Re-Os molybdenite and LA-ICPMS-MC U-Pb zircon geochronology for the Milpillas porphyry copper deposit: insights for the timing of mineralization in the Cananea District, Sonora, Mexico
Re-Os molybdenite and LA-ICPMS-MC U-Pb zircon geochronology for the Milpillas porphyry copper deposit: insights for the timing of mineralization in the Cananea District, Sonora, Mexico
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Milpillas 斑岩铜矿床 Re-Os 辉钼矿和 LA-ICPMS-MC U-Pb 锆石地质年代学：墨西哥索诺拉州 Cananea 区成矿时间的见解
DOI：
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发表时间：
2006
影响因子：
0.8
通讯作者：
M. Valencia
中科院分区：
文献类型：
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作者：
V. Valencia;B. Noguez;F. Barra;J. Ruíz;G. Gehrels;Francisco Quintanar;M. Valencia
这里介绍的新的地质年代学数据提高了对卡纳尼亚矿区，特别是米尔皮利亚斯斑岩铜存款（墨西哥索诺拉东北部）的时间演变的理解。采用激光烧蚀ICP-MS多收集器对Milpillas存款矿化所在的石英二长斑岩单元进行铀-铅锆石分析，得出结晶年龄为63.9 ± 1.3 Ma（2-sigma）。两个500 m以上钻孔岩芯样品的Re-Os辉橄榄岩年龄相同，均为63.1 ± 0.4 Ma（2-σ），表明成矿时代为局限期。这些年龄表明，Milpillas存款是最古老的Laramide斑岩铜矿存款迄今为止在卡纳尼亚区。我们的新Re-Os数据加上以前的Re-Os数据，表明该地区的矿化发生在约400万年内。在~59 Ma、~61 Ma和~63 Ma的三个离散脉冲中，这与之前的模型形成鲜明对比，在之前的模型中，卡纳尼亚地区的成矿作用是连续热液系统的结果，该系统开始于~62 Ma，结束于~52 Ma。
New geochronological data presented here improves the understanding of the temporal evolution of the Cananea Mining District, and particularly of the Milpillas porphyry copper deposit (northeastern Sonora, Mexico). Uranium-lead zircon analyses, using laser ablation ICP-MS multi-collector, from the quartz monzonite porphyry unit that host the mineralization at the Milpillas deposit, yielded a crystallization age of 63.9 ± 1.3 Ma (2-sigma). Re-Os molybdenite ages from two drill core samples from more than 500 m depth yielded an identical age of 63.1 ± 0.4 Ma (2-sigma), suggesting a restricted period of mineralization. These ages indicate that the Milpillas deposit is the oldest Laramide porphyry copper deposit recognized so far in the Cananea District. Our new Re-Os data in addition to previous Re-Os data, suggest that mineralization within the district, occurred within a ~4 m.y. period in three discrete pulses at ~59 Ma, ~61 Ma and ~63 Ma. This is in contrast to the previous model in which mineralization at the Cananea District was the result of a continuous hydrothermal system that started at ~62 Ma and ended at ~52 Ma.