Abstract A hydrogeochemical study using high resolution ICP-MS was undertaken at the Taurus and other porphyry Cu-Mo(-Au) occurrences and Ag-Au-Cu (+/- Pb, Zn) occurrences with epithermal-style characteristics in the Yukon-Tanana upland region of eastern Alaska. Surface water samples were collected from 30 sites on creeks that drain known deposits and occurrences and surrounding presumably unmineralized areas. Water samples for the entire ∼9 km length of McCord Creek, which drains the Taurus deposit, and those from streams draining the areas at and near the Bluff and Dennison porphyry occurrences have high conductivity values (492 to 1250 μS/cm) and consistently high concentrations of B (3-250 μg/L), Co (2.3 to 42 μg/L), Mn (339 to 4750 μg/L), Re (0.012 to 0.1 μg/L), and SO42- (>200 mg/L), all of which are well above the median value for this data set and significantly greater than concentrations in water samples from the unmineralized areas. These are the best pathfinder elements specifically for porphyry style deposits because most of them are not anomalous in waters near epithermal occurrences. Copper concentrations are high (up to 115 μg/L) in some low-pH water samples from McCord Creek and drainages around Bluff, and a few near neutral pH waters have high molybdenum (>1 μg/L), but neither element is consistently anomalous in close vicinity to the porphyry occurrences, possibly due to a metal-poor, sulfide-poor leached cap (average of ∼50 m) that overlies supergene and hypogene mineralized zones and is the dominant rock at surface. High concentrations of Bi and/or As occur in many waters associated with mineralized areas, particularly the Bluff and Dennison occurrences. In general, the element associations related to porphyry deposits reflect the deposit mineralogy, as well as size of the footprint related to alteration and mineralization.

中文翻译：

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阿拉斯加中东部育空-塔纳纳高地地区的水文地球化学：斑岩型矿床的可能勘探工具

摘要 使用高分辨率 ICP-MS 在育空地区的金牛座和其他斑岩型 Cu-Mo(-Au) 矿点和 Ag-Au-Cu (+/- Pb, Zn) 矿点进行了水文地球化学研究阿拉斯加东部的塔纳纳高地地区。地表水样品是从小溪上的 30 个地点收集的，这些小溪排干了已知的沉积物和矿点，以及周围可能未矿化的区域。整个约 9 公里长的 McCord Creek 的水样，它排出金牛座矿床，以及来自布拉夫和丹尼森斑岩矿区及其附近地区的溪流的水样具有高电导率值（492 至 1250 μS/cm）并且始终处于高水平B (3-250 μg/L)、Co (2.3 to 42 μg/L)、Mn (339 to 4750 μg/L)、Re (0.012 to 0.1 μg/L) 和 SO42- (>200 mg/L) 的浓度L), 所有这些都远高于该数据集的中值，并且明显高于未矿化地区水样中的浓度。这些是专门用于斑岩型矿床的最佳探路者元素，因为它们中的大多数在超热液发生附近的水域中没有异常。来自 McCord Creek 和 Bluff 周围排水系统的一些低 pH 值水样中的铜浓度很高（高达 115 μg/L），并且一些接近中性 pH 值的水具有高钼（>1 μg/L），但两种元素都不是始终如一异常靠近斑岩产地，可能是由于贫金属、贫硫化物的浸出盖（平均约 50 m）覆盖在表生和次生矿化带上，是地表的主要岩石。与矿化区相关的许多水域中都存在高浓度的铋和/或砷，特别是布拉夫和丹尼森事件。一般来说，与斑岩矿床相关的元素组合反映了矿床矿物学，以及与蚀变和矿化相关的足迹大小。