Цифровой репозиторий ГГМ РАН
Репозиторий переведен на новую версию - DSpace 9.0. В репозитории содержится 46 500 публикации с тематикой "Науки о земле".
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listelement.badge.dso-typeЭлемент, EXOGENIC AND NEOTECTONIC PROCESSES IN THE WEST SPITSBERGEN UNDERWATER MARGIN DURING THE LATE CENOZOIC(2007) Zakharenko V.S.; Tarasov G.A.; Matishov G.G.; Romanchenko A.Y.The purpose of this study is to define basic faults in the bottom topography of the West Spitsbergen underwater margin and estimate proportions between exogenic and endogenic processes in this region during the Quaternary. This work is based on the following materials of the Marine Arctic Geological Expedition: seismoacoustic time sections, a map of local topography, a map of tectonic deformations based on CMP data, a map of basement structural zoning, a neotectonic map, and a state geological map.listelement.badge.dso-typeЭлемент, THE 230Th/U DATING OF SULFIDE ORES IN THE OCEAN: METHODICAL POSSIBILITIES, MEASUREMENT RESULTS, AND PERSPECTIVES OF APPLICATION(2007) Kuznetsov V.Yu.; Maximov F.E.; Cherkashev G.A.; Shilov V.V.; Stepanova T.V.; Bel'tenev V.E.; Lein A.Yu.Hydrothermal sulfide ores discovered in 1978 (21° N East Pacific Rise, Pacific Ocean) and 1985 (Mid-Atlantic Ridge) have attracted great scientific and applied interest owing to high concentrations of many useful components (Cu, Zn, Au, and others) in them. Among various aspects of oceanic hydrothermal processes, the important issue of dating ore-forming stages remains poorly studied. Elucidation of this problem is crucial not only for reconstruction of the initiation and evolution of ore formation, but also for solution of several essential issues. Isotope geochronology of sulfide ores and metalliferous sediments is the main tool used for the dating.listelement.badge.dso-typeЭлемент, Au-Bi-Te MINERALIZATION OF THE KONTAKTOVYI STOCK IN NORTHEAST RUSSIA(2007) Sidorov V.A.; Volkov A.V.; Sidorov A.A.; Wolfson A.A.In recent years, interest in gold deposits in granitoid intrusions has been boosted by the successful development of gold deposits in Alaska and Australia, such as Fort Knox (>350 t), Pogo (150 t), Dublin Gulch (>100 t), and Tefler (>500 t). At present, more than 30 deposits of this type have been discovered in various metallogenic belts of Northeast Asia. Many of these deposits can be large and superlarge objects. In previous publications, we discussed examples of ore occurrences and deposits in the Yana–Kolyma metallogenic belt and the perivolcanic zone of the Okhotsk–Chukot volcanogenic belt (OCVB). However, some ore occurrences associated with granite porphyry stocks are confined to sedimentary sequences at the base of the OCVB. These stocks were likely to be emplaced in the course of the tectonomagmatic cycle of the Late Jurassic–Early Cretaceous Uda–Murgal island-arc volcano-plutonic belt. The most promising ore occurrence was discovered in 2005 in the Kontaktovyi (i.e., Contact) granite porphyry stock.listelement.badge.dso-typeЭлемент, MAGMATIC SOURCES OF QUATERNARY LAVAS IN THE KURIL ISLAND ARC: NEW DATA ON SR AND ND ISOTOPY(2007) Martynov Yu.A.; Kimura J.-I.; Khanchuk A.I.; Rybin A.V.; Chashchin A.A.; Martynov A.Yu.Subduction zones of oceanic plates are among the most complicated tectonomagmatic systems in our planet. The relative contribution of the three major geochemical reservoirs into magma genesis (suprasubduction mantle wedge, crust, and oceanic lithosphere) is substantially governed by the geodynamic parameters of the subduction process, including the vector of the convergence of interacting plates, the inclination of the subducting plate, and the activity of back-arc processes and transform faults. Therefore, resolution of issues related to the origin and evolution of primary melts in island arcs requires a complex approach, which includes the study of lateral isotope-geochemical variations in the composition of igneous rocks.listelement.badge.dso-typeЭлемент, AGE AND ISOTOPIC GEOCHEMICAL CHARACTERISTICS OF ARCHEAN CARBONATITES AND ALKALINE ROCKS OF THE BALTIC SHIELD(2007) Zozulya D.R.; Bayanova T.B.; Serov P.A.Occurrences of Archean alkaline rocks are insignificant. Only a few complexes in the Canadian Shield (Superior Province), Greenland, Australia (Yilgarn Block), and South Africa are known to date. They are composed of alkali and nepheline syenites, foidolites, carbonatites, peralkaline granites, lamprophyres, and potassic volcanic rocks. The age of the oldest alkaline rocks is estimated at ~2.7 Ga. The Neoproterozoic and Phanerozoic alkaline rocks occur in three main geodynamic settings: (1) continental rifts, (2) oceanic islands, and (3) subduction zones (peralkaline granites in back-arc zones). The Early Precambrian alkaline rocks formed at hotspots of the oceanic crust and are unknown in continental rifts. Therefore, the geodynamic setting of the Archean alkaline rocks is interpreted as a subduction-related environment and the depleted mantle is thought to be their source. The Late Archean subduction-related alkaline complexes presumably formed at the final stages of the evolution of greenstone belts, while the depleted source is accounted for by the absence of metasomatic processes in the Archean mantle.