Large-scale mafic dikes are developed in Northern Daba Mountain-Wudang Mountain- Shiyan and Suizhou areas of the South Qinling Orogen.Their petrogenesis and tectonic evolution are widely of interst to geologists.In this paper,whole-rock geochemistry,SHRIMP zircon U-Pb age and the LA-MC-ICP-MS zircon Hf isotopic compositions are used to study the gabbro occurring in the Huanglong-fangtan area of Wudang Mountain.The result indicates that these gabbros intruded during the Late Triassic (221.2 ±2.5 Ma);whole-rock geochemical data shows that the gabbros are sub-alkaline tholeiitic series with moderate concentrations of Ti,Zr,Hf and Nb,while exhibiting depletions of the large ion lithophile elements (LILE) such as Rb and Sr.The rare earth element (REE) distribution patterns display negative slopes with slight light rare earth element (LREE) enrichment and depletion of heavy rare earth elements (HREE),which are similar to that of enriched mid-ocean ridge basalt (E-MORB).The εHf（t） value of magmatic zircons are between -13.5 and -6.18 with ancient two-stage Hf model ages (2103~1640 Ma).In addition,the gabbros appear to have all originated from low-pressure and medium degree of partial melting of spinel lherzolite.The regional tectonic evolution combined with the new evidence for mantle enrichment,and the E-MORB affinities of the gabbros in this paper,suggests that these rocks formed in a convergent tectonic setting,affected by subduction of the Mianlue Ocean basin,and may thus be the product of the subduction-collisional stage.