The Bronze Age in the Western Tianshan, China: A new model for determining seasonal use of sites

The economy of the Western Tianshan Mountains from prehistory to present has been almost exclusively focused on transhumant pastoralism. Settlement sites are located in a variety of different ecological zones, but the location does not always provide a clear indication of the original season of occupation. Other tools for identifying seasonality of occupation for prehistoric pastoral sites presently rely largely on analysis of faunal and botanical data which may produce ambiguous results. In this paper we correlate an ethnographic study based on data from local informants with a NDVI-based model on vegetation cycles to analyze why and how modern herders in the Western Tianshan select their range lands, and whether these patterns are applicable to Bronze Age land use in the same region. Micro-climates play an important role in the choice of optimal locations for any given season, and despite small climatic fluctuations the data strongly suggest that the seasonality of the Bronze Age sites in the Bortala (Bo'ertala) Valley can be correlated with modern land use. Thus pasture analysis applied to the location of prehistoric sites in the Tianshan can provide significant insights on seasonal use.