Geochemical similarities between the Vesuvius, Phlegraean Fields and Stromboli Volcanoes: petrogenetic, geodynamic and volcanological implications
Geochemical similarities between the Vesuvius, Phlegraean Fields and Stromboli Volcanoes: petrogenetic, geodynamic and volcanological implications
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维苏威火山、坎皮莱格瑞火山和斯特龙博利火山之间的地球化学相似性：岩石成因、地球动力学和火山学意义
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发表时间：
2001
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通讯作者：
A. Peccerillo
中科院分区：
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作者：
A. Peccerillo
维苏威火山和斯特龙博利火山是两座被广泛研究的活火山，传统上被认为具有不同的喷发类型、岩石成分和构造背景。数据显示，这两座火山在成分上有着密切的联系。富含13-15 Ka的老斯特龙博利白闪铁质岩石具有放射性成因同位素特征，除Rb和K外，不相容元素的丰度和比值与维苏威火山的相同。弗勒格雷地区也显示出与这些火山的密切联系。鉴于斯特龙博利白榴石-辉铜矿和维苏威火山在构造特征、喷发行为和基岩类型方面的差异，这两座火山之间的相似之处不可能是低压过程的结果。相反，观察到的地球化学特征很可能代表了原始岩浆成分，并揭示了两套岩石的共同同质来源。维苏威火山岩石中K和Rb含量较高，可能是岩浆上升过程中的选择性富集作用，也可能是地幔深熔过程中金云母熔融的作用。维苏威火山、菲勒格雷气田和斯特龙博利的大多数原始岩石揭示了弧和板内火山岩之间的中间成分。据推测，这些火山之下的地幔来源由板内和板片来源的成分混合而成。板内物质可能是从阿普利亚板块和/或第四纪海区流入俯冲爱奥尼亚海板块上方的楔形体的软流期地幔提供的。下沉板块和相关沉积物释放的流体或熔体对板内物质进行了交代改造，板内物质的熔融产生了斯特龙博利、维苏威和弗勒格莱伊磁场岩浆。本研究表明，通过对意大利南部不同火山中心的比较研究，可以澄清一些涉及岩浆起源和演化、地幔来源的组成和地球动力学意义的问题，这些问题长期以来一直存在争议，如果孤立地考虑个别火山，这些问题很难解决。
Summary Vesuvius and Stromboli are two active and extensively studied volcanoes that traditionally have been considered as having different styles of eruption, rock composition and tectonic setting. Data reveal close compositional affinities between these two volcanoes. The abundant 13–15 Ka old Stromboli leucite-tephritic rocks have radiogenic isotope signatures, and abundances and ratios of incompatible elements with the exception of Rb and K, which are identical to those of Vesuvius. The Phlegraean Fields also show close affinities to these volcanoes.The similarity between Stromboli leucite-tephrites and Vesuvius rocks cannot be the result of low pressure processes, given the differences between the two volcanoes in terms of structural features, eruptive behaviour and type of basement rocks. Instead, the observed geochemical signatures are likely to represent a primary magma composition and reveal a common homogeneous source for the two suites. The higher K and Rb contents in the Vesuvius rocks suggest either selective enrichment during magma ascent or a role for phlogopite melting during mantle anatexis.The most primitive rocks from Vesuvius, Phlegraean Fields and Stromboli reveal intermediate compositions between arc and intraplate volcanics. It is suggested that the mantle sources beneath these volcanoes consist of a mixture of intraplate- and slab-derived components. Intraplate material was probably provided by inflow of asthenosheric mantle into the wedge above the subducting Ionian Sea plate, either from the Apulian plate and/or from the Tyrrhenian Sea region. Fluids or melts released from the sinking slab and associated sediments generated metasomatic modification of the intraplate material, whose melting gave rise to the Stromboli, Vesuvius and Phlegraean Fields magmas.The present study demonstrates how comparative investigations of various volcanic centres from southern Italy allow clarification of a number of problems involving magma genesis and evolution, composition of mantle sources and geodynamic significance, which have been long debated and are difficult to solve if individual volcanoes are considered in isolation.