Ore Genesis And Tectonic Setting Of Scheelite Mineralization Of Yangbishan Iron-Tungsten Deposit In Shuangyashan Of Heilongjiang Province,NE China

The Yangbishan iron-tungsten deposit is located in Shuangyashan area of Heilongjiang Province,and situated in the central of Jiamusi massif,the eastern of Central Asian Orogenic Belt,Uplift of the Huanan in Jiamusi massif uplift.The Yangbishan iron-tungsten deposit was found earlier and is a typical large sedimentary metamorphic iron ore and a medium-sized tungsten ore.Previous studies on the genesis and tectonic background of its tungsten ore are relatively weak.On the basis of collecting geological data of mining area and area,this paper makes a systematic study on the tungsten deposit through field geological research,indoor testing and comprehensive analysis.Ore-bearing rocks of tungsten mineralization in the Yangbishan deposit include granet skarn and diopside skarn.Metallic minerals in the tungsten ore are dominated by scheelite and pyrrhotite,with a small amount of magnetite,pyrite,chalcopyrite,sphalerite,cassiterite,arsenopyrite and molybdenite.The study of metallogenic geological conditions and geological characteristics of ore deposits indicates The layered iron orebodies are mainly hosted in the lowest rock section of Dapandao Formation.The lenticular and vein scheelite rebodies,occur in the footwall of iron orebodies.The tungsten ore body is controlled by the contact zone between gneissoid granite and marble of Xingdong group and its adjacent skarn belt.It is showed that genetic type of tungsten deposit is contact metasomatic type（skarn type）.Theδ¹⁸O_quartz value of scheelite-quartz veins in Yangbishan deposit is 10.9‰¹4.8‰,theδ¹⁸O_quartz value is 3.6‰⁷.5‰and theδD value is-120.9‰^-66.2‰,which show that the ore-forming fluid of the scheelite mineralization is priority to magmatic water.Theδ³⁴S value of metal sulfides in the skarn change from 16.1‰to 18.1‰,²⁰⁶Pb/²⁰⁴Pb value from 17.879 to 18.863,²⁰⁷Pb/²⁰⁴Pb value between 15.537 to 15.603,and 208Pb/204Pb value between 38.202 to 38.544.The data presented in this paper indicate that the S and Pb in the metal sulfides mainly come from the ore-hosting strata and remelting-type granitic magma.According to LA-ICP-MS zircon dating,the Yangbishan ore-related gneissic granite has an Early Paleozoic crystallization age of 520.6±2.8Ma.This study,together with previous data,indicates that the massifs of northeastern China,including Erguna,Xing’an,Songliao,Jiamusi,and Khanka massifs,belonged to an orogenic belt that existed along the southern margin of the Siberian Craton during the late Pan-African period（⁵00Ma）.The significant continental movements of this orogeny resulted in widespread magmatic activity in northeastern China from 530 Ma to 470 Ma under a tectonic setting that transitioned from compressional syn-collision to extensional post-collision.