ISSN 1028-334X, Doklady Earth Sciences, 2016, Vol. 466, Part 2, pp. 173–176. © Pleiades Publishing, Ltd., 2016. Original Russian Text © D.I. Rezvukhin, V.G. Malkovets, I.S. Sharygin, D.V. Kuzmin, K.D. Litasov, A.A. Gibsher, N.P. Pokhilenko, N.V. Sobolev, 2016, published in Doklady Akademii Nauk, 2016, Vol. 466, No. 5, pp. 587–591. 173 Rutile, one of the most abundant accessory miner- als, is present in various metamorphic, igneous, and sedimentary rocks. It is the most important concen- trator of high field strength elements (HFSEs: Nb, Ta, Zr, Hf) and in spite of the low modal content, may be their major concentrator in the rock [1]. The findings of rutile in the lithospheric mantle rocks are of signifi- cant interest; it has been found mostly in rocks of eclogitic [2, 3] or mantle metasomatic (e.g., MARID [4]) associations. Rutile in mantle peridotites (lherzo- lites–harzburgites) occurs significantly rare: its find- ings are known mostly in metasomatized xenoliths of spinel facies from alkali basalts [5] and also as inclu- sions in Cr-pyrope xenocrysts of the lherzolite paragenesis from ultramafic breccias of a Garnet Ridge diatreme, Arizona, United States [6]. In xenogenic material of kimberlites of the Siberian craton, rutile was found as inclusions in diamonds mostly of eclogitic paragenesis or as intergrowths with them [2, 3, 7], as well as inclusions in Cr-pyropes from the Internatsionalnaya pipe and lamprophyres of the Aldan Shield [8]. In this work, we provide new data on the chemical composition of rutile inclusions in 39 xenocrysts of garnet of ultrabasic paragenesis from the Devonian (360 Ma [9]) highly diamondiferous (9 ct/ton) Inter- natsionalnaya kimberlite pipe (Mirnyi field). Inclu- sions of rutile often occur in assemblage with Ti-rich oxides: picroilmenite and crichtonite group minerals. The following mineral assemblages of inclusions were identified in pyropes studied (the number of samples is given in brackets): rutile (22), rutile + picroilmenite (9), rutile + crichtonite group minerals (6), rutile + ilmenite + crichtonite group minerals (1), and rutile + chromite (1). By morphology, two groups of rutile inclusions in pyrope were distinguished: an oriented lattice of tiny (<5 μm across) acicular rutile and not abundant larger (10–80 μm across) individual elongated inclusions. By most researchers, the origin of rutile of the first group is considered to be related to the exsolution [1]. In this work, we studied rutile of the second group. The internal structure and chemical composition of pyropes and inclusions were studied using a JEOL JSM-6510LV SEM coupled with an Oxford Instru- ments INCA Energy 350 EDS and a JEOL JXA-8100 microprobe at the Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences (Novosibirsk) and a JEOL JSM-7001F SEM equipped with an Oxford Instruments INCA Energy X-act EDS and a JEOL JXA-8800 microprobe at the Institute for Study of the Earth’s Interior (Misasa, Japan). The chemical compositions of pyrope and rutile are shown in Figs. 1 and 2. The representative analyses of rutile are given in Table 1. According to the classification CaO–Cr 2 O 3 plot [10], 37 pyropes belong to the lherzolitic paragenesis and two belong to the wehrlitic paragenesis (Fig. 1). The composition of pyropes within a single grain is homogeneous. The maximum Cr 2 O 3 content in pyrope with rutile inclusions is 5.75 wt %. Inclusions of Cr- and Cr–Nb-Rutile in Pyropes from the Internatsionalnaya Kimberlite Pipe, Yakutia D. I. Rezvukhin a , V. G. Malkovets a, c , I. S. Sharygin a , D. V. Kuzmin a, b , K. D. Litasov a, b , A. A. Gibsher a , Academician N. P. Pokhilenko a, b , and Academician N. V. Sobolev a, b Received May 12, 2015 Abstract—The results of study of rutile inclusions in pyrope from the Internatsionalnaya kimberlite pipe are presented. Rutile is characterized by unusually high contents of impurities (up to 25 wt %). The presence of Cr 2 O 3 (up to 9.75 wt %) and Nb 2 O 5 (up to 15.57 wt %) are most typical. Rutile inclusions often occur in assemblage with Ti-rich oxides: picroilmenite and crichtonite group minerals. The Cr-pyropes with inclu- sions of rutile, picroilmenite, and crichtonite group minerals were formed in the lithospheric mantle beneath the Mirnyi field during their joint crystallization from melts enriched in Fe, Ti, and other incompatible elements as a result of metasomatic enrichment of the depleted lithospheric mantle. DOI: 10.1134/S1028334X1602015X a Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, pr. Koptyuga 3, Novosibirsk, 630090 Russia b Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090 Russia c Institute for Study of the Earth’s Interior, Okayama University, Japan e-mail: m.rezvukhin@gmail.com GEOCHEMISTRY