Geodynamics & Tectonophysics (E-Journal) / Геодинамика и тектонофизика
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БРЯНСК-КУРСК-ВОРОНЕЖСКИЙ ВНУТРИКОНТИНЕНТАЛЬНЫЙ КОЛЛИЗИОННЫЙ ОРОГЕН (ВОСТОЧНО-ЕВРОПЕЙСКИЙ КРАТОН)
Get PDFThe article presents new data on the deep crustal structure, origin and evolution of the Bryansk-Kursk-Voronezh orogen in the south-eastern segment of the East European craton; it is composed of the Paleoproterozoic formations and areas of reworked Archean crust. The purpose of this paper is the development and improvement of ideas on intra-continental orogens. The deep structure of the orogen is presented by the 3D model based on results of geological mapping of the Precambrian basement and interpretations of geophysical fields and seismic images of the crust along geotraverse 1-EB and profile DOBRE. It is established that the orogen originated with riftogenic extension of the crust at 2.6–2.5 Ga, that was repeated at 2.2–2.1 Ga, and formation of wide depressions that were efficiently filled in with volcanosedimentary layers including BIF, which accumulation was followed by high-temperature up to granulite facies metamorphism. Suprasubduction magmatism took place at 2.10–2.08 Ga and resulted in formation of the Lipetsk-Losevka volcano-plutonic complex. The active margin was completely formed at about 2.05 Ga. The short duration of subduction-related magmatic activity and the lack of relics of the oceanic lithosphere suggest short-term and spatially limited developing of the oceanic structure. The tectonothermal activity of collisional and postcollision stages was expressed in emplacement of alkaline ultramafic (2.1–2.0 Ga) and gabbro-syenite (1.8–1.7 Ga) complexes. It is difficult or impossible to explain specific features of the structure and evolution of the orogen in framework of the model of the Cordilleras type accretionary orogen. Mafic-ultramafic magmatism and indications of intensive heating of the crust suggest a special role of plume type processes that provided for influx of mantle heat and juvenile mantle derived matter.
ПРОГНОЗ ЗЕМЛЕТРЯСЕНИЙ ПО ДАННЫМ МОНИТОРИНГА ГИДРОГЕОДЕФОРМАЦИОННОГО ПОЛЯ
Get PDFThe paper discusses further ways to improve the geodynamic informativity of the hydrogeodeformation field (HGD field) monitoring. New methods for efficient assessment of the stressstrain state of the geological environment and seismic hazard are proposed. There are described the methods of monitoring data processing, distinguishing of HGD cycles, and construction of «forecasting» contours along extremums of these cycles. It is revealed that responses of the HGD field to development of planetaryscale endogenic geodynamic processes of earthquake preparation (with M>7) are simultaneously manifested in all seismically active regions of Russia which are remote from each other. Such responses occur from one to three months prior to such seismic events. The mechanism of this phenomenon can be disputed. The authors support the «planetary pulsation» concept which is up for the most recent debates. As evidenced by the HGD field monitoring data, strong earthquakes are a consequence of this phenomenon
ГЕОЛОГИЧЕСКАЯ СРЕДА И ПОДЗЕМНАЯ ГИДРОСФЕРА
Get PDF The article informs about the history, the staff, researches and scientific activities of the Laboratory of Hydrogeology and the Laboratory of Engineering Geology and Geoecology of the Institute of the Earth’s Crust, SB RAS. It reviews the major results of scientific research projects implemented from 2009 to 2013, which provided for determination of characteristics of the geological medium and hydrosphere of East Siberia and Mongolia in natural and technogenic conditions and modeling of the evolution of natural, natural-technogenic hydrogeological and engineering geological systems in regions with contrasting climate conditions and specific geological settings. В настоящей статье представлены материалы по истории, кадровому составу, научной и научно-организационной деятельности лаборатории гидрогеологии и лаборатории инженерной геологии и геоэкологии Института земной коры СО РАН. Основная часть статьи посвящена результатам научно-исследовательских работ 2009–2013 гг., позволившим охарактеризовать состояние геологической среды и подземной гидросферы Восточной Сибири и Монголии в природных и техногенных условиях, а также создать модели эволюции природных, природно-техногенных гидрогеологических и инженерно-геологических систем в регионах с контрастными климатическими условиями и геолого-структурной обстановкой.
НЕЛИНЕЙНОСТЬ И ФРАКТАЛЬНЫЕ СВОЙСТВА СЕЙСМОТЕКТОНИЧЕСКОЙ МОДЕЛИ EВРОПЕЙСКО- CРЕДИЗЕМНОМОРСКОГО РЕГИОНА
Get PDFThis paper presents research results of the study which aim is to reveal and quantitatively describe fractal properties of the European-Mediterranean seismotectonic model applied for seismic hazard assessment of the region under study.Several seismotectonic provinces are defined, and their nonlinear properties are calculated using both linear elements (boundaries of seismogenic units) and surface areas of the seismogenic units.The research is conducted on the basis of only formal relationships, not with data on real fault structures or other seismogenic elements, as the relationships have been accepted for seismic hazard calculations by the team of SESAME Project (Project Leader M. Jimenec) and published by Jimenec et al. [2001].Special attention is paid to the Balkan seismotectonic model in order to develop a common seismotectonic model which uses data from the seismic hazard map for a period of 475 years (according the EUROCODE8), that was published in Muco et al. [2008].All the calculations considered only the seismogenic units located in the earth crust, but not deeper seismogenic layers.It is concluded that most of the seismogenic provinces are similar in their fractal properties, which varied in a narrow range, except for the Adriatic one. The formal approach does not permit to explain these peculiarities