Porphyry copper deposits are associated with large alteration footprints, and alteration mapping plays a key role in the exploration of these deposits. Imaging spectroscopy is commonly deployed for exploration targeting, yet it has rarely been used to map deposit-scale alteration patterns before initiating drilling. To close this gap, the Shadan porphyry Cu-Au deposit was thoroughly studied using the HyMap hyperspectral data (visible near-infrared–short-wave infrared) at 5-m resolution corroborated by rock geochemistry, magnetometry, and laboratory spectroscopy. Shadan is a well-exposed deposit with near-perfect zonation located in the volcanic belts of eastern Iran containing >135 Mt of ore at 0.3% Cu and 0.4 g/t Au. Thirteen minerals, including white mica, Al smectite, kaolinite, ferric/ferrous minerals, biotite, actinolite, epidote, chlorite, tourmaline, and jarosite, were mapped by applying the multifeature extraction methodology. The propylitic zone was partitioned into actinolite, epidote, and chlorite subfacies. The compositions of biotite and white mica were observed to become Fe and Al rich, respectively, toward the mineralized zones. The chemistry of actinolite was observed to change from Fe to Mg rich inward, providing a new vectoring tool for porphyry copper exploration. The study provided significant information about fluid-rock interactions and the chemistry of the circulating fluids including the oxidation-reduction states and acidity. By integrating the mineral maps with other data sets using the fuzzy logic method, the promising (ore) zones were identified and used to plan the next-stage drilling. This work demonstrated that imaging spectroscopy can be effectively used to better understand porphyry systems and provide deposit-scale vectors toward the mineralized centers, facilitating drilling.

中文翻译：

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使用机载成像光谱数据绘制沙丹斑岩铜金矿床（伊朗）的蚀变矿物图：对勘探钻探的影响

斑岩铜矿床与大型蚀变足迹有关，蚀变测绘在这些矿床的勘探中发挥着关键作用。成像光谱通常用于勘探目标，但很少用于在开始钻探之前绘制沉积物规模蚀变模式。为了弥补这一差距，利用 HyMap 高光谱数据（可见近红外 - 短波红外）以 5 米分辨率对沙丹斑岩铜金矿床进行了彻底研究，并通过岩石地球化学、磁力测量和实验室光谱学证实。 Shadan 是一个暴露良好的矿床，位于伊朗东部的火山带，具有近乎完美的分带，含有超过 135 公吨的矿石，铜品位为 0.3%，金品位为 0.4 克/吨。通过应用多特征提取方法，对白云母、铝蒙皂石、高岭石、铁/亚铁矿物、黑云母、阳起石、绿帘石、绿泥石、电气石和黄钾铁矾等 13 种矿物进行了绘图。青盘岩带被划分为阳起石、绿帘石和绿泥石亚相。观察到黑云母和白云母的成分分别向矿化带变得富含铁和铝。观察到阳起石化学成分由Fe向内转变为富镁，为斑岩铜矿勘探提供了新的矢量工具。该研究提供了有关流体-岩石相互作用和循环流体化学性质（包括氧化还原态和酸度）的重要信息。通过使用模糊逻辑方法将矿物图与其他数据集集成，确定了有前景的（矿石）区域并用于规划下一阶段的钻探。这项工作表明，成像光谱可以有效地用于更好地了解斑岩系统，并提供朝向矿化中心的沉积物规模矢量，从而促进钻探。