Central Taimyr accretionary belt (Arctic Asia): Meso–Neoproterozoic tectonic evolution and Rodinia breakup

The structure and tectonic position of the Neoproterozoic Central Taimyr accretionary belt of northwestern Siberia is dominated by the Faddey and Mamont-Shrenk granite-gneiss terranes, ophiolites, and back-arc volcanic rocks. Granites in the granite-gneiss terranes are S-type and formed between 900 and 850 Ma from 1.9 to 1.8 Ga continental crust. U–Pb and Sm–Nd isotopic studies show that the plagiogranites of the Chelyuskin ophiolite belt formed between 850 and 740 Ma. The ophiolite complex was metamorphosed to garnet amphibolite grade around 600 Ma, which is considered to be when the accretionary belt was obducted onto the Siberian continent. Comparison of principal structures of the Central Taimyr accretionary belt with similar structures in Arctic countries permits definition of the principal stages of the Neoproterozoic destruction of the supercontinent Rodinia, in the Arctic region.     

Causes of Cretaceous Remagnetization on the Southwestern Periphery of the Archipelago of the New Siberian Islands

This study demonstrates rock-magnetic and paleomagnetic investigations of Devonian and Mesozoic deposits of Kotelny, Stolbovoy, and Great Lyakhovsky islands. The results indicate that local remagnetization took place on the southwestern periphery on the archipelago of the New Siberian Islands. A comparison of new data with the apparent polar wander path for Siberia shows that the remagnetization happened during collisional events between 140 and 80 Ma and affected only the marginal part of the terrane of the New Siberian Islands that was directly facing the deformation front. The consistent younging of the remagnetization age from the south to the north indicates dextral rotation of the terrane of the New Siberian Islands during its collision with Siberia.     

Paleomagnetism of traps of the Franz Josef Land Archipelago

The paper presents results of paleomagnetic studies of traps of the Franz Josef Land (FJL) Archipelago. This area is considered to be part of the Barents Sea Large Igneous Province (LIP) and is usually associated with the Early Cretaceous stage of plume activity, by analogy with other manifestations of late Mesozoic trap magmatism in the High Arctic. Recent isotope-geochemical studies, however, suggest a much longer history of basaltoid magmatism in the FJL area, from Early Jurassic through Early Cretaceous, with three pulses at 190, 155, and ≈ 125 Ma. Given a significant difference in age, paleomagnetic directions and corresponding virtual geomagnetic poles are supposed to form discrete groups near the Jurassic-Early Cretaceous paleomagnetic poles of Eastern Europe. However, the calculated virtual geomagnetic poles, on the contrary, show a single “cloud” distribution, with its center being shifted to the Early Cretaceous paleomagnetic poles of Siberia. The performed analysis demonstrates that the significant variance is caused mostly by the high-latitude position of the FJL and secular variations of the geomagnetic field during the formation of the traps. Products of the Early Cretaceous magmatism evidently prevail in the data sample. The coincidence of the average paleomagnetic pole of the FJL traps with the Early Cretaceous (145-125 Ma) interval of the apparent polar wander path of Siberia rather than Eastern Europe confirms the hypothesis of the Mesozoic strike-slip activity within the Eurasian continent. This activity might be a natural result of the evolution of the Arctic Ocean.     

Paleomagnetic Evidence for the Iceland Plume Paleogeographic Stationarity and Early Cretaceous Manifestation in the High Arctic

Doklady Earth Sciences - Here we present reconstructions indicating the stationary position and paleogeography of the Iceland plume, as well as its direct connection to the Mesozoic–Cenozoic...     

Late Jurassic (151–147 Ma) Dike Magmatism of the Northeastern Margin of the Siberian Craton

Doklady Earth Sciences - Dikes of intermediate and felsic composition from the area of the Vyun deposit and the Shumnyi occurrence, both of which belong to the Yano–Kolyma gold belt...     

一种新型人工“流体包裹体”：融合二氧化硅毛细管技术

利用融合二氧化硅毛细管技术制作了纯H2O体系、纯CO2体系、H2O-NaCl体系和H2O-CO2体系的人工包裹体样品,并对样品进行了显微测温和激光拉曼光谱测试工作。实验结果显示毛细管样品中的流体成分具有代表性,而且常规的流体包裹体显微测温和显微激光拉曼光谱分析技术完全适于毛细管样品的测试。对样品的显微测温和拉曼光谱研究...     

Concerning tectonics and the tectonic evolution of the Arctic

The particularities of the current tectonic structure of the Russian part of the Arctic region are discussed with the division into the Barents–Kara and Laptev–Chukchi continental margins. We demonstrate new geological data for the key structures of the Arctic, which are analyzed with consideration of new geophysical data (gravitational and magnetic), including first seismic tomography models for the Arctic. Special attention is given to the New Siberian Islands block, which includes the De Long Islands, where field work took place in 2011. Based on the analysis of the tectonic structure of key units, of new geological and geophysical information and our paleomagnetic data for these units, we considered a series of paleogeodynamic reconstructions for the arctic structures from Late Precambrian to Late Paleozoic. This paper develops the ideas of L.P. Zonenshain and L.M. Natapov on the Precambrian Arctida paleocontinent. We consider its evolution during the Late Precambrian and the entire Paleozoic and conclude that the blocks that parted in the Late Precambrian (Svalbard, Kara, New Siberian, etc.) formed a Late Paleozoic subcontinent, Arctida II, which again “sutured” the continental masses of Laurentia, Siberia, and Baltica, this time, within Pangea.     

Neoproterozoic A-type granites of the Garevka massif, Yenisey Ridge: Age, sources, and geodynamic setting

This paper presents the results of geochemical, isotopic (Sm-Nd), and geochronological (U-Pb and Ar-Ar) investigations of leucogranites from the Garevka massif in the Transangara segment of the Yenisey Ridge. The most distinctive geochemical characteristics of these A-type granitoids are the enrichment in silica, potassium, iron, and fluorine and a considerable depletion in europium. Using U-Pb zircon geochronology, the age of the Garevka leucogranites was estimated as 752 ± 3 Ma, which allowed us to attribute them to a previously established Neoproterozoic tectonic event related to the collision of the Central Angara terrane and the Siberian craton. The parental melts of the granitoids were probably derived by melting of a mixed source composed of continental crustal rocks of Paleoproterozoic and Mesoproterozoic and (or) Neoproterozoic ages. Based on the obtained petrological, geochemical, and geochronological data, the leucogranites of the Garevka massif were assigned to the Neoproterozoic postcollisional Glushikha complex.     

Paleomagnetism and geochronology of volcanogenic-sedimentary rocks of Henrietta Island (De Long Archipelago,Arctic Ocean)

The paper presents results of geochronological and paleomagnetic studies of the volcanogenicsedimentary sequence of Henrietta Island in the East Siberian Sea. Our ⁴⁰Ar/³⁹Ar investigations confirm existing ideas that the bottom part of the section formed in the Ediacaran (~565 Ma) and that the basalts in the top of the section formed before the middle Cambrian (~520 Ma). Calculated paleomagnetic data confirm that during the rocks formation the territory of present-day Henrietta Island was located close to the 20° latitude, which lets us adjust some information published earlier on the age and natural remanent magnetization of the dolerite dikes of the nearby Jeannette Island. The new data also let us propose that a regional tectonothermal event, probably caused by accretion-related processes, took place at the beginning of the Ordovician.     

Early Paleozoic tectonics for the New Siberian Islands terrane (Eastern Arctic)

The New Siberian Islands archipelago is one of the few research objects accessible for direct study on the eastern Arctic shelf. There are several models that have different interpretations of the Paleozoic tectonic history and the structural affinity of the New Siberian Islands terrane. Some infer a direct relationship with the passive continental margin of the Siberian paleocontinent. Others connect it with the marginal basins of Baltica and Laurentia, or the Chukotka-Alaska microplate. Our paleomagnetic investigation led us to create an apparent polar wander path for the early Paleozoic interval of geological history. Based on it we can conclude that the New Siberian Islands terrane could not have been a part of these continental plates. This study considers the possible tectonic scenarios of the Paleozoic history of the Earth, presents and discusses the corresponding global reconstructions describing the paleogeography and probable mutual kinematics of the terranes of the Eastern Arctic.