Taphonomic evaluation of the degree of historical representation of the archaeological bone samples in anaerobic versus aerobic environments: The Neolithic site of La Draga (Banyoles, Spain)

摘要

The site of La Draga is located in the central part of the eastern shore of Lake Banyoles, 172 m a.s.l. Archaeological work began in 1990. It is the only Early Neolithic lakeshore site in the western Mediterranean currently being excavated. Two different occupations have been documented within a timeline of 5430-4796 cal BC. An extent of about 800 m~2 has been excavated out of the minimum surface area of 8000 m2. An added peculiarity is that different excavated sectors have distinct characteristics regarding their condition, due to the changing water levels of the lake in historic times: Sector A (328 m~2) is the emerged land sector; Sectors B and D (132 m~2 and 48 m~2 respectively) are located in the perennial phreatic level; and Sector C (310 m~2) is completely underwater. The analysis of more than 20,000 retrieved faunal remains evidences the exploitation of at least 51 different animal species (46 wild and 5 domestic). Comparative taphonomic analyses performed on assemblages in the terrestrial and phreatic sectors have focused on evaluating how the different conditions at the site influence the composition and characteristics of samples, both quantitatively and qualitatively. Emphasis is placed on the specific and anatomical variability documented in each sector, the proportions of mature and immature animal bone remains and on the animal carcass integrity. The estimation of the degree of historical representation of the faunal assemblages in each of the excavation sectors shows important differences between peat/ anaerobic and dry/aerobic environments, documenting significant biases in sector A. These results demonstrate that the identification of taphonomic processes that operate at intrasite level and their effects are crucial data with important implications for the understanding of past social and economic dynamics.