Инд. авторы:	Lesnov F.P., Koz'menko O.A, Nikolaeva I.V., Palesskii S.V.
Заглавие:	Residence of incompatible trace elements in a large spinel lherzolite xenolith from alkali basalt of Shavaryn Tsaram-1 paleovolcano (western Mongolia)
Библ. ссылка:	Lesnov F.P., Koz'menko O.A, Nikolaeva I.V., Palesskii S.V. Residence of incompatible trace elements in a large spinel lherzolite xenolith from alkali basalt of Shavaryn Tsaram-1 paleovolcano (western Mongolia) // Russian Geology and Geophysics. - 2009. - Vol.50. - Iss. 12. - P.1063-1072. - ISSN 1068-7971. - EISSN 1878-030X.
Внешние системы:	DOI: 10.1016/j.rgg.2009.11.005; SCOPUS: 2-s2.0-70449900654;
Реферат:	eng: We have studied a large (12 × 22 × 30 cm) spinel lherzolite xenolith with undeformed margins in alkali basalt (basanite) from the eroded crater of Late Cenozoic Shavaryn Tsaram-1 volcano in western Mongolia. The xenolith was sampled along its median transversal profile, at every 15-20 mm for bulk chemistry of lherzolite and basalt (ICP-MS) and at 4-10 mm for the chemistry of olivine, orthopyroxene, clinopyroxene, and Cr-spinel minerals, and of material filling cracks (LA ICP-MS). Incompatible elements (especially, LREE) are distributed unevenly over the xenolith, both in lherzolite and in its constituent minerals, as well as in crack-filling material, with abnormal LREE enrichment in some specimens. Judging by the measured trace-element spectra compared with the model patterns, incompatible elements reside in different amounts as interstitial impurity in cracks inside and between mineral grains in lherzolite, also being a substitutional impurity in the lherzolite constituent minerals. Experimental acid leaching of specimens from sites of high crack density showed (La/Yb)n ratios in the crack fill to be much higher than in the basalt host and more so in bulk lherzolite (180 against 33 and 1.5-3.6, respectively). The proportional contents of P and Ca in the leaching solution, especially in that from the xenolith's center mark the presence of an apatite microphase, which can be a LREE repository. The observed patterns of LREE and other incompatible elements in the xenolith and in the host alkali basalt fit a model implying that mobile elements residing as interstitial impurity came with fluids which were released from rising basaltic magma and percolated into the xenolith along cracks. © 2009.
Ключевые слова:	leaching; lherzolite; mantle chemistry; olivine; orthopyroxene; rare earth element; spinel; trace element; xenolith; Asia; Eurasia; Far East; Mongolia; Cenozoic; apatite; alkali basalt; trace-element chemistry; spinel lherzolite; REE and incompatible elements; Mongolia; mantle xenolith; clinopyroxene; alkali basalt fluids;
Издано:	2009
Физ. характеристика:	с.1063-1072