Magmatism And Metallogenesis Of The Jinchang Gold Deposit In Heilongjiang,China

Jinchang gold deposit is in the joint position of the uplifted zone of Proterozoic Taipingling dones and Mesozoic Laoheishan fault basin,which is belong in the southern margin of Xingkai massif.This area is located in the south margin of North China plate,in the north part of Jiamusi,Xingkai plate,and also in the contact site of the central Asia-Mongolia tectonic domain and the West Pacific.Through collecting the basic geologic information,studying outside in the wild and analyzing test data of Jinchang gold deposit,the author analyzed the background,the elements of forming a deposit,the process of it;and also studied the geological features,materials and enrichment conditions;in the end summarized the magatic evolution,the contact between structure and ore-controlling factors.Through studying the Age geology,the author found that diorite age ofJinchang gold is 100.59 Ma and 111.13 Ma,which belonged to Late Yanshan,The age of the ore bearing granite porphyry is 111.1Ma.Diorite belonged to Late Yanshan is a kind of quasi aluminacalc alkaline gabbro diorite.The granite porphyry is a kind of high-k calc alkaline peraluminous rock,Through wild work and drill research making sure the relationship of the different magma,with the studying of the Age geology,the author found that diorite age of Jinchang gold was 100.59 Ma and 111.13 Ma.One of the age of ore bearing granite porphyry was 111.1Ma.Diorite belonged to Late Yanshan was a kind of quasi alumina calc alkaline,and the granite porphyry was a kind of high-k calc alkaline peraluminous.The main and rare elementsdata shows thatdiorite is lack of high field-strength element Zr?Y?Yb,rich of large ion lithophile element(LILE)Rb?Th?U?K,etc,Europium has weak positive anomalies,the fractionation of light and heavy rare is weak,average value of La/Yb is7.49,LREE is relative rich,while HREE is vice versa.The distribution model is similar to that of the Andean calc alkaline andesite series,but is quite different from the flat curve of the island arc calc alkaline series;granite porphyry is rich of large ion lithophile element(LILE)Rb?K,but lack of high field-strength element Ni?Ta?Ti,it shows positive anomalies ofNd and Hf.The total amount of REE varies greatly,the fractionation of light and heavy rare is stronger than the diorite,average value of La/Yb is 8.1,LREE is relative rich,while HREE is vice versa.Compared with the diorite,these two kinds of rocks had closed relationship.The magma,which belonged to the Late Yanshan,developed in the island arc environment of Andean type active continental margin.The magma maybe come from the partial melting of the mantle wedge,which was replaced by subduction plate fluid,in the process of subduction from Isawa Nagasaki plate to east China continent.By the proving of the fluid inclutions factors,the fluid of Jinchang gold deposit were two migration directions,one was from J-0 to J-1,and the other was heading from J-XI to J-1.Jinchang gold deposit has closed relationshio with the magma activities,so the granite porphyry(Late Yanshan)is the point in next prospecting direction.