GEOCHEMISTRY AND GEOCHRONOLOGY OF PERMO-TRIASSIC BASITES IN THE NORTHWESTERN ALTAI-SAYAN FOLDED AREA
G.S. Fedoseev, V.I. Sotnikov, and L.P. Rikhvanov*
Institute of Geology, Siberian Branch of the RAS, 3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
* Tomsk Polytechnical University, 30 prosp. Lenina, Tomsk, 634050, Russia
Keywords: Basites, dikes, sills, geochemistry, 40Ar/39Ar geochronology, Kolyvan'-Tomsk folded zone, Kuznetsk basin
Pages: 287-301
Abstract
Petrogeochemical and isotope-geochronological data are of paramount importance for refining the geologic correlation between weakly exposed magmatites of the Kolyvan'-Tomsk folded zone and Kuznetsk basin. We report data on dike and dike-sill basite complexes of shallow-depth genesis. According to the 40Ar/39Ar age estimates, basites in the Kuznetsk and Gorlovka basins are older than dikes free of xenogenous matter in the Tomsk magmatic area (248.95 ± 1.81-246.2 ± 1.4, 259.1 ± 3.4, and 241.6 ± 2.7-238.0 ± 5.2 Ma, respectively) and are close in petrogeochemistry to basites of the Tashara complex in the Novosibirsk magmatic area. These data suggest the synchronous occurrence of magmatic events related to the Permo-Triassic plume activity within the West Siberian Plate, Siberian Platform, and their southern folded framing.
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