THE AGE OF CARBONATITES AND MAFIC ROCKS (SHRIMP-II and Rb-Sr dating) FROM THE OSHURKOVO APATITE-BEARING PLUTON ( western Transbaikalia )
G.S. Rippa, A.G. Doroshkevicha, V.F. Posokhova, I.A. Izbrodina, D.L. Konopel'kob, and S.A. Sergeevc
a Geological Institute, Siberian Branch of the Russian Academy of Sciences, ul. Sakh'yanovoi 6a, Ulan-Ude, 670047, Russia
b St. Petersburg State University, Universitetskaya nab. 7/9, St. Petersburg, 199034, Russia
c A.P. Karpinsky Russian Geological Research Institute (VSEGEI), Center of Isotopic Research, Srednii pr. 74, St. Petersburg, 199106, Russia
Keywords: Geochronology, age, carbonatites, gabbros
Pages: 517-525
Abstract
The paper presents geochronological data on silicate and endogenic carbonate rocks from the Oshurkovo apatite-bearing pluton, namely, the U-Pb and Rb-Sr isochron age of gabbros and carbonatites. The U-Pb age of the carbonatites from this pluton (126.55 ± 0.85 Ma) is close to that of other carbonatite occurrences in southwestern Transbaikalia. Also, its similarity to the age of the gabbro (125.4 ± 2 Ma), which makes up the bulk of the pluton, suggests that these rocks are comagmatic.
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