Melt Inclusions at the Millennium: Toward a Deeper Understanding of Magmatic Processes

Chemical Geology 183 (2002) 1–3 www.elsevier.com/locate/chemgeo Preface Melt inclusions at the millennium: toward a deeper understanding of magmatic processes

The beginning of the new millennium finds standstill due to the difficulty of heating melt geochemistshardatworktryingtounderstand inclusions to the temperatures required for melting. the enormous compositional variability preserved Barrabe´ and Deicha (1956) were the first to in magmatic melt inclusions. Melt inclusions are successfully homogenize quartz-hosted melt inclu- tiny (typically 10s of microns in diameter) drops sions by heating at high temperatures, sparking a of melt enclosed inside crystals of magmatic surge of interest in melt inclusions that remains to minerals. Melt inclusions are trapped during crys- this day. Observations of silicate melt inclusion tal growth and thus physically separated from the homogenization under the microscope were begun magmatic environment outside the host crystal. with the construction of high-temperature heating Melt inclusions are the silicate-rich endmember stages by Yermakov (1950) with improvements by of the general category of fluid inclusions Dolgov and Bazarov (1965), culminating in the described by Roedder (1984). Melt and fluid rapid-quench ‘‘Vernadsky Stage’’ of Sobolev et al. inclusions often coexist in the same crystal and (1980), which has found use in laboratories world- occasionally in the same cavity, but unlike their wide. fluid counterparts, melt inclusions are solid at With the ability to homogenize and quench room temperature. This convenient property of silicate melt inclusions in the laboratory, inclusion melt inclusions makes them readily amenable to studies moved from measurements of melting and study using a variety of microbeam analytical homogenization temperatures to the arena of geo- techniques. chemistry (a stage that the study of fluid inclu- The first observations of melt inclusions were sions had already reached; see Roedder, 1984). made by Sorby (1858), who made the connection Landmarks in the geochemical study of silicate between fluid inclusions and the growth environ- melt inclusions include the first measurements of ment of crystals, and who first proposed that vapor major element composition by electron microprobe bubbles were formed due to shrinkage of the (Carron, 1961), the first non-destructive (Cloc- enclosed fluid. Fouque´ and Michel-Le´vy (1879) chiatti, 1971) and quantitative IR measurements subsequently recognized similarities between melt (Anderson et al., 1989), the first trace element inclusions and the properties of extrusive igneous analysis by ion probe (Sobolev and Shimizu, rocks. While work on homogenization temperatures 1993), and the first measurements of stable iso- of fluid inclusions rapidly advanced in order to test topes (Gurenko and Chaussidon, 1997) and radio- Sorby’s hypothesis on shrinkage bubbles, similar genic isotopes (Saal et al., 1998) in individual work on silicate melt inclusions remained at a melt inclusions. Despite these analytical landmarks

0009-2541/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. PII: S 0009-2541(01)00368-0 2 Preface achieved in North America and Europe, it has only improve as analytical techniques evolve. We been Russian scientists who have led the way in hope that this special volume of Chemical Geology most of the petrological applications and scientific will provide an overview of the unique insight of discoveries associated with silicate melt inclusions; melt inclusion-based studies, and will be a useful see reviews by Sobolev and Kostyuk (1975) and reference for the exciting research on melt inclusions Sobolev (1996). that will be a prominent part of geochemistry in the In March of 2000, scientists gathered at the next millennium. Chateau de Sassenage in Grenoble for the Work- shop on Melt Inclusions, organized by Nick Arndt with the support of Elsevier and the Commission of References Igneous and Metamorphic Petrology. This vol- ume of Chemical Geology is the fruit of that Anderson Jr., A.T., Newman, S., Williams, S., Druitt, T., Skirius, C., meeting. The spirited discussion at the Grenoble Stolper, E., 1989. H2O, CO2, Cl and gas in Plinian and ash-flow meeting focussed on the philosophy of using melt Bishop rhyolite. Geology 17, 221–225. inclusions as recorders of petrologic processes; Barrabe´, L., Deicha, G., 1956. Experiences de fusion et de cristal- lisation magmatique sur des reliquats vitreux des quartz dihex- advantages and pitfalls of various techniques for ae´driques de la Guadeloupe. Bull. Soc. Fr. Mine´ral. Cristallogr. studying melt inclusions; and implications of data 79, 146–155. on major elements, trace elements, volatiles and Carron, J.-P., 1961. Premieres donne´s sur la composition de certains isotopes in melt inclusions from a wide variety of reliquats magmatiques. Compt. Rend. Acad. Sci. Paris 253, tectonic environments. The results validated the use 2016–2018. Clocchiatti, R., 1971. Composition chimique des inclusions vi- of melt inclusions as unique petrologic indicators, treuses des phe´nocristaux de quartz de quelques laves acides highlighted areas both of clarity and of poor par l’analyse a la microsonde e´lectronique. Compt. Rend. Acad. understanding, and demonstrated a clear and val- Sci. Paris 272, 2045–2047. uable future for melt inclusion-based investigations. Dolgov, Y.A., Bazarov, L.S., 1965. A chamber for investigating The papers in this volume begin with a frank inclusions of mineral-forming solutions and melts at high tem- peratures. Mineralogicheskaya Termometriya i Barometriya, discussion of assumptions, analytical pitfalls, and vol. 2. Nauka Press, Moscow, pp. 64–69. technique development associated with melt inclu- Fouque´, F., Michel-Le´vy, A., 1879. Mine´raux reproduits artificiell- sion studies (Danyushevsky, Gaetani, Michael, Hal- ment par voie igne´e. Bull. Soc. Fr. Mine´ral. 2, 105–113. ter, Massare, Hauri), moves on to data for melt Gurenko, A.A., Chaussidon, M., 1997. Boron concentrations and inclusions from mantle-derived magmatic phenoc- isotopic composition of the Icelandic mantle: evidence from glass inclusions in olivine. Chem. Geol. 135, 21–34. rysts from environments such as hotspots (Hauri, Roedder, E., 1984. Fluid inclusions. In: Ribbe, P.H. (Ed.), Reviews Norman, Nikogosian), continental and oceanic rifts in Mineralogy, vol. 12. Mineralogical Society of America, (Kirstein, Sours-Page), and subduction-related mag- Washington, DC, 644 pp. matic arcs (Kent, Kamenetsky, Gurenko), and con- Saal, A.E., Hart, S.R., Shimizu, N., Hauri, E.H., Layne, G.D., 1998. cludes with melt inclusion studies of magma– Pb isotopic variability in melt inclusions from oceanic island basalts, Polynesia. Science 282, 1481–1484. fluid–crystal relationships (Schmitt, Kamenetsky, Sobolev, A.V., 1996. Melt inclusions in minerals: a source of prin- Solovova, Sokolov). By focussing mainly on melt ciple petrologic information. Petrologiya 4, 228–239. inclusions in mafic rocks, this special issue (like Sobolev, V.S., Kostyuk, V.P., 1975. Magmatic crystallization based the Grenoble meeting) has a distinctly mantle- on the study of melt inclusions, partial translation in ‘‘Fluid In- derived flavor, and so represents only part of the clusion Research’’. Proc. COFFI 9 (1976), 182–253. Sobolev, A.V., Shimizu, N., 1993. Ultradepleted primary melt in- wide spectrum of research topics influenced by cluded in olivine from the Mid-Atlantic Ridge. Nature 363, studies of silicate melt inclusions. 151–154. The year 2000 has seen the publication of Sobolev, A.V., Dmitriev, L.V., Barsukov, V.L., Nevsorov, V.N., Slut- approximately 60–70 research papers on subjects sky, A.B., 1980. The formation conditions of the high-magne- related to melt inclusions, a large increase from the sian olivines from the monomineralic fraction of Luna 24 regolith. Proc. 11th Lunar Sci. Conf., pp. 105–116. 10 such papers published a decade ago (A.V. Sobo- Sorby, H.C., 1858. On the microscopic structure of crystals, indi- lev, pers. comm.). Clearly, the impact of research cating the origin of minerals and rocks. J. Geol. Soc. 14, 453– using melt inclusions is wide and deep, and can 500. Preface 3

Yermakov, N.P., 1950. Issledovaniya Mineraloobrazuyushchikh Adam J.R. Kent Rastvorov (Investigations Into Mineral-Forming Solutions) Dansk Lithosfærecenter, Øster Voldgade 10, Khar’kov Univ. Press, Moscow, USSR, 459 pp. 1350 Copenhagen K, Denmark

Nicholas Arndt Erik H. Hauri* LGCA, Universite´ de Grenoble, Department of Terrestrial Magnetism, 1381 rue de la Piscine, Carnegie Institution of Washington, 38041 Grenoble, France 5241 Broad Branch Road NW, Washington, DC 20015, USA 9 July 2001 E-mail address: [email protected]

* Corresponding author. Fax: +1-202-364-8726.