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U-Pb (SIMS) dating of zircons from granite of the Petrokamensk gabbro-granitoid complex, marking termination of the Devonian island-arc magmatism in the Verkhisetsk-Tura Zone of the Middle Urals, gave an age of 386 ± 3 Ma. Zircons from the West Verkhisetsk granitoids, the formation of which corresponds to the beginning stage of magmatism of the continental margin in the region, yielded ages of 386.6 ± 4.1 and 381.8 ± 6.0 Ma. This suggests that the change in the regime of the island-arc geodynamic mode to an active continental margin took place at the boundary of the Middle and Late Devonian. The upper boundary of existence of the continental margin subduction zone is determined by the closure of the Ural paleo-ocean and the beginning of continental collision processes, which resulted in accumulation of flysch in the Ural foreland trough from the second half of the Bashkirian Stage. [ABSTRACT FROM AUTHOR]

The formation of the Large Igneous Province (LIP) approximately 1380 Ma old in the South Urals was related to the Mashak riftogenic event in the Bashkir meganticlinorium, which was synchronous with the emplacement of different magmatic bodies (the Berdyaush pluton of rapakivi granites and associated rocks, the Main dike of the Bakal ore field, and the Medvedev, Guben, and Kusa massifs, among others) localized among sedimentary deposits of the Burzyan and Yurmatin Groups representing Lower and Middle Riphean type units of northern Eurasia. The U-Pb ID-TIMS age of 1379.6 Ma (MSWD = 1.3) obtained with an accuracy of ±2.9 Ma (confidence interval 95%) combined with the available published U-Pb ID-TIMS data constrain the age and duration of the Early-Middle Riphean pulse in the LIP formation in the Southern Urals. [ABSTRACT FROM AUTHOR]

The U-Pb dating of zircons from the Mazara granite massif (Southern Urals) by means of the SHRIMP II technique resulted in the conclusion that the zircons were constituted of two key generations belonging, respectively, to the substrate and to the intrusion proper. The age of the granite substrate presented by zircon cores is estimated at 1527-1548 Ma; the final stage of the substrate evolution is characterized by a concordant date of 1388 ± 16 Ma. The latter estimate is much closer to the Mesoproterosoic stage of magmatism. The information on the formation of granites of the Mazara intrusion is mainly contained in the outer parts of the crystals, with two stages distinguished within the formation history. The early and final stages are determined by the datings of 746.6 ± 24.3 and 709.1 ± 5.2 Ma, respectively (both estimates conform to the Neoproterozoic). [ABSTRACT FROM AUTHOR]

The article discusses mineralization of Voznesenskoe copper–porphyry deposit in the Main Uralian Fault Zone in Russia. Topics discussed include parental rocks' composition, research on composition of plagiogranite–porphyries, and Uranium–lead (U–Pb) dating of zircons. Other topics include use of Samarium-neodymium (Sm-Nd) dating method and composition of gabbro diorites from the Karagaikul ore.

The article discusses Uranium-Lead (U-Pb) systematics of Proterozoic magnesites from Satka Deposit, South Urals which provides information on the age and the environment of their formation. It mentions that U-Pb of carbonate rocks it is assumed that the formation of metasomatic magnesite of the Satka deposit occurred during the Middle Riphean.

The article discusses a study which presents the first uranium-lead (U-Pb) isotope results of detrital zircons from the Riphean Stratotype of the Southern Urals. It tackles detrital zircon age dating which aims to investigate the age data of strata and deposits. The data gathered shows that at first approximation, zircons can be divided into three populations. It adds that the age spectra difference in zircons show that the Bashkir Meganticlinorium formed due to terrigenous material.

U-Pb dating of zircons (SHRIMP-II) has been performed for the first time for granites, granodiorites, and synplutonic granodiorite and melanodiorite bodies of the Shartash and Shabry massifs in the Middle Urals. The time of the formation of the massifs is 300-306 Ma, which is 25 Ma younger than the previous estimates. The age data obtained are in line with the time of the formation of the adamellite-granite series of the Verkhisetsk Batholite (the master sample of tonalite-granodiorite-granite magmatism in the Middle Urals), the series of which is petrochemically close to the rocks of the massifs. [ABSTRACT FROM AUTHOR]

The article discusses the results of the first zircon uranium-lead (U-Pb) dating of Silurian ophiolites at the Urals mountains in Russia. Researchers used the SHRIMP II ion microprobe, which revealed good evidence of Silurian ophiolites occurrence. Such occurrence of signs of layering and features of composition characteristics have enabled researchers to consider these situations as a fragment of the upper horizons of the layered part of the ophiolite section. The authors noted that the Silurian age of the ophiolite association has a correlated formation of the ophiolite group of the eastern zone of the Middle Urals.

The article discusses the study on the mineralogy, geochemistry and age peculiarities of zircon distribution on gneissose leucocratic miaskites of the Ilmenogorsk massif deposit at the southern region of Ural Mountains in Russia. Researchers conducted recrystallization of the zircon samples from amphibole miaskites that yielded formation of emulsion structures, crushing and corrosion, and new growth. From the authors' findings, ages of miaskite crystallization, 434 plus 15 minus 10 million years (Ma), and metamorphism, 239 plus 40 minus 45 Ma, were determined by standard uranium-lead (U-Pb) dating method.