This paper presents the first release of an Informational System（IS）devoted to the systematic collection of all available data relating to Pliocene-Quaternary faults in southern East Siberia,their critical analysis ...This paper presents the first release of an Informational System（IS）devoted to the systematic collection of all available data relating to Pliocene-Quaternary faults in southern East Siberia,their critical analysis and their seismotectonic parameterization.The final goal of this project is to form a new base for improving the assessment of seismic hazard and other natural processes associated with crustal deformation.The presented IS has been exploited to create a relational database of active and conditionally active faults in southern East Siberia（between 100°-114° E and 50°-57° N）whose central sector is characterized by the highly seismic Baikal rift zone.The information within the database for each fault segment is organized as distinct but intercorrelated sections（tables,texts and pictures,etc.）and can be easily visualized as HTML pages in offline browsing.The preliminary version of the database distributed free on disk already highlights the general fault pattern showing that the Holocene and historical activity is quite uniform and dominated by NE-SW and nearly E-W trending faults;the former with a prevailing dip-slip normal kinematics,while the latter structures are left-lateral strike-slip and oblique-slip（with different proportion of left-lateral and normal fault slip components）.These faults are mainly concentrated along the borders of the rift basins and are the main sources of moderate-to-strong（M≥5.5）earthquakes on the southern sectors of East Siberia in recent times.As a whole,based on analyzing the diverse fault kinematics and their variable spatial distribution with respect to the overall pattern of the tectonic structures formed and/or activated during the late Pliocene-Quaternary,we conclude they were generated under a regional stress field mainly characterized by a relatively uniform NW-SE tension,but strongly influenced by the irregular hard boundary of the old Siberian craton.The obtained inferences are in an agreement with the existing models of the development of the Baikal region.展开更多
The data of the last decade investigations of ophiolites in western m argin of Siberian platform were summarized. The study of geology, geoche mistry and geochronology show that the interrupted ophiolitic belt of Neop...The data of the last decade investigations of ophiolites in western m argin of Siberian platform were summarized. The study of geology, geoche mistry and geochronology show that the interrupted ophiolitic belt of Neoprotero zoic age is 2000 km long, from the Taimir Peninsula to the Northern Transbaikali a Region through the Yeniseyski Khryazh and the Sayanskii Range. These studies i ndicated that the major differences of the Neoproterozoic ophiolites from younge r Phanerozoic ophiolite complexes are as follows: 1) occurrence of komatiite and picritie-like, high-magnesium rocks among the ophiolite volcanics; 2) ophioli te volcanics with both MOR and island-arc tholeiites; 3) ophiolite sequence where sheeted dikes and layered complex ("low gabbro") are usually absent. These pecu larities indicate that the Neoproterozoic ophiolites of Eastern Siberia were gen erated at suprasubduction environment and the Neoproterozoic oceanic crust was n ot as thick as Phanerozoic one.展开更多
基金supported by the Russian Foundation for Basic Research(grant 12-05-91161-GFEN)Ministry of education and science of Russia(grants 8316 and 8357)
文摘This paper presents the first release of an Informational System（IS）devoted to the systematic collection of all available data relating to Pliocene-Quaternary faults in southern East Siberia,their critical analysis and their seismotectonic parameterization.The final goal of this project is to form a new base for improving the assessment of seismic hazard and other natural processes associated with crustal deformation.The presented IS has been exploited to create a relational database of active and conditionally active faults in southern East Siberia（between 100°-114° E and 50°-57° N）whose central sector is characterized by the highly seismic Baikal rift zone.The information within the database for each fault segment is organized as distinct but intercorrelated sections（tables,texts and pictures,etc.）and can be easily visualized as HTML pages in offline browsing.The preliminary version of the database distributed free on disk already highlights the general fault pattern showing that the Holocene and historical activity is quite uniform and dominated by NE-SW and nearly E-W trending faults;the former with a prevailing dip-slip normal kinematics,while the latter structures are left-lateral strike-slip and oblique-slip（with different proportion of left-lateral and normal fault slip components）.These faults are mainly concentrated along the borders of the rift basins and are the main sources of moderate-to-strong（M≥5.5）earthquakes on the southern sectors of East Siberia in recent times.As a whole,based on analyzing the diverse fault kinematics and their variable spatial distribution with respect to the overall pattern of the tectonic structures formed and/or activated during the late Pliocene-Quaternary,we conclude they were generated under a regional stress field mainly characterized by a relatively uniform NW-SE tension,but strongly influenced by the irregular hard boundary of the old Siberian craton.The obtained inferences are in an agreement with the existing models of the development of the Baikal region.
基金supported by the National Natural Science Foundation of China[grant numbers 41991280 and 42025502]the Guangdong Major Project of Basic and Applied Basic Research[grant number 2020B0301030004]the State Scholarship Fund by China Scholarship Council[grant number 202109045003].
文摘The data of the last decade investigations of ophiolites in western m argin of Siberian platform were summarized. The study of geology, geoche mistry and geochronology show that the interrupted ophiolitic belt of Neoprotero zoic age is 2000 km long, from the Taimir Peninsula to the Northern Transbaikali a Region through the Yeniseyski Khryazh and the Sayanskii Range. These studies i ndicated that the major differences of the Neoproterozoic ophiolites from younge r Phanerozoic ophiolite complexes are as follows: 1) occurrence of komatiite and picritie-like, high-magnesium rocks among the ophiolite volcanics; 2) ophioli te volcanics with both MOR and island-arc tholeiites; 3) ophiolite sequence where sheeted dikes and layered complex ("low gabbro") are usually absent. These pecu larities indicate that the Neoproterozoic ophiolites of Eastern Siberia were gen erated at suprasubduction environment and the Neoproterozoic oceanic crust was n ot as thick as Phanerozoic one.
