WATER CONTENT IN MINERALS OF MANTLE XENOLITHS FROM THE UDACHNAYA PIPE KIMBERLITES (Yakutia)
A.L. Ragozin1,2,3, A.A. Karimova4, K.D. Litasov1,2,3, D.A. Zedgenizov1,2,3, V.S. Shatsky5,6
1pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
2Novosibirsk State University
3ul. Pirogova 2, Novosibirsk, 630090, Russia
4Institute of Mineralogy and Petrography, University of Innsbruck, Innrain 52f, 6020 Innsbruck, Austria
5pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia, ul. Favorskogo 1a, Irkutsk, 664033, Russia
6A.P. Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences
Keywords: Nominally anhydrous minerals, upper mantle, eclogite, peridotite, IR spectroscopy
Abstract
Distribution of water among the main rock-forming nominally anhydrous minerals of mantle xenoliths of peridotitic and eclogitic parageneses from the Udachnaya kimberlite pipe, Yakutia, has been studied by IR spectroscopy. The spectra of all minerals exhibit vibrations attributed to hydroxyl structural defects. The content of H2O (ppm) in minerals of peridotites is as follows: 23–75 in olivine, 52–317 in orthopyroxene, 29–126 in clinopyroxene, and 0–95 in garnet. In eclogites, garnet contains up to 833 ppm H2O, and clinopyroxene, up to 1898 ppm (~0.19 wt.%). The obtained data and the results of previous studies of minerals of mantle xenoliths show wide variations in H2O contents both within different kimberlite provinces and within the Udachnaya kimberlite pipe. Judging from the volume ratios of mineral phases in the studied xenoliths, the water content varies over narrow ranges of values, 38–126 ppm. At the same time, the water content in the studied eclogite xenoliths is much higher and varies widely, 391–1112 ppm.
DOI: http://dx.doi.org/10.1016/j.rgg.2014.03.002
|
