Enigmatic massive sulphide mineralization in the High Arctic Large Igneous Province, Nunavut, Canada
Enigmatic massive sulphide mineralization in the High Arctic Large Igneous Province, Nunavut, Canada
复制标题
加拿大努纳武特地区高北极大型火成岩省的神秘块状硫化物矿化
DOI：
--
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
M. Williamson
中科院分区：
文献类型：
--
作者：
D. Wilton;B. Saumur;A. Gordon;M. Williamson
现代矿产勘探策略应考虑给定地质环境的非传统成矿模型。在这里，我们记录了对与高北极大型火成岩省 (HALIP) 和斯维尔德鲁普盆地相关的块状硫化物的首次详细研究，事实上，这只是加拿大北极群岛伊丽莎白女王群岛阿克塞尔海伯格岛描述的第二个矿化实例。所显示的Between Lake（阿克塞尔海伯格岛西部）是一个位于辉长岩大山脊下方碎石/距岩内的小型块状硫化物矿点。勘探者最初将其描述为闪长质岩脉内的正射岩浆硫化物矿点。新的岩相学和矿物学分析表明，该矿区主要由磁黄铁矿和少量黄铁矿、微量黄铜矿和稀有闪锌矿组成。未检测到含镍或含铅的硫化物矿物。从地球化学角度来看，该矿层含有一些钴和铜、稀有的锌以及通常非常低的镍含量（<9 ppm）。硫化物矿物的硫同位素比范围为+3.6至+6.6‰，比预期的岩浆衍生硫稍重，但同位素比当地蒸发岩底辟相关的硫轻（+5.8‰至+12.2‰）。闪长岩中的正岩浆硫化物通常表现出更轻的同位素比，为–3.9‰至–1.00‰。这些数据与 HALIP 中首次记录的潜在镁铁质-硅质碎屑火山成因块状硫化物矿化等一致。与广泛的 HALIP 岩浆作用相关的高热流可能是这种矿化的驱动力。加拿大高纬度北极地区的矿产前景预测是基于岩浆 Ni – Cu – 铂族元素硫化物矿化的潜在存在。我们的研究结果并没有否定这种潜力，而是为努纳武特地区的其他成矿潜力提供了证据。
Modern mineral exploration strategies should take into account nontraditional metallogenic models for a given geological environment. Here we document the first detailed study of a massive sulphide showing associated with the High Arctic Large Igneous Province (HALIP) and Sverdrup Basin and in fact, only the second example of mineralization described from Axel Heiberg Island, Queen Elizabeth Islands, Canadian Arctic Archipelago. The Between Lake showing (western Axel Heiberg Island) is a small massive sulphide occurrence within scree/talus below a large ridge of gabbro. It was originally described by explorationists as an orthomagmatic sulphide occurrence hosted within a dioritic dyke. New petrographic and mineralogical analyses indicate that the showing consists predominantly of pyrrhotite with lesser pyrite, trace chalcopyrite, and rare sphalerite. No Ni- or Pb-bearing sulphide minerals were detected. Geochemically, the showing contains some Co and Cu, rare Zn, and generally very low Ni contents (<9 ppm). Sulphur isotope ratios of sulphide minerals range from +3.6 to + 6.6‰, somewhat heavier than expected for magmatic-derived S but isotopically lighter than S associated with local evaporite diapirs (+5.8‰ to +12.2‰). Orthomagmatic sulphides hosted in the diorite typically exhibit even lighter isotopic ratios of –3.9‰ to –1.00‰. The data are consistent with potential mafic–siliciclastic volcanogenic massive sulphide mineralization, or the like, the first documented in the HALIP. High heat flow associated with extensive HALIP magmatism was likely the driving force for such mineralization. Mineral prospectivity in Canada’s High Arctic had been predicated upon the potential presence of magmatic Ni – Cu – platinum group element sulphide mineralization. Rather than negating this potential, our findings provide evidence for additional metallogenic potential for this region of Nunavut.