Micromorphological Features and Formation of the Cultural Layer in the Early Medieval Town of Dzhankent (Eastern Aral Sea Region, Kazakhstan)

This paper presents the results of a study on the stratigraphy, morphology, micromorphology, and chemical and physicochemical characteristics of the cultural layer in the residential area of the Early Medieval town of Dzhankent (Eastern Aral Sea region, Kazakhstan). The town is located in an arid paleodeltaic landscape with a dynamic water supply. Sets of diagnostically significant micromorphological features are described, including: (1) features resulting from anthropogenic input and redistribution of matter (plant detritus, phytoliths, bone fragments, etc.); (2) pedofeatures resulting from the transformation of human-introduced material (pyrogenic forms of carbonates, organic and phosphate-organic pedofeatures); and (3) pedofeatures consisting of carbonates, gypsum, and iron oxides, mainly associated with natural processes. Stratigraphic units of the cultural layer, along with the processes and conditions of their formation, were defined, and the archaeological context was interpreted for each lithostratigraphic unit based on their morphological and analytical characteristics. The upper stratigraphic unit consists of the destruction products of clayey adobes, with ash interlayers, some of which are stratigraphically traceable and may correspond to fire events. The middle unit comprises residential and domestic sediments, including a series of living surfaces, and contains an ash layer possibly resulting from a fire event. The lower unit is composed of alluvial-deltaic deposits slightly impacted by residential activities and periodically affected by fluctuating groundwater. The distribution of organic carbon and phosphorus in the cultural layer correlates well with the observed organic substrates at the macrostratigraphic level, being significantly higher in loose layers rich in plant detritus, charcoals, ash, and bones. However, the analytical characteristics of the cultural layer (pH, electrical conductivity, contents of organic carbon, phosphorus, carbonates, and gypsum), determined from homogenized samples of the stratigraphic units, do not always align with the composition observed at the micromorphological level (abundance of micro-artifacts, anthropogenic and natural microfeatures). These discrepancies are primarily due to the extremely high lateral and microstratigraphic heterogeneity of the cultural layer.