Abstract The Jogran copper prospect in southern Ontario, Canada, is located on the northeastern shoulder of the North American Midcontinent rift system where it is centered on two small, closely spaced quartz monzonite porphyry intrusions emplaced into Neoarchean mafic metavolcanic rocks. Notwithstanding an atypical alteration zoning pattern, the distinctive alteration styles and veinlet types confirm its porphyry copper affiliation. Two samples of molybdenite from chalcopyrite-bearing quartz veinlets in the two centers returned Re-Os ages of 1101 ± 5 and 1094 ± 5 Ma, showing that the mineralization took place during the main stage of extension and magmatic activity that gave rise to the Midcontinent rift and associated large igneous province (LIP). The nearby copper-bearing Tribag breccia pipes and Coppercorp veins have been shown previously to also be intrusion related, and likely formed penecontemporaneously with Jogran. The Jogran and nearby copper mineralization overlapped temporally with generation of low-grade magmatic copper-nickel-PGE deposits in the Duluth intrusive complex but predated the strata-bound native copper and chalcocite deposits in the Keweenaw Peninsula, which are believed to have formed from basinal fluids during rift inversion. Although such magmatic and strata-bound copper deposits typify intracontinental rift metallogeny, porphyry copper deposits are normally confined to convergent margin magmatic arcs, thereby making the rift-LIP setting of Jogran exceptional and possibly unique.

中文翻译：

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中大陆裂谷成矿背景下加拿大安大略省 Mamainse Point 中元古代斑岩铜矿化

摘要 加拿大安大略省南部的 Jogran 铜矿勘探区位于北美大陆中部裂谷系统的东北肩部，其中心是两个小的、间隔很近的石英二长斑岩侵入体，侵入新太古代基性变质火山岩。尽管具有非典型的蚀变分区模式，但独特的蚀变样式和细脉类型证实了其斑岩铜隶属关系。两个中心含黄铜矿石英细脉的两个辉钼矿样品返回 Re-Os 年龄为 1101±5 和 1094±5 Ma，表明成矿发生在形成中大陆的伸展和岩浆活动的主要阶段裂谷和相关的大型火成岩省 (LIP)。附近的含铜 Tribag 角砾岩管和 Coppercorp 矿脉先前已被证明也与侵入有关，并且很可能与 Jogran 同期形成。Jogran 和附近的铜矿化在时间上与 Duluth 侵入杂岩中低品位岩浆铜-镍-PGE 矿床的生成重叠，但早于 Keweenaw 半岛的地层原生铜和辉铜矿矿床，据信这些矿床是由盆地形成的裂谷反演期间的流体。尽管这种岩浆和地层束缚铜矿床是陆内裂谷成矿的典型特征，但斑岩铜矿床通常仅限于会聚边缘岩浆弧，从而使 Jogran 的裂谷-LIP 环境异常且可能是独一无二的。Jogran 和附近的铜矿化在时间上与 Duluth 侵入杂岩中低品位岩浆铜-镍-PGE 矿床的生成重叠，但早于 Keweenaw 半岛的地层原生铜和辉铜矿矿床，据信这些矿床是由盆地形成的裂谷反演期间的流体。尽管这种岩浆和地层束缚铜矿床是陆内裂谷成矿的典型特征，但斑岩铜矿床通常仅限于会聚边缘岩浆弧，从而使 Jogran 的裂谷-LIP 环境异常且可能是独一无二的。Jogran 和附近的铜矿化在时间上与 Duluth 侵入杂岩中低品位岩浆铜-镍-PGE 矿床的生成重叠，但早于 Keweenaw 半岛的地层原生铜和辉铜矿矿床，据信这些矿床是由盆地形成的裂谷反演期间的流体。尽管这种岩浆和地层束缚铜矿床是陆内裂谷成矿的典型特征，但斑岩铜矿床通常仅限于会聚边缘岩浆弧，从而使 Jogran 的裂谷-LIP 环境异常且可能是独一无二的。据信，它们是在裂谷反演期间由盆地流体形成的。尽管这种岩浆和地层束缚铜矿床是陆内裂谷成矿的典型特征，但斑岩铜矿床通常仅限于会聚边缘岩浆弧，从而使 Jogran 的裂谷-LIP 环境异常且可能是独一无二的。据信，它们是在裂谷反演期间由盆地流体形成的。尽管这种岩浆和地层束缚铜矿床是陆内裂谷成矿的典型特征，但斑岩铜矿床通常仅限于会聚边缘岩浆弧，从而使 Jogran 的裂谷-LIP 环境异常且可能是独一无二的。