Paleoecology and land use patterns based on the study of cultural layers and a buried soil of the Tula Kremlin

The study of the buried soil and cultural layers in the Tula Kremlin allowed providing paleoenvironmental reconstruction for the period between 16th century and present, to reveal the early land use practices, and also to explain the location of a large cultural and economic center of the late Middle Ages at a low hypsometric level in the immediate vicinity of the edge of the Upa River. The research is based on the morphology, micromorphology and analytical features of the buried soil and cultural layers, including geochemical ratios and phytolith assemblages. It is shown that the site where the fortress is located has never been flooded with a river. The soil is formed in mantle (loesslike) loams and is similar to the soils of the surrounding uplands; gleying (waterlogging) features in it are nearly absent. In a short period before the erection of fortifications, this site was used for arable land or vegetable garden. The cultural layers show accumulation of artifacts and elements that are foreign to the soils of the area. Pedogenic features preserved in the cultural layers made it possible to reconstruct the paleoclimatic dynamics in different periods of the Kremlin's construction or rebuilding. Thus, cultural layer 1 (17th-18th centuries) was formed in relatively humid climate, and during formation of cultural layer 2 (16th-17th centuries) it was slightly drier, but also colder than today.