ИСТИНА

Dark Earth is widely studied and discussed in archaeology and paleopedology over the decades but still, it is not enough well-defined and formulated concept. Usually, two groups of objects are described under this name: Amazonian Dark Earth (ADE) of pre-Columbian settlements and early medieval European Dark Earth (EDE). Both ADE and EDE have two features in common: dark colour due to enrichment with organic matter, and poor stratification. The general understanding of ADE and EDE is rather different. ADE is recognized to be originating from agricultural practices, including clearance and manuring. It contains high contents of black carbon (charred plant matter, i.e., charcoal). EDE is usually met in an urban context and related to the period after the decline of the Roman Empire. It is considered a hiatus in the accumulation of anthropogenic sediments and reworking of earlier habitation deposits (cultural layers, archaeological sediments) by pedogenic processes. Dark Earth is often declared as an issue not related to soil classification, though since 2014 there is pretic diagnostic horizon in WRB system, and this horizon is directly related to Amazonian Dark Earths. A lot of questions on formation processes, geographical and archaeological diversification, and classification of Dark Earths still need to be answered. We set below some of these questions. Can the term Dark Earth refer to archaeological soils (sediments) which are dark coloured and contain a lot of organic carbon and/or black carbon but have prominent stratification at least in some parts of the section? What are the formal criteria for “poorly stratified” sediment? If archaeological sediments (soils) contain a lot of organic matter but not enough dark-coloured can ones be called Dark Earth? How dark should be the sediments to be considered Dark Earth? Can we refer to the Dark Earth archaeological deposits rich in dark organic matter due to natural contemporary or paleoenvironmental reasons? For example, permafrost-affected soils and deposits where the trans-formation of organic matter is suppressed resulting in accumulation of moder organic matter; or deposits exposed to post-anthropogenic Chernozem-like pedogenesis in steppe landscapes which produces mull organic matter. Does all Dark Earths satisfy the diagnostic criteria of pretic horizon and vice versa: do all pretic horizons are DEs? How different varieties of DE can be classified in WRB system? We will discuss a wide variety of medieval habitation deposits answering these questions in a frame of the Dark Earth concept: 1) extremely rich in organic matter medieval deposits of Veliky Novgorod; 2) undifferentiated and rich in organic matter units within thick and variable habitation deposits in Mos-cow; 3) thick habitation deposits of Staraja Ladoga under changing hydrological regime; 4) exposed and buried in the floodplain Viking Age habitation deposits of Gnezdovo (within the mixed forest zone); 5) different habitation deposits of steppe and forest-steppe regions: Fanagoria, Muromskij Gorodok, Malaja Ryazan’; 6) rich in organic matter units in habitation deposits of Hisorak in desert highlands of Tadzhikistan etc.