Study On The Ore-bearing Potential Evaluation Of Mafic-ultramafic Intrusions At Eastern Tianshan Of Xinjiang

Easten Tianshan is an important Cu-Ni ore-concentrated area, where exist a series of magmatic copper-nickel sulfide deposit, including three big scale Cu-Ni deposits of Huangshan, Huangshandong and Tulaergen, many medium and small scale Cu-Ni deposits such as Tudun, Xiangshan, Hulu, Getashankou and Baixintan and many Cu-Ni mineralization. Along the Kangguertage-Huangshan shear zone, from west to east, exist a series of mafic-ultramafic intrusions that the mineralization potential did’t evaluate, such as Erhongwa, Hongshigang, Heishiliang, Yaziquanbeishan, Chuanzhu, Mati, Tulaergennan, Xianshuiquan, Langjing, Sidingheishan.A lot of deep study have been made for the Cu-Ni deposits in this area. But systematic study and comparation of difference between ore-baering and ore-free intrusions is poor. There is not an effective ore-bearing evaluation yet.This article study on Cu-Ni sulfide deposites and mafic-ultramafic intrusions in Easten Tianshan, aiming at ore-bearing evaluation of the intrusions by comparing the intrusions systematicly in macroscopic geology, mineralogy and petrogeochemistry and analysing the difference between ore-bearing intrusions and ore-free intrusions. And analyses the geology and geochemistry characteristics of Tulaergen intrusion detailedly. Through targeted test and analysis of Tulaergennan, Hongshigang, Langjing, Mati and Yaziquanbeishan mafic-ultramafic intrusions, we try to evaluate their mineralization potential. The main results are as follows:1. Study on the geological, geochemical and physical geography characteristics of Tulaergen,Tulaergennan, Hongshigang, Langjing, Mati and Yaziquanbeishan mafic-ultramafic intrusions, enriching the basic date of intrusions in the study area.2. Analysis and comparison on the geological, geochemical and physical geography characteristics of ore-forming intrusions and ore-free intrusions, summarizing the ore-bearing evaluation of the mafic-ultramafic intrusion in Eastern Tianshan: The ore-forming intrusions with a lot of rock types are small and differentiate adequately. The ore-bearing lithofacies that have mineral association of chrysolite-bronzite are most suffered strong alteration. The m/f value of the ore-forming intrusions is more than 2~6. The Cu/Zr ratio with larger content and range has good positive correlation with Ni. The degree of REEs distribution of ore-forming intrusions is right-dip curve, while ore-poor or ore-free is flat. The geophysical composite anomalies of ore-bearing intrusions is ―three higher and one lower‖.3. Use the ore-bearing evaluation, evaluating the mineralization potential of several mafic-ultramsfic intrusions in Easten Tianshan: Tulaergennan, Langjing and Mati intrusions differentiate adequately and most suffered strong alteration. Their m/f value is more than 2~6 and the degree of REEs distributiona are all right-dip curve. Hongshigang intrusion shows certain mineralization potential, but still need to be verified next. Yaziquanbeishan is large intrusion and differentiate more weakly. Its value of m/f and Cu/Zr are below 1. So Hongshigang and Yaziquanbeishan intrusions are unfavorable for Cu-Ni deposit.