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IF 4.4 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Mineralium Deposita Pub Date : 2025-03-26 DOI:10.1007/s00126-025-01356-w

María José Tapia, Fernando Barra, Martin Reich, Rurik Romero, Andrés Ojeda

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引用次数: 0

摘要

斑岩型铜矿床（PCD）是全球铜的主要来源，其中智利安第斯山脉的新生代斑岩型铜矿床以规模大、矿石品位高而著称。智利北部沿海科迪勒拉山系的白垩纪多金属结核矿床规模相对较小，主要处于次经济地位。本研究调查了与矿石有关的白垩纪侵入岩和贫瘠侵入岩中的锆石地球化学特征，以评估岩浆肥度指纹是否能区分大型和小型多金属结核系统。早白垩世（116-108 Ma）PCD（包括Tricolor、Dos Amigos、Cachiyuyo和Pajonales）中与矿石相关的侵入岩具有高Eu/Eu*比值（> 0.4）和相对氧化条件（ΔFMQ ~ 0至+ 1）的特征。另一方面，在晚白垩世时期（98-93 Ma）形成的贫瘠侵入岩的 Eu/Eu* 比率（< 0.4）较低，ΔFMQ ~ -1 至 + 1。相比之下，安第斯科迪勒拉山系的新生代超巨型PCD，如萨尔瓦多、Chuquicamata和El Teniente，显示出较高的Eu/Eu*比值（> 0.4），且氧化程度更高（ΔFMQ ~ + 1至+ 3）。这项研究的结果表明，YbN/DyN 和 (Eu/Eu*)/(DyN/YbN) 比率可有效区分不同的 PCD 设置。与岩浆分异有关的矿床，如早白垩世的矿床，含水量较高，位于相对浅到中等层位（< 40千米），其特征是YbN/DyN值约为10-18，(Eu/Eu*)/(DyN/YbN)比率约为6-14。相比之下，岩浆分异发生在地壳更深处（约 40 千米）的沉积，如安第斯山脉的大型新生代沉积，其 YbN/DyN 值约为 3-12，(Eu/Eu*)/(DyN/YbN) 比率约为 1.5-6。此外，我们的数据凸显了地球动力条件的关键作用，如水平构造应力、岩浆分异深度等，它们可能决定斑岩铜矿系统的规模。

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Large versus small Andean porphyry Cu deposits: insights from zircon petrochronology of porphyry Cu–Mo ± Au deposits from the Coastal Cordillera, northern Chile

Porphyry copper deposits (PCDs) are the primary global source of copper, with Cenozoic PCDs in the Chilean Andes being notable for their large size and high ore grades. The Cretaceous PCDs of the Coastal Cordillera in northern Chile are comparatively smaller and predominantly sub-economic. This study investigated zircon geochemical signatures in ore‐related and barren Cretaceous intrusive rocks to assess whether magmatic fertility fingerprints differentiate between large and small PCD systems. Ore-related intrusive rocks from Early Cretaceous PCDs (116–108 Ma), including Tricolor, Dos Amigos, Cachiyuyo, and Pajonales, are characterized by high Eu/Eu* ratios (> 0.4) and relatively oxidized conditions (ΔFMQ ~ 0 to + 1). On the other hand, barren intrusive rocks emplaced during the Late Cretaceous period (98–93 Ma) display lower Eu/Eu* ratios (< 0.4) and have ΔFMQ ~ –1 to + 1. In comparison, supergiant Cenozoic PCDs of the Andean Cordillera, e.g., El Salvador, Chuquicamata, and El Teniente display high Eu/Eu* ratios (> 0.4), and are more oxidized (ΔFMQ ~ + 1 to + 3). Results from this study show that the Yb_N/Dy_N and (Eu/Eu*)/(Dy_N/Yb_N) ratios can effectively discriminate between different PCDs settings. Deposits related to magmatic differentiation with a high-water content at relatively shallow to intermediate levels (< 40 km), such as those from the Early Cretaceous, are characterized by Yb_N/Dy_N values of ~ 10–18 and (Eu/Eu*)/(Dy_N/Yb_N) ratios of ~ 6–14. In contrast, deposits where magmatic differentiation occurred at greater depth within the crust (> 40 km), like the large Cenozoic deposits in the Andes, show Yb_N/Dy_N values of ~ 3–12 and (Eu/Eu*)/(Dy_N/Yb_N) ratios of ~ 1.5–6. Furthermore, our data highlight the crucial role of geodynamic conditions, such as horizontal tectonic stress, the depth of magmatic differentiation, which may determine the size of porphyry Cu systems.

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来源期刊

Mineralium Deposita 地学-地球化学与地球物理

CiteScore

11.00

自引率

6.20%

发文量

审稿时长

6 months

期刊介绍： The journal Mineralium Deposita introduces new observations, principles, and interpretations from the field of economic geology, including nonmetallic mineral deposits, experimental and applied geochemistry, with emphasis on mineral deposits. It offers short and comprehensive articles, review papers, brief original papers, scientific discussions and news, as well as reports on meetings of importance to mineral research. The emphasis is on high-quality content and form for all articles and on international coverage of subject matter.