, indicating that the Dazhuyuan fluorite deposit was formed in Caledonian, and the ages are consistent with the ages (477~410 Ma) of the MVT lead and zinc deposits in west Hunan-east Guizhou area. The fluorite-barite deposits in this area are closely related to the main lead-zinc (mercury) deposits, and therefore the authors infer that they had the similar sources, and constituted a metallogenic series which had genetic relationship and were formed during the same tectonic movement period. All this indicates that Caledonian period was an impor-tant medium-low temperature hydrothermal metallogenic period for the formation of fluorite-barite and lead-zinc (mercury) deposits.