The scientists of the Faculty of Geography of Lomonosov Moscow State University created a database with information on the sea level in the western and central sectors of the Russian Arctic over the past 25 thousand years - from the maximum of the last glaciation to the present day. The database "Changes in the sea level of the Russian Arctic in the postglacial time" includes 630 locations and covers the territory of the coasts of the White, Barents, Kara, and Laptev Seas.
The database is based on the results of the project of the Russian Foundation for Basic Research "Sea level changes in the Russian Arctic in the late Quaternary: amplitudes, factors, mechanisms". It combines literary and own field data of the employees of the Geoecology of the Northern Territories laboratory of the Faculty of Geography of Moscow State University. The data shows the spread of geological and geomorphological indicators of the position of sea level in the past.
"The indicators, that is, geological and geomorphological evidence of sea level changes, are divided into three types in the database. First, these are the indicators of the precise position of sea level, which show exact water level in the past. Second, these are continental indicators that indicate continental conditions and limit the possible position of sea level on the surface. And third, the marine indicators that indicate relatively deep sea conditions and limit the possible sea level below. The database includes 371 level indicators, 107 continental and 152 marine indicators. Geographically, the locations of the database are divided into 26 regions with different scenarios of changes in the relative sea level," said the creator of the database, Candidate of Geographical Sciences, researcher at the Geoecology of the Northern Territories laboratory of the Faculty of Geography of Moscow State University, Alisa Baranskaya.
The information on sea level in the Arctic over the past 25 thousand years - on a geological scale corresponding to the Late Pleistocene and Holocene - is valuable because it can be used to calibrate numerical models of glacioisostatic compensation developed using field data from other regions of the world (North America, Barbados and other).
Glacioisostasis and glacioisostatic movements are very slow vertical and horizontal movements of the earth's surface in the territories of ancient and modern glaciation, caused by the subsidence of the lithosphere under the weight of the glacier and its subsequent rise after the load is removed as a result of melting ice. Modeling these processes makes it possible to reconstruct changes in sea level anywhere in the world in the past and to predict its changes in the future.
In 2020-2021, using their own database on the seas of the western Arctic, the geographers of Moscow State University will for the first time compare it with the world's leading models of glacioisostatic compensation, and with new innovative models that include the spatial variability of the parameters of the lithosphere and mantle (the so-called 3D models).
"Such a comparison will reveal areas of discrepancy between the model and field data, and allow to analyze their causes. In particular, it will help to identify tectonic vertical movements of the earth's crust and determine the regions most sensitive to spatial changes in the properties of the lithosphere and mantle," Alisa Baranskaya shared.
In the future, the geographers of Moscow State University will supplement the database with materials from their own research based on the results of expeditions. All this will help to find out what changes in the relative level of the seas of the Russian Arctic took place in the Pleistocene and Holocene in the most problematic areas. The key region will be the coast of the Kara Sea - the area of the supposed periglacial compensatory trough, which is important for understanding the processes of glacioisostasis in the Arctic.