投稿时间：2025-12-05
修订日期：2026-03-24
网络发布日期：2026-04-22
中文摘要:位于东昆仑造山带的夏日哈木Ni-Co矿床是目前在全球造山带发现的最大的岩浆硫化物矿床，矿体主要赋存于斜方辉石岩和方辉橄榄岩中，但2种岩相中形成的矿石结构类型截然不同。文章基于钻孔矿石样品的X射线面扫描以及三维CT成像，对不同矿石结构中硫化物的几何形态与连通性进行了系统分析，以探讨硫化物熔体在开放岩浆通道中的动力学行为。研究表明：在方辉橄榄岩中，硫化物熔体对橄榄石的润湿性与硅酸盐熔体对橄榄石的润湿性接近，因而硫化物熔体在重力驱动下可沿橄榄石堆晶孔隙渗透下移，并置换晶间残留的硅酸盐熔体，形成网脉状的稠密浸染状矿石或斑杂状矿石；而在斜方辉石岩中，硫化物熔体对斜方辉石的润湿性远低于硅酸盐熔体对斜方辉石的润湿性，硫化物熔体难以置换斜方辉石晶间的硅酸盐熔体。因此，在斜方辉石岩中常见以小珠滴和离散斑块为主、总体连通性较差的斑杂状矿石，这种硫化物斑块并非仅为堆晶后渗透产物，而是岩浆通道底部沟槽早期沉淀的硫化物团块被后续补充的岩浆重新扰动、卷起，并经历短距离搬运后，与硅酸盐矿物共同堆积的结果。如果这种硫化物熔体斑块受到挤压，则可能向周围渗透，形成浸染状结构。同时，硫化物在不同岩相中的分布不均以及结构差异还会导致矿体内Ni品位的剧烈变化。上述研究揭示了岩浆通道过程以及堆积晶与硫化物熔体润湿关系对矿石结构的控制作用，为硫化物岩浆通道成矿的富集机制研究与成矿预测提供新的约束。
Abstract:The Xiarihamu Ni-Co deposit in the East Kunlun Orogenic Belt is the largest magmatic sulfide deposit discovered in an orogenic setting, with mineralization hosted mainly in orthopyroxenite and harzburgite. However,the sulfide-silicate textures developed in these two lithologies are markedly different. In this study, we use microbeam XRF mapping and 3D X-ray computed tomography of drill core samples to quantify the geometry of sulfide in contrasting ore textures and to investigate sulfide transport and deposition mechanism within magma plumbing systems. Our results show that in harzburgite, sulfide melt is able to percolate downward through the pores of olivine. Sulfide percolation displaces intercumulus silicate melt and produces net textures. When sulfide percolation confines silicate melt into progressively smaller, enclosed pockets, capillary resistance increases geometrically and further percolation is arrested, producing the observed patchy net-texture. By contrast, weak wetting of orthopyroxene by sulfide inhibit displacement of intercumulus silicate melt in orthopyroxenite, leading to disseminated ore textures. Moreover, orthopyroxenite contains several semi-massive sulfide horizons that are poorly connected to one another. The presence of sulfide matrix with silicate inclusions cannot be simply attributed to post accumulation percolative aggregation of sulfide droplets; rather, we infer that sulfide melt were re-entrained in conduit flow, underwent only partial fragmentation during transport, and were deposited as the observed massive bodies. Consequently, orthopyroxenite commonly contains both disseminated sulfide droplets and sulfide matrix, and overall sulfide connectivity within orthopyroxenite is low. The Xiarihamu deposit formed in a dynamic conduit system. Multiple injections of ultramafic magma propagated from West to East along a longlived conduit system. Dense sulfide melt ponded in hydraulic traps along channel floors, producing massive sulfide accumulations. Subsequent magma pulses re-entrained the sulfide accumulations and transported them short distances; in widened, low velocity conduit segments sulfide liquid and silicate melt co-deposited as semi-massive bodies in the central part of the intrusion. These observations demonstrate that gravity driven percolation and the wetting relationships between cumulus phases and sulfide melt exert dominant control on ore texture development, and they provide new constraints on the mechanisms of sulfide enrichment and on exploration models for magmatic conduit deposits.
keywords:sulfide percolation wetting behavior magma conduit magmatic sulfide deposit Xiarihamu deposit
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基金项目:国家自然科学基金(编号:42102094、42330807);河北省自然科学基金(编号:D2021402020、D2025402002)项目联合资助
引用文本：
王开元,宋谢炎,Stephen J BARNES,谢伟,邢乐才.2026.夏日哈木超大型Ni-Co矿床不同矿石结构的成因意义探讨[J].矿床地质,45(2):209~228WANG KaiYuan,SONG XieYan,Stephen J BARNES,XIE Wei,XING LeCai.2026.Textural constraints on sulfide accumulation and metallogenesis in Xiarihamu Ni-Co deposit[J].Mineral Deposits45(2):209~228
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