Chrono-sequences of alluvial terraces and fossilized water bodies as a predictive model for detecting Lower and Middle Palaeolithic sites in the Negev desert, Israel

The Negev desert is a part of the northern Saharo-Arabian desert belt, a major physical barrier between Africa and southwest Asia. Its location at the crossroads of the two continents makes it a perfect region to trace the presence of early hominins on the route from Africa to the Levant in major dispersal events. Geomorphological mapping in the central Negev region allows a reconstruction of the Plio-Pleistocene landscape, and the processes that shaped the Negev desert. Features that characterize this arid to hyper-arid region are sequences of alluvial terraces and small-scale wetland deposits, covering the last 2 Ma, now evident in the present-day landscape as a series of abandoned alluvial terraces standing 100-5 m above the active stream channels, containing conglomerates, fine silty sediments and travertines. In this study we integrate alluvial terraces with scattered outcrops of travertines and wetland deposits, marking the locations of past water resources in the central Negev. The environmental reconstruction enabled us to conceive a conceptual model and produce a detailed map that predicts the preferable locations for archaeological sites from the Lower and Middle Paleolithic periods. The outcome of this study is a validated model for tracing Paleolithic sites in their geomorphological contexts and a better understanding of the role of the Negev in Middle Pleistocene hominin dispersals.

The geoarchaeological survey, supported by luminescence ages, demonstrates that the Q1 surface, composed of several individual alluvial terraces, is 310-350 ka, corresponding to the Lower Paleolithic Acheulian handaxes. The Q2 surface shows two sub-terraces deposited between 150-90 ka, that correspond to Middle Paleolithic occurrences while the Q3 surface is composed of a single terrace deposited between 70-18 ka, corresponding to the last glacial event. This terrace contains the MP-UP transition. This study demonstrates the advantage of integrating geomorphological mapping, numerical dating of alluvial terraces and prehistoric surveys. This approach substantially increased the number of Lower and Middle Paleolithic sites and findspots in a region that had been surveyed in the past. The results show both Mousterian and Acheulian presence in the Central Negev area are associated with specific dated geomorphological surfaces. This alone, in our view, is an important addition to the archaeological knowledge gathered in previous works. The presence of Lower and Middle Paleolithic localities in the study area suggest that the Negev was inhabited during the Middle Pleistocene dispersal events, but this topic needs to be further studied by archaeological excavations. The dating of alluvial indicates that during the Middle and Late Pleistocene, the same sequence of alluvial terraces (Q1-Q3) developed in drainage basins regardless of their final drainage outlet (Eastern Mediterranean or Dead Sea). Our model for tracing Paleolithic sites in their geomorphological contexts can be valid in other desert regions of the Levant, and possibly in other arid regions world-wide.