from veined mantle xenoliths, Kamchatka

• Main Authors: Insights Into Li, Li Isotope Cycling, Sub-arc Metasomatism, William F. Mcdonough, R. Halama, R. L. Rudnick, W. F. Mcdonough, I. P. Savov
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Kamchatka
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.296.1344; http://www.geol.umd.edu/~mcdonoug/Halama_etal_(CMP_09).pdf

Abstract Harzburgitic xenoliths cut by pyroxenite veins from Avachinsky volcano, Kamchatka, are derived from the sub-arc mantle and record element transfer from the slab to the arc. Olivine and orthopyroxene in the harzburgites have Li isotopic compositions (d 7 Li =?2.8 to?5.6) comparable to estimates of the upper mantle (d 7 Li *?4 ± 2). The pyroxenite veins, which represent modal metasomatism and may therefore provide information about the metasomatic agent, have mantle-normalized trace element characteristics that suggest overprinting of their mantle source by an aqueous, slab-derived fluid. These include relative enrichments of Pb over Ce, U over Th and Sr over Nd. Li is enriched relative to the HREE, and ortho- and clinopyroxene from the veins are in Li elemental and isotopic equilibrium with each other and the Communicated by J. Hoefs. Electronic supplementary material The online version of this article (doi:10.1007/s00410-009-0378-5) contains supplementary material, which is available to authorized users.