Taphonomic features of lithic and bone finds: use of fabric analysis for identifying the impact of natural processes on the formation of archaeological horizons

Fabric analysis is a method of determining the role of natural processes in the formation of archaeological horizon based on orientations and inclination angles of finds. A system of indices (isotropy and elongation indices) characterizes mutual location of long axes of objects. Plotted on ternary diagram, the indices show what kind of natural processes affected the archaeological horizon, since each area of the diagram corresponds to a certain position of the long axes, diagnostic for a specific distortion of sediments. However, the question of universality of indices for the finds from different materials has remained open. This article attempts to identify specific features of taphonomic mechanisms for lithic artifacts and bones based on the published data. Fabric analysis for bone and lithic finds was done separately using the evidence from archaeological horizon 4 at the Tolbor-21 site (Mongolia), corresponding to the Initial Upper Paleolithic. The results were compared on the ternary diagram with the published data on other Paleolithic sites. It was found that bone indices may differ from indices of lithic artifacts discovered in the same layer at open-air sites. Increased isotropy indices of lithic finds compared to faunal finds was common to the available examples. Literature shows that specific aspects of bone burials, in addition to scattering by animals and weathering, depend on water impact and trampling by animals or humans. In frozen ground, lithic objects undergo the impact offrost heave due to differences in thermal conductivity with the surrounding sediments, as well as their nearly vertical position. These factors may result in different distribution of lithic and bone objects in the sediments from the same natural processes. Separate analysis of lithic and faunal finds, combined with data from other sources (geology, stratigraphy, etc.), can provide more information on the formation of archaeological horizons.