Mid-Holocene occupation of Egypt and global climatic change
Introduction
Global teleconnections between sea surface temperatures, the Asian monsoon and movement of the Inter-Tropical Convergence Zone (ITCZ) are known to have affected human occupation of the southern Egyptian Sahara during the early to mid Holocene (Nicoll, 2001, Kuper, 2006, Wendorf et al., 2007). Evidence for human occupation and movement of the ITCZ are correlated, although the specifics of regional environmental responses are likely to have varied (Kröpelin et al., 2008). Occupation of the southern Egyptian Sahara declined after 6000 BP when the ITCZ moved south and the Sahara dried to its present day hyper-arid state (Hassan et al., 2001, Nicoll, 2001, Kuper, 2006, Kuper and Kröpelin, 2006, Wendorf et al., 2007 cf. Kröpelin et al., 2008). However, environmental influences on the occupation of the Fayum depression, located 80 km southwest of modern Giza, were more complex and are the topic of much interest because the Fayum has long been recognised as showing early use in Egypt of the southwest Asian domesticates. Radiocarbon determinations indicate that mid-Holocene occupation of the Fayum corresponded with the abandonment of the Sahara, movement of southwest Asian populations along the Mediterranean coast and occupation of the Nile Delta (e.g. Merimde Beni Salama). During this period, the fresh water lake Qarun in the Fayum rose to 10–12 m asl, well above its modern level (−44 m asl) (Hassan, 1986). However, occupation around Lake Qarun was short lived with an abrupt abandonment at approximately 6000 BP and only limited subsequent evidence of resource specific (mining related) occupation in the region until the Ptolemaic period some 3500–4000 years later.
The development of agricultural societies in the Egypt has undergone recent revision to develop more sophisticated socio-economic models that emphasize distinctive trajectories (e.g. Wengrow, 2006). The evidence from the Fayum remains critical in understanding the nature of the relationship between environmental change, the timing of the introduction of domesticates into Egypt, and the development of Egyptian agriculture as emerging in the Predynastic Period.
From the beginning of the Holocene until the Roman period, Lake Qarun filled with the influx of water from the Nile and as a consequence lake levels fluctuated with Blue Nile flow from monsoonal rainfall in Ethiopia, and to a lesser degree central east African rainfall via the White Nile (Williams et al., 2000). If the Fayum occupation was dependent on the Nile influx, a correlation between fluctuations in the monsoon, changes in the ITCZ and human occupation of the eastern Sahara including the Fayum might be expected. Hassan (1986:489, 1997a, b) for instance, has attempted to explain the hiatus in occupation of the Fayum by sudden declines in the level of Lake Qarun due to changes in Nile influx. Alternatively, if a correlation between abandonment and lake level decline cannot be shown, a different set of environmental factors may have influenced the Fayum occupation, including those related to shifts in local North African rainfall unrelated to the summer monsoon.
Recent studies of the process of plant and animal domestication in the southwest Asia indicate dispersal from northern southwest Asia and central Anatolia (Turkey) into southern areas of southwest Asia and ultimately Egypt via either the Mediterranean coast or the Red Sea. Although Near Eastern domestic species entered Egypt well after they were present in the southwest Asia, their date of introduction makes sense when considered in relation to the timing and nature of their dispersal into the Mediterranean basin, particularly along the North African littoral. Recent evidence emphasizes how the uptake of Near Eastern domesticates was socially and environmentally complex (Zeder, 2008). Date ranges from around the Mediterranean suggest the movement of Neolithic populations was rapid, and better described as a form of ‘leap-frog’ movement rather than the traditional ‘demic-diffusion’ once suggested (Zilhão, 2001, Skeates, 2003, Zeder, 2008, Knapp, 2010). This paper argues that the adoption of domesticates by societies in Egypt should be viewed as one of a range of unique low-level food producing societies that developed around the Mediterranean mid-Holocene (Smith, 2001, Holdaway et al., 2010). Near Eastern domesticates were introduced into Egypt during a period when the environment was in some aspects similar to southwest Asia. Environmental change during the late Holocene meant however, that the growing of certain domesticates was no longer sustainable in Egypt and required significant shifts in agricultural strategy before they were viable long term.
Evaluating the relationship between past environments, use of domesticates and the duration and timing of occupation and abandonment of the Fayum is made possible by comparing chronologies from different parts of northern Egypt. A series of radiocarbon determinations from hearths discovered in archaeological deposits adjacent to high lake stand shorelines of Lake Qarun is compared with published radiocarbon determinations from oases in the Egyptian Western desert. The interest is to determine if variation in occupation of the Fayum correlates with shifts in the ITCZ, the Nile flood cycles or other climatic shifts and how environmental correlations may provide information on the nature of early crop production in the north of Egypt.
Section snippets
Radiocarbon determinations from the Fayum
Concentrations of burnt stones occur in both surface and buried contexts in locations around the ancient Lake Qarun shoreline in the form of hearths that often protect charcoal suitable for radiocarbon determinations (Fig. 1). Survey results indicate archaeological deposits close to high stand shorelines of Lake Qarun and to a lesser extent the banks of the wadi that flowed into the lake. In addition, excavations at two stratified deposits, Kom K and Kom W originally discovered by
Comparison with radiocarbon determinations from eastern Saharan sites
A large number of radiocarbon determinations are available from published sources for sites in the eastern Sahara. Many of these come from the ACACIA project (Arid Climate, Adaptation and Cultural Innovation in Africa) and reflect samples taken from hearths and other human modified organic sources (Kuper, 2006). They indicate times when eastern Saharan locations were actively being used by people during the early to mid Holocene. Additional determinations were obtained from archaeological
Results
The probability plot for the Fayum determinations indicate a substantial peak between 6200 and 6500 BP representing the Neolithic occupation at Kom K and Kom W and a smaller number of peaks ranging in age back to 9200 BP that represent Epipalaeolithic occupations. A comparison with a summed probability plot for all the determinations from the eastern Saharan sites illustrates how gaps in the Fayum record occur during periods when the eastern Saharan sites were occupied. When using differenced
Inter-Tropical Convergence Zone (ITCZ)
As noted above, Kuper and Kröpelin (2006) connect occupation of the eastern Sahara with the early-mid-Holocene increase in monsoon intensity and the northward shift of the ITCZ (known as the African Humid Period). Plots of the de-trended radiocarbon determination probabilities from the eastern Saharan locations illustrate occupation, abandonment and subsequent reoccupation of locations at a temporal scale that is consistent with shifts in environment that Kuper and Kröpelin discuss (Hassan
Cereal cultivation in the Nile Valley
Stanley and Warne (1993) suggest that the occupation of the Delta was made possible after the Mediterranean sea-level rise between 8500 and 7500 BP and the creation of the Delta floodplain with the deposition of Nile silt. Subsequent occupation continued into Dynastic period, although it was not always continuous at individual sites. The Fayum, however, was abandoned quite suddenly ca. 6200–6000 BP (Wenke, 2009) suggesting that during the Neolithic, cereal cultivation was possible in the Fayum
Conclusion
Radiocarbon determinations from hearths in the Fayum correlate closely with determinations from the Delta but poorly and sometimes negatively with eastern Saharan locations further to the south. This suggests that mid-Holocene occupation of the Fayum was not related to the southward movement of the ITCZ. The lack of occupation before and after ca. 6000–6500 BP in the Fayum correlates best with environmental shifts that brought winter rains to northern Egypt. A reliance on these rains for
Acknowledgements
This study has been made possible by the Supreme Council of Antiquities in Egypt, and the project is thankful to its Secretary General, Dr. Zahi Hawass, and the Chief Inspector of the Fayum, in subsequent years: Dr. AbderRahman al-Ayedi and Mr. Ahmed Abd el Aal. The UCLA/RUG/UoA Fayum project in Egypt has been supported by the National Geographic Society, the Regents of the University of California, The Cotsen Institute of Archaeology, R. E. Taylor, Cotsen Institute of Archaeology, UCLA and
References (64)
Holocene trends in 18O in land snail shells from the Negev desert and their implications for changes in rainfall source areas
Quaternary Research
(1991)Holocene lakes and prehistoric settlements of the Western Faiyum, Egypt
Journal of Archaeological Science
(1986)- et al.
Palaeoenvironment and Holocene land use of Djara, Western desert of Egypt
Quaternary Science Reviews
(2006) After 5000 BC: the Libyan desert in transition
Comptes Rendus Palevol
(2006)- et al.
Middle Holocene environments of north and east Africa, with special emphasis on the African Sahara
- et al.
Dating stratified settlement sites at Kom K and Kom W: Fifth millennium BCE radiocarbon ages for the Fayum Neolithic
Nuclear Instruments and Methods in Physics Research B
(2010) - et al.
Late Quaternary environments in the White Nile region, Sudan
Global and Planetary Change
(2000) Late Pleistocene environments in the Nile basin
Global and Planetary Change
(2009)- et al.
Late Quaternary floods and droughts in the Nile valley, Sudan: new evidence from optically stimulated luminescence and AMS radiocarbon dating
Quaternary Science Reviews
(2010) - et al.
Mediterranean moisture source for an Early-Holocene humid period in the northern Red sea
Science
(2003)