Abstract Titanium oxide minerals along the P2 fault in the eastern Athabasca Basin are characterized to constrain their origin and the geological history of the area. Two types of rutile are recognized in the basement rocks. Early rutile is disseminated in graphitic metapelite and quartzite, and it formed during regional metamorphism and post-metamorphic hydrothermal activity. Late rutile occurs as a needle-like alteration product of mica and likely formed during retrogression of the basement. In graphitic metapelite, early rutile commonly occurs with an assemblage of oxy-dravite, quartz, graphite, zircon, pyrite, biotite, and muscovite. In quartzite, rutile occurs with quartz, sillimanite, muscovite, and zircon. Metamorphic rutile is characterized by high Nb/ Ta ratios (up to 47) with high concentrations of U (up to 126 ppm) and V4+ (up to 1.44 wt%; V valance calculated from EPMA data). Hydrothermal rutile contains distinctly low Nb/Ta (as low as 4.80) with high Ta (≤3050 ppm), and relatively low V (as V3+; as low as 0.02 wt%) and U (as low as 9.06 ppm), reflecting fluids in reduced oxidation conditions. Anatase forms small anhedral (rarely coarse and euhedral) grains in the basal sandstones and altered basement rocks. In sandstones, anatase occurs with the late diagenetic mineral assemblage, whereas in basement rocks it commonly occurs with the clay-sized minerals related to uranium mineralization. In both rocks, anatase likely formed through the dissolution of rutile and/or other Ti-bearing minerals. Anatase is characterized by variably high Fe (up to 0.99 wt%; possibly contributed by hematite micro-or nanoinclusions) and U (up to 180 ppm). The mineral assemblages and composition of anatase suggest its protracted crystallization from relatively low temperature, oxidizing, acidic, uraniferous fluids of the sandstones during late diagenesis and hydrothermal activity. Therefore, the occurrence of anatase records the incursion of basin fluids into the basement, and the interaction of basement rocks with fluids responsible for the formation of the McArthur River uranium deposit. The results of this study confirm that Ti-oxides are useful in unraveling the geological history of an area that underwent prolonged hydrothermal activity.

中文翻译：

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加拿大阿萨巴斯卡盆地下方和内部的钛氧化物矿物的起源

摘要 阿萨巴斯卡盆地东部 P2 断层沿线的氧化钛矿物特征限制了其成因和该地区的地质历史。在基底岩石中识别出两种类型的金红石。早期金红石散布于石墨变泥质岩和石英岩中，形成于区域变质作用和后变质热液活动。晚金红石是云母的针状蚀变产物，很可能是在基底退化过程中形成的。在石墨变泥质岩中，早期金红石通常与含氧辉石、石英、石墨、锆石、黄铁矿、黑云母和白云母的组合一起出现。在石英岩中，金红石与石英、硅线石、白云母和锆石一起出现。变质金红石的特点是 Nb/Ta 比值高（高达 47）和高浓度的 U（高达 126 ppm）和 V4+（高达 1。44 重量％；V 价从 EPMA 数据计算）。热液金红石含有明显低的 Nb/Ta（低至 4.80）和高 Ta（≤3050 ppm），以及相对较低的 V（如 V3+；低至 0.02 wt%）和 U（低至 9.06 ppm），反映流体在还原氧化条件下。锐钛矿在基底砂岩和蚀变基底岩中形成小的反面体（很少是粗的和自面体的）颗粒。在砂岩中，锐钛矿与晚期成岩矿物组合一起出现，而在基底岩中，它通常与与铀矿化有关的粘土大小的矿物一起出现。在这两种岩石中，锐钛矿可能是通过金红石和/或其他含钛矿物的溶解形成的。锐钛矿的特点是 Fe（高达 0.99 wt%；可能由赤铁矿微米或纳米夹杂物贡献）和 U（高达 180 ppm）。锐钛矿的矿物组合和组成表明，它在晚期成岩作用和热液活动期间从相对低温、氧化性、酸性、含铀的砂岩流体中长期结晶。因此，锐钛矿的出现记录了盆地流体侵入基底，以及基底岩石与流体的相互作用导致麦克阿瑟河铀矿床的形成。这项研究的结果证实，钛氧化物可用于揭示经历了长时间热液活动的地区的地质历史。锐钛矿的出现记录了盆地流体侵入基底，以及基底岩石与流体的相互作用导致麦克阿瑟河铀矿床的形成。这项研究的结果证实，钛氧化物可用于揭示经历了长时间热液活动的地区的地质历史。锐钛矿的出现记录了盆地流体侵入基底，以及基底岩石与流体的相互作用导致麦克阿瑟河铀矿床的形成。这项研究的结果证实，钛氧化物可用于揭示经历了长时间热液活动的地区的地质历史。