摘要
图拉尔根、白石泉两处镍铜矿床的发现被认为是近年在新疆地区铜镍找矿中的重大突破,两者均属于和超镁铁-镁铁质杂岩有关的岩浆熔离贯入型矿床,前者更富含钴。矿石中磁黄铁矿-镍黄铁矿-黄铜矿共生为本矿床及同类矿床之共同特征。文章对岩体的含矿性及其中Co、Ni元素的赋存状态进行了研究,以等离子质谱对岩体中的Co、Ni、Cu及稀土元素分析和S元素丰度的湿法化学分析,揭示出两处岩体含矿性颇佳。通过X射线衍射、扫描电镜、电子探针分析并辅以常规显微镜,查明了Ni、Co两元素主要以独立的硫化物和硫砷化合物状态存在。在图拉尔根矿区发现的钴独立矿物镍辉砷钴矿和钴辉砷镍矿,属于辉砷钴矿和辉砷镍矿的同质多像变种。对此类金属矿物均作了较深入的分析与研究,为阐明矿床的成矿规律以及扩大找矿提供了重要的事实依据;也冀望对将来矿山选、冶方案的优化制定有所裨益。
The East Tianshan area is one of the most important Cu-Ni ore belts in China. The discovery of the Tulargen and Baishiquan Cu-Ni deposits is regarded as a great breakthrough in Cu-Ni exploration in Xinjiang in the past ten years. Both deposits are magmatic differentiated deposits related to mafic-ultramafic complexes, with the Tulargen deposit possessing richer Co than the Baishiquan deposit. So far, both ore districts have still been under prospecting. In the Tulargen deposit the proved reserves are copper metal 80000 tons with an average grade of 0.4%, Ni 125000 tons with an average grade of 0.6%, and Co 10000 tons with the grade varying from 0.01 to 0.09%. Baishiquan now is a medium-sized Cu-Ni deposit. The ore potential and the existent minerals of Co and Ni were systematically studied in this paper. Analyses of Co-Ni and trace elements by ICP-MS show a positive mineralization potential. Various kinds of lithofacies in the two deposits possess high Ni, Cu and Co with the Ni/Co ratio from 10.21 to 10.98, whereas REE patterns show LREE enrichment with 51.4-81.1 for ∑REE, similar to things of such known famous Cu-Ni deposits in China as Jinchuan, Hongqiling and Huangshan. These ore-bearing ultramafic lithofacies show higher sulfur contents （12400×10^-6-26400×10^-6） than barren lithofacies （300×10^-6-700 ×10^-6）. Ni contents of olivine from regional ore-bearing intrusions in East Tianshan area vary from 964 ×10^-6 to 1818 ×10^-6, lower than the normal value of 2200 × 10^-6, suggesting that the well-differentiated mafic-ultramafic magma is more favorable for Cu-Ni-Co mineralization. Fo parameters of olivine vary in a very small range from 82.01 to 84.92 for the Tulargen deposit. Pyrrhotite, pyrite, pentlandite, chalcopyrite and violarite exist together in ores, similar to things of other deposits of this type. The ore mineral assemblage indicates that the ore-forming process can be divided into three sub-stages, with the second stage being most important. Ni and Co elements occur as isolated sulfides and sulfur-arsenic mineral compositions, as shown by such analytical means as X-ray diffraction, SEM, electron microprobe, and scanning microscope. The authors identified two independent isomorphous cobalt minerals, i.e., Ni-cobaltite and Co-gersdorffite. A systematic analysis of these rock-forming and ore-forming minerals can reveal the ore-forming process and supply important information for further exploration, thus beneficial to the study of ore processing and smelting.
出处
《矿床地质》
CAS
CSCD
北大核心
2007年第1期1-14,共14页
Mineral Deposits
基金
国家自然科学基金项目(40672069)
中国科学院知识创新工程重要方向项目(KZCX3-SW-137)
国家"十五"科技攻关新疆305项目东天山东段铜矿专题(2003BA612A-06-07)的共同资助
作者简介
秦克章，男，1964年生，研究员，博导，从事造山带与成矿作用研究。E-mail：kzq@mail．igcas．ac．cn，Tel：010-62008348。
