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American Mineralogist, Volume 98, pages 1074–1077, 2013 0003-004X/13/0506–1074$05.00/DOI: 1074 Letter High-pressure aragonite phenocrysts in carbonatite and carbonated syenite xenoliths within an alkali basalt VratisLaV Hurai,1,* Monika HuraioVá,2 rastisLaV MiLoVský,3 JarMiLa LuptákoVá,3 and Patrik konečný4 1Geological Institute, Slovak Academy of Sciences, Dúbravská cesta 9, 840 05 Bratislava, Slovakia 2Department of Mineralogy and Petrology, Comenius University, Mlynská dolina, 842 15 Bratislava, Slovakia 3

Introduction The addition of H 2 O drastically reduces the solidus temperatures of mantle peridotites ( Kushiro 1972 ); therefore, the influx of H 2 O-rich substances released from the subducting slab into the overlying mantle wedge contributes significantly to the genesis of island arc magmatism (e.g., Tatsumi and Eggins 1995 ). Recent active petrological investigations of peridotite xenoliths from island-arc volcanoes have provided possible evidence for metasomatism caused by inputs of subduction components released from the subducting slab. In particular

American Mineralogist, Volume 93, pages 1061–1065, 2008 0003-004X/08/0007–1061$05.00/DOI: 10.2138/am.2008.2746 1061 Arsenide in a metasomatized peridotite xenolith as a constraint on arsenic behavior in the mantle wedge Satoko IShImaru* and ShojI araI Department of Earth Sciences, Kanazawa University, Kanazawa 920-1192, Japan abStract An arsenide (low-Ni, high-Co löllingite) was found in a peridotite xenolith, which is strongly metasomatized by slab-derived melt or fluid from Avacha volcano, located in the Kamchatka arc. This is the first finding of a

Chemistry and mineralogy of earth’s mantle Mantle-derived guyanaite in a Cr-omphacitite xenolith from Moses Rock diatreme, Utah† daniel J. sChulze1,*, roberta l. flemming2, PatriCk h.m. shePherd2 and herwart helmstaedt3 1Department of Earth Sciences and Department of Chemical and Physical Sciences, University of Toronto, Mississauga, Ontario L5L 1C6, Canada 2Department of Earth Sciences, Western University, London, Ontario N6A 5B7, Canada 3Department of Geological Sciences and Geological Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada

American Mineralogist, Volume 80, pages 810-822, 1995 Armalcolite in crustal paragneiss xenoliths, central Mexico JODIE L. HAYOB, * ERIC J. ESSENE Departmentof GeologicalSciences,Universityof Michigan,Ann Arbor,Michigan48109,U.S.A. ABSTRACT Aluminous armalcolite has been found in two sillimanite-bearing xenoliths that were recently exhumed from the lower crust of central Mexico. The ranges of compositions are (Fe5.1s-0.66Mgo.lS-0.2SAlo.lS-0.lS V6.66-o.lOFe6.6o-o.o6 Titt4-l.s6)Os and (Fefi1o-o.S1 MgO.lS-0.29Alo.16-0.19- V6.62-0.06Fe6.1o-o.s1Ti1.19-1.71)Os

. 2003 ; Leung et al. 1990 ; Mathez et al. 1995 ; Trumbull et al. 2009 ). In this study, we report a new discovery of SiC-dominated mineral assemblage in carbonatitic xenoliths carried by the Neogene basalt from Dalihu, Inner Mongolia ( Gao and Liu 2008 ; Liu et al. 2015 ). These carbonatitic xenoliths offer a rare example of deep mantle recycling of sedimentary carbonate with little altered limestone chemical composition ( Liu et al. 2015 ). Here, we provide a detailed investigation using microanalysis techniques including SIMS, laser Raman microspectroscopy, and

1 Introduction Mafic xenoliths in volcanic rocks can provide valuable information about the petrology and chemistry of unexposed subvolcanic basement, the composition of parental mafic magmas and differentiation processes during the early stage of magmatic evolution [ e.g . 1 – 5 ]. Most of the mafic xenoliths in volcanic rocks from island arc systems fall into one of three categories: cognate xenoliths that are indicative of magma mixing [ e.g . 6 , 7 ], plutonic blocks derived from middle to lower crustal sources [ e.g . 8 , 9 ], or cumulate rocks formed

exchanged between conductive mantle (lithosphere) and underlying convective mantle (asthenosphere) ( McKenzie and Bickle 1988 ; Anderson 1995 ; O’Reilly and Griffin 1996 ; Fischer et al. 2010 ). The LAB is thus regarded as a thermal boundary layer or a rheological boundary layer ( McKenzie and Bickle 1988 ; Sleep 2005 , 2006 ). Processes taking place in the boundary zone affect heat and material transport from the Earth’s interior to the surface but are not well understood. Mantle xenoliths are fragments of mantle materials brought to Earth’s surface by alkali basalt

C h em ica l C o m p o s itio n o f a n U n u su a l X eno lith o f th e A llende M e te o r ite H. Palme*, G. Kurat**, B. Spettel*, and A. Burghele* * Max-Planck-Institut für Chemie, D-6500 Mainz, FRG ** Naturhistorisches Museum, A-1014 Wien, Austria Z. Naturforsch. 44a, 1005-1014 (1989); received August 5, 1989 Dedicated to Prof. Heinrich Wänke on the occasion of his 60th birthday The chemical composition of an unusual xenolith (All-AF) from the Allende meteorite was determined by neutron activation and x-ray fluorescence analyses. The xenolith is

American Mineralogist, Volume 98, pages 1870–1880, 2013 0003-004X/13/0010–1870$05.00/DOI: 1870 Olivine from spinel peridotite xenoliths: Hydroxyl incorporation and mineral composition EsthEr schmädickE1,*, JürgEn gosE1, gudrun Witt-EickschEn2 and hElEnE Brätz1 1Universität Erlangen-Nürnberg, Geozentrum Nordbayern, Schlossgarten 5a, D-91054 Erlangen, Germany 2Universität Köln, Institut für Geologie und Mineralogie, Zülpicher Strasse 49a, 50674 Köln, Germany aBstract Traces of water in mantle minerals strongly influence