Abstract The Paymogo Volcano-Sedimentary Alignment (PVSA) is an essentially igneous sequence associated with VHMS deposits of the Iberian Pyrite Belt. Unlike other areas of this Iberian mining district, where mafic igneous rocks are abundant, in the PVSA these are essentially felsic. Two facies associations have been distinguished based on petrographic and chemical features: a lower dacite facies association and an upper rhyolite facies association. The main ore horizons appear related to volcanic breccias of the rhyolite facies association. A detailed petrographic study of these breccias suggests they are resedimented hyaloclastite deposits. The analysis of volcanic facies indicates that the volcanism developed at water depths deeper than 500 m, consistent with the minimum depth at which VHMS deposits can form. We conclude that detailed volcanological studies provide effective constraints to palaeoenvironmental interpretations, which are relevant in assessing regional stratigraphy and area selection for VHMS exploration.

中文翻译：

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伊比利亚黄铁矿带水下长英质火山作用的相结构和古环境约束：Paymogo 火山-沉积排列

摘要 Paymogo 火山-沉积排列 (PVSA) 是一个与伊比利亚黄铁矿带 VHMS 沉积物相关的基本上火成岩序列。与这个伊比利亚矿区的其他地区不同，那里的镁铁质火成岩丰富，在 PVSA 中，这些地区基本上是长英质的。根据岩石学和化学特征区分了两种相组合：下部英安岩相组合和上部流纹岩相组合。主要矿层似乎与流纹岩相组合的火山角砾岩有关。对这些角砾岩的详细岩相研究表明它们是再沉积的透明碎屑岩沉积物。火山相分析表明，火山作用发育在水深超过 500 m 处，与 VHMS 沉积物可以形成的最小深度一致。