The Atlas porphyry Cu–Au deposit is located in central Cebu Island in the Philippines, with a proven mineral reserve of 1420 Mt at 0.45% Cu, 0.24 g/t Au, 0.018 g/t Mo, and 1.8 g/t Ag. It is associated with the Lutopan quartz diorite porphyry stock that was emplaced into the Cretaceous volcano-sedimentary sequences of the Cansi Formation. Two stages of hypogene alteration have been identified at Atlas: stage I quartz–magnetite ± chalcopyrite ± pyrite veins associated with potassic and propylitic alteration and stage II anhydrite–pyrite–chalcopyrite ± specularite veins associated with phyllic alteration. Supergene gypsum veins are also present. Mineralization is mainly associated with the stage I and stage II veins. The Lutopan quartz diorite porphyry yielded a zircon U–Pb age of 108.5 ± 1.6 Ma and is characterized by high Sr/Y (54–69), with the corresponding magma having high oxygen fugacity (avg. ΔFMQ +2.7, avg. Ce 4+ /Ce 3+ of zircon = 439) and H 2 O concentrations (presence of amphibole and biotite phenocrysts) and low magmatic temperatures (avg. Ti-in-zircon thermometry = 706 °C). The relatively low La/Yb ratios (9–11), listric-shaped normalized REE patterns with weak or absent Eu anomalies, together with zircon ε Hf (t) values of 3.4 to 10.0, whole-rock I Sr values of 0.70373–0.70382, ε Nd (t) values of 2.4–3.4 and Mg numbers of 49–53 suggest that the Lutopan quartz diorite porphyry was likely derived from partial melting of young lower continental crust or interaction between asthenospheric melts and lower crust melts, that evolved to adakite-like trace element compositions through amphibole fractionation. Stage I veins yielded a pyrite Re–Os isochron age of 110.2 ± 5.6 Ma, making Atlas the only Mesozoic porphyry deposit discovered in the Philippines.

中文翻译：

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菲律宾中生代斑岩铜金矿化和相关埃达克岩岩浆作用：来自巨大阿特拉斯矿床的见解

阿特拉斯斑岩铜金矿床位于菲律宾宿务岛中部，已探明矿产储量为 1420 公吨，含 0.45% 铜、0.24 克/吨金、0.018 克/吨钼和 1.8 克/吨银。它与位于 Cansi 组白垩纪火山沉积层序中的 Lutopan 石英闪长斑岩储量有关。在 Atlas 中已经确定了两个次生蚀变阶段：I 阶段石英-磁铁矿 ± 黄铜矿 ± 黄铁矿脉与钾和青铁矿蚀变相关，以及 II 阶段硬石膏-黄铁矿-黄铜矿 ± 镜面岩脉，与 phyllic 蚀变相关。还存在表生石膏脉。矿化主要与I期和II期脉有关。Lutopan 石英闪长斑岩的锆石 U-Pb 年龄为 108.5 ± 1.6 Ma，以高 Sr/Y (54-69) 为特征，相应的岩浆具有高氧逸度（平均ΔFMQ +2.7，平均Ce 4+ /Ce 3+ 锆石= 439）和H 2 O浓度（存在角闪石和黑云母斑晶）和低岩浆温度（平均Ti锆石内测温 = 706 °C）。相对较低的 La/Yb 比率 (9-11)，具有弱或不存在 Eu 异常的列表形归一化 REE 模式，以及锆石 ε Hf (t) 值为 3.4 至 10.0，全岩 I Sr 值为 0.70373-0.70382 , ε Nd (t) 值为 2.4-3.4 和 Mg 值为 49-53 表明 Lutopan 石英闪长斑岩很可能来自年轻的下大陆地壳的部分熔融或软流圈熔体和下地壳熔体之间的相互作用，演化为埃达克岩通过闪石分馏类似微量元素组成。阶段 I 矿脉产生了 110.2 ± 5 的黄铁矿 Re-Os 等时线年龄。