Magma Conduit System And Magmatic Evolution Of Jinchuan Cu-Ni Sulfide Deposit

The JinChuan Cu-Ni (PGE) sulfide deposit is located in the Longshou Mountain, southwestern margin of Northern China plate, and Many scholars have done a lot of research for a long time. The theory of magma conduit system have been approved by the vast majority. However, the research of magma conduit system focus mostly on the magma experienced multiple magma chamber’s evolution in the vertical direction, so the magma conduit system which offer the metallogenic substance of Jinchuan deposit was not studied partly in previous research, and the research of parallel magma conduit system in the horizontal direction is far less than the research of magma chamber’s evolution in the vertical direction. The are also many different views in the effect of Jinchuan deposit fault systems in the magma conduit and the form of fault systems transforming the orebody in post-ore stage. The discovered Jinchuan Cu-Ni(PGE) sulfide deposit occues in two ultrabasic dykes, and the two biggest orebody, Ⅱ-1orebody and Ⅱ-2orebody in mining area Ⅱ in the middle of the deposit, occur in one ultrabasic dyke. In this paper, Ⅱ-1orebody and Ⅱ-2orebody were compared to analysis the evolution feature of parallel magma conduit system and the fault systems influencing on Jinchuan orebody and restoring original form of the orebody. These provide a basis for forecasting in outer and deeper areas of this deposit.Mainly based on a large number of relevant information and field research, by the field investigation collecting specimen, thin section and polished section microscope observation, geochemical investigation and method of tectonics, we focus on researching evolution of the Jinchuan’s ore-controlling structure and magma conduit system. The research results are obtained as following:①Rsearching the faults in the Jinchuan deposit and classify them according to their trait;②Major elements, trace elemensts and PGE elements geochemistry of Ⅱ-1orebody and Ⅱ-2orebody were compared to analysis of the relationship between them by research in several aspects: evolution of magma sources, crustal contamination, magma condensation and evolution features of PGE elements;③Research the form of faults system transform the Jinchuan orebody and restore orebody’s original form according to the geotectonic position of the Jinchuan deposit in pre-ore stage, ore stage and post-ore stage;④Metallogenic model of magma conduit system and its entrance location of Jinchuan Cu-Ni sulfide deposit is discussed.