The Gibraltar Cu-Mo deposit, with a total tonnage of 3.2 million tons (Mt) Cu, is located in the Canadian Cordillera and hosted by the Late Triassic Granite Mountain batholith. The batholith formed through multiple intrusions of tonalitic rocks over a period of ~25 m.y. beginning at 229.2 ± 4.4 Ma in the Quesnel island arc before the accretion of the arc to the North American continent. Late in its evolution, Cu fertile magmas intruded in the center of the batholith, during at least three events from 218.9 ± 3.1 to 205.8 ± 2.1 Ma. The fertile magmas were hotter and more mafic than older barren magmas. They generated magmatic-hydrothermal activity, forming potassic alteration and white mica alteration, and produced Cu mineralization as chalcopyrite-quartz veinlets and disseminated chalcopyrite. Zircon in the Cu-bearing tonalite intrusion (218.9 ± 3.1 Ma) shows high Ce⁴⁺/Ce³⁺ (681 ± 286 [2σ], n =15) compared to those from older barren intrusions (129 ± 56 [2σ], n = 118). Oxidation conditions for parental magmas are calculated using the compositions of zircon and amphibole. The magmas for Cu-bearing intrusions have an average of fayalite-magnetite-quartz buffer (FMQ) +1.7 ± 0.7 (2σ, n = 73), whereas those for older barren intrusions have slightly lower f_O2 (avg FMQ +1.3 ± 0.5 [2σ], n = 108), although the values are overlapping for the two.The bulk rocks of Cu-bearing tonalite intrusions in the Granite Mountain batholith have low Sr/Y ratios (<22) independent of the degrees of alteration. The low ratios are also reflected by low Sr/Y in zircon, suggesting that the low Sr/Y ratios of bulk rocks represent those of unaltered rocks. The values are low compared to those associated with many other porphyry Cu deposits globally. The data suggest that igneous rocks elsewhere with low Sr/Y in bulk rocks may have a potential to host economic Cu deposits. Ratios of Ce/Nd and Ce/Ce* (=Ce/((NdN)2SmN)) in zircon are positively correlated with the Ce⁴⁺/Ce³⁺ in zircon from the Granite Mountain batholith. Since the former two ratios can be obtained solely from zircon composition, these ratios from detrital zircon may be useful in evaluating the occurrences of oxidized intrusions in regional mineral exploration.

中文翻译：

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不列颠哥伦比亚省直布罗陀斑岩铜钼矿床的长期岩浆作用和矿化热液活动

直布罗陀铜钼矿总吨位为320万吨，位于加拿大山脉，由晚三叠世花岗岩山岩床托管。在约25我的时间段内，在Quesnel岛弧段开始于229.2±4.4 Ma时，多次侵入胶状岩，形成岩基，之后弧向北美大陆增加。在其演化的后期，至少在从218.9±3.1到205.8±2.1 Ma的三个事件中，铜肥沃的岩浆侵入了基岩的中心。肥沃的岩浆比年长的贫瘠岩浆更热，黑手党。它们产生了岩浆热液活动，形成钾质蚀变和白云母蚀变，并以黄铜矿-石英细矿和弥散的黄铜矿的形式产生了铜矿化作用。锆石在含Cu的tonalite侵入中（218.9±3。⁴⁺ / Ce ³⁺（681±286 [2σ]，n = 15），相比之下，较老的贫瘠入侵（129±56 [2σ]，n = 118）。母体岩浆的氧化条件是使用锆石和闪石的组成来计算的。含铜侵入岩浆的平均铁橄榄石-磁铁矿-石英缓冲区（FMQ）+1.7±0.7（2σ，n = 73），而较贫瘠的侵入岩浆的f _{O 2}略低（平均FMQ +1.3±0.5 [2σ]，n = 108），尽管这两个值是重叠的。花岗岩山岩基中含铜斜长石侵入体的块状岩石具有较低的Sr / Y比（<22）独立变化的程度。锆石中的低Sr / Y比也反映出较低的比率，这表明块状岩石的低Sr / Y比代表未改变的岩石。与全球其他许多斑岩型铜矿床相比，该值较低。数据表明，散装岩石中Sr / Y低的其他地方的火成岩可能具有蕴藏经济铜矿的潜力。锆石中Ce / Nd和Ce / Ce *（= Ce /（（（NdN）2SmN））的比率与Ce ⁴⁺ / Ce ³⁺正相关花岗岩山基岩中的锆石中。由于前两个比率只能从锆石成分中获得，因此碎屑锆石的这些比率可能有助于评估区域矿产勘探中氧化侵入的发生。