Distal alteration related to porphyry Cu mineralization is typically characterized by an abundance of green minerals, such as epidote, tremolite, and chlorite, within the propylitic and sodic-calcic alteration zones and extends far outside (>1 km) the mineralized zone(s). Glacial erosion and dispersal derived from rocks affected by propylitic and sodic-calcic alteration have resulted in the development of extensive dispersal trains of epidote in till (glacial sediment) that can reach 8 to 330 km² as observed at four porphyry Cu study sites in the Quesnel terrane of south-central British Columbia: Highland Valley Copper, Gibraltar, Mount Polley, and Woodjam deposits. At each of these sites, epidote is more abundant in heavy mineral concentrates of till collected directly over and down-ice from mineralization and associated alteration. Epidote grains in till with >0.6 ppm Sb and >8 ppm As (as determined by laser ablation-inductively coupled plasma-mass spectrometry) are attributed to a porphyry alteration provenance. There is a greater abundance of epidote grains with high concentrations of trace elements (>12 ppm Cu, >2,700 ppm Mn, >7 ppm Zn, and >37 ppm Pb) in each porphyry district compared to background regions. This trace element signature recorded in till epidote grains is heterogeneously distributed in these districts and is interpreted to reflect varying degrees of metal enrichment from a porphyry fluid source. Tracing the source of the epidote in the till (i.e., geochemically tying it to porphyry-related propylitic and/or sodic-calcic alteration), coupled with porphyry vectoring tools in bedrock, will aid in the detection of concealed porphyry Cu mineralization in glaciated terrains.

中文翻译：

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追踪冰川地带斑岩铜矿蚀变晕衍生的碎屑绿帘石：寻找覆盖矿化

与斑岩铜矿化相关的远端蚀变通常以青盘岩和钠钙蚀变带内丰富的绿色矿物为特征，例如绿帘石、透闪石和绿泥石，并延伸到矿化带之外很远（>1公里） 。受青盘岩和钠钙蚀变影响的岩石所产生的冰川侵蚀和扩散导致了绿帘石在蒂尔（冰川沉积物）中的广泛扩散系列的发展，如在印度的四个斑岩铜研究地点所观察到的，其范围可达 8 至 330 km ² 。不列颠哥伦比亚省中南部的康奈尔地体：高地谷铜矿、直布罗陀、波利山和伍德贾姆矿床。在这些地点中的每一个地点，绿帘石在矿化和相关蚀变直接在冰上和冰下收集的重矿物浓缩物中更为丰富。矿床中的绿帘石颗粒含有 >0.6 ppm Sb 和 >8 ppm As（通过激光烧蚀-电感耦合等离子体质谱测定），归因于斑岩蚀变来源。与背景区域相比，每个斑岩区都有更丰富的含有高浓度微量元素（>12 ppm Cu、>2,700 ppm Mn、>7 ppm Zn 和 >37 ppm Pb）的绿帘石颗粒。绿帘石颗粒中记录的微量元素特征在这些区域中分布不均匀，并被解释为反映斑岩流体源不同程度的金属富集。追踪矿床中绿帘石的来源（即，在地球化学上将其与斑岩相关的青盘岩和/或钠钙蚀变联系起来），再加上基岩中的斑岩矢量工具，将有助于探测冰川地带中隐伏的斑岩铜矿化。