Abstract
Mineralogical-geochemical data obtained on a large xenolith of spinel lherzolite from basanites of Shavaryn Tsaram volcano (Middle Pleistocene) provide evidence that the xenolith was affected by heat and fluid that came from the basalt melt and induced geochemical heterogeneity of the xenolith. Olivine crystals from the central portion of the xenolith contain much more CaO than this mineral from the peripheral zones of the xenolith as well as in xenocrystals of the host basalts. The large xenolith was unevenly annealed by the host basalt melt, and this predetermined the heterogeneous diffusion-controlled “purification” of olivine crystals from their CaO admixture. The xenolith is heterogeneously enriched in LREE and some trace elements (Zr, Hf, Nb, Th, and U), and their distribution demonstrates unclearly pronounced concentric zoning: these elements enriched the outer portions of the xenolith. The enrichment of the xenolith in LREE and other mobile trace elements is explained by their occurrence not only as structurally bound (isomorphic) components in minerals but also in the form of nonstructural admixtures (contaminant), as minute grains of compounds hosted in the interstitial space and tiny cracks cutting mineral grains. The enrichment of the xenolith in these admixtures proceeded via their infiltration-controlled introduction with fluid from the basalt along minute cracks.
Similar content being viewed by others
References
D. A. Ionov, “Xenoliths in Continental Basalts,” in Magmatic Rocks. Ultrabasic Rocks, Ed. by E. E. Laz’ko and E. V.Sharkov (Nauka, Moscow, 1988), pp. 311–332 [in Russian].
D. A. Ionov, A. W. Hofmann, and N. Shimizu, “Metasomatism-Induced Melting in Mantle Xenoliths from Mongolia,” J. Petrol. 35, 753–785 (1994).
F. P. Lesnov, “Deep-Seated Ultramafic Xenoliths in Alkaline Basaltic Provinces: Features of Rare-Earth Geochemistry,” Tikhookean. Geol., No. 2, 15–37 (2003).
L. V. Agafonov, G. V. Pinus, F. P. Lesnov, et al., “Deep-Seated Xenoliths in the Alkaline Basaltoid Pipes of Shavaryn Tsaram, Mongolia,” Dokl. Akad. Nauk SSSR 224, 1163–1165 (1975).
L. V. Agafonov, G. V. Pinus, F. P. Lesnov, et al., “Xenoliths of Pyrope Lherzolites in the Cenozoic Basalts of Central Khangai,” in Principal Geological Problems of Mongolia (Nauka, Moscow, 1977), pp. 156–167 [in Russian].
L. V. Agafonov, V. A. Kutolin, and F. P. Lesnov, “Influence of Basaltic Magma on Ultrabasic Xenoliths and the Relative Stability of Minerals in the Basaltic Melt,” in Materials on Petrology and Mineralogy of Ultrabasic and Alkaline Rocks (Nauka, Novosibirsk, 1978), pp. 67–84 [in Russian].
F. P. Lesnov, L. V. Agafonov, G. V. Pinus, and Yu. O. Lipovskii, “On the First Find of Moissanite in Mongolia,” Geol. Geofiz., No. 6, 119–122 (1976).
L. V. Agafonov and Yu. A. Erkushev, “Rare Earth Element Distribution in Rocks from Shavaryn Tsaram Volcano, Mongolia,” Geol. Geofiz., No. 6, 65–76 (1984).
V. V. Kepezhinskas, Cenozoic Alkaline Basaltoids of Mongolia and Mantle Nodules in Them (Nauka, Moscow, 1979) [in Russian].
H.-G. Stosch, G. W. Lugmair, and V. I. Kovalenko, “Spinel Peridotite Xenoliths from the Tariat Depression, Mongolia. II: Geochemistry and Nd and Sr Isotopic Composition and Their Implications for the Evolution of the Subcontinental Lithosphere,” Geochim. Cosmochim. Acta 50, 2601–2614 (1986).
I. D. Ryabchikov, L. N. Kogarko, V. I. Kovalenko, et al., “Rare-Earth Elements as Indicators of the Geochemical Evolution of the Mantle: Evidence from Peridotite Nodules,” Dokl. Akad. Nauk SSSR 302, 440–443 (1988).
V. I. Kovalenko, I. D. Ryabchikov, and H.-G. Stosch, “Rare-Earth Element Geochemistry in Spinel Lherzolite Nodules: A Model of Primitive Mantle,” Geokhimiya, No. 6, 771–784 (1989).
F. P. Lesnov, “Moissanite,” in Minerals of Mongolia (2006), p. 22.
Minerals. A Guidebook. Vol. 3, Vyp. 1 (Nauka, Moscow, 1972) [in Russian].
W. F. McDonough and F. A. Frey, “Rare Earth Elements in Upper Mantle Rocks,” in Geochemistry and Mineralogy of Rare Earth Elements, Ed. by B. R. Lipin and G. A. McKay, Rev. Mineral. 21, 99–146 (1989).
V. S. Shatskii, E. S. Sitnikova, O. A. Koz’menko, et al., “Behavior of Incompatible Elements during High-Pressure Metamorphism,” Geol. Geofiz. 47(4), 485–498 (2006).
F. P. Lesnov, A. A. Mongush, G. N. Anoshin, et al., “ICPMS Studies of REE and PGE Distribution in Rocks from Mafic-Ultramafic Massifs of Tuva: First Data,” in Petrology of Magmatic and Metamorphic Complexes (Izd-vo Tomsk. Gos. Univ., Tomsk, 2005), pp. 268–277 [in Russian].
E. V. Krivonosova, V. V. Yarmolyuk, and A. A. Mongush, “Geological-Geomorphological Features and Evolution of the Formation of the Late Cenozoic Volcanic Area of the Tariat Depression, Mongolia,” in State and Development of Natural Resources of Tuva and Adjacent Regions of Central Asia. Geoecology of Nature and Socium. Vyp. 8 (Tuv. IKOPR. SO RAN, 2005), pp. 92–99 [in Russian].
S. S. Sun and W. F. McDonough, “Chemical and Isotopic Systematics of Oceanic Basalt: Implications for Mantle Composition and Processes,” in Magmatism in Ocean Basins, Ed. by A. D. Saunders and M. J. Norry, Geol. Soc. Spec. Publ. 42, 313–345 (1989).
N. M. Evensen, P. J. Hamilton, and R. K. O’Nions, “Rare Earth Abundances in Chondritic Meteorites,” Geochim. Cosmochim. Acta 42, 1199–1212 (1978).
A. E. Ringwood, I. D. MacGregor, and F. R. Boyd, “Petrographic Composition of the Upper Mantle,” in Petrological Composition of the Upper Mantle (Mir, Moscow, 1968), pp. 272–277 [in Russian].
A. G. Betekhtin, Treatise on Mineralogy (Gosgeoltekhizdat, Moscow, 1956) [in Russian].
L. P. Rikhvanov, Radiogeochemical Systematics of Ore-Magmatic Systems (Geo, Novosibirsk, 2002) [in Russian].
H.-G. Stosch and H. A. Seck, “Geochemistry and Mineralogy of Two Spinel Peridotite Suites from Dreiser Weiher, West Germany,” Geochim. Cosmochim. Acta 44, 457–470 (1980).
H.-G. Stosch, “Rare Earth Partitioning between Minerals from Anhydrous Peridotite Xenoliths,” Geochim. Cosmochim. Acta 46, 793–811 (1982).
S. M. Eggins, R. L. Rudnick, and W. F. McDonough, “The Composition of Peridotites and Their Minerals: A Laser-Ablation ICP-MS Study,” Earth Planet. Sci. Lett. 154, 53–71 (1998).
I. V. Ashchepkov, N. V. Vladykin, I. V. Nikolaeva, et al., “Mineralogy and Geochemistry of Mantle Inclusions and Mantle Column Structure of the Yubileinaya Kimberlite Pipe, Alakit Field, Yakutia,” Dokl. Akad. Nauk 395(4), 1–7 (2004) [Dokl. Earth Sci. 395, 378–384 (2004)].
E. I. Dontsova, “Distribution of Oxygen Isotopes in Mineral and Rocks and Problem of Their Genesis,” in Proceedings of 23rd International Geological Congress (Academia, Prague, 1968), pp. 67–78.
I. N. Bindeman, V. V. Ponomareva, J. C. Bailey, and J. W. Valley, “Volcanic Arc of Kamchatka: A Province with a High-δ18O Magma Source and Large-Scale 18O/16O Depletion of the Upper Crust,” Geochim. Cosmochim. Acta 68, 841–865 (2004).
J. W. Velley, P. D. Kinny, D. J. Schulze, and M. J. Spicuzza, “Zircon Megacrysts from Kimberlite: Oxygen Isotope Variability among Mantle Melts,” Contrib. Mineral. Petrol. 133, 1–11 (1998).
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text © F.P. Lesnov, S.V. Palesskii, I.V. Nikolaeva, O.A. Koz’menko, A.M. Kuchkin, V.N. Korolyuk, 2009, published in Geokhimiya, 2009, No. 1, pp. 21–44.
Rights and permissions
About this article
Cite this article
Lesnov, F.P., Palesskii, S.V., Nikolaeva, I.V. et al. Detailed mineralogical-geochemical study of a large spinel Lherzolite xenolith in alkali basalt of Shavaryn Tsaram paleovolcano, Mongolia. Geochem. Int. 47, 18–40 (2009). https://doi.org/10.1134/S0016702909010029
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S0016702909010029