本文为第二次青藏科考（编号2019QZKK0801）、科技部国家重点研发计划项目（编号2022YFC2903503）、国家自然科学基金项目（编号42122013、92162102、92162323）和中国科学院地质地球所重点部署项目（编号IGGCAS- 202204）联合资助的成果
WANG Shuo
1) Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China； 2) Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing 100029, China；3) College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, ChinaSHAN Pengfei
1) Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China； 2) Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing 100029, China；3) College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, ChinaLI Guangming
1) Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China； 2) Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing 100029, China；3) College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, ChinaCAO Mingjian
1) Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China； 2) Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing 100029, China；3) College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China钴是一种重要的战略性关键金属，随着新能源、新材料和航空航天技术的快速发展，钴资源的重要性日益显现。矽卡岩型矿床中的钴是我国钴资源的重要来源之一，钴常作为伴生组分出现在矽卡岩矿床中，部分矿床中伴生的钴资源量可达大型规模。西藏冈底斯成矿带分布众多矽卡岩型矿床，但对其中钴的富集特征和赋存状态尚缺乏系统认识和深入研究。本文对冈底斯东段的甲玛、龙马拉、春哲、知不拉、蒙亚啊、努日、邦浦、浦桑果、亚圭拉矽卡岩型矿床，以及冈底斯西段的帮布勒和查个勒等矽卡岩型矿床进行调查。通过手持X射线荧光分析、光学和扫描电子显微镜观察以及电子探针分析方法，对上述矽卡岩型矿床中代表性矿石钴的富集特征及赋存状态进行研究。手持X射线荧光分析结果显示冈底斯东段的矿床均不同程度存在钴的富集，其中甲玛、知不拉、浦桑果和春哲矿床中矿石的平均钴含量可分别达853×10-6、410×10-6、460×10-6和898×10-6；西段的帮布勒和查个勒矽卡岩型矿床中矿石钴含量基本低于检出限（< 3×10-6）。光学和扫描电子显微镜观察以及电子探针分析结果显示：钴元素在甲玛矿床中主要以辉砷钴矿的独立矿物形式存在；在浦桑果矿床中主要以辉砷钴矿和硫铜钴矿的独立矿物形式存在；在知不拉矿床中主要以硫镍钴矿的独立矿物形式存在；而在东段其他矽卡岩型矿床中缺乏独立钴矿物，钴元素主要以类质同象的形式分布在黄铁矿、斑铜矿、黄铜矿、闪锌矿、黝铜矿、碲银矿中。综上所述，冈底斯东段矽卡岩型矿床钴的富集程度明显优于冈底斯西段矽卡岩型矿床，表明冈底斯东段比西段更具钴富集潜力，冈底斯东段矽卡岩富钴的特征空间上大致受控于深部岩石圈结构，其成因可能与东段存在更多新生下地壳的部分熔融有关，此外，矿质沉淀不排除受到大气降水的影响。本次研究对西藏冈底斯成矿带中矽卡岩型矿床钴的富集特征、成矿机理及后续勘探工作提供重要参考。
As an important strategic key metal, cobalt will become increasingly vital with the rapid development of new energy, new materials and aerospace technology. Cobalt often appears in skarn deposits as an associated resource that, in some skarn deposits, can reach a large scale. Cobalt in skarn deposits is an important source of cobalt resources in China. There are many skarn deposits in the Gangdese metallogenic belt, Tibet. However, research on the enrichment characteristics and occurrence states of cobalt is lacking. In this paper, the Jiama, Longmala, Chunzhe, Zhibula, Mengyaa, Nuri, Bangpu, Pusangguo and Yaguila skarn deposits in the eastern Gangdese, and the Bangbule and Chagele skarn deposits in the western Gangdese were investigated. The enrichment characteristics and occurrence states of cobalt in representative ores in the deposit were studied by means of hand- held X- ray fluorescence analyzer, optical electron microscopy observation, scanning electron microscopy observation and electron probe microanalysis. The results of hand- held X- ray fluorescence analysis show that the deposits in the eastern Gangdese are enriched with cobalt to varying degrees. The average cobalt contents of Jiama, Zhibula, Pusangguo and Chunzhe deposits are 853×10-6, 410×10-6, 460×10-6 and 898×10-6 respectively, while the cobalt contents of Bangbule and Chagele deposits in the western Gangdese is lower than the detection limit (<3×10-6). The results of optical electron microscopy observation, scanning electron microscopy observation and electron probe microanalysis show that cobalt mainly exists in the form of cobaltite in the Jiama deposit, cobaltite and carrollite in the Pusangguo deposit, siegenite in the Zhibula deposit. Other skarn deposits in the eastern Gangdese are mostly distributed in the form of isomorphism in pyrite, bornite, chalcopyrite, sphalerite, tetrahedrite, tellurite, rather than independent minerals. Based on all the above experimental results and analyses, the enrichment degree of cobalt in the skarn deposits in the eastern Gangdese is distinctly higher than that in the western Gangdese, indicating that the former has better cobalt enrichment potential than the latter. The cobalt enrichment characteristics of skarns deposits in the eastern Gangdese would be controlled by the deep lithosphere structure. These characteristics may be related to the partial melting of juvenile lower crust in the eastern Gangdese, and the mineralization does not exclude the mixing of atmospheric precipitation. The main purpose of this research is to develop an understanding of cobalt enrichment characteristics and metallogenic mechanism, which can provide reference for subsequent exploration works.
王硕,许源,单鹏飞,斯郎旺堆,李光明,曹明坚.2024.西藏冈底斯成矿带矽卡岩矿床钴赋存状态及富集特征[J].地质学报,98(1):163-180.
WANG Shuo, XU Yuan, SHAN Pengfei, SILANG Wangdui, LI Guangming, CAO Mingjian.2024. The occurrence of cobalt and enrichment characteristics in skarn deposits of the Gangdese metallogenic belt, Tibet[J]. Acta Geologica Sinica,98(1):163-180.
