The article discusses postglacial landscape transformation in the Northern Hemisphere Middle Pleistocene glaciation area located in the center of the Russian Plain.We attempted to verify the regional paleogeographic m...The article discusses postglacial landscape transformation in the Northern Hemisphere Middle Pleistocene glaciation area located in the center of the Russian Plain.We attempted to verify the regional paleogeographic model by reconstructing the Late Pleistocene incision-infill cycles at the Eastern Borisoglebsk Upland based on a comparison of inactive interfluves headwaters and actual fluvial network palaeoarchives.The study was also aimed to determine the past extent of fluvial systems.Interdisciplinary research of the actual and buried topography,Ethology and pedogenic properties of surface deposits was carrid out with remote sensing data interpretation,DGPS survey,and detailed description of geological cores involved.The study was followed by analysis of grain size,chemical and organic contents,microstructure,and numerical dating.Integrating the available results,we propose a scenario of the fluvial network transformation at the Eastem Borisoglebsk Upland over the last 150 ka.At least four fluvial incision stages were determined while network extent has significantly changed through the Late Pleistocene.Three can be generally associated with the regional base level decrease-Late Moscow,Late Valdai and Late Holocene and accompanying isolation of the Nero Lake terraces of 130 m,100-105 m and 95-98 m.Incision stages were separated by landscape stability or aggradation periods those were asynchronous at the middle and upper parts of the fluvial network.The main agent of initial valley infill appears to be local lacustrine sedimentation altered by alluvial and colluvial deposition towards the second half of Valdai.Revealed landscape conditions variability emphasize the importance of comprehensive local correlations for regional retrospective models.展开更多
基金the Russian Foundation for Basic Research,Russia[projects№16-35-00605 and№18-05-01118],the Department of Geomorphology and Paleogeography,Faculty of Geography,Lomonosov MSU,Russia[GM AAAA-A16-11632810089-5]and Department of Soil Geography and Evolution,Institute of Geography,RAS,Russia[GM 0148-2019-0006]in part of field working organization and Russian Science Foundation,Russia[project№14-27-00133]in part of microscopic and radioisotope research.Authors are grateful to A.P.Vergun and M.M.Ivanov for the provided aerial photo imagery,to Google Earth and Yandex Maps services for remote sensing data and open sources of global satellite radar DEMs(SRTM,ALOS 3D).
文摘The article discusses postglacial landscape transformation in the Northern Hemisphere Middle Pleistocene glaciation area located in the center of the Russian Plain.We attempted to verify the regional paleogeographic model by reconstructing the Late Pleistocene incision-infill cycles at the Eastern Borisoglebsk Upland based on a comparison of inactive interfluves headwaters and actual fluvial network palaeoarchives.The study was also aimed to determine the past extent of fluvial systems.Interdisciplinary research of the actual and buried topography,Ethology and pedogenic properties of surface deposits was carrid out with remote sensing data interpretation,DGPS survey,and detailed description of geological cores involved.The study was followed by analysis of grain size,chemical and organic contents,microstructure,and numerical dating.Integrating the available results,we propose a scenario of the fluvial network transformation at the Eastem Borisoglebsk Upland over the last 150 ka.At least four fluvial incision stages were determined while network extent has significantly changed through the Late Pleistocene.Three can be generally associated with the regional base level decrease-Late Moscow,Late Valdai and Late Holocene and accompanying isolation of the Nero Lake terraces of 130 m,100-105 m and 95-98 m.Incision stages were separated by landscape stability or aggradation periods those were asynchronous at the middle and upper parts of the fluvial network.The main agent of initial valley infill appears to be local lacustrine sedimentation altered by alluvial and colluvial deposition towards the second half of Valdai.Revealed landscape conditions variability emphasize the importance of comprehensive local correlations for regional retrospective models.
