The U–Th–Pb Age of Detrital Zircons from Oolitic Limestones of the UK Formation: Traces of the Grenville Provenance Areas in the Late Riphean of the Southern Urals
Т. S. Zaitseva, А. Б. Кузнецов, Н. Д. Сергеева, E. V. Adamskaya, Yu. V. Plotkina
Abstract
The results of U–Th–Pb LA-ICP-MS dating of detrital zircons from oolitic limestones of the lower subformation of the Uk Formation are presented. The Uk Formation represents the upper level of the Late Riphean stratotype in the Southern Urals. The obtained data show that half of the detrital zircons were supplied by eroded Archean and Paleoproterozoic complexes in the adjacent territory of the East European Platform. Igneous complexes (Berdyaush, Ryabinovsky, Gubensky, and Akhmerovsky granitoids; 1.35–1.40 Ga) located in the Bashkirian meganticlinorium could supply less than a tenth of grains. Nevertheless, the Mesoproterozoic (Middle Riphean) rocks (1.13–1.40 Ga) were the main source of detrital zircons in the Early Uk time. A potential Mesoproterozoic source could have been either the Fennoscandian rapakivi granites (1.44–1.56 Ga) and the rocks of the Sveconorwegian (Grenville) orogenic belt (1.13–1.16 Ga) or an unknown continental block joined during the Grenville orogeny.