Palaeoenvironment and Holocene Land Use of Djara, Western Desert of Egypt

ARTICLE IN PRESS

Quaternary Science Reviews 25 (2006) 1619–1637

Palaeoenvironment and Holocene land use of Djara, Western Desert of Egypt

Karin Kindermanna,Ã, Olaf Bubenzerb,Ã, Stefanie Nussbauma, Heiko Riemera, Frank Dariusb, Nadja Po¨llathc, Ursula Smettana

aForschungsstelle Afrika, University of Cologne, 50823 Cologne, Germany bDepartment of Geography, University of Cologne, 50923 Cologne, Germany cInstitute of Palaeoanatomy and History of Veterinary Medicine, Ludwig-Maximilians-University, 80539 Munich, Germany

Received 1 March 2005; accepted 20 December 2005

Abstract

The results of the interdisciplinary project ACACIA support the assumption of a more humid climate at Djara, on the Egyptian Limestone Plateau, which is a hyper-arid desert today, during the early and mid-Holocene. The ancient plant and animal inventories give new impetus for the suggestion of an interﬁngering of two climatic regimes, the winter rains from the north and west and the summer monsoonal rains from the south, on the latitude of Djara. A playa sediment sequence, the composition of plant and animal taxa as well as the reconstructed settlement patterns indicate a semi-arid climate with alternating more humid and drier conditions. The concentration of prehistoric sites in the Djara depression points to locally favourable conditions in contrast to the surrounding plateau surface. The widespread catchment and a distinct system of palaeochannels offered fresh water over a period of time due to the run-off from the plateau surface after rain events. Although the ecological conditions were better during the Holocene humid phase than they are today, a sedentary way of life was improbable. The hydrological constraints require altogether highly mobile subsistence strategies. Shells of the Nile bivalve Aspatharia sp. (Spathopsis sp.) give evidence for contacts between Djara and the Nile Valley, which remains beside the Egyptian oases an important retreat area with perennially available water. The decrease of radiocarbon dates and related archaeological sites around 6300 BP (c. 5300 cal BC) indicate the depopulation of the Djara region as a consequence of the drying trend. While the drop off of the 14C-dates can also be observed in other desert research areas of the ACACIA-project, we date the end of the Holocene humid phase about 300 years earlier than previously suggested. r 2006 Elsevier Ltd. All rights reserved.

1. Introduction The landscape of Djara is characterized by small limestone hills and shallow playa depressions (Fig. 2), in The Cologne-based Collaborative Research Centre which there are numerous prehistoric sites, dating to the ACACIA—Arid Climate, Adaptation and Cultural Inno- early and mid-Holocene. In the course of several expedi- vation in Africa—focuses on the study of human response tions in-between 1995 and 2002 it was noticed that the to climatic and environmental changes in arid areas. One of archaeological remains were associated with distinct the research sectors, the region of Djara, is situated on the environmental settings; this led to an interdisciplinary Egyptian Limestone Plateau halfway between Asyut in the approach in order to understand the interactions of Nile Valley and the Farafra Oasis. Forming part of the environmental conditions and cultural developments in Western Desert of Egypt, the plateau covers an area of this arid landscape. Deserts are difﬁcult environments approximately 200,000 km2 of rough tableland west of the where resources are highly variable in time and space. That Nile (Fig. 1). is just why arid zones form an almost experimental situation, as key resources are limited factors, and environmental constraints can be separated from other ÃCorresponding authors. E-mail addresses: [email protected] non-environmental factors. Necessarily, there are a range (K. Kindermann), [email protected] (O. Bubenzer). of factors shaping societies that are not environmental, and

Fig. 1. Map of Egypt showing the Djara region and the locations of Figs. 3 and 5. The appearance of escarpments exceeding relative heights of 50 m was calculated by the GTOPO 30 digital evaluation model and was corrected visually by Landsat-data.

it is wise to consider other possible interpretations of the the environmental conditions are crucial for human data (e.g. Messerli et al., 2000; Woodward et al., 2001). occupation. To this end, different archives, such as playa However, there is no denying that particularly in deserts deposits, charcoal remains, bones and archaeological ARTICLE IN PRESS K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637 1621

Fig. 2. Predominant landscape of the Djara region showing undulating to level hamada surfaces, shallow depressions with rounded limestone hilltops, wadi terraces and playa remnants (photo H. Thaler).

artefacts, were analysed by the participating scientific in the summer monsoonal rain (Nicholson and Flohn, disciplines, namely archaeology, archaeobotany and ar- 1980; Geb, 2000). On the basis of archaeobotanical remains chaeozoology, physical geography, ecology and pedology. from the Great Sand Sea and the Abu Ballas area Neumann (1989a, b) suggests a maximum precipitation 2. Palaeoenvironmental and archaeological investigations amount of 100 mm for the mid-Holocene humid phase. In summary, a generally arid environment with short humid 2.1. Climate intermediate stages can be deduced (e.g. Bubenzer and Hilgers, 2003). Today, the Western Desert of Egypt is part of the hyper- arid Eastern Sahara (UNESCO, 1977) and belongs to the subtropical desert climate zone (Griffiths, 1987). High 2.2. Geological and geomorphological setting temperatures, low humidity and strong winds cause high potential evaporation rates in excess of 5000 mm per year Although basic geological and geomorphological infor- (Griffiths, 1972; Haynes 1982; Darius, 1989). In contrast, mation on the Limestone Plateau is available (e.g. the interpolated annual precipitation sum is less than 5 mm Beadnell, 1909; Ball, 1912; Butzer, 1965; Abu Al-Izz, with sparse rain on only 1–5 days per year on average (New 1971; Said, 1990; Kro¨pelin, 1993; Hassan et al., 2001; et al., 1999). Mandel and Simmons, 2001), the central part of the region Palaeoenvironmental observations have shown that the of Djara has not yet been explored in detail. regional climate during the Holocene differed from the The plateau is predominantly comprised of marine present situation (e.g. Ritchie et al., 1985; Kutzbach and carbonate rocks of the Lower Eocene Thebes Group Liu, 1997; Pachur and Hoelzmann, 2000). Due to oscilla- overlying the Esna- and Garra-formation. The sequence tions in the Earth’s orbit, summer insolation in the dips at very low angles to the northeast. Since the post- Northern Hemisphere rose to peak levels approximately early Eocene regression and the subsequent uplifting and 8% higher than today 11,000 years ago (Berger and Loutre, erosion phases, terrestrial conditions have prevailed 1991; deMenocal et al., 2000; Tuenter et al., 2003). The (Hermina, 1990; Stampfli et al., 2001). Quaternary insolation created an enhanced monsoonal summer pre- sediment accumulations are restricted to the sand dunes cipitation in North Africa during the early and mid- of the Abu Moharik dune belt as well as to sand and Holocene (Holocene humid phase or humid optimum). lacustrine sediments in the flat depressions or pans (Figs. 2 Other studies postulate both an enhanced summer pre- and 3). The arid climate during much of the Pleistocene cipitation from the south, and increased mediterranean and the modern hyper-aridity has encouraged strong wind winter rains from the west and the north due to stronger abrasion and the development of dune formations, hamada westerlies with cyclonic disturbances, as well as an increase and serir surfaces (Brookes, 2001, 2003). ARTICLE IN PRESS 1622 K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637

Fig. 3. ASTER-satellite image of the central part of the Djara region with archaeological sites. The inset left shows the hypothetical drainage area (approx. 11,600 km2) of the region, calculated from ASTER digital elevation data by the use of the TOPAZ-model (Watershed Modeling System, WMS). Note that all camp sites are located within the depression that beneﬁted from a water surplus from the palaeodrainage system during the Holocene climatic optimum (geology after Klitzsch et al., 1987). The location of this site is shown in Fig. 1.

The region of Djara is situated in the upper parts of the escarpments of the Dakhla–Kharga depression. Hence, the Naqb-formation, which consists of fossiliferous platform botanical observations made in 1873–74 by Schweinfurth limestones with minor shale intercalations, possibly result- and Ascherson during the Rohlfs expedition still remain ing in layers with reduced water permeability (Fig. 3). To the most valuable source of information for the study area the north lies the Minia-formation (lower to middle (Rohlfs, 1875; Ta¨ckholm, 1974). Eocene) that is composed of well-bedded grey limestone Land suitability assessments including soil surveys (Klitzsch et al., 1987) containing layers of chert (flint). resulted in a soil classification for the southern parts of Long periods of intense insolation and salt weathering have the Western Desert of Egypt (Smettan, 1987; Alaily, 1993). yielded an ideal raw material for the prehistoric stone tool Alaily (1993) divided the soils of the Abu Tartur production. The relief forms a karstic landscape with subplateau according to relief and bedrock, classifying rounded hilltops, flat depressions and drainage channels them as Solonchaks on level ground and shallow depres- developed during former wetter climate phases of the sions, and lithic Leptosols on outcrops and within strongly Oligocene (El Aref et al., 1987; Kro¨pelin, 1993). eroded areas. Due to the geographical position southeast of the 2.3. Vegetation and soil Bahariya Oasis our study area should be classified as an extreme desert type 2 (sensu Bornkamm and Kehl, 1989). The botanical investigations by e.g. Bornkamm and The vegetation is a contracted type, restricted to the Kehl (1990), Kehl and Bornkamm (1993),andAbd el- drainage lines and pans with vegetation cover much lower Ghani (2000) led to a first phytogeographic analysis, a than 0.1%, and predominantly of the accidental type refined definition of ecosystem types and vegetation units, (Kassas, 1952; Bornkamm, 2001). From a phytogeogra- and a preliminary vegetation map for the low-lying plains phical point of view, the present Saharo-Arabian flora of the sandstone terrain including the Gilf Kebir (Nubian shows a weak northern influence with a low proportion of Desert sensu El Hadidi, 1980). Surveys on limestone were Mediterranean and Irano-Turanean geo-elements, and mainly restricted to the Qattara region and along the reflects a relationship with the south containing a ARTICLE IN PRESS K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637 1623 substantial contribution of Sudanian elements (Abd el- to separate relevant chrono-stratigraphic phases and to Ghani et al., 2003). reconstruct the spatial configuration of sites and centres of activity using high-resolution excavation grids. Associated 2.4. Archaeology botanical and zoological remains were recovered by dry sieving of sediments. A growing interest in Holocene archaeology in the oases Geomorphological fieldwork was carried out by the around the Egyptian Limestone Plateau has developed acquisition of landform attributes, such as shape, dimen- since the 1970s, beginning with the Combined Prehistoric sion (of wadis or outcrops), gradient, aspect, curvature, Expedition (CPE) in the Nabta Playa/Bir Kiseiba region and topo-sequence position (e.g. Dikau et al., 1999). (Wendorf and Schild, 1980; Wendorf et al., 1984, 2001). It Pedological research followed the standard methods was followed by the Dakhleh Oasis Project (DOP) prescribed by FAO-UNESCO (1988/1997) for 25 soil (Churcher and Mills, 1999), the Italian–Egyptian mission profiles, including documentation of the main pedological in the Farafra Oasis (Barich and Hassan, 1988; Barich parameters e.g. horizon description, colour, texture, et al., 1991; Hassan et al., 2001), as well as the cementation, rock fragments, biological features, pH- investigations in the Oases of Bahariya (Hassan, 1979) value, electrical conductivity (EC), and the calculation of and Siwa (Fakhry, 1973; Hassan, 1976; Hassan and Gross, salinity (for methodological details see Schlichting et al., 1987; Cziesla, 1989). However, archaeological investiga- 1995). Dating derived from typo-chronological classifica- tions have focused only on certain areas of the Limestone tion of diagnostic artefacts, 14C-dating, and OSL-dating of Plateau, e.g. the southern escarpment near to the Dakhla sediments. oasis (McDonald, 1999; Hawkins and Kleindienst, 2002) The botanical data of the recent vegetation were also or the southwestern part between Asyut in the Nile Valley collected along the survey-transects. The data based on and the Kharga Oasis (Caton-Thompson, 1931; Caton- species lists and 127 releve´s following the Braun-Blanquet Thompson, 1952; Nicoll et al., 1999; Mandel and system. A releve´plot size of 100 m2 was used throughout. Simmons, 2001; Kleindienst et al., 2003). A good source Dead and dormant plant individuals were listed separately. of comparative data with large-scale geoarchaeological In extended (but very open) vegetation stands, transects surveys is given by the Northern Dongola Reach Survey were investigated following the methods of Whittaker (NDRS) in the Sudanese Nile Valley (Woodward et al., (1982)—an approach that was successfully used in arid 2001; Welsby et al., 2002). regions by Kehl and Bornkamm (1993). The nomenclature The region of Djara was first mentioned by the German of the species followed Boulos (1995, 1999, 2000) and the explorer Rohlfs in his travelogue ‘Drei Monate in der anthracological analysis was based on the identification libyschen Wu¨ste’ (Rohlfs, 1875). His expedition made key by Neumann and Schoch (2000). camp near a place called Djara, which he described as a spacious stalactite cave. In 1989 the cave was ‘rediscovered’ by the German ‘camel nomad’ Bergmann and in 1990, a 4. Topo-sequence group of geographers and archaeologists from Berlin, Cologne and Cairo made preliminary evaluations of the The predominant landforms of the Djara region are archaeological potential of this area, and carried out test undulating to flat hamada surfaces with shallow pans, excavations (Kuper, 1996). A first brief field campaign was partly covered by serir, and major depressions with undertaken in 1993 by the Heinrich-Barth-Institute rounded limestone hilltops, wadi terraces, playa remnants (University of Cologne) and the research was continued and occasionally sand accumulations. The identification of in 1995 by the ACACIA-project (ClaXen et al., 2001; geomorphological and ecological units provides the basis Gehlen et al., 2002; Kindermann, 2003). Alongside the for distinguishing eight different landscape units—apart archaeological fieldwork, initial archaeobotanical and from Djara cave—with specific soil types and vegetation archaeozoological investigations were undertaken. units (Fig. 4; Table 1). Most of the plateau surface has a slope of less than 11 3. Methods and consists of a rough wind-polished limestone hamada (unit 1, Fig. 4). The limestone hamada is devoid of any The strategy for gathering archaeological field data vegetation due to the recently prevailing climatic condi- combined large-scale reconnaissance surveys along various tions. Most of the rare rain that falls cannot infiltrate the transects across the entire plateau running from Seton Hill dry surface and gathers via a dense channel system into in the north to the Dakhla–Kharga depression in the south. lower-lying depressions and pans. Additionally, ascending A detailed local study perimeter was established in the water containing soluble salts leads to high salt- and Djara region, stretching from north to south c. between gypsum-contents near the surface. Most of the small- 281N and 26.71N and from the escarpment in the west to grained surface material has been eroded and the remain- the Abu Moharik dune belt (Fig. 1). Analyses of ing soils are shallow. Due to the small size of the pans on archaeological sites were done by excavations and com- the plateau (unit 2, Fig. 4), water collection and storage is plete surface collections. The excavations were carried out not sufficient to maintain permanent vegetation. The high ARTICLE IN PRESS 1624 K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637

remnants are covered with serir. There is no evidence for current erosion or aggradation. Although the relief position allows the inflow of water from higher areas, the present moisture penetration is not high enough to dissolve the salt. Nevertheless, sparse vegetation covers of leaf and stem succulent halophytes are sustained. Contracted vegetation with low density is restricted to the drainage channels and pools of the depression (units 4 and 6, Fig. 4; Table 1). The plant species composition shows similarities to the precipitation-dependent permanent plant associations further north (Bornkamm and Kehl, 1990). The vegetation of the study area forms species-poor stands of the following plant associations: Anastatica hierochuntica–Anabasis articulata ass., Stipagrostis plumosa ass., Cornulaca monacantha–Fagonia arabica ass., and Pulicaria crispa ass. The low salt contents show that the channels episodically carry water. Thick loamy sand over dense subsoil and the surplus of water from the plateau enables the establishment of a vegetation cover of about 5% after precipitation events. This vegetation, which sometimes includes the rarely occurring phreatophytes of the genus Tamarix, whose deep roots reach subsurface groundwater, may resist the subsequent drought for periods ranging from several months up to years. The Holocene playa residuals (unit 5, Fig. 4) have a maximum thickness of 2 m and consist of re-deposited red weathered material. A typical remnant of playa sediment was investigated in detail within the archaeological site Djara 98/20 (Figs. 5 and 6; Bubenzer and Hilgers, 2003). It has been protected against wind erosion by limestone scree and burned stones from hearth mounds (called Steinpla¨tze; Gabriel, 1973). The sediment profile is situated in a pan at the mouth of a small wadi system. The base of the section is an ancient red soil, which developed under warm humid karstic conditions. Grain size analyses, Scanning Electron Microscopy and Luminescence dating show that the profile strata have different layers of sandy or loamy-clayey sediments without stones or gravel (Bubenzer and Hilgers, 2003). This sequence results from changing climatic conditions during the early and mid-Holocene humid phase, which are concordant with those described in other investigations in the Western Desert (Hassan et al., 2001; Haynes, 2001). Four luminescence dates from the profile range between 6.8170.5 and 8.6770.5 ka (OSL) and show that the entire playa sediments accumulated during the early and mid-Holocene (Bubenzer and Hilgers, 2003). Fig. 4. Geomorphological sequences of the Djara region (not to scale). The water surplus in the pools (unit 6, Fig. 4) is able to For more detailed information about soils and vegetation see Table 1. dissolve the salts of the loamy soils during episodic precipitation events. Low contents of salt and high amounts of carbonates enable calcite-tolerant species to salt concentration only allows the germination of very salt grow. The density of the diffuse vegetation cover is, tolerant plants. together with that of the wadi channels, the highest in the The soils of the depression are thicker (415 cm) and study area. finer than those of the plateau. The slopes (unit 3, Fig. 4) The soil development in the recent aeolian sands (unit 7, that join the plateau with the depression bottoms have Fig. 4) is low. Only the upper 5 cm show a slightly brown gradients of 2–51. The dominating fans and older terrace horizon without any changes in the grain size distribution. ARTICLE IN PRESS K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637 1625

Table 1 Results of the geomorphological, pedological and botanical research

Plateau Depression Sands (7) Limestone hamada (1)

Hilltops Plain Pans (2) Slopes and Wadi Playa (5) Pools (6) edges (3) channels (4)

Soil type Eutric Gypsic Gypsic Eutric Eutric Leptosol Calcaric Eutric Leptosol Calcaric Arenosol Leptosol Solonchak Solochak/ Leptosol Cambisols Calcaric Cambisols Soil texture fS (aeolian) Su3–Sl3 Ut3–Tu3 Tl3 Sl2 fSl3–Lt4 fS–(fSl4)–Tu3 fS (aeolian) Soil depth (cm) 5–15 20 420 20 o15 o200 30(470) 420 Stone cont. (%) 10–15 (0) 5–10 o5 5–10 50–80 0 (o5) 10–50 (90) 0 CaCO3 cont. C3 C3 C3 C3–C4 C3–C4 C3–C4 C2–C3 C3 Salt Soda Soda EC ++ +++ — ++ — (+) — — — pH-value 7.5 7.0 7.5 8.5 7.5 7.5 7.0–8.0 6.5 Remarks Gypsum Gypsum Run-on Fire places Cracks, bedrock Rhizome Run-on conditions Special habitats crust crust conditions casts Vegetation — — Chenopodiaceae Isolated Tamaricaceae, — Tamaricaceae, Salsola Calligonum individuals of Chenopodiaceae, imbricata, Cornulaca comosum, Pulicaria Anabasis Zygophyllaceae, monacantha, Fagonia undulata, Stipagrostis articulata Cruciferae, arabica plumosa Leguminosae

Numbers in brackets show the landscape units (Fig. 4).

The available moisture capacity is relatively high and the given by a radiocarbon date around 8600 BP (c. 7700 cal water-surplus of the catchment area causes dissolution of BC) (Fig. 7). A developed blade technology with well- salt. Hence, the low present-day precipitation on these sites prepared cores and microlithic tools as backed points and allows the growth of shrubs and grasses. elongated triangles (Fig. 8(14–19)), probably used as insets The Eocene limestone bedrock (unit 8, Fig. 4) shows in arrow shafts for game hunting, seems characteristic of karstic features such as caves, occasional dolines, re- these desert dwellers (Gehlen et al., 2002; Nicoll, 2004). crystallized calcite and ancient red Terra Rossa soil (compare L1–L3 in Fig. 3). The bottom of the Djara cave 5.2. Djara A 7600–7200 BP (c. 6400–6100 cal BC) is filled with sand (unit 9, Fig. 4), which was transported in through the breakdown of the entrance. The bulk of radiocarbon dates falls into the mid- Holocene phases Djara A and Djara B (Fig. 7). A 5. Archaeological sequence fundamental change in the technology and the blank procurement for tool production is visible in the transition More than 80 early and mid-Holocene sites were from the Epipalaeolithic to Djara A around 7700 BP (c. recorded during the field survey in Djara. The typo- 6500 cal BC). The mid-Holocene phases are characterized chronological classification of the diagnostic types and the by a flake-orientated blank-production without an elabo- flaking technique of stone artefacts led to a differentiation rate preparation. For the tool production, a high percen- of the occupation period in Djara during the Holocene tage of naturally weathered flint ‘blanks’ or preforms was humid optimum. 28 14C-dates from anthropogenic features also used (Kindermann, 2003, 2004). Elongated triangles provided the chronological sequence with absolute settings and backed points were replaced in Djara A by facial and of the phases (Gehlen et al., 2002; Fig. 7, Table 2). lateral retouched tanged arrowheads and small leaf-shaped points (Fig. 8(11–13)). The earliest bifacially retouched 5.1. Epipalaeolithic 8600–7800 BP (c. 7700–6700 cal BC) arrowheads were found in Djara A assemblages.

The Epipalaeolithic (‘Early Neolithic’ of Nabta/Kiseiba 5.3. Djara B 6900–6300 BP (c. 5800–5300 cal BC) region) is not well represented in the Djara region and only a few chronologically classifiable sites of exclusively game Characteristic new tool elements are knives, side-blow hunter-subsistence occur. Although data from other flakes (Fig. 8(7)) and planes (Fig. 8(9)). In this chron- regions indicate that the early Holocene re-occupation of ological phase the bifacial retouch of stone artefacts is the the desert areas in Egypt after the hyper-arid Pleistocene dominate modification technique. Pottery did not occur in began after 10,000 BP (e.g. Wendorf et al., 1984; the Djara sites, apart from a few thin-walled sherds, McDonald, 1998, 2001; Schild and Wendorf, 2001; Gehlen which might have parallels to fabrics from the Late et al., 2002), Djara’s earliest evidence of desert dwellers is Bashendi A in Dakhla (Hope, 2002; Kindermann, 2004) ARTICLE IN PRESS 1626 K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637

Fig. 5. Archaeological–geomorphological plan view of site Djara 98/20 showing a diagnostic playa depression and remains of a large long-term camp dating to the early and mid-Holocene. The isohyets are expressed in a local system (surface measurement by electronic Tachymeter). The location of this site is shown in Fig. 3. and its surroundings (Gehlen et al., 2002). Archaeological arid and hyper-arid conditions led to the deflation of the sites from the Djara B phase are characterized by the fine sediments and to the degradation of these sites, and it occurrence of numerous grinding implements made out of seems that the Djara region was no longer attractive for local fossil limestone or, rarely, out of quartzitic sandstone humans. from the Nubia formation, which reflects the growing utilisation of wild plants in the diet at this time. 6. Settlement patterns Radiocarbon dates and related archaeological sites decreased rapidly after around 6300 BP (c. 5300 cal BC), A significant change of settlement patterns occurs during indicating the depopulation of the region as a consequence the Holocene humid phase from the Epipalaeolithic to the of the drying of the Eastern Sahara (Gehlen et al., 2002; mid-Holocene phases as indicated by the following trends: Nicoll, 2004; Bubenzer and Riemer, in press). A final occupation phase falls around 5900 BP (c. 4800 cal BC) 1. In general the number of artefacts on the sites increases evidenced by only two 14C-dates, which may represent and the sites increase in area, indicating a longer short-term revivals of precipitation. After this time, the duration of stay and multiple occupation events. ARTICLE IN PRESS K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637 1627

Blank production rarely occurs, and often reflects ad hoc- manufacture. Based on survey results and the classification of geomorphological units, according to the elements of the topo-sequence described above, regularities of site location and setting in the landscape become apparent. Most archaeological sites recorded in the Djara region are concentrated in the depression area, which has the highest density of 2.5 sites per km2. The most intensively occupied landscape units are the fine-grained playa deposits of the depressions (see also Djara 98/20; Fig. 5), but sites also occur in the wadi channels and on the edges of the depressions. However, they tend to be located near playa deposits or along the shoreline of the temporary ponds. The plateau surface, in contrast, has a site density of 0.3 sites per km2. Combining settlement patterns and site location, the most striking aspect is the predominance of large camps on or near the playa deposits (Fig. 9). In contrast, the plateau hamada yielded the smallest sites together with a low density of findings. Atelier sites were found in the vicinity of the depression area up to 15 km (a day’s march) away from the large long- term camps. They are mostly situated on limestone bedrock or rocky hills, where good-quality flint nodules are present in the limestone formations, as observed, for example, within the geological Minia-formation (lower to middle Eocene). Testing and core preparation as well as workshops for the blank production occur; however Fig. 6. Profile Djara 98/20-2 (location s. Fig. 5) with sampling positions retouched tools, fireplaces or grinding implements are rare for OSL-dating, grain-size depth-concentration, and dose rate (Do) or non-existing and indicate a very short stay. determination (using the single-aliquot regenerative-dose (SAR) protocol (Murray and Wintle, 2000). OSL-ages were calculated for sample discs 7. Archaeoflora and -fauna with 8 mm or 1–2 mm diameter, covered by quartz grains. Palaeodose calculation was derived from quartz grains of 100–250 mm. Note that the whole profile was deposited during the Holocene optimum and that the The anthracological analysis of the macro remains found sediment sequence exposing an alternation of finer (lacustrine) and coarser on site Djara 90/1–3, which was excavated inside the (aeolian) layers. In particular, the sandy layers have characteristic vertical stalactite cave, shows important aspects of the ecology calcite tubes, which mark former stem casts of reed or cattail (comp. during the mid-Holocene (Table 3). This site includes a Bubenzer and Hilgers, 2003). 10–15 cm thick ashy layer on a large block of rock fall. Two radiocarbon measurements date this layer to between 7300 and 8060 BP (c. 6200 and 7000 cal BC). Only a few 2. The variety of artefact classes per site increases marking unmodified blanks were excavated, which made a detailed a growing complexity of activities performed on the sites archaeological separation of this stratum impossible. as well as a longer duration of stay. Extraordinarily well-preserved charcoals were found, 3. The total number of sites increases after 7700 BP representing predominantly trees of the genus Acacia, (c. 6500 cal BC), suggesting a more intensive land use. Tamarix and of the family Capparaceae (Fig. 10). Long vessel raws are characteristic of the species Maerua Djara A and B show the beginnings of a functional crassifolia, other fragments have characteristics of Cap- differentiation of sites, characterized by small transitory paris. Tamarix is the dominant taxon of the macro remains, sites with a reduced artefact spectrum, specialized atelier with more than 50% of the specimens. Fruits of Zilla sites for raw material procurement, and large long-term spinosa and Anastatica hierochuntica (Fig. 11) are present. camps (4200 m extension) with a high number of artefacts Stolons and a caryopse represent the Gramineae. and a complex activity spectrum (Fig. 3). The large camp The inventory of the macro remains from the Djara cave sites incorporate activities such as blank and tool produc- shows similarities to other archaeobotanical inventories tion, plant food processing on grinding stones, manufac- found at excavations on limestone in Egypt. Neumann ture of ostrich eggshell beads as well as butchering (1989a, b) identified the taxa Acacia, Tamarix and Cheno- and consumption of hunted animals. Smaller sites are podiaceae for the Qattara Depression (Sitra) dated around characterized by fireplaces and a low number of tools. 6700 BP (c. 5600 cal BC). These taxa are part of the recent ARTICLE IN PRESS 1628 K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637

Fig. 7. Probability distributions of 28 calibrated 14C-dates from desert areas mentioned in the text. The ticks on the cal scale represent the cal median values, calculated by ﬁtting Gaussian curves to the cal distribution of the individual dates. The chronological phases are shaded. The dates are calculated and plotted by the 2-D Dispersion Calibration Program Version Cologne 2003 of CALPAL (Cologne Radiocarbon Calibration & Palaeoclimate Research Package) by Bernhard Weninger, Radiocarbon Laboratory, University of Cologne.

vegetation at the Qattara Depression, therefore Neumann Panicum association; Walter, 1985). The inventory of the suspects a difference in cover density rather than in species Hidden Valley is rich and resembles the inventories of diversity. She assumed a dry shrubland on the plain and a Nabta Playa (Wasylikowa, 1997) dated to 8000 BP (c. 6900 contracted vegetation cover of Acacia and Tamarix along cal BC) and Eastpans (Barakat and Fahmy, 1999) dated to the wadi channels and within the depressions. Barakat and 6200 BP (c. 5200 cal BC). These settlements are situated Fahmy (1999) and Fahmy (2001) reported 32 taxa within within large depressions, where extensive areas of former the plant remains from archaeological features of the grassland were accessible to the inhabitants (Barakat and Hidden Valley (Farafra Oasis) also dated to 6700 BP Fahmy, 1999), but this is not true for the Djara region. (c. 5600 cal BC), of which 30% are annual and perennial Even though Djara is situated on limestone, as is the grasses. Acacia-charcoal and fragments of Tamarix and Hidden Valley and receives almost the same amount of Chenopodiaceae were also identiﬁed. They deduced the precipitation, it lies 200 m higher than Hidden Valley. At growth of open thorny and scrub savanna including the higher altitude the temperature is lower and therefore perennial grasses such as Panicum turgidum (Acacia- limits the occurrence of species with a more southerly ARTICLE IN PRESS K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637 1629

Table 2 List of the 28 14C-dates used for the calibration in Fig. 7

Lab. no. 14C-Age (BP71s) d13C(%) Material Context Cal BC

KN-4423 8620790 25.0a Ch Surface 90/1 77007110 KIA-12422 8055760 25.4 Ch Ashy layer 90/1-3 69807120 UtC-9460 7913743 3.1 OES Fireplace 90/1-6 68407130 KN-4422 7820790 7.1 OES Surface 90/1 67207170 KN-4602 7588782 25.0a Ch Fireplace 90/1-2 6410790 UtC-9464 7500760 26.6 Ch Steinplatz 98/20-3 6340770 KN-4603 7421774 25.0a Ch Fireplace 90/1-2 6280790 Erl-2863 73037109 24.5 Ch Ashy layer 90/1-3 61707120 KN-4326 7260780 6.3 OES Surface 90/1 6120780 Erl-2862 7215781 25.8 Ch Steinplatz 90/1-13 6090790 KIA-15960 7040750 23.6 Ch Fireplace 90/1-15 5910760 KIA-20681 7030740 2.5 Sh Surface 90/1 5910760 UtC-9463 6959746 17.2 Ch Steinplatz 90/1-8 5830760 UtC-9462 6900750 26.1 Ch Fireplace 90/1-6 5780750 KIA-16644 6885730 42.4 Ch Steinplatz 90/1-10 5760740 HD-16311 6786749 21.0 Ch Fireplace 90/1-1 5680740 HD-16313 6753753 24.0 Ch Fireplace 90/1-1 5660750 Erl-2872 6713775 25.8 HA Steinplatz 90/1-13 5620770 Erl-2859 6696794 25.9 Ch Fireplace 90/1-6 5610780 KN-4600 6685790 25.0a Ch Fireplace 90/1-1 5600780 Erl-2858 6605774 7.4 OES Fireplace 99/28 5550760 UtC-9459 6597742 4.0 OES Surface 98/5 5550750 KN-4601 6448769 25.0a Ch Fireplace 90/1-1 5410760 UtC-9465 6430750 7.0 OES Surface 98/20-1 5400750 Erl-2860 64067105 27.2 Ch Steinplatz 90/1-8 53607100 KIA-16645 6365730 23.9 Ch Steinplatz 98/20-6 5360750 Erl-2861 5982778 25.1 Ch Steinplatz 90/1-12 48707100 Erl-2871 5866798 25.2 HA Steinplatz 99/8 47207120

Radiocarbon procedures include conventional radiometric technique on the laboratories of Cologne and Heidelberg, as well as Accelerator Mass Spectrometry (AMS) in Kiel, Utrecht, and Erlangen. 14C-dates are made on charcoal, ostrich eggshell, and bivalve shell (correction for isotopic fractionation based on d13C). Abbreviations: Ch ¼ charcoal; OES ¼ ostich egg shell; HA ¼ humic acid; Sh ¼ bivalve Aspatharia sp. (Spathopsis sp.). aEstimated value.

distribution (Sudano-Sambesian region). Hence, the spe- conditions. During the Djara B occupation phase, a change cies composition of the wadi channels and pans within the in subsistence becomes apparent. From site Djara 90/1, a depression on the Limestone Plateau (Qattara Depression, proximal radius fragment of a domesticated sheep (Berke, Djara region) could have been poor stands of the rich 2001) has been recorded (Fig. 12). Stone tool inventories dry scrub savanna of the lower-lying, warmer oasis-like belonging to phases Djara A and B, indeed, show a high depressions of Eastpans (Barakat and Fahmy, 1999), number of arrowheads, implying that game hunting was Hidden Valley (Fahmy, 2001) and Nabta Playa (Wasyli- still important for human subsistence during the mid- kowa, 1997). Holocene. For archaeozoological work, the state of preservation of the bone material from prehistoric sites in Egypt is often a 8. Reconstruction of the early and mid-Holocene problem (van Neer and Uerpmann, 1989; Gauthier, 2001) Palaeoenvironments because frequently, the excavated bones are heavily fragmented and therefore fragile. The Epipalaeolithic Key factors for human occupation are the presence or artefact concentrations of Djara did not contain identifi- absence of vegetation and surface water. Both factors are able bones, but when compared to contemporaneous dependent on the relief structure, soil parameters and on sites in the Western Desert (e.g. Regenfeld, Great Sand climatic conditions. Sea), a subsistence based on hunting and gathering can be assumed. 8.1. Relief structure and soil parameters The identified material from the mid-Holocene phases Djara A and B contains wild species such as Gazella dorcas To understand the environmental conditions during the (dorcas gazelle), G. dama (dama gazelle), Addax nasoma- early and mid-Holocene humid phase it is necessary to culatus (addax), Oryx dammah (scimitar-horned oryx) and consider geomorphological processes under previous cli- Caracal caracal (caracal) reflecting a fauna adapted to dry matic conditions. The Djara basins are karstic features, ARTICLE IN PRESS 1630 K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637

Fig. 8. Characteristic stone tools from the archaeological sequence of Djara. Djara B: 1–6 arrowheads, 7 side-blow ﬂake, 8 side scraper, 9 plane—DjaraA: 10 side scraper, 11–13 arrowheads—Epipalaeolithic: 14 strangulated blade, 15–16 truncated bladelets, 17–19 elongated scalene triangles. ARTICLE IN PRESS K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637 1631

with caves, wind eroded stalagmites, and dolines (see L1–L3 in Fig. 3 and Djara 90/1 in Fig. 4). In addition, the plateau surface is subdivided by an endorheic dendritic palaeodrainage system (Fig. 3, inset). The larger wadis are covered with serir and ﬂow into shallow depressions with a maximum depth of 20 m below the plateau surface (see Figs. 3 and 4). The relief determines water availability and hence the density and composition of the plant cover. The pedological analyses show a higher salt content for the plateau soils but not for those in pools and wadis of the depression. These soils consist of sandy to loamy lacustrine deposits and aeolian sands. The latter are of high ecological value due to the coarse texture and the low salt content. Sand aids water storage in arid regions, because the rainwater inﬁltrates directly to deeper layers. It is protected against evaporation and available to the vegetation on the surface. The lacustrine sediments originate from the soils of the plateau surface that were previously thicker than they are today. During the humid phases of the Late Pleistocene Fig. 9. Distribution of site sizes on the different landscape units of Djara and early to mid-Holocene, episodic or periodic precipita- (n ¼ 81). Numbers in brackets show the landscape units (s. Fig. 4). tion induced surface run-off. Due to the run-off, the

Table 3 Results of the botanical observations at Djara

Species Family Recent Macro remains Type of macro Choro Main vegetation Djara cave remains type distribution (%)

Monsonia nivea Geraniaceae x Sar. s/w Reseda alba Resedaceae x Sar./Medit. w Oligomeris linifolia Resedaceae x Cent. Sah. w Noaea mucronata Boraginaceae x Sah. w Calligonum polygonoides ssp. Polygonaceae x N. Sah. w comosum Pulicaria undulata Compositae x Sar. s/w Fagonia arabica Zygophyllaceae x Sar. w Fagonia glutinosa Zygophyllaceae x Sar. w Ephedra alata Ephedraceae x Sar. w Anabasis articulata Chenopodiaceae x Sar. w Haloxylon articulatum Chenopodiaceae x Cent. Sah./ w Medit. Salsola imbricata ssp. gaetula Chenopodiaceae x N. Sah. w Salsola villosa Chenopodiaceae x Sar./Medit. w Cornulaca monacantha Chenopodiaceae x Sar. s/w Indet. Chenopodiaceae x 7.0 Charcoal Holarct. w Shouwia thebaica Cruciferae x Sar. w Moricandia nitens Cruciferae x Sar./Medit. w Matthiola longipetala ssp. bicornis Cruciferae x Medit. w Zilla spinosa ssp. spinosa Cruciferae x x 0.7 Fruit Sar. s/w Anastatica hieruchuntica Cruciferae x 3.3 Fruit Sar./Medit. w Stipagrostis plumosa Gramineae x Sar. w Indet. Gramineae x 3.5 Glume s/w Astragalus spinosus Leguminosae x Sar./Medit. w Acacia Type Leguminosae x 5.4 Charcoal Sahel./Sar. s/w Tamarix nilotica Tamaridaceae x Sar. s/w Tamarix amplexicaulis Tamaridaceae x Sahel./Sar. w Tamarix passerinoides Tamaridaceae x Sar. w Tamarix Type Tamaridaceae x 54.0 Charcoal Holarct. w Capparis/Maerua Type Capparaceae x 26.0 Charcoal Palaeotrop. s

The species list of the vegetation on the Limestone Plateau with the family, the type of observation (recent vegetation or macro remains of the Djara cave), type of macro remains (charcoal, fruit or glume), the choro type (phyto-geographical distribution: Medit. ¼ Mediterranean; Cent. Sah. ¼ Central Sahara; N. Sah. ¼ North Sahara; Holarct. ¼ Holarctic; Sar. ¼ Saharo-arabic; Sahel ¼ Sahelic; Palaeotrop. ¼ Palaeotropic) and the main distribution (s ¼ summer rain; w ¼ winter rain). ARTICLE IN PRESS 1632 K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637

Fig. 10. Scanning electron micrograph of Capparaceae (charcoal, broken cross-section).

Fig. 12. Proximal radius fragment of domesticated sheep from site Djara 90/1 (scale: 1 cm).

Fig. 11. Charred fruit of Anastatica hierochuntica from Djara 90/1-3. the Saharan Holocene. For the Egyptian Limestone 14 ancient red soil was eroded from the plateau surface and Plateau, a total of 28 C-dates were generated from deposited in the wadis and pools. The surplus of rainwater contexts of archaeological sites (Fig. 7; Table 2). The gained from the plateau run-off infiltrated the lacustrine cumulative histogram of these dates shows that the deposits and scoured out the salt. maximum occupation phase occurred between 7600 and Compared to other depression and drainage systems on 6300 BP (c. 6400-5300 cal BC). The onset of the drying the Limestone Plateau, the region of Djara had the most trend can be estimated as early as 6300 BP (c. 5300 cal BC) 14 favourable conditions for occupation during the early to when the C-curve drops off, as the occupational mid-Holocene, based on the large area of the drainage development of the desert areas outside the oases and the system and the presence of a distinct underground cave Nile Valley is closely linked to the changing climatic 14 system. The combination of winter rainfall and high water conditions. While the drop off of the cumulative C- capacity due to an extended catchment region as well as a histograms at 6300 BP (c. 5300 BC) can also be observed cave system supports the hypothesis of near surface water in other parts of the desert (Gehlen et al., 2002; Bubenzer availability during this time. und Riemer, in press), radiocarbon curves from the oases and other more favoured locations such as Nabta Playa/Kiseiba region and the Gilf Kebir lasted longer 8.2. Climate conditions (McDonald, 2001; Wendorf et al., 2001; Linsta¨dter and Kro¨pelin, 2004). Generally it has been accepted that large radiocarbon The macro remains from the Djara cave also give a fresh databases (Kuper, 1988; Vernet, 1995; Nicoll, 2001; Gehlen impetus to the continuing discussion about Holocene et al., 2002; Vermeersch, 2002) are valuable resources to climatic changes in Egypt and Northern Sudan. When reconstruct past environmental and climatic changes for the Holocene plant species inventories are compared to ARTICLE IN PRESS K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637 1633 those of the recent vegetation, the presence of the taxa of the channels and pools of the depression is differed from Capparaceae and Anastatica hierochuntica within the those of the plateau surface. The channels and pools charred macro remains indicates conditions for the early received additional water from the plateau surface. The Holocene were obviously more humid than they are at sand input by wind was high and the salt content low due present. to the flowing water. A different vegetation type with a When the data are considered in detail, it can be southern distribution could have developed in the depres- observed that the tree taxa found at the prehistoric sites are sion: a dry scrub savanna type with a tree layer of not found continuously within the Djara region nowadays. phraeatophytes such as Acacia-, Tamarix-andCappar- The trees of the genera Acacia, Capparis and Maerua—two aceae-species and a grass layer with annual or perennial possible taxa of the identified Capparaceae—are absent species. today. Acacia tortilis ssp. raddiana and A. ehrenbergiana The macro remains, such as internodes of grass-axes and occur further north near the Qattara Depression, further glum fragments, supports the argument of a grass canopy. south on the Limestone Plateau (261450N, 291400E) and to The gathering of wild grasses is additionally documented the east in the Red Sea Mountains. Capparis decidua is by the archaeological findings of grinding stones in Djara. found in deep wadi sediments further south (261330N, The deeper-lying warmer depressions could have served as 301270E), whereas Maerua crassifolia has recently been abundant pasture for oryx and caracal as well as for the found in the Gilf Kebir and further south in the Uweinat domesticated sheep. This animal can go without water up and Wadi Howar region. to 30 days during the cold season (Smith, 1980), while the Seeds and fruits especially from therophytes are even range is reduced to a maximum of 2–3 days without water better indicators for environmental conditions due to their under summer conditions, as the evaporation is several stronger dependence on seasonality of the precipitation times higher than in winter. This could perhaps explain regime. Anastatica hierochuntica (Cruciferae), the Jericho why domesticated animals were not introduced into desert rose, is a species, which is currently found on the coastal areas under summer rain dominance (c.f. van Neer and plain of Egypt and the Negev of Israel. On the plateau Uerpmann, 1989). north of Siwa and the Qattara Depression Anastatica The faunal spectrum recorded from the Limestone hierochuntica represents, together with Anabasis articulata Plateau shows a fauna adapted to dry conditions for (Chenopodiaceae), a plant community (Anastatica hier- the early as well as for the mid-Holocene. Whereas dorcas ochuntica—Anabasis articulata association) whose species and dama gazelle occur mainly in the sparsely vegetated partly occur in the Djara region to the present day, namely areas of the real desert, in semi-desert landscapes and, Zygophyllum coccineum, Stipagrostis plumosa, Salsola occasionally, in sub-desert steppes addax is an inhabitant imbricata ssp. gaetula, Astragalus trigonus and Fagonia of both stony and sand desert and rarely occurs in semi- arabica (Bornkamm and Kehl, 1990). Anastatica hiero- desert landscapes. Addax as well as the two gazelle species chuntica has not yet been found living on the Egyptian can go without drinking for weeks (Dorst and Dandelot, Limestone Plateau. The southernmost appearance of 1970). Anastatica hierochuntica on the Gilf Kebir (Monod, 1995) Oryx and caracal, on the other hand, have somewhat at 1000 m altitude (300 m above the surrounding area) higher ecological demands. Caracal is ubiquitous in arid supports the argument that the west wind circulation with landscapes except for the real desert. Today, this felid dominating winter rain (Nicholson and Flohn, 1980) inhabits the semi-arid woodlands and the Saharan moun- reached further south. Species with similar environmental tain ranges, since the species needs cover for hunting preferences, such as Anastatica hierochuntica, may have herbivores such as hare, dorcas gazelles and even larger occurred on higher plains within the Western Desert, such antelopes. The scimitar-horned oryx often frequents the as the Egyptian Limestone Plateau as far south as the sub-desert steppes and arid grasslands, but will occur latitude of the Gilf Kebir. With the retreat of the winter occasionally in the vegetated spots of the real desert after rainfall margin, these communities likewise withdrew to the the rains. In contrast to the caracal, the scimitar-horned north and to more temperate altitudes such as the Gilf oryx is now almost extinct. Both caracal and oryx can also Kebir Plateau. Today, Anastatica hierochuntica can be obtain most of the moisture required from their food. interpreted as a relic on the plateau. Capparis decidua and The faunal spectrum at Djara indicates a mosaic Maerua crassifolia, the two possible Capparaceae-species, landscape around the site consisting of real desert, semi- are otherwise indicators of summer rainfall. desert shrub vegetation and arid grasslands. This also Under more humid conditions than today, a diffuse, points to ecologically more favourable conditions in the carbonate-tolerant vegetation type well adapted to an arid region during the mid-Holocene, as does the evidence from regime could have developed on the plateau surface of playa sediments. The postulated enhanced precipitation for Djara. A climatic situation with seasonal precipitation North Africa, caused by a higher insolation in the supports the development of a diffuse dry shrubland, with Northern Hemisphere, is strongly supported by our field a dominating layer of chamaephytes, mostly of the observations (Nicholson and Flohn, 1980; Berger and common taxa Chenopodiaceae, approximately 50 cm high Loutre, 1991; deMenocal et al., 2000; Geb, 2000; Tuenter (Bornkamm and Kehl, 1990). The environmental condition et al., 2003). ARTICLE IN PRESS 1634 K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637

9. Reconstruction of the Holocene land use

The concentration of prehistoric sites in the region of Djara points to locally favourable conditions in contrast to the surrounding plateau surface. A major reason was certainly the availability of fresh water over a period of time. Djara is one of the deepest and largest depressions on the whole plateau. Situated as it was at the end of a widespread palaeochannel-system (Fig. 3), it received a certain amount of water-surplus due to run-off after rain. Because of the occurrence of shales in the under- lying strata, the water permeability was relatively low (Fig. 5). Playa deposits in Djara led to a partial sealing of the ground and also indicate that surface water collected in Aspatharia Spathopsis these depressions. Nevertheless, the surface water was Fig. 13. Shell of Nile bivalve sp. ( sp.) from site Djara 90/1. available only for a short period of time because of the high evaporation rates. The short-term and irregular inundation of the playa basins is evidenced by a lack of bio-remains in the sediments, with the exception of the stem casts of reed Underpinning the ecological factors, the ready avail- or cattail. Thus, during times of rainfall Djara formed a ability of flint raw material was also important. For the temporary ‘refuge’ in the midst of unpredictable desert prehistoric people, the surrounding depressions were of without water resources. interest due to the availability of additional resources. Although the ecological conditions were better during More vegetation occurred here than on other parts of the the Holocene humid phase than they are today, a sedentary plateau, which were hamada, barren of vegetation, and way of life was improbable. There is no evidence here for hence the depressions probably provided good hunting or an agricultural way of life, which implies settlements, for herding places, as evidenced by the small archaeological the desert dwellers of Djara. Remains of hut or house sites, which were used for brief stays. structures have not been found in this area and domesticated plants have not been identified in the archaeobo- 10. Conclusions tanical material. Moreover, sickle elements, which were normally used for cutting the cultivated plants as, for Considering all results of our interdisciplinary approach example, emmer and wheat in the Fayum A culture (c.f. we are able to reconstruct the Holocene palaeoenvironment Caton-Thompson and Gardner, 1934), were not present at and the land use of Djara on the Egyptian Limestone Djara. Fish hooks and harpoon points, which can be seen Plateau within the Eastern Sahara. as an indicator of exploitation of fish resources from According to the evidence of playa sediments and the permanent or seasonal water bodies, as they are known recorded botanical and zoological remains the climate was from the Fayum (c.f. Caton-Thompson and Gardner, more humid during the early and mid-Holocene. The playa 1934), were likewise absent here. sediments show different layers of sandy or loamy-clayey The hydrological constraints require highly mobile material, which indicate alternations from more humid to subsistence strategies because the oases and the Nile Valley drier conditions during a semi-arid climate regime. The were the retreat areas where water was perennially floral inventories of the macro remains support this available. Some support for episodic movements of groups assumption as the recorded taxa belong to plant commu- through the inhospitable desert were found in the archae- nities found in semi-arid deserts. A diffuse dry shrubland, ological record. The shells of the Nile bivalve Aspatharia with a dominating layer of chamaephytes such as the sp. (Spathopsis sp.), found on different sites in the region of recorded taxa of the family Chenopodiaceae and Anastatica Djara, give evidence for direct contacts between Djara and hierochuntica could have developed on the plateau surface. the Nile Valley (Fig. 13), as Aspatharia can only live in Whereas an azonal dry scrub savanna type with trees such regularly swamped areas. The shells found in Djara often as the recorded taxa of the family Capparaceae and grasses show use traces along their edges, as well as remains of could be suggested along the channels and in the pools of charcoal on their inner surfaces. the depression, where the temperature reached higher than Regular contacts between Djara and the surrounding on the plateau and which received additional water from oases are indicated by the very similar lithic tool kits used the plateau surface. The latter is also shown in the all around the Egyptian Limestone Plateau (Kindermann, geomorphic mapping and modeling, and in the different 2004). Another similarity between Djara and the Dakhla salt contents of the soils. oasis is the presence of a type of thin-walled, fine-grained Much of the palaeoclimatic research published to date pottery (c.f. Riemer, 2003). has predominantly inferred that the Holocene humid phase ARTICLE IN PRESS K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637 1635 was a consequence of the northward shifting of the and H. Besler, as well as all those who participated in the monsoonal summer rain. Within the framework of our fieldwork. results we suggest an interfingering of two climatic regimes, The archaeozoological material was identified in co- the winter rains from the north and west and the summer operation with H. Berke (Cologne) by comparison with the monsoonal rain from the south. On the one hand, the plant reference collection of the Institut fu¨r Palaöanatomie und species Anastatica hierochuntica and the radius bone Geschichte der Tiermedizin (Ludwig-Maximilians Univer- fragment of a domesticated sheep support the argument sity, Munich). The charred botanical macro-remains were that the west wind circulation with dominating winter rain identified using the reference collection of the Heinrich- reached further south on the Limestone Plateau than Barth-Institut (Cologne) and by comparison with the today. On the other hand, a northward shifting of the herbarium specimens of the Herbarium Berlin-Dahlem. summer rain regime is indicated by the appearance of the We thank H. Scholz (Berlin) for determining the grasses taxa Capparis/Maerua. and A. Hilgers (Department of Geography, University of This environmental scenario described above can be Cologne) for the luminescence dating. The radionuclide confirmed by the archaeological results. The majority of content was determined by neutron activation analysis the archaeological sites concentrate in the depression along (NAA, Becquerel Laboratories, Sydney/Australia). Thanks the drainage lines and on the playa deposits. In contrast, are due to R. Lyons (Wanaka, New Zealand) and K. Heller the plateau yielded the smallest sites combined together (Cologne) for discussion and correcting the English as well with a low-density of artefacts. A major reason for this as to the reviewers K. Nicoll and J. Woodward for the settlement pattern was certainly the availability of fresh valuable advice and the useful comments on the manu- water over a period of time because Djara is one of the script. largest and deepest depressions on the whole plateau, located at the mouth of a distinct palaeodrainage system. Thus, during times of rainfall it formed a temporary References ‘refuge’ in the midst of unpredictable desert without major Abd el-Ghani, M.M., 2000. Floristics and environmental relations in two water resources. Although the ecological conditions were extreme desert zones of western Egypt. Global Ecology and better during the Holocene humid phase than they are Biogeography 9, 499–516. today, a sedentary way of life was improbable. 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Journal of Arid Environments 17, 271–277. associates of the Egyptian Supreme Council of Antiquities Bornkamm, R., Kehl, H., 1990. The plant communities of the Western (SCA), especially to S. Yamany (Dakhla Inspectorate) for Desert of Egypt. Phytocoenologia 19 (2), 149–231. his support. The fieldwork was performed by the ACA- Boulos, L., 1995. Flora of Egypt, Checklist. Cairo. Boulos, L., 1999. Flora of Egypt, vol. 1. Cairo. CIA-subproject A1 ‘‘Climatic Change and Human Settle- Boulos, L., 2000. Flora of Egypt, vol. 2. Cairo. ment between the Nile Valley and the Central Sahara’’. Brookes, I.A., 2001. Aeolian erosional lineations in the Libyen Desert, We would like to thank both project directors R. Kuper Dakhla Region, Egypt. Geomorphology 39, 189–209. ARTICLE IN PRESS 1636 K. Kindermann et al. / Quaternary Science Reviews 25 (2006) 1619–1637

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