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New data on paleomagnetism and isotope geochronology of Jurassic and Early Cretaceous basic igneous rocks on Franz Josef Land Archipelago (FJL) represented by flows and dikes are discussed. The first paleomagnetic data obtained for these rocks offer the opportunity to suggest a model of spatial changes in the FJL block position during the Jurassic?Cretaceous. In the Early Jurassic, the block occupied a different position relative to Europe from the modern one. It was displaced in the northeasterly direction by a distance of approximately 500 km and rotated clockwise by about 40° relative to its modern position. By the Early Cretaceous, the FJL block occupied a position close to the present-day one avoiding subsequent substantial relative displacements. The data obtained are of principal significance for reconstructing the geodynamic evolution of Arctic structures in the Mesozoic and contribute greatly to the base of paleomagnetic data for the Arctic region, development of which is now in progress.  相似文献   
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This paper reports the results of the experimental determination of the coefficient of sorption of rare-earth elements and yttrium (REY) under conditions of acidic pH using several strains of heterotrophic bacteria (Microbacterium sp., Curtobacterium sp., Bacillus subtilis, Pseudomonas putida, and Bacillus pumilis) that are widespread in natural and technogenic waters of the Far East (Russia). Insignificant fractionation between heavy and light rare-earth elements, negative cerium and dysprosium anomalies, and a positive europium anomaly were revealed. The selectivity of REY biosorption by gram-positive and gram-negative bacteria, as well as inertia of the biosorption process under more acidic conditions of the medium, were shown.  相似文献   
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The assemblages of the Early Jurassic (Hettangian–Pliensbachian) and Late Jurassic–Early Cretaceous (Tithonian–Berriasian) radiolarians were described for the first time in the eastern part of the Ekonai Zone of the Koryak Highland. The Hettangian–Pliensbachian assemblage was found in siliceous rocks of the Ionai Nappe and this finding expands the stratigraphic interval of its siliceous sequences from the Carboniferous to the Early Jurassic. The Tithonian–Berriasian assemblage was found in volcanosiliceous rocks of the Yanranai accretionary complex. Both assemblages contain taxa abundant in the Tethyan regions.  相似文献   
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Aquatic Geochemistry - Spring waters with high-pCO2 content are widely distributed in the Sikhote-Alin region in Russia. Mukhen spa is one such spring located in the northern Sikhote-Alin region....  相似文献   
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Abstract This paper contains extended abstracts of the seven papers presented at the symposium 'Radiolarians and Orogenic Belts' held at the seventh meeting of the International Association of Radiolarian Paleontologists (INTERRAD). Important results of the symposium include the following: (1) Upper Paleozoic and Mesozoic cherts are widely distributed within accretionary complexes in the circum-Pacific orogenic belt. Radiolarian dating reveals that long durations of chert sedimentation in a pelagic environment are recorded on both sides of Pacific-rim accretionary complexes (e.g. New Zealand, Japan, Russian Far East, Canadian Cordillera). (2) Triassic radiolarian faunas from New Zealand and the Omolon Massif, northeast Siberia are similar in composition and are characterized by the absence of typical Tethyan elements. This suggests that radiolarian faunal provincialism may have been established as early as the Triassic. High-latitude radiolarian taxa exhibit a bi-polar distribution pattern. (3) The Lower Triassic interval in chert dominant pelagic sequences is mechanically weaker than other levels and acted as a décollement in accretionary events. This lithologic. contrast in physical property is considered to reflect radiolarian evolution, such as the end-Permian mass extinction.  相似文献   
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Published and new data on the Earth’s past magnetic field have been interpreted in terms of its links with the frequency of magnetic polarity reversals and with tectonic events such as plume-related eruptions and rifting. The paleointensity and reversal frequency variations show an antiphase correlation between 0 and 160 Ma, and the same tendency likely holds for the past 400 Myr. The geomagnetic field intensity averaged over geological ages (stages) appears to evolve in a linearly increasing trend while its variations increase proportionally in amplitude and change in structure. Both paleointensity and reversal frequency patterns correlate with rifting and eruption events. In periods of high rifting activity, the geomagnetic field increases (15 to 30%) and the reversals become about 40% less frequent. Large eruption events between 0 and 150 Ma have been preceded by notable changes in magnetic intensity which decreases and then increases, the lead being most often within a few million years.  相似文献   
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New data on Middle Triassic radiolarians from the central part of Kotel’nyi Island are discussed. The Triassic section is represented by clays and mudstones with diverse macro- and microfossils, which confirm the presence of lower Anisian, upper Anisian, and upper Ladinian sediments on the island. The lower Anisian Substage 10–15 m thick is composed of clays with ammonoid species Karangatites evolutus. The upper Anisian Substage 20 m thick consists of clays with phosphate concretions and bivalves Daonella sp. cf. D. moussoni Merian, D. americana Smith, ammonoid form Indigirophyllites sp. ex gr. I. spetsbergensis (Oeberg), and radiolarian assemblage with Glomeropyle boreale Bragin. The upper Ladinian Substage 25–30 m thick is composed of clays with phosphate concretions and bivalves including Daonella frami Kittl., ammonoid species Indigirophyllites sp. ex gr. I. oimekonensis Popow, and radiolarian assemblage with Muelleritortis firma (Gorican). The middle Anisian and lower Ladinian substages are missing, which may be explained by the incompleteness of the section. The Middle Triassic section of Kotel’nyi Island is first stratified on the basis of radiolarians, which are supplemented by the data on cephalopods and bivalves. Glomeropyle saccum Bragin, sp. nov. is described.  相似文献   
9.
The succession of radiolarian assemblages in the Struganik section of western Serbia is described for the first time. The following radiolarian beds are defined in carbonate flyschoid sequences represented by thin-platy limestones with calcarenite and bentonite clay intercalations (from the base upward): Theocampe urna-Dictyomitra koslovae (presumably lower Santonian); Afens perapediensis-Clathropyrgus titthium (presumably uppermost lower Santonian-basal upper Santonian); Alievium gallowayi-Crucella espartoensis (upper Santonian). The examined assemblages are characterized by high taxonomic diversity. The upper Santonian Alievium gallowayi-Crucella espartoensis Assemblage exhibits significant similarity with the coeval radiolarian assemblage of the Crimean Mountains (Ukraine). Archaeocenosphaera (?) karamatai sp. nov. is described.  相似文献   
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