Lobach-Zhuchenko S.B.,Russian Academy of Sciences |
Kaulina T.V.,Murmansk State Technical University |
Baltybaev S.K.,Russian Academy of Sciences |
Balagansky V.V.,Murmansk State Technical University |
And 11 more authors.
Geological Society Special Publication | Year: 2017
Multidisciplinary studies of zircons, rock-forming minerals and the whole-rock composition of granulite samples from the Bug Granulite-Gneiss Complex, Ukraine (including ion microprobe REE analysis, secondary ion mass spectrometry (SIMS) U-Pb and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) Lu-Hf analysis of zircons from a single sample) have revealed three major stages in the geological evolution of the complex. (i) At 3.66 Ga, a mafic intrusion contaminated with felsic rocks formed, as evidenced by 3.74 Ga zircon xenocrysts with inclusions of plagioclase, K-feldspar and quartz. (ii) At 3.59-3.55 Ga, high-temperature and high- to moderate-pressure granulite-facies metamorphism accompanied by migmatization and deformation resulted in the formation of mafic granulites. (iii) At 2.1- 2.0 Ga, metamorphic overprinting occurred, and metatrachybasaltic dykes intruded at approximately 2.0 Ga. The metamorphic mineral assemblages recorded in the dykes formed at temperatures similar to those of the 3.59-3.55 Ga metamorphism but at pressures 2-3 kbar lower. This metamorphism disturbed the Sm-Nd whole-rock system, altered the Hf isotope system of the older zircons and resulted in Pb loss in small zircon grains. This complex event history recorded in zircons from a single rock corresponds to major stages of the geological evolution of both the Dniester-Bug Province and the entire Ukrainian Shield. © 2017 The Author(s).
Vernikovskaya A.E.,Russian Academy of Sciences |
Datsenko V.M.,Krasnoyarsk Research Institute of Geology |
Vernikovsky V.A.,Russian Academy of Sciences |
Matushkin N.Yu.,Russian Academy of Sciences |
And 5 more authors.
Doklady Earth Sciences | Year: 2013
Neoproterozoic carbonatites and related igneous rocks, including A-type granites in the Tatarka-Ishimba suture zone of the Yenisey Ridge are confined to a horst-anticlinal structure that was formed in a transpression setting during the oblique collision between the Central Angara terrane and the Siberian craton. The carbonatites, associating mafic (including alkaline) dikes as well as the Srednetatarka nepheline syenites are the oldest igneous formations of the Tatarka active continental margin complex. Geochronological data indicate that magmatic evolution continued in the studied anticline for nearly 100 m.y. On the earliest stage carbonatites were formed and on the last stage - the emplacement of mantle-crustal A-type Tatarka granites took place. According to new U/Pb zircon studies, the earliest rocks in the Tatarka pluton are A-type leucogranites aged 646 ± 8 Ma. The younger 40Ar/ 39Ar ages of carbonatites obtained for phlogopites (647 ± 7 and 629 ± 6 Ma) are related to the last tectonic events in the studied region of the Tatarka-Ishimba suture zone, which are coeval with the formation of the A-type granitoids (646-629 Ma). © Pleiades Publishing, Ltd., 2013.
Danukalova M.K.,Russian Academy of Sciences |
Tolmacheva T.Y.,Karpinsky Russian Geological Research Institute |
Mannik P.,Tallinn University of Technology |
Suyarkova A.A.,Karpinsky Russian Geological Research Institute |
And 3 more authors.
Stratigraphy and Geological Correlation | Year: 2015
Much of the material of Paleozoic successions of Kotelnyi Island (New Siberian Islands) is composed of various carbonates, which accumulated in relatively shallow conditions in the Ordovician–Middle Devonian. Such deposits are widespread in synchronous sections throughout the Eastern Arctic and therefore attract attention as a potential tool for interregional correlations. In paleotectonic reconstructions, Kotelnyi Island either is included in terrain which was disconnected from the Siberian Platform in the Paleozoic or is joined to it. These different interpretations result from lack of primary evidence. This paper presents new data on stratigraphy and macroand microfauna of the Upper Ordovician and Silurian of the central regions of Kotelnyi Island. For this interval, we propose a correlation of the studied sections with those of adjacent regions. A conclusion is drawn on the basis of the similarity of lithology and fossil assemblages and also shared trends in the evolution of the sedimentary environment that the Upper Ordovician–Silurian beds of Kotelnyi Island, Taimyr, and the Siberian Platform accumulated in a single shelf basin, which apparently also extends to northeastern Chukotka. © 2015, Pleiades Publishing, Ltd.
Degtyarev K.E.,Russian Academy of Sciences |
Tolmacheva T.Y.,Karpinsky Russian Geological Research Institute |
Tretyakov A.A.,Russian Academy of Sciences |
Kotov A.B.,Russian Academy of Sciences |
Shatagin K.N.,RAS Institute of Geology and Mineralogy
Geotectonics | Year: 2016
A comprehensive study of the Lower Palaeozoic complexes of the Kokchetav Massif and its fringing has been carried out. It has allowed for the first time to discover and investigate in detail the stratified and intrusive complexes of the Cambrian–Early Ordovician. Fossil findings and isotope geochronology permitted the determination of their ages. The tectonic position and internal structures of those complexes have also been defined and their chemical features have been analyzed as well. The obtained data allowed us to put forward a model of the geodynamic evolution of Northern Kazakhstan in the Late Ediacaran–Earliest Ordovician. The accumulation of the oldest Ediacaran to Earliest Cambrian siliciclastics and carbonates confined to the Kokchetav Massif and its fringing occurred in a shallow shelf environment prior to its collision with the Neoproterozoic Daut island arc: complexes of the latter have been found in the northeast of the studied area. The Early Cambrian subduction of the Kokchetav Massif under the Daut island arc, their following collision and exhumation of HP complexes led to the formation of rugged ground topography, promoting deposition of siliceous–clastic and coarse clastic units during the Middle to early Late Cambrian. Those sediments were mainly sourced from eroded metamorphic complexes of the Kokchetav Massif basement. At the end of the Late Cambrian to the Early Ordovician within the boundaries of the massif with the Precambrian crust, volcanogenic and volcano-sedimentary units along with gabbros and granites with intraplate affinities were formed. Simultaneously in the surrounding zones, which represent relics of basins with oceanic crust, N-MORB- and E-MORB-type ophiolites were developed. These complexes originated under extensional settings occurred in the majority of the Caledonides of Kazakhstan and Northern Tian Shan. In the Early Floian Stage (Early Ordovician) older heterogeneous complexes were overlain by relatively monotonous siliceous–clastic units, that were being deposited until the Middle Darrivilian Stage (Middle Ordovician). © 2016, Pleiades Publishing, Inc.
Gusev N.I.,Karpinsky Russian Geological Research Institute
Geology of Ore Deposits | Year: 2011
The Kalguty ore-magmatic system (OMS) contains economic greisen and vein rare-metal-tungsten-molybdenum mineralization. The data on U-Pb zircon (SHRIMP II) age of nine samples of igneous rocks from the Kalguty OMS are accompanied by chemical, ICP-MS, and ICP-AES analyses of the main rock varieties. Porphyritic biotite granite of the main phase of the Kalguty pluton is characterized by the concordant age of 207.5 ± 1.7 Ma (MSWD = 0.034). The concordant age of the leucogranitic dikes pertaining to the East Kalguty Complex is 204 ± 2 Ma (MSWD = 0.65) for elvan and 200.8 ± 1.1 Ma (MSWD = 0.72) for ultrapotassic rhyolite porphyry. The two-mica and muscovite leucogranite of the Eastern stock is significantly younger: 195 ± 2.7 Ma (MSWD = 0.076) and 193.1 ± 2.1 Ma (MSWD = 0.0009). Thus, the Chingadatui Complex (the main phase of the Kalguty pluton) and dikes of the East Kalguty Complex are Late Triassic in age. The two-mica leucogranites of the Eastern, Zhumaly, and other stocks are most likely correlated to the Early Jurassic Alacha Complex of rare-metal granites. The superposition of greisen mineralization on elvan and ongonite dikes may be related to the emplacement of younger, Early Jurassic ore-forming two-mica and muscovite granites. Judging from zircon xenocrysts in granites, the Mesoproterozoic igneous rocks dated at 1.5 Ga and products of erosion of the rocks dated at 1.7 and 2.5 Ga occur in the basement of the Kalguty volcanic-tectonic structure. This is sound evidence for the occurrence of ancient continental crustal blocks in the southwestern part of the Altai-Sayan region. © 2011 Pleiades Publishing, Ltd.
Shishkin M.A.,Karpinsky Russian Geological Research Institute |
Lebedeva E.A.,Karpinsky Russian Geological Research Institute
Geoinformatics 2010 - 9th International Conference on Geoinformatics: Theoretical and Applied Aspects | Year: 2010
Peiome Computer database included field geological information is obligatory part of State Geological Maps of Russian Federation scale 1:200 000 (second edition). Main principles of new database structure are priority of GIS-layers of geological map and employment traditional forms of field geological documentation. ESRY shape-format is accepted as the base format of GIS-layers. Microsoft Access database is accepted for preservation of initial field geological information. Connection between GIS and Microsoft Access database is realized by independent program manager.