Last autumn (2014) the geomorphology of the settlement complex at Skomack Wielki (Ostrów) was investigated by a team of dr hab. prof. Ewa Smolska and dr Piotr Szwarczewski from the University of Warsaw Department of Geomorphology, Faculty of Geography and Regional Studies.
To gain a general idea about the local geomorphology and surface formations the project team took a number of soil core samples at Góra Grodzisko (Hillfort Hill), the area at its foot, to the west and south, and Zamkowa Góra (Castle Hill). A list of individual drill sample series was made, complete with a photographic documentation; the input from the macroscopic assessment was used to develop a lithological description of the obtained core profiles.
The geomorphological study completed at Skomack Wielki (Ostrów) helped identify the landforms and geological formations building the hummocky topography of Góra Grodzisko and Góra Zamkowa (Hillfort Hill and Castle Hill, respectively). Surface sediments identified in the soil core samples include: sands with gravel, sorted sand and silt, and glacial till. These sediments and the position of the central part of Lake Orzysz and Lake Wylewy between extensive kettles are typical for dead-ice moraines. The depressions around the dead-ice moraine contain deposits of lake or meadow marl overlain by peat, and only in the upper section, of mineral alluvial sediments. The slopes of the elevation on which the hillfort was founded, and the central part of the slope below were found to be heavily eroded – with the bedrock recorded right below the soil (ploughsoil level).
The lower part of the slopes of the same elevation are built by glacial formations overlain by colluvium, sediments containing humus deposited in the course of soil erosion, triggered by forest clearance, agricultural use and other causes. Both the stratigraphy of these slope deposits and their lithology are understood to record human activity. Used as input to laboratory sedimentology and geochemistry analyses they can help trace the changes to the environment of the site at Skomack Wielki (Ostrów) conditioned by human activity and climate change.
