CAMBRIAN GRANODIORITES AND THEIR PALEOWEATHERING PRODUCTS IN THE SOUTHEAST OF THE WEST SIBERIAN GEOSYNECLISE: PETROGRAPHY, GEOCHEMISTRY, AND 40Ar/39Ar AGE
S.V. Saraev and V.A. Ponomarchuk
United Institute of Geology, Geophysics and Mineralogy, Siberian Branch of the RAS,
3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
Keywords: West Siberian geosyneclise, granodiorites, absolute age, Cambrian, weathering
Pages: 1115-1120
Abstract
Using the 40Ar/39Ar method, an Early Cambrian age has been established for granodiorites stripped in the bottom-hole zone (4824-5005 m) of Vezdekhodnaya BH-4 (Tomsk Region) in the southeast of the West Siberian geosyneclise. Primitive crust of weathering is developed on the granodiorites. The rocks are overlain by gritstones of sedimentary nature. The results obtained suggest a short time gap between the intrusion of the granodiorites into volcanosedimentary strata and the first effusion of the overlying submarine basalts.
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