Isotope stratigraphy and U-Pb dating of detrital zircons from the Vendian-Cambrian deposits of the North Muya block

U-Pb dating of detrital zircons from the sandstones of the Mamakan Formation has been made. Geochemical and isotope parameters of the carbonate deposits of the Yanguda Formation in the Vendian-Cambrian cover of the North Muya continental block have been estimated. It has been established that only the Neoproterozoic (630-915 Ma) rocks of the North Muya block were the provenances of terrigenous material. In the least altered carbonate rocks of the Yanguda Formation, the ⁸⁷Sr/⁸⁶Sr ratio is within 0.70814-0.70879 and δ¹³C varies from -0.4 to + 1.9‰. Comparison of the evaluated isotope parameters with those of carbonate rocks of typical Vendian-Cambrian sections shows that the carbonate deposits of the Yanguda Formation accumulated in the Early Cambrian, about 520 Ma. Sedimentation of the Mamakan and Yanguda Formations took place in the local sedimentary basin in the Vendian-Early Cambrian, in the absence of tectonic activity within the North Muya block. Detrital material that formed during the destruction of the rocks of the Siberian Platform basement and cover was not supplied into the basin.     

Paleozoic Age of Metaterrigenous Sequences of the Maksyutov Metamorphic Complex (Southern Urals): Results of U–Pb Dating of Detrital Zircons

Doklady Earth Sciences - The first U–Pb (LA–ICP–MS) isotope dating of detrital zircons from quartzites of two strata of the Maksyutov metamorphic complex (Southern Urals) was...     

Late Precambrian Metamorphic Complexes of the Ulutau Massif (Central Kazakhstan): Age,Composition, and Formation Settings of Protoliths

Geotectonics - This work presents the results of a study of metamorphic rocks of the Bekturgan and Balazhezdy groups of the Precambrian Ulutau massif (Central Kazakhstan), which have been...     

Neoproterozoic Age of the Iron Ore Volcanogenic–Sedimentary Series of the Ulutau Terrane (Central Kazakhstan)

Doklady Earth Sciences - The metamorphosed iron ore volcanogenic–sedimentary strata of the Karsakpai series in the eastern Ulutau Precambrian terrane of Central Kazakhstan are studied. The...     

Quartzite–Schist Sequences of the Aktau–Mointy Massif (Central Kazakhstan): Structural Position,Provenance, and Formation Stages of the Earth Crust in the Precambrian

Geotectonics - Detrital zircons from quartzite–schist sequences of the Aktau–Mointy Massif (Central Kazakhstan), which occur in various structural positions relative to the Early...     

The Late Neoproterozoic Age of Differentiated Volcanic Complexes of the Ulutau Massif: Results of U–Th–Pb (SIMS) Dating

Doklady Earth Sciences - The metamorphosed differentiated volcanogenic strata of the Aralbai Group have been studied in the eastern part of the Precambrian Ulutau massif of Central Kazakhstan. The...     

First Results of Study of Detrital Zircons from Late Precambrian Quartzite–Schist Sequences of the Aktau–Mointy Block,Central Kazakhstan

For the first time, the U–Pb age is determined for detrital zircons of quartzite–schist sequences, which are part of the Precambrian basement of the Aktau–Mointy Block (Central Kazakhstan) along with Neoproterozoic felsic volcanic (925–920 Ma) and granitic (945–917 Ma) rocks [6]. We analyzed 219 zircon grains from small-grained quartzites of the northern part of the block (Mt. Bol’shoi Alabas) including 206 grains with concordant age (1149–1273, 1276–1975, 2354–2592 Ma). These ages indicate the Mesoproterozoic, Paleoproterozoic, and Neoarchean rocks as provenances. The youngest statistically significant age peak of 1209 Ma indicates that the quartzite–schist sequences accumulated 1200–900 Ma ago (at the end of the Mesoproterozoic and beginning of the Neoproterozoic) prior to the formation of the Early Neoproterozoic felsic rocks and granites.     

First results of U–Pb dating of detrital zircons from the Ordovician clastic sequences of the Sol-Iletsk Block,East European Platform

The first LA–ICP–MS U–Pb isotopic ages of detrital zircons from the Ordovician sandstones of the Sol–Iletsk Block (well 2–Ordovician), located at junction of the East European Platform with the Pre-Caspian Basin and the Pre-Uralian foredeep, are presented. Two detrital zircons with well-defined ages of 561 ± 4 and 570 ± 5 Ma were found in sample K15–501. They confirm the Ordovician age of the sandstones, which earlier had been defined on the basis of seismic–stratigraphic and lithological correlations. The age distribution of the detrital zircons indicates the significant role of Late Precambrian rocks as provenance sources. However, those rocks still remain unknown in the Early Precambrian basement of the Volga–Ural part of the EEP.     

Early Neoproterozoic (~920 Ma) Granite–Gneiss of the Junggar Alataw,South Kazakhstan: Age Substantiation Based on the Results of U–Th–Pb (SIMS) Dating

Doklady Earth Sciences - Based on the results of U–Th–Pb (SIMS) dating, an Early Neoproterozoic (924 ± 4 Ma) age was obtained for granite–gneiss of the Sarychabyn Complex,...     

Sedimentary complexes of the cover of the Dzabkhan continental block: Different sedimentary basins and source areas

The geochemical and Sm–Nd isotope characteristics of Late Precambrian and Early Cambrian sandstones previously related to the sedimentary cover of the Dzabkhan continental block are reported. It is established that the Riphean and Vendian sedimentary rocks of the Ul’zitgol’skaya and Tsaganolomskaya Formations were accumulated within the Dzabkhan continental block as a result of recycling of the terrigenous deposits formed at the expense of destruction of basement rocks and younger granite. The formation of terrigenous rocks of the Bayangol’skaya Formation after a gap in sedimentation occurred in the sedimentary basin, where only the Late Riphean formations of the juvenile crust, probably of the Dzabkhan–Mandal block were the sources, without the contribution of the ancient crustal material. The Tsaganolomskaya and Bayangol’skaya Formations were formed in different sedimentary basins and cannot be related to the same complex.