Aspects and methods in reconstructing the medieval terrain and deposits in Vilnius

The article deals with the geomorphological diversity (confluence of Neris and Vilnia rivers, junction of two ice ages, erosion hill terrains, terrace levels, etc.) of Vilnius city which played an important role in choosing the place for the city to be established and in formation of its defence structure. The diversity of terrain of Vilnius city and its environs is demonstrated by the distinguished morphogenetic zones: 20 morphogenetic units including 5 zones within the area of the medieval city. From the point of view of the history of environment, the historical relief of Vilnius city has five types of relief. The research was carried out in one of the five types of city topography: moraines left by glaciers (part of the Kuprijoniškės-Salininkai morainic complex). The shallow till acted as an impermeable barrier and created conditions for accumulation of groundwater. Springs emanated at the slope bottom turning into streams. The largest among them is the Vingrė River, which marks the boundary between two types of topography. The studied territory occupies 2.6 km2. Through the reconstruction of the primordial terrain, it would be possible to trace the direction of Vingrė stream and the location of the defensive wall. LIDAR topography and borehole data, topographic maps of 1842 and 1994, and archaeological data were used. Geophysical and digital methods were applied. The research contributes to reconstruction of the pre-anthropogenic terrain, indicating possibilities for its optimal use and living conditions.