Ultramafic xenoliths

Sources of information about the isotopic composition of the upper portion of the lithospheric mantle come from the direct analysis of unaltered ultramafic xenoliths brought rapidly to the surface in explosive volcanic vents. Due to rapid transport, these peridotite nodules are in many cases chemically fresh and considered by most... 

Nishio Y, Nakai S, Yamamoto J, Sumino H, Matsumoto T, Prikhod ko VS, Arai S (2004) Lithium isotope systematics of the mantle derived ultramafic xenoliths imphcations for EMI origin. 

Several ejected blocks are found in the Somma-Vesuvio pyroclastics. These include lavas, sedimentary carbonate rocks, skams, and mafic and ultramafic xenoliths (e.g. Joron et al. 1987). The latter have been suggested... 

Downes H (2001) Formation and modification of the shallow sub-continental lithospheric mantle a review of geochemical evidence from ultramafic xenolith suites and tectonically emplaced ultramafic massifs of Western and Central Europe. J Petrol 42 233-250... 

Bernatowicz, T. J. (1981) Noble gases in ultramafic xenoliths from San Carlos, Arizona. Contrib. Mineral. Petrol., 76, 84-91. 

Farley, K. A., Poreda, R. X (1991) Rare gas composition of Samoan ultramafic xenoliths. EOS Trans. Amer. Geophys. Union, 72, 536-7. 

Valbracht, P. I, Honda, M., Matsumoto, T., Mattielli, N., McDougall, I., Ragettli, R., Weis, D. (1996) Helium, neon and argon isotope systematics in Kerguelen ultramafic xenoliths Implications for mantle source signatures. Earth Planet. Sci. Lett., 138, 29-38. 

Irving A. J. (1980) Petrology and geochemistry of composite ultramafic xenoliths in alkalic basalts and impUcations for magmatic processes within the mantle. Am. J. Sci. 280A,... 

Morgan J. W. (1986) Ultramafic xenoliths clues to Earth s late accretionary history. J. Geophys. Res. 91(B12), 12375-12387. 

Peridotite fertilization may also result from the fractional solidihcation of exotic (deep-seated) melts inhltrated in wall rocks of translithospheric magma conduits. This process was hrst described in composite mantle xenoliths (Wilshire and Shervais, 1975 Gurney and Harte, 1980 Irving, 1980 Wilshire et al., 1980 Boivin, 1982 Harte, 1983 Harte et al, 1993 Menzies et ah, 1987), where it is referred to as modal metasomatism when new (generally hydrous) minerals are precipitated (Dawson, 1984 Kempton, 1987), or Fe-Ti metasomatism (Menzies et al., 1987) when the attention is focused on chemical enrichment. In contrast with ultramafic xenoliths, the tectonically emplaced and oceanic peridotites contain only sparse rock types attributable to mantle metasomatism by deep-seated melts. Examples of wall-rock, modal, and Fe-Ti metasomatism were nevertheless described in IP orogenic Iherzolites, notably in the Pyrenees (Fabrics et al., 1989 Bodinier et al., 1988, 1990, 2003 McPherson et al., 1996 Woodland et al., 1996). 

Wilshire H. G. and Shervais J. W. (1975) Al-augite and Cr-diopside ultramafic xenoliths in basaltic rocks from Western United States structural and textural relationships. Phys. Chem. Earth 9, 257-272. 

Franz L., Brey G. P., and Okrusch M. (1996b) Re-equilibration of ultramafic xenoliths from Namibia by metasomatic processes at the mantle boundary. J. Geol. 104, 599-615. 

Griffin W. L., Shee S. R., Ryan C. G., Win T. T., and Wyatt B. A. (1999c) Harzburgite to Uierzolite and back again metasomatic processes in ultramafic xenoliths from the Wesselton kimberlite. Kimberley, South Africa. Contrib. Mineral. Petrol. 134, 232-250. 

Kurat G., Palme H., Spettel B., Baddenhausen H., Hofmeister H., Palme C., and Wanke H. (1980) Geochemistry of ultramafic xenoliths from Kapfenstein, Austria evidence for a variety of upper mantle processes. Geochim. Cosmochim. Acta 44, 45-60. 

Menzies M. A. (1983) Mantle ultramafic xenoliths in alkaline magmas evidence for mantle heterogeneity modified by magmatic activity. In Continental Basalts and Mantle Xenoliths (eds. C. J. Hawkesworth and M. J. Norry). Shiva, Nantwich, pp. 92-110. 

Porcelli D., O Nions R. K., Galer S. J. G., Cohen A. S., and Mattey D. P. (1992) isotopic relationships of volatile and lithophile trace elements in continental ultramafic xenoliths. Contrib. Mineral. Petrol. 110, 528-538. 

Tatsumoto M., Basu A. R., Wankang H., Junwen W., and Guanhong X., Sr (1992) Nd and Pb isotopes of ultramafic xenoliths in volcanic rocks of eastern China enriched components, EMI and EMU in sub-continental lithosphere. Earth Planet. Sci. Lett. 113, 107-128. 

Vaselli O., Downes H., Thirwall M. F., Dobosi G., Coradossi N., Seghedi L, Szakacs A., and Vannucci R. (1995) Ultramafic xenoliths in Plio-pleistocene alkali basalts from the eastern Transylvanian Basin depleted mantle enriched by vein metasomatism. J. Petrol. 36, 23 —53. 

Figure 7 Published He/ He for phenocrysts and ultramafic xenoliths from various continental localities worldwide (reproduced by permission of Mineralogical Society of America from Rev. Mineral. Geochem., 2002, 47, 380).

There are few constraints on the heavier noble gases in ultramafic xenoliths. While obtaining credible heavy isotope compositions is hampered by low concentrations, more refined analyses and... 

Carlson R. W. and Irving A. J. (1994) Depletion and enrichment history of subcontinental lithospheric mantle— an Os, Sr, Nd, and Pb isotopic study of ultramafic xenoliths from the northwestern Wyoming craton. Earth Planet. Sci. Lett. 126, 457-472. 

Kyser T. K. and Rison W. (1982) Systematics of rare gas isotopes in basic lavas and ultramafic xenoliths. J. Geophys. Res. 87, 5611-5630. 

Coltorti M., Bonadiman C., Hinton R. W., Siena F., and Upton B. G. J. (1999) Carbonatite metasomatism of the oceanic upper mantle evidence from clinopyroxenes and glasses in ultramafic xenoliths of Grande Comore, Indian Ocean. J. Petrol. 40, 133-165. 

Ionov D. A., Hoefs J., Wedepohl K. H., and Wiechert U. (1992) Content and isotopic composition of sulphur in ultramafic xenoliths from central Asia. Earth Planet Sci. Lett. Ill, 269-286. 

Schiano P., Clocchiatti R., Shimizu N., Weis D., and Mattielh N. (1994) Cogenetic sihca-rich and carbonate-rich melts trapped in mantle minerals in Kerguelen ultramafic xenoliths implications for metasomatism in the oceanic upper mantle. Earth Planet. Sci. Lett. 123, 167—178. 

Xue X., Baadsgaard H., Irving A. J., and Scarfe C. M. (1990) Geochemical and isotopic characteristics of lithospheric mantle beneath West Kettle river, British Columbia evidence from ultramafic xenoliths. J. Geophys. Res. 95(B10), 15879-15891. 

Kyle P. R., Wright A., and Kirsch 1. (1987) Ultramafic xenoliths in the late Cenozoic McMurdo volcanic group, western Ross Sea embayment, Antarctica. In Mantle Xenoliths (ed. P. H. Nixon). Wiley, New York, pp. 287-294. 

Wilshire H. W., Meyer C. E., Nakata J. K., Calk L. C., Shervais J. W., Nielson J. E., and Schwarzman E. C. (1988) Mq c and Ultramafic Xenoliths from Volcanic Rocks of the Western United States. Prof. Paper, USGS, Washington, DC, West Sussex, UK. 

Helmstaedt H. and Schulze D. J. (1988) Eclogite-facies ultramafic xenoliths from Colorado Plateau diatreme breccias comparison with eclogites in crustal environments, evalation of the subduction hypothesis, and implications for eclogite xenoliths from diamondiferous kimberlites. In Eclogite and Eclogite Facies Rocks (ed. D. C. Smith). Elsevier, New York, pp. 387-450. 

Yogodzinski G. M. and Kelemen P. B. (2000) Geochemical diversity in primitive Aleutian magmas evidence from an ion probe study of clinopyroxene in mafic and ultramafic xenoliths. EOS 81, F1281. 

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