Mantle source heterogeneity for South Tyrrhenian magmas revealed by Pb isotopes and halogen contents of olivine-hosted melt inclusions

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• 作者：Estelle F. Rose-Koga^a ; ^b ; ^c ; ^{e.koga@opgc.univ-bpclermont.fr} ; Kenneth T. Koga^a ; ^b ; ^c ; Pierre Schiano^a ; ^b ; ^c ; Marion Le Voyer^d ; Nobumichi Shimizu^e ; Martin J. Whitehouse^f ; Roberto Clocchiatti^g
• 关键词：Melt inclusion ; Pb isotopes ; Volatile elements ; Halogen ; Arc magma ; Italy
• 刊名：Chemical Geology
• 出版年：2012
• 出版时间：12 December, 2012
• 年：2012
• 卷：334
• 期：Complete
• 页码：266-279
• 全文大小：1499 K

文摘

Nineteen olivine-hosted melt inclusions from seven volcanoes (Etna, Stromboli, Vulcano, Ustica, Alicudi, Marsili and Vavilov) from the southern Italy region were analyzed for abundances of major, trace, and volatile elements, along with Pb isotope ratios (²⁰⁷Pb/²⁰⁶Pb, ²⁰⁸Pb/²⁰⁶Pb and ²⁰⁶Pb/²⁰⁴Pb). The systematics of primary volatile (in particular F and Cl) compositions and Pb isotopes identify three main geochemically distinct mantle sources for this region: (1) a component with radiogenic Pb (²⁰⁷Pb/²⁰⁶Pb = 0.780) and low volatile element abundances typified by the Etnean melt inclusions, (2) a component with moderately radiogenic Pb (²⁰⁷Pb/²⁰⁶Pb = 0.798) and high volatile abundance mainly associated with Sommata magmas, and (3) a component with moderate volatile abundances associated with a MORB-like ²⁰⁷Pb/²⁰⁶Pb (0.830).

The variation of F/Nd and Pb isotopes among the southern Italy melt inclusions reflects mixing between a slightly modified depleted mantle (DMM-EMII mixture) and radiogenic (HIMU-like) mantle components expressed in Pb isotope space, superimposed by slab-derived metasomatic components represented by F/Nd (F/Nd > 30).