The shell mounds of the Farasan Islands - An isotopic study of seasonality and coastal exploitation

The focus of this thesis is to assess the value of the coastal landscape of the southern Red Sea after the aridification of the environment following the early Holocene wet period (11,000–6,000 cal BP). It presents data from the Farasan Islands shell midden complex, encompassing over 3,000 shellmounds accumulated between 6,500 and 4,500 cal BP, and indicating heavy reliance on marine molluscs as food. In the context of the overall aridity, there are crucial questions surrounding such intensive shellfish exploitation: a) were shellfish the main food source on the islands? b) were they a reliable food source and could they have supported a permanent settlement? c) was the exploitation of shellfish linked to the environmental change? Exploitation patterns of shellfish are reconstructed using seasonality data based on 2,100 stable isotope measurements (δ18O and δ13C) of the marine gastropod Conomurex* fasciatus* (Born 1778). This enables an assessment of the seasonal consumption of this species, and hence whether it could have been exploited all year round, or whether movement to the mainland (with its more temperate mountains) was necessary. Additionally, environmental data based on the same proxy is used to reconstruct climatic conditions. Early and late periods (6,500–4,800 cal BP) are compared to analyse the degree of aridity and the possibility of a longer2lasting early Holocene wet phase. Results indicate that year2round shellfish gathering took place, with more intensive exploitation occurring in the summer dry season, and that 6,500 years ago climate was already extremely dry. This suggests that the intensive coastal exploitation was not due to landscape aridification, it also indicates that seasonal migration to the mainland was not a necessity, as shellfish were available throughout the year. These results significantly extend the current understanding of subsistence strategies in the southern Red Sea and the value of shellmounds worldwide