ISSN 1028-334X, Doklady Earth Sciences, 2014, Vol. 455, Part 1, pp. 336–340. © Pleiades Publishing, Ltd., 2014. Original Russian Text © E.I. Mikheev, A.G. Vladimirov, N.I. Volkova, T.B. Bayanova, A.V. Travin, D.S. Yudin, A.S. Mekhonoshin, D.A. Orsoev, 2014, published in Doklady Akademii Nauk, 2014, Vol. 455, No. 3, pp. 317–322. 336 Study of the tectonic setting, composition, and age of deeply metamorphosed rocks and the associated magmatic complexes, the formation of which occurred at deep levels of the Earth’s crust, is one of the fundamental tasks of geology, petrology, and geochemistry. In this relation, of key importance is the study of granulites providing reconstruction of geody- namic environments of their formation occurring dur- ing the accretion–collisional processes and growth of the continental crust in the Phanerozoic [1]. We studied granulites from the Svyatoi Nose Penin- sula, which are possibly the most deeply metamor- phosed fragments of the Early Caledonian accretion– collisional system of the Baikal region [2] (Fig. 1), as well as synkinematic granosyenite–granite veins entering the “svyatonosite” rock group [3]. We should specially emphasize that granulites and injection gra- nosyenite–granite veins were sampled in the same geological outcrop (Fig. 2), which allows us to recon- struct their thermochronological history reliably. Metamorphic rocks of the Svyatoi Nose Peninsula are represented by alternating bands of basic gneiss and a triad of graphite marble, diopside plagioschist, and minor quartzite layers. Gneiss bands prevail in the southern and northern parts of the peninsula, and quartzite–schist–carbonate bands predominate in its central part (Fig. 2). The band of clinopyroxene– amphibole gneiss has a northeastern strike and steep dipping to the northwest. The presence of marble mélange zones with metagabbroid inclusions is a spe- cific feature of this band. Basic gneiss contains numer- ous veins of garnet-bearing granosyenite–granite and injection veins of granite pegmatite. Metamorphic rocks are intruded by granitoids of the Barguzin Com- plex of the Angara–Vitim batholith with an age of 300–280 Ma [5]. Garnet–biotite–amphibole, biotite–garnet–cli- nopyroxene–amphibole, and garnet–amphibole– biotite–clinopyroxene basic gneisses are the most abundant rocks in the granulite complex of the Svyatoi Nose Peninsula. These are medium-granular, poorly foliated rocks with a granonematoblasitic texture. Accessory minerals are represented by magnetite and titanite. Secondary alterations are not observed. These gneisses are characterized by low alkalinity and corre- spond to the normal series of magmatic rocks. According to the chemical composition, rocks are related to the calc-alkaline series, which suggests island-arc volcanic rocks as a protolith [3]. REE spec- tra are characterized by a poor negative slope provid- ing evidence for enrichment in LREE in comparison with HREE, (Ce/Yb) N = 3.92–8.28. The presence of negative Eu anomalies with (ΔEu/Eu*) N = 0.69–0.74 and, only in one case, a positive Eu anomaly with (ΔEu/Eu*) N = 1.42 is observed. We registered negative anomalies of the Th, Nb, and Ti concentrations con- firming the island-arc genesis of protoliths. These petrogeochemical data allow us to correlate granulites of the Chernorudskaya zone of Priol’khon’e and those of the Svyatoi Nose Peninsula [2, 6]. Estimations of the Р–Т parameters of metamor- phism of garnet–biotite–amphibole–clinopyroxene gneiss from the Svyatoi Nose Peninsula calculated by 10 independent reactions using the THERMOCALC software [7] are the following: 813–858°С and 7.9– 8.3 kbar. The obtained results are consistent with the Р–Т estimations of metamorphic conditions for the Chernorudskaya zone of the Ol’khon region: 770– 820°С and 7.7–8.6 kbar [6]. This allows us to con- Thermochronology of Granulites from the Svyatoi Nose Peninsula (Transbaikalia) E. I. Mikheev a , A. G. Vladimirov b, c , N. I. Volkova a , T. B. Bayanova d , A. V. Travin a , D. S. Yudin a , A. S. Mekhonoshin e , and D. A. Orsoev f Presented by Academician F.A. Letnikov October 20, 2012 Received December 17, 2012 DOI: 10.1134/S1028334X14030313 a Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia b Tomsk State University, Tomsk, Russia c Novosibirsk State University, Novosibirsk, Russia d Geological Institute, Kola Science Center, Russian Academy of Sciences, Apatity, Murmansk oblast, Russia e Vinogradov Institute of Geochemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia f Geological Institute, Siberian Branch, Russian Academy of Sciences, UlanUde, Russia e-mail: vladimir@igm.nsc.ru GEOCHEMISTRY