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American Mineralogist, Volume 88, pages 316–329, 2003 0003-004X/03/0203–316$05.00 316 INTRODUCTION Isotopic studies published during the last decade have em- phasized multiple sources for rhyolite magma in the mantle, and the lower and upper crust (Hildreth et al. 1991; Riciputi et al. 1995). Despite this recognition that rhyolite typically evolves through open-system processes involving crustal assimilation, it remains clear that many silicic systems have experienced profound episodes of crystal fractionation. This fractionation is manifested through very

Fayalite oxidation processes in Obsidian Cliffs rhyolite flow, Oregon Audrey M. MArtin1,2,*, etienne MédArd3, BertrAnd devouArd3,4, LindsAy P. KeLLer1, Kevin righter1, JeAn-Luc devidAL3 And ZiA rAhMAn1 1NASA Johnson Space Center, Mailcode KT, 2101 NASA Parkway, Houston, Texas 77058, U.S.A. 2Earth, Environmental and Planetary Sciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44118, U.S.A. 3Laboratoire Magmas et Volcans, Université Blaise Pascal-CNRS-IRD, OPGC, 5 rue Kessler, 63038 Clermont-Ferrand, France 4CEREGE, AMU-CNRS-IRD (UM34

Electron Paramagnetic Resonance of Rhyolite and γ-Irradiated Trona Minerals F. Köksal, R. Köseoğlua, and E. Başaranb Physics Department, Faculty of Arts and Sciences, Ondokuz Mayıs University, Samsun, Turkey a Physics Department, Faculty of Arts and Sciences, Niğde University, Niğde, Turkey b Physics Department, Faculty of Arts and Sciences, Gebze HighTechnology Institute, İstanbul, Turkey Reprint requests to Prof. F. K.; Fax: +90-362-457 6081; E-mail: koksalf@omu.edu.tr Z. Naturforsch. 58a, 293 – 298 (2003); received January 2, 2003 Rhyolite from the

; White et al. 2000; Ren et al. 2000) and high field- strength elements (HFSE) (Larsen 1979; Watson 1979; Watson and Harrison 1983; Horng et al. 1999). This study is concerned solely with alkali feldspar, because alkali feldspar is the dominant phase in peralkalic quartz tra- chyte and rhyolite and exerts the greatest influence over the bulk partition coefficient for most trace elements during frac- tional crystallization (Mahood and Stimac 1990; Nicholls and Carmichael 1969; Roux and Varet 1975). In this paper, new empirical equations for the partitioning of several

-X-ray transparency makes it an ideal candidate for medical and analytical applications. For these reasons, Be is on the “Strategic and Critical Materials” list of the U.S. Department of Defense and of the European Union ( Thomason et al. 2013 ). The Miocene rhyolite of the Spor Mountain Formation in western Utah ( Lindsey 1977 , 1982 ; Christiansen et al. 1984 ) hosts one of the largest beryllium deposits in the world and was responsible for producing 85% of the beryllium mined worldwide in 2010 ( Boland 2012 ). Materion Brush Beryllium and Composites owns and operates the mine

SPECIAL COLLECTION: PERSPECTIVES ON ORIGINS AND EVOLUTION OF CRUSTAL MAGMAS Formation of rhyolite at the Okataina Volcanic Complex, New Zealand: New insights from analysis of quartz clusters in plutonic lithics† Karina a. Graeter1,*, rachel J. Beane1, chad d. deerinG2, darren Gravley3 and Olivier Bachmann4 1Department of Earth and Oceanographic Science, Bowdoin College, Brunswick, Maine 04011, U.S.A. 2Department of Geological and Mining Engineering Sciences, Michigan Technological University, Houghton, Michigan 49931, U.S.A. 3Department of Geology, University

American Mineralogist, Volume 96, pages 1838–1850, 2011 0003-004X/11/1112–1838$05.00/DOI: 10.2138/am.2011.3857 1838 In situ ion-microprobe determination of trace element partition coefficients for hornblende, plagioclase, orthopyroxene, and apatite in equilibrium with natural rhyolitic glass, Little Glass Mountain Rhyolite, California James G. Brophy,1,* TsuTomu oTa,2 Tak kunihro,2 TaTsuki TsuJimori,2 and eizo nakamura2 1Department of Geological Sciences, Indiana University, Bloomington, Indiana 47401, U.S.A. 2The Pheasant Memorial Laboratory for

American Mineralogist, Volume 97, pages 1685–1699, 2012 0003-004X/12/0010–1685$05.00/DOI: http://dx.doi.org/10.2138/am.2012.4006 1685 Quantifying crystallization and devitrification of rhyolites by means of X-ray diffraction and electron microprobe analysis Michael c. Rowe,* Ben S. elliS, and aBBie lindeBeRg School of the Environment, Washington State University, Pullman, Washington 99164, U.S.A. aBStRact Devitrification of silicic volcanic rocks is a relatively common process, resulting in the production of microcrystalline silica and feldspar components

a magma, concomitant partitioning of Au from the melt into the MVP, egress and ascent of the MVP from the magma chamber, and precipitation of metals as physico-chemi- cal changes in the MVP decrease the solubility of Au (Holland 1972; Burnham 1979; Candela and Holland 1984; Gammons and Williams-Jones 1997; Hedenquist and Richards 1998). The efficiency with which Au will partition into the MVP from a melt is a function of the concentration of Au-complexing ligands * E-mail: asimon@geol.umd.edu Experimental determination of Au solubility in rhyolite melt and

An updated calibration of the plagioclase-liquid hygrometer-thermometer applicable to basalts through rhyolites Laura E. WatErs1,* and rEbEcca a. LangE1 1Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, Michigan 48109, U.S.A. abstract An updated and expanded data set that consists of 214 plagioclase-liquid equilibrium pairs from 40 experimental studies in the literature is used to recalibrate the thermodynamic model for the plagio- clase-liquid hygrometer of Lange et al. (2009); the updated model is applicable to metaluminous