Journal of Human Evolution 52 (2007) 690e701

New age constraints on the Middle Stone Age occupationsof Kharga Oasis, Western Desert, Egypt

Jennifer R. Smith a,*, Alicia L. Hawkins b, Yemane Asmerom c, Victor Polyak c,Robert Giegengack d

a Department of Earth and Planetary Sciences, Washington University, Campus Box 1169, 1 Brookings Dr., St. Louis, MO 63130, USAb Anthropology Department, Laurentian University, Sudbury, ON P3E 2C6, Canada

c Department of Earth and Planetary Sciences, University of New Mexico, 200 Yale Blvd., NE, Albuquerque, NM 87131, USAd Department of Earth and Environmental Science, University of Pennsylvania, 240 S. 33rd St., Philadelphia, PA 19104, USA

Received 31 May 2006; accepted 17 January 2007

Abstract

Spring-deposited carbonate rocks, or tufas, exposed along the flanks of the Libyan Plateau near Kharga Oasis, Western Desert, Egypt, canprovide a directly datable stratigraphic context for Middle Stone Age/Middle Paleolithic (MSA/MP) archaeological material, if such material canbe found in situ within tufa strata. Two such localities (Mata’na Site G and Bulaq Wadi 3 Locus 1) described by Caton-Thompson were revisitedand sampled for uranium-series analysis. At Mata’na Site G (KH/MT-02), Middle Stone Age (‘‘Upper Levalloisian’’) material is underlain bytufa with a uranium-series age of 127.9� 1.3 ka, and overlain by tufa with an age of 103� 14 ka. At Bulaq Wadi 3 Locus 1, a uranium-seriesage of 114.4� 4.2 ka on tufa capping a small collection of Middle Stone Age artifacts also provides a minimum age constraint on that material.Tufa underlying an MSA workshop (KH/MD-10) indicates that this assemblage, characterized by use of several Levallois reduction methods,was deposited after w124 ka. Furthermore, uranium-series ages averaging w133 ka on a Wadi Midauwara tufa (WME-10) without associatedarchaeological material suggest that one period of spring flow in the region began during the Marine Isotope Stage 6/5e transition, prior tothe warmest portion of the last interglacial period. The dated archaeological material suggests that the distinction that has been identifiedbetween Nubian and non-Nubian complexes in the Nile Valley may hold for the Western Desert, although local complexity has yet to be fullydescribed.� 2007 Elsevier Ltd. All rights reserved.

Keywords: Uranium-series geochronology; North Africa; Climate change; Marine Isotope Stage 5e; Middle Stone Age

Introduction

Cultural variability and change in the North African MiddleStone Age/Middle Paleolithic (MSA/MP) have the potential toenhance our understanding of the Pleistocene human dispersalout of Africa and the nature of the emergence of modernhuman behavior (McBrearty and Brooks, 2000). While the

* Corresponding author. Tel.: þ1 314 935 9451; fax: þ1 314 935 7361.

E-mail addresses: jensmith@wustl.edu (J.R. Smith), ahawkins@

laurentian.ca (A.L. Hawkins), asmerom@unm.edu (Y. Asmerom), polyak@

unm.edu (V. Polyak), gieg@sas.upenn.edu (R. Giegengack).

0047-2484/$ - see front matter � 2007 Elsevier Ltd. All rights reserved.

doi:10.1016/j.jhevol.2007.01.004

occupation of arid northern Africa during the MSA/MP haslong been known (e.g., Clark, 1967), a lack of chronometricdeterminations associated with archaeological materials, com-bined with application of different analytical systems, has hin-dered comparison between localities and regions. Van Peerand Vermeersch (1990; Van Peer 1998) present one of theonly general frameworks for classification of the MSA/MParchaeological complexes of the Nile Valley, Eastern Desert,and Eastern Sahara:

In general terms . a distinction can be made between as-semblages with bifaces, bifacial foliates, thick ‘‘Nubian’’scrapers, and the special Levallois point production

691J.R. Smith et al. / Journal of Human Evolution 52 (2007) 690e701

methods labeled Nubian 1 and Nubian 2 (Guichard andGuichard 1965, 1968), and assemblages that lack any ofthese types. The former have been grouped as Nubian Mid-dle Palaeolithic or Nubian Stone Age and the latter as non-Nubian Middle Palaeolithic (Van Peer, 1998: S118).

The first assemblage is also referred to as the ‘‘Nubian Com-plex’’ (Van Peer, 1998: S120), and the second as the ‘‘LowerNile Valley Complex.’’ Technologically, the latter group ismarked by use of ‘‘classical’’ Levallois reduction and a lackof production of points by any method (Van Peer, 1998).Van Peer (1998) argued that the Nubian complexes may repre-sent a group of migrant populations from the south, whose ad-aptation included hunting.

This framework, although it greatly simplifies the complexMSA/MP record of northeastern Africa, also provides a start-ing point for consideration of new dates for archaeological as-semblages from the eastern Sahara. Van Peer (1998) argued,based on evidence from Bir Sahara and Bir Tarfawi, thatboth complexes are present in the Western Desert. Both theAterian, which dates to ca. 60 ka and later (Cremaschi et al.,1998), and the earlier MSA with foliates may be consideredpart of the Nubian Complex (Van Peer, 1998: S118; Wendorfet al., 1993a). Non-Nubian sites include those that apparentlylack evidence of Nubian cores, foliates, or other markers of theNubian Complex [Van Peer, 1998; but a small number ofLevallois points are reported for several of these sites(Wendorf et al., 1993a)]. At Bir Sahara and Bir Tarfawi, theNubian Complex possibly replaced the Nile Valley Complexafter a hyperarid period between approximately 155 ka and135 ka (Van Peer, 1998; for other views of the NubianComplex, see Garcea, 1998; Schild, 1998; Kleindienst, 2003,2005).

These assertions by Van Peer lead to several questions.First, does this broad classification of the MSA apply else-where in the Western Desert? If so, do the ages of sites con-taining Nubian and non-Nubian complex artifacts correlatewith those from Bir Sahara and Bir Tarfawi? Kleindienst(1999: 104) stated that her ‘‘null hypothesis’’ was that Dakh-leh Oasis was habitable for at least the last 300,000 years, andpossibly longer. If oases such as Dakhleh and Kharga providedstable sources of water from artesian springs, we might expectthat the apparent replacement of one complex by another seenat Bir Tarfawi and Bir Sahara East would not be evident inthese locations. Instead, one might hypothesize either a gradualchange in the cultural material produced by more stable pop-ulations, and/or cultural complexity related to interactions be-tween a migrant group or groups and resident groups.

Background

We present here new uranium-series ages, environmentaldata, and technological descriptions of lithic assemblages froma series of localities on the Kharga Escarpment in the WesternDesert. The locations under discussion were investigated in2001 as part of an ongoing larger investigation by the KhargaOasis Prehistory Project (Hawkins et al., 2001; Kleindienst

et al., in press). Caton-Thompson and Gardner (1932; Gardner,1932, 1935; Gardner and Caton-Thompson, 1933; Caton-Thompson, 1935, 1952) originally discovered several of theselocalities in the course of their work in Kharga Oasis in the1930s. The framework of Stone Age development for KhargaOasis that Caton-Thompson and Gardner presented is based inlarge part on the numerous escarpment localities they discov-ered. We are now able to place some age constraints on the ar-chaeological materials from several of these localities and tooffer technological descriptions of material for comparisonwith archaeological material from the Nile Valley. Furthermore,we present a different view of the depositional events that led tothe formation of several of these localities, one that calls intoquestion some, but certainly not all, of the archaeological unitsproposed by Caton-Thompson.

The habitability of North Africa has varied substantiallyduring the Quaternary as regional climate oscillated betweenthe arid regime that is characteristic of the present and sub-stantially wetter conditions (e.g., Caton-Thompson, 1952;Wendorf and Schild, 1980; Churcher and Mills, 1999). Theseclimatic fluctuations are recorded outside northern Africa byvariations in the influxes of terrestrial dust to marine basins(e.g., Moreno et al., 2001; Abrantes, 2003) and freshwater tothe Mediterranean Basin (e.g., Rossignol-Strick, 1983; Calvertand Fontugne, 2001), among other paleoclimatic archives.Within the Sahara, lacustrine, paludal, fluvial, and spring-deposited sediments are the primary indicators of increasedamounts of surface water relative to the present (e.g., McCauleyet al., 1982; Churcher et al., 1999; Hoelzmann et al., 2000;Smith et al., 2004a; Kleindienst et al., 2004; Churcher andKleindienst, in press). The principal mechanism for the‘‘greening’’ of the southern Sahara is generally thought to bean insolation-driven, northward movement of the African (At-lantic) monsoon, based on global-circulation models (GCMs),direct dates on sediments indicative of humid climates, and theisotopic composition of Saharan groundwaters (e.g., Sonntaget al., 1979; Claussen and Gayler, 1997; Kropelin and Petit-Maire, 2000; Larrasoa~na et al., 2003; Sturchio et al., 2004).Climate proxies internal and external to the Sahara andGCMs indicate that Marine Isotope Stage (MIS) 5e was a par-ticularly humid time for the region (e.g., Prell and Kutzbach,1987; Kallel et al., 2000; Mandel and Simmons, 2001), thoughdirect dates on spring and lacustrine sediments (e.g., Szaboet al., 1989; Causse et al., 1989; Schwarcz and Morawska,1993; Szabo et al., 1995; Zouari et al., 1998) suggest thatgroundwater discharge may have increased in northern Africaprior to the peak of the last interglacial period due to rechargealong the southern margin of the Sahara during early phases ofmonsoon intensification (Petit-Maire et al., 1991).

In central Egypt, springs along the edge of the Libyan Pla-teau became active during MIS 6 and 5e, resulting in the de-position of spring carbonate rocks (tufas) at many locationsalong the escarpment itself, as well as in the adjacent lowlands(Fig. 1; Crombie et al., 1997; Sultan et al., 1997; Hamdan,2000; Smith et al., 2004a; Kleindienst et al., in press). Thesedimentology of the tufas indicates that, during humidphases, waterfalls, marshes, small ponds, and streams were

692 J.R. Smith et al. / Journal of Human Evolution 52 (2007) 690e701

Fig. 1. (A) MODIS image of Egypt, courtesy of NASA Visible Earth, Jacques Descloitres, MODIS Land Science Team. (B) Hillshade map of Kharga Oasis es-

carpment region, with tufa deposits indicated (from Caton-Thompson, 1952); Hillshade model generated from SRTM DEM, 3-arc second, courtesy USGS. ASTER

imagery (courtesy of USGS LP DAAC) of (C) Bulaq, (D) Mata’na, and (E) Wadi Midauwara with localities mentioned in text.

common elements in the landscapes surrounding activesprings (Crombie et al., 1997; Nicoll et al., 1999; Smithet al., 2004a), though the tufa stable-isotope geochemistry sug-gests that regional soils were neither particularly thick nor bi-ologically productive (Smith et al., 2004b). Plant casts in tufasfrom Kharga record the presence of fig trees (Ficus ingens, Fi-cus salicifolia, and Ficus sycomorus), reeds (Arundo sp.), ferns(Pteris vittata), African hackberry (Celtis integrifolia), and anunidentified palm in areas of spring activity (Caton-Thompson,1952). In southern Egypt, lacustrine environments prevailed atBir Tarfawi and Bir Sahara during MIS 5 (Wendorf et al.,1993a). Sedimentological, geochemical, and faunal evidence

from these lacustrine deposits suggest rainfall of at least500 mm/yr and the presence of wooded savanna and lakesthat remained fresh for extended periods of time, though evap-orative episodes indicative of drier climates did occur duringthe lifetime of the lakes (Wendorf et al., 1993a).

Methods

Archaeological localities described by Caton-Thompson werereached by interpolating coordinates from her maps (Caton-Thompson, 1952) and navigating to these locations using

693J.R. Smith et al. / Journal of Human Evolution 52 (2007) 690e701

a Global Positioning System (GPS). While Caton-Thompson’s(1952) map of Bulaq contained a coordinate grid, her sketchedmap of the Mata’na tufa deposits and archaeological localitiesdid not. Caton-Thompson’s map was therefore overlain onaerial photographs of the region, and geologic units on hermap matched to outcrops visible on the aerial photographs.These photographs were themselves registered to a geographiccoordinate system using GPS ground control points. At bothNaqb Bulaq and Naqb Mata’na, Caton-Thompson’s orGardner’s w70-year-old excavation trenches were visible,thus confirming that we had identified the locations she de-scribed. Tufa samples were collected from Wadi Midauwaraas part of an ongoing geologic and archaeological survey(Hawkins et al., 2001; Smith et al., 2004a).

Where archaeological material was stratigraphically associ-ated with tufas, we obtained tufa samples from contexts asclose to artifactual material as possible. At both of Caton-Thompson’s localities discussed here, however, the artifact-bearing stratigraphic unit was a marl (calcium carbonatesilt). As these fine, often unconsolidated silts are particularlysusceptible to diagenetic alteration or detrital contaminationthat may complicate uranium-series dating (e.g., Wendorfet al., 1993b; Szabo et al., 1995), sampling in these locationswas confined to the stratigraphically closest framestone orboundstone tufas (nomenclature following Pedley, 1990; ap-proximately equivalent to Caton-Thompson’s ‘‘cellular’’ tufas;Caton-Thompson, 1952). Because we were largely restrictedto sampling deposits in stratigraphic proximity to artifactualmaterial, we were unable to choose only the ideal tufa facies(those deposited with a low primary porosity, e.g., laminatedtufas) for dating.

Therefore, all samples underwent petrographic analysisprior to selection for dating in order to eliminate obviouslyhighly altered samples from consideration. Unequivocal deter-mination that a particular sample consists of unaltered calciteis difficult, if not impossible. Thus, we sought rather to iden-tify and disqualify from further analyses samples that ex-hibited significant postdepositional alteration. Kharga tufashave been shown to preserve primary fabrics (e.g., organo-sedimentary lamination, clotted/peloidal textures), as well assecondary features (pore-filling cements, aggrading neomor-phism) indicating diagenesis under a variety of conditions(Crombie et al., 1997; Nicoll et al., 1999). Although therehas been some suggestion that diagenetic alteration of tufascan be recognized isotopically (e.g., Janssen et al., 1999), dis-tinct populations of ‘‘altered’’ and ‘‘unaltered’’ samples cannotbe identified in the Kharga tufas by this method (Smith et al.,2004b). In addition to qualitative identification of tufa fabric,point counts (500 points per sample) were performed in orderto estimate porosity and relative proportions of micrite (gener-ally, though not exclusively, primary) and sparite (usually sec-ondary) in each sample (following Crombie et al., 1997).Detrital material within the tufa (predominantly quartz andiron oxides) was noted where observed. Because the petro-graphic analysis did not guarantee selection of unaltered sam-ples, additional precautions were taken during uranium-seriesanalysis (see below).

Uranium-series chronology

We drilled between 140 and 261 mg of powder from visu-ally clean, nonporous carbonate for 234U-230Th dating (230Thages) at the Radiogenic Isotope Laboratory, University ofNew Mexico. The samples were dissolved in 15N HNO3,and a 233U-236U-229Th-mixed spike was added, and U andTh were separated using our standard column chemistry tech-nique, described in Polyak and Asmerom (2001). Our labora-tory U and Th procedural blanks range from 10 to 40 pg and 5to 20 pg, respectively, and although corrected for, these haveno significant influence on the ages. The Th and U isotopeswere measured on a Micromass Sector 54 thermal-ionizationmass spectrometer with an ion-counting Daly. Our d234U value(the & variation in the 234U/238U ratio of a sample from thesecular equilibrium value, which is equal to the ratio of thehalf-lives of 234U and 238U) for NBL-112A is �37.4� 0.5 &

(n¼ 82). The reported uncertainties (Table 1) in the ratiosare 2s of the mean; 230Th-age uncertainties include uncer-tainties related to the initial 230Th/232Th correction. Althoughthe samples contain variable amounts of detrital Th, the initial230Th/232Th (atomic ratio) correction chosen conservatively as8.8 ppm is not large relative to the measured 230Th/232Thratios used to correct the 230Th ages of these samples. Withincreasing age, the fraction of 230Th that is unsupported(detrital) diminishes with increasing radiogenic 230Th, makingthe 230Th dating of tufas very robust.

Results

Tufa petrography

The four samples dated here, though highly porous (28e40% pore space based on point counts), exhibit relatively littletextural evidence of secondary cementation or recrystalliza-tion. Sparite was only detected in point counts in sampleWME10, where it constituted 2% of the sample, though mi-crospar was observed during nonsystematic examination ofseveral samples. The most common texture observed in thesesamples was the clotted, peloidal, micritic texture that is verycommon in Kharga tufas, and tufas in general (Pedley, 1990;Nicoll et al., 1999; Smith et al., 2004a). Detrital quartz wasa minor component of the Bulaq Wadi 3 sample (small silt-sized grains occurred infrequently), and all but the Mata’nasample contained iron-oxide coatings on the margins of porespaces. Iron minerals in the tufas may either be authigenicor detrital (Nicoll, 1996; Nicoll et al., 1999). Nothing wasobserved in these samples that would make them particularlyunsuitable for dating.

Uranium-series geochronology

Results of uranium-series dating are presented in Table 1.For three of the four samples (01-MT-001-G, WM-037B,and WM-E10), we split processed subsamples and analyzedthe individual halves separately, with results reported asa weighted average for the sample. In addition, for the Wadi

694 J.R. Smith et al. / Journal of Human Evolution 52 (2007) 690e701

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Midauwara samples (WM-037B and WM-E10), an additionalsubsample was processed and analyzed to evaluate further theerror that diagenetic alteration may have introduced into sam-ple ages. If secondary material were present in significantquantities within the samples, it would be unlikely to be dis-tributed homogeneously throughout the sample. Thus, if a sam-ple had been heavily altered, then drilled subsamples wouldnot contain equivalent fractions of (older) primary materialand (younger) secondary material, and therefore they wouldreturn significantly different ages. Since subsamples WM-037B and WM-037Ba are within analytical error of each other,the ‘‘age’’ of WM-037B will be presented as the average of thetwo subsample ages, 124.8� 4.0 ka. Subsamples WM-E10and WM-E10a, however, yielded slightly different ages at2s (136.0� 2.2 ka and 130.5� 2.8 ka). This result suggeststhat the relatively minor amount of secondary material ob-served in the point counts of WM-E10 was enough to affectthe determined age; as such, the averaged WM-E10 ura-nium-series age of 133.3� 5.3 should be taken as a minimumconstraint on the time of tufa deposition.

Mata’na Site G (KH/MT-02)

Site G at Mata’na (Gardner, 1935) is located just below theedge of the Libyan Plateau, in a small section of tufa incisedinto older, higher tufa sheets draped down the escarpmentflanks (Fig. 1). Caton-Thompson (1952: 41) describeda ‘‘crumbly and silty’’ upper tufa, overlying a 10e50-cm-thicksilt ‘‘containing a Palaeolithic floor,’’ above w5 m of a ‘‘harderand cleaner’’ leaf-bearing tufa (Fig. 2). These deposits repre-sent a typical stratigraphic succession for ‘‘perched spring-line,’’ or ‘‘fluviatile barrage’’ tufas (following Pedley, 1990),in which phytoherm or phytoclast tufas (deposited in flowingwater) interfinger with intraclast and micritic silts and siltytufas (deposited in small ponds). The artifact-bearing silt layerwas deposited in a shallow pond, probably w100 m2 in area(based on outcrop extent and valley width), with occasionalpatches of aquatic vegetation. The artifacts excavated byGardner may have been deposited in situ when the pondpartially or completely dried out, as Caton-Thompson (1952)suggested based on the volume of material she recovered.However, granule-sized edgewise clasts of the local Tertiarybedrock (a white shale) in a matrix-supported w8-cm-thicklayer towards the base of the silt suggest that some of thematerial deposited in this pond was washed in during rela-tively high-energy events, though no clasts, shale or otherwise,hydraulically equivalent to the excavated artifacts were ob-served within the section. Although we cannot rule out fluvialtransport of the artifactual material, the location of the pondnear the top of the Libyan Plateau escarpment means that thereis very little area upslope of the pond from which artifacts mayhave been washed in. Thus, if the material were moved, it waslikely not moved very far. This is supported by the very freshcondition of the material; however, Caton-Thompson’sdescription of the site as a ‘‘Palaeolithic floor’’ does notseem to be supported, given that artifacts were distributed ver-tically throughout the exposed section.

695J.R. Smith et al. / Journal of Human Evolution 52 (2007) 690e701

Fig. 2. (A) Photograph of Mata’na Site G by ALH, 1/2006. (B) Stratigraphy of Mata’na Site G, revised after Caton-Thompson, 1952.

We conducted archaeological fieldwork at Mata’na G thatincluded collection of artifacts exposed on the eroding faceof the section and from the unconsolidated sediment below,as well as from two discard piles located at either end of theexcavated section. Objects collected from the discard pileshad tufa adhering to them, and, with the exception of one‘‘side-blow flake’’ with an orange desert varnish, they werein the same condition as the material collected from the exca-vation face. In the limited time available for fieldwork, it wasnot possible to excavate further the face of the section; there-fore, our assessment is based on Caton-Thompson’s publisheddescriptions and the material we collected.

Caton-Thompson (1952: 142) described this location asa flaking station and encampment. Her first assessment wasbased on the high proportion of flakes and cores and the lownumbers of tools. She arrived at the second conclusionbased on the presence of a ‘‘pot boiler’’ and burnt flakes(Caton-Thompson 1952: 142). We also discovered discoloredflakes with potlidding in the section face, lending support toCaton-Thompson’s assertion that some of the material hasbeen altered by fire. However, it is probable, as discussedabove, that the artifacts have been redeposited. They are infresh condition and bear no evidence of desert varnish, suggest-ing that they did not lie on the surface for a long period and thatthey were not transported a long distance. However, at thistime, we must treat the age determination on the associatedtufa as limiting the minimum age of the material.

Caton-Thompson (1952: 27e28, 142e143) assigned thematerial from Mata’na G to a unit she termed ‘‘Upper Leval-loisian.’’ The hallmarks of this unit are cores that are primarilyoval and discoidaldthose that would be described as ‘‘classi-cal’’ Levallois in Van Peer’s (1998) framework. We recoveredfive cores, one of which we collected from the excavation face.Four of these are round or oval and have been prepared by cen-tripetal removals. Two are preparations for a single large flakeremoval, while two bear evidence of repreparation after strik-ing. An opposed-platform blade core collected from one of the

discard piles is of the same condition as the other material butis not described by Caton-Thompson. It may have been col-lected at another location, or Caton-Thompson may havebased her published description only on material that wasphysically removed from the site. She did note the presenceof flake blades. In either case, production of blades elsewherein Africa and the Levant is well documented at this time (e.g.,McBrearty et al., 1996). Caton-Thompson discovered two tri-angular Levallois cores (for production of pointed flakes usingthe Nubian II method) and three triangular Levallois flakes.These constitute only a small proportion of the reported coresand flakes (5% and 9%, respectively). In terms of tool types,Caton-Thompson described and illustrated two tools that shedescribed as Tabalbalat points. These tools have been basallythinned on the ventral and probably dorsal face in order to aidin hafting. Although this could be construed as evidence ofuse of points in hunting, at least one of these objects ismore likely to be a scraper than a point (Caton-Thompson1952: Plate 72).

An age of 127.9� 1.3 ka for the lower, leaf-bearing tufa isconsistent with the date of 103� 14 ka obtained previously onthe capping tufa (Smith et al., 2004a), though the differencebetween the mean ages (w24 kyr) is greater than would be ex-pected given the w75-cm stratigraphic separation between thetwo samples and the sedimentation rates common in tufa-depositing environments. Even using relatively low observedvalues for tufa and calcite-silt accumulation rates [1.5 mm/yrfor tufa (Kano et al., 2003) and 0.1 mm/yr for authigenic silts(i.e., minimum average values for carbonate portions of annualvarves; Lotter et al., 1997)], the sediments preserved betweenthe two dated tufa samples should represent only w5.2 kyr.This indicates either that substantial periods of nondepositionoccurred, or that a significant portion of this stratigraphicsection has been lost. The irregular contact between the arti-fact-bearing silt and the underlying tufa suggests that somethickness of sediment was lost prior to the establishment ofthe pond. Thus, the age of the upper tufa stratum may be

696 J.R. Smith et al. / Journal of Human Evolution 52 (2007) 690e701

more representative of the depositional age of the artifactualmaterial than that of the lower tufa, as there is no obvious un-conformity between the two.

In sum, our assessment of the material at Mata’na G sug-gests redeposition of artifacts that were produced sometimebefore 103� 14 ka. There are traces of the material indicativeof the Nubian Complex, but we cannot exclude the possibilityof mixing of materials of different ages; the dating allows fora time span of many millennia to be represented.

Bulaq, Wadi 3 Locus 1 (KH/BQ-04)

Wadi 3 Locus 1 (defined by Caton-Thompson, 1952) (KH/BQ-04) is very similar to Mata’na G in its geomorphic andstratigraphic setting, with artifact-bearing strata occupying alow terrace incised into older deposits close to the edge ofthe Libyan Plateau (Caton-Thompson, 1952; Fig. 1). The gen-eral stratigraphic sequence for the terrace consists of gravels(minimum thickness w1.5 m), overlain by silts with tufalenses (approximately 1 m thick), capped by 2.5 to 3 m of tufa,with artifacts present in all three strata (Caton-Thompson,1952). Tufa overlying the obvious excavations along Wadi 3(Fig. 3) was not sampled, in part because of difficulty ofaccess, and also because the tufa immediately above theexcavated region appeared particularly porous, friable, andcoarsely crystalline, and thus unsuitable for dating. The datedsample was taken w30 m north of Caton-Thompson’s

excavations at Locus 1, approximately 50 cm above the con-tact between the tufa and the silts. Although the tufa terraceis itself somewhat dissected, making it impossible to directlyrelate all three of Caton-Thompson’s described loci (Fig. 1)to the dated sample, the proximity of the three loci to eachother, the relatively consistent slope of the terrace remnant sur-face, and the similarity in stratigraphic sequence along thelength of the terrace support Caton-Thompson’s (1952) asser-tion that the materials at all three loci may be considered asbeing deposited at approximately the same time.

We examined the exposed section at Bulaq Wadi 3 Locus1 and were unable to locate artifacts near the section or in theexposed profile. Caton-Thompson (1952: 127) classified thismaterial as ‘‘Levalloiso-Khargan.’’ She defined this unit asintermediate between the Levalloisian and the Khargan; thelatter unit is now thought to postdate the Aterian (Wiseman,1999). The defining characteristics of the Levalloiso-Khargan, in Caton-Thompson’s view, are the presence ofLevallois cores and flakes in two size categories: large corescomparable to those of the Levalloisan, and smaller ones.Flakes are modified by basal truncation and steep marginaltrimming.

Caton-Thompson’s collection of material from Bulaq Wadi 3Locus 1 was very smalldshe described twelve objects and illus-trated six. It is not possible to determine, based on her 1952publication, which of the artifacts derive from Wadi 3 Locus1 and which derive from Wadi 3 Loci 2 and 3. Although

Fig. 3. (A) Photograph of Wadi 3 Locus 1 by ALH, 3/2001. (B) Plate 3 (3) from Caton-Thompson (1952), illustrating Wadi 3 Locus 1.

697J.R. Smith et al. / Journal of Human Evolution 52 (2007) 690e701

Caton-Thompson described the material from Bulaq Wadi 3 asbeing not ‘‘much rolled or battered,’’ we again must assume thatat least some of these materials have been transported, particu-larly those that were recovered from gravels, and that the age ob-tained on the tufa represents a minimum age for the artifactassemblage. Furthermore, if, as Caton-Thompson (1952: 125)asserted, ‘‘the beds are so clearly homogeneous that it is safeto consider collectively the implements from the three findspots,’’ then the production of points using Nubian II technologywould be placed earlier than 114.4� 4.2 ka. However, we urgecaution with respect to interpretation of the assemblage beyondthis: the steep retouch described by Caton-Thompson may havebeen produced through battering during redeposition or possiblytrampling before redeposition (McBrearty et al., 1998). Further-more, our examination of the excavations at Bulaq A suggestthat the archaeological material at this location is also redepos-ited, suggesting that the ‘‘Levalloiso-Khargan’’ is not knownfrom any in situ locality and the term is best avoided.

Comparable to the 103� 14 ka age on the tufa overlyingMata’na Site G, the 114.4� 4.2 ka date for the tufa thatcaps artifact-bearing silts at Bulaq is among the youngestages for tufa strata in Kharga Oasis (Sultan et al., 1997; Smithet al., 2004a; Kleindienst et al., in press), although tufa forma-tion is documented at a comparable time in Kurkur Oasis(w100e120 ka; Crombie et al., 1997). Although it would beexpected that a southward migration of the Atlantic monsoonduring the cooler substages of MIS 5 would result in drier con-ditions in the eastern Sahara, and thus dates on lacustrine andspring sediments would cluster during substages 5e, 5c, and 5a(e.g., Szabo et al., 1995), the data set on timing of pluvial con-ditions is not yet sufficiently extensive or precise to allow foridentification of any such trends.

Wadi Midauwara, KH/MD-10

Although the majority of the tufa deposits at Wadi Midau-wara occupy the gently sloping floor of the fault-controlled

embayment in the Libyan Plateau (Smith et al., 2004a), por-tions of the escarpment slopes are covered with several gener-ations of tufa deposited in environments similar to thosediscussed above at Bulaq and Mata’na. The archaeological lo-cality MD-10 (see below) occurs on the discontinuous upperreaches of a tufa sheet sloping down to the west (Figs. 1 and4), and the tufa sample (WM-037B) was taken from the sur-face of a w0.5-m-thick outcrop directly beneath one of the ar-chaeological collection locations. It is difficult to determinethe precise environments represented by these tufas, as thereis so little outcrop; however, a larger tufa sheet, w400 m northof MD-10, and somewhat older (150� 13 ka; Smith et al.,2004a), contains several well-developed barrage dams, whichrecord the presence of small (w1e3 m) waterfalls along thisportion of the escarpment. These barrage tufas also contain ev-idence of local vegetation besides the reed casts that are nearlyubiquitous in Kharga tufas (Smith et al., 2004a): tree-trunkcasts (10e20 cm in diameter) and several leaf casts, probablyFicus.

Much of the archaeological record in the eastern Sahara lieson the desert surface; such was the case at MD-10. Gray-brown chert crops out locally, and chert nodules are also pres-ent in the colluvium. We collected all archaeological materialon the surface of nine 5� 5 m squares (Fig. 4). The density ofmaterial varied considerably, and it appears to increase as oneprogresses downslope. However, it does not appear that ob-jects have been transported: refits from within the same unitwere noted, and the material is in fresh condition. Evidenceof post-MSA use comes in the form of one side-blow flakecore and one small pressure-flaked foliate. However, every-thing else we recovered fits easily within what is expectedfor the MSA: of 46 analyzed cores, 44 are Levallois and twoare discoidal. Although it is not possible to determine site-for-mation processes, we suggest that this workshop and otherMSA workshops in the Western Desert were formed by re-peated use of the same location for production of blanks andpossibly cores for transport. Therefore, the material collected

Fig. 4. Location of collection squares and tufa outcrops at MD10. Map generated using Trimble Pathfinder ProXR DGPS, accuracy w10 cm horizontal, w20 cm

vertical.

698 J.R. Smith et al. / Journal of Human Evolution 52 (2007) 690e701

probably represents use over a significant period of time, mostlikely thousands of years. The locality would have been attrac-tive, given the abundant raw material and the splendid viewinto the oasis lowland.

A number of modes of Levallois reduction are representedin this assemblage: centripetal preparation for the removal ofone flake (preferential), and centripetal preparation for the re-moval of multiple flakes (recurrent) account for 20% and 13%of the collected cores, respectively. The proportions of coresfor point production are interesting in consideration of VanPeer’s hypothesis regarding the production of points. Severalmethods of point production are represented in this assem-blage. Two of the methods appear to correspond with the Nu-bian I and II methods described by Guichard and Guichard(1965, 1968), and in addition, some triangular cores show ev-idence of preparation without formation of a steep distal keel.Altogether, cores on which pointed flakes were produced makeup 24% (�6%) of the assemblage. The age of 124.8� 4.0 karepresents a maximum age for this assemblage.

Wadi Midauwara, WM-E10

Sample WM-E10 was taken from a low tufa terrace slopingto the south along the northern margin of the Wadi Midauwaraembayment (Fig. 1). This particular terrace was selected forsampling because it was the topographically lowest of a seriesof tufas along the escarpment flanks north of Midauwara, oc-cupying a surface only w3 m above the floor of the moderngully incised into the tufas. This terrace thus could be ex-pected to record the latest spring activity along this local por-tion of the Wadi Midauwara escarpment flank, where, basedon the preservation state of macroscopic depositional features(following Smith et al., 2004a), tufa terraces are most likelyyounger at lower elevations. The average age of two subsam-ples of this tufa, 133.3� 5.3 ka, is the same (within 2s error)as the w124.8� 4.0 ka age for tufa at MD-10 and the agespreviously obtained on the youngest tufas within the embay-ment itself (136� 3 ka and 126� 4 ka; Smith et al., 2004a).These ages suggest that the final phase of tufa deposition inthe Midauwara region may have ended earlier at Midauwarathan at Bulaq or Mata’na, though additional dates are requiredto test this hypothesis.

We found no archaeological artifacts in association withthis tufa deposit.

Discussion

Caton-Thompson (1952) proposed a sequence of Stone Ageunits for Kharga Oasis based on three seasons of fieldwork inboth the escarpment region and the lowland oasis. Kleindienstet al. (in press) subsequently suggested that at least two ofthese units, the ‘‘Levalloiso-Khargan’’ and the ‘‘Acheulio-Levalloisian,’’ require reevaluation and should possibly be dis-carded. Our examination of the Bulaq A and Bulaq Wadi 3material leads us to the conclusion that the artifacts Caton-Thompson used as the basis for definition of the ‘‘Levalloiso-Khargan’’ are redeposited and could represent material from a

number of different depositional episodes. Furthermore, thefact that the artifacts are found in gravels in both cases sug-gests that some of the reported tools may have been modifiedby battering during a high-energy fluvial event.

The ‘‘floor’’ that Caton-Thompson (1952) described atMata’na G was not evident on further examination of the sec-tion she reported; instead, artifacts appear throughout the sec-tion. This pattern may be due to postdepositional verticalmovement of artifacts through saturated plastic sediment oralong shrinkage cracks during desiccation of the water bodiesin which artifact-bearing silts were deposited. Alternatively,bioturbation of sediments caused by animals walking throughthe shallow ponds or other processes may have redistributedthe artifacts. In either of these cases, variable orientation of ar-tifacts in the section would be predicted; this was observed atMata’na. However, distribution of artifacts throughout theclastic sediments in these locations could also indicate thatthe material was washed into the site in a series of depositionalepisodes.

Conclusions

The results of this investigation may be viewed in twoways: how they contribute to our understanding of changingclimate in the Western Desert during the Pleistocene, andhow they contribute to understanding human occupation ofthis region.

The uranium-series dates obtained on four tufas from threeregions of tufa deposition near Kharga Oasis all fall within thelate MIS 6eMIS 5 humid phase recognized across northernAfrica (see above; Fig. 5). A comparison of these new dateswith those on Pleistocene sediments indicating humid condi-tions at Kharga and Dakhleh oases (Sultan et al., 1997; Smithet al., 2004a; Kleindienst et al., in press), at Kurkur Oasis(Crombie et al., 1997), and at several other localities in south-ern Egypt and northern Sudan, including Bir Sahara/Bir Tar-fawi (Szabo et al., 1995), suggests that discrete clusters ofages at certain times are not evident, even within this relativelylimited geographic region. The broad distribution of dates maysimply be a function of the often large (>10 ka) errors associ-ated with many of the published uranium-series ages, in whichcase additional work refining the chronology of known pluvialdeposits in central and southern Egypt may clarify the timingof distinct humid phases. Alternatively, recharge of aquifersduring times of enhanced rainfall may have allowed springflow to continue well after the cessation of local precipitation.In that case, the availability of surface water would have per-sisted after times of maximum rainfall over northern Africa, aspredicted by GCMs and climate records external to this region.Spring flow supported by extraregional recharge could also po-tentially occur prior to these times as a response to much ear-lier rainfall events within the springs’ recharge area. Thus,minor humid phases, in which rainfall never penetrated asfar north as Kharga, may nonetheless have had a delayed ef-fect on spring flow in the region. Marine Isotope Stage 5, how-ever, does seem to have been a particularly humid time in

699J.R. Smith et al. / Journal of Human Evolution 52 (2007) 690e701

Imbrie and Duffy,1990

1 2 3 4 5 6 7 8 9 10

Age (ka)0 50 100 150 200 250 300 350

This study

Smith et al.,2004a

Kleindienst et al.,in press

Crombie et al.,1997

Sultan et al., 1997

Szabo et al., 1995

Fig. 5. Uranium-series dates on sediments indicating humid conditions (relative to the present) in Egypt and northern Sudan. Marine isotope stages (numbers) are

indicated by shading (shaded ¼ glacial, unshaded ¼ interglacial) on the SPECMAP stack (normalized) d18O curve (Imbrie and Duffy, 1990). Stage boundaries are

from Bradley (1999).

Egypt, based on the numbers of dates from different regionsthat reflect spring and lake activity during that time.

We may draw several conclusions about human occupationbased on the archaeology. First, Van Peer’s division of archae-ological complexes into Nubian and non-Nubian appears to bepartially supported. At only one locality (MD-10) did we dis-cover a significant number of Levallois point cores producedusing Nubian methods. The age of this locality may be youn-ger than other localities, but at this time, we can only state thatage determination on MD-10 (124.8� 4.0 ka) representsa maximum age, while the other determinations on Mata’naSite G and Bulaq Wadi 3 (127.9� 1.3 and 114.4� 4.2 ka) rep-resent minimum ages. Van Peer placed the Nubian Complex inthe Western Desert at 135 ka and later; thus, MD-10 fits expec-tations. The co-occurrence of Nubian point production withfoliates, tangs, and/or Nazlet Khater points cannot be evalu-ated at this time because MD-10 represents a former workshopand is essentially devoid of formed tools.

While we note the presence of Nubian materials at WD-10,we must also point out that we find markers of the NubianComplex in small amounts at Bulaq Wadi 3 and Mata’na G.Van Peer’s classification system is based on presence or ab-sence rather than proportions; thus, following his nomencla-ture, these two locations should also be classified as NubianComplex. However, we suggest that the minor proportionsof points and point cores could mark an indigenous innovation,variation arising from differences in site function, or the resultof contact between populations from different cultural tradi-tions. The record from the Nile Valley shows evidence of com-plexity; as more chronometrically dated localities from theWestern Desert are described, it is likely that we will discoversimilar complexity.

We note in closing that the framework for the Stone Age ofKharga Oasis proposed by Caton Thompson and Gardner onthe basis of only three seasons of fieldwork in the 1930s isremarkably robust. On the basis of our 2001 fieldwork, wepropose that the ‘‘Levalloiso-Khargan’’ be discarded, as sug-gested by Kleindienst (1999: 102). However, the placement

of the ‘‘Upper Levalloisian’’ as an MSA unit predating theAterian appears appropriate. Caton-Thompson and Gardner’sexploration and study of the tufa deposits of Kharga Oasishas provided an extremely valuable foundation for further re-search in the region.

Acknowledgments

Fieldwork in 2001 was carried out as part of the KhargaOasis Prehistory Project (KOPP), with the permission of theSupreme Council of Antiquities of Egypt (concession grantedto KOPP Codirector Maxine R. Kleindienst). We thank Pro-fessor Emerita Kleindienst for helpful comments on this man-uscript and for her continued support of and involvement inresearch on the prehistory of Kharga Oasis. For assistancethat was integral to this work, we thank Chief InspectorBahgat Ahmed Ibrahim, New Valley Office of the Departmentof Antiquities; Antiquities Inspector Mohammed Sha’aban;and Mr. Yousry Attia, Cairo Geological Museum. This workwas supported by NSF grant EAR-0447357, American Chem-ical Society Petroleum Research Fund grant 40650-G8, anda Leakey Foundation grant to JRS, and a Foundation Coalgrant to RG. Emily Pohlman carried out point counts on tufas.As always, we thank Tony Mills, director of the Dakhleh OasisProject, for his continued support and assistance.

References

Abrantes, F., 2003. A 340,000 year continental climate record from tropical

Africa; news from opal phytoliths from the equatorial Atlantic. Earth

Planet Sci. Lett. 209, 165e179.

Bradley, R., 1999. Paleoclimatology: Reconstructing Climates of the Quater-

nary. Academic Press, San Diego.

Calvert, S., Fontugne, M., 2001. On the late Pleistocene sapropel record of

climatic and oceanographic variability in the eastern Mediterranean. Pale-

oceanography 16, 78e94.

Caton-Thompson, G., 1935. A revision of recent research upon some Stone-

Age problems in North Africa. Man 35, 74.

700 J.R. Smith et al. / Journal of Human Evolution 52 (2007) 690e701

Caton-Thompson, G., 1952. Kharga Oasis in Prehistory. Athlone Press,

London.

Caton-Thompson, G., Gardner, E.W., 1932. The prehistoric geography of

Kharga Oasis. Geogr. J. 80, 369e409.

Causse, C., Coque, R., Fontes, J.C., Gasse, F., Gibert, E., Ouezdou, H.B.,

Zouari, K., 1989. Two high levels of continental waters in the southern

Tunisian chotts at about 90 and 150 ka. Geology 17, 922e925.

Churcher, C.S., Mills, A.J. (Eds.), 1999. Reports from the Survey of Dakhleh

Oasis, Western Desert of Egypt, 1977e1987. Oxbow Press, Oxford.

Churcher, C.S., Kleindienst, M.R., Schwarcz, H.P., 1999. Faunal remains from

a middle Pleistocene lacustrine marl in Dakhleh Oasis, Egypt: palaeoenvir-

onmental reconstructions. Palaeogeogr. Palaeoclimatol. Palaeoecol. 154,

301e312.

Churcher, C.S., Kleindienst M.R. Great lakes in the Dakhleh Oasis: Mid-Pleis-

tocene freshwater lakes in the Dakhleh Oasis depressions, Western Desert,

Egypt. In: Mills, A.J. (Ed.), The Oasis Papers IV. Oxbow Books, Oxford, in

press.

Clark, J.D., 1967. Atlas of African Prehistory. University of Chicago Press,

Chicago.

Claussen, M., Gayler, V., 1997. The greening of the Sahara during the mid-

Holocene: results of an interactive atmosphere-biome model. Glob. Ecol.

Biogeogr. Lett. 6, 369e377.

Cremaschi, M., Di Lernia, S., Garcea, E.A.A., 1998. Some insights on the Ate-

rian in the Libyan Sahara: Chronology, environment and archaeology. Afr.

Arch. Rev. 15, 261e286.

Crombie, M.K., Arvidson, R.E., Sturchio, N.C., Alfy, Z.E., Zeid, K.A., 1997.

Age and isotopic constraints on Pleistocene pluvial episodes in the West-

ern Desert, Egypt. Palaeogeogr. Palaeoclimatol. Palaeoecol. 130, 337e

355.

Garcea, E.A.A., 1998. Comment on Van Peer, ‘The Nile Corridor and the Out-

of-Africa model’. Curr. Anthropol. 39 (Suppl.), S131eS132.

Gardner, E., 1935. The Pleistocene fauna and flora of Kharga Oasis, Egypt.

Q.J. Geol. Soc. 91, 479e518.

Gardner, E.W., 1932. Some problems of the Pleistocene hydrography of

Kharga Oasis, Egypt. Geol. Mag. 69, 386e409.

Gardner, E.W., Caton-Thompson, G., 1933. Summary report on the Kharga

Expedition of 1932e33. Man 33, 178e179.

Guichard, J., Guichard, G., 1965. The Early and Middle Palaeolithic of Nubia:

A preliminary report. In: Wendorf, F. (Ed.), Contributions to the Prehistory

of Nubia. Southern Methodist University Press, Dallas, pp. 57e116.

Guichard, J., Guichard, G., 1968. Contributions to the study of the Early

and Middle Palaeolithic of Nubia. In: Wendorf, F. (Ed.), The Prehistory

of Nubia, vol. I. Southern Methodist University Press, Dallas, pp. 148e193.

Hamdan, M.A., 2000. Quaternary travertines of Wadis Abu Had-dib area East-

ern Desert, Egypt: Paleoenvironment through field, sedimentology, age,

and isotopic study. Sed. Egypt 8, 49e62.

Hawkins, A.L., Smith, J.R., Giegengack, R., McDonald, M.M.A.,

Kleindienst, M.R., Schwarcz, H.P., Churcher, C.S., Wiseman, M.F.,

Nicoll, K., 2001. New research on the prehistory of the escarpment in

Kharga Oasis, Egypt. Nyame Akuma 55, 8e14.

Hoelzmann, P., Kruse, H.-J., Rottinger, F., 2000. Precipitation estimates for the

eastern Saharan palaeomonsoon based on a water balance model of the

West Nubian palaeolake basin. Global Planet. Change 26, 105e120.

Imbrie, J., Duffy, A., 1990. SPECMAP Archive #1. IGBP PAGES/World Data

Center-A for Paleoclimatology Data Contribution Series # 90-001. NOAA/

NGDC Paleoclimatology Program. Boulder, CO, USA.

Janssen, A., Swennen, R., Podoor, N., Keppens, E., 1999. Biological and dia-

genetic influences in Recent and fossil tufa deposits from Belgium. Sed.

Geol. 126, 75e95.

Kallel, N., Duplessy, J.-C., Labeyrie, L., Fontugne, M., Paterne, M.,

Montacer, M., 2000. Mediterranean pluvial periods and sapropel formation

over the last 200 000 years. Palaeogeogr. Palaeoclimatol. Palaeoecol. 157,

45e58.

Kano, A., Matsuoka, J., Kojo, T., Fujii, H., 2003. Origin of annual laminations

in tufa deposits, southwest Japan. Palaeogeogr. Palaeoclimatol. Palaeoecol.

191, 243e262.

Kleindienst, M.R., 1999. Pleistocene archaeology and geoarchaeology of the

Dakhleh Oasis: A status report. In: Churcher, C.S., Mills, A.J. (Eds.),

Reports from the Survey of the Dakhleh Oasis 1977e1987. Oxbow

Books, Oxford, pp. 83e108.

Kleindienst, M.R., 2003. Strategies for studying Pleistocene archaeology

based upon surface evidence: first characterisation of an older Middle

Stone Age unit, Dakhleh Oasis, Egypt. In: Bowen, G.E., Hope, C.A.

(Eds.), The Oasis Papers 3: Proceedings of the Third International Confer-

ence of the Dakhleh Oasis Project. Dakhleh Oasis Project Monograph 14.

Oxbow Books, Oxford, pp. 1e42.

Kleindienst, M.R., 2005. On naming things: behavioural changes in the later

Middle Pleistocene, viewed from the eastern Sahara. In: Hovers, E.,

Kuhn, S. (Eds.), Transitions Before the Transition: Evolution and Stability

in the Middle Paleolithic and Middle Stone Age. Springer, New York, pp.

13e28.

Kleindienst, M.R., Churcher, C.S., Smith, J.R., Schwarcz, H.P., 2004. Mid- to

late Pleistocene palaeolakes in the Dakhleh Oasis, Western Desert, Egypt.

Annu. Meet. Geol. Soc. Am. Abstr. Prog. 36, 122.

Kleindienst, M.R., Schwarcz, H.P., Nicoll, K., Churcher, C.S., Frizano, J., Gie-

gengack, R., Wiseman, M.F. Water in the desert: First report on uranium-

series dating of Caton-Thompson’s and Gardner’s ‘‘classic’’ Pleistocene

sequence at Refuf Pass, Kharga Oasis. In: Wiseman, M.F. (Ed.), Oasis

Papers II: Proceedings of the Second Dakhleh Oasis Project Research

Seminar. Oxbow Books, Oxford, in press.

Kropelin, S., Petit-Maire, N., 2000. Paleomonsoon variations and environmen-

tal change during the late Quaternary. Global Planet. Change 26, viieviii.

Larrasoa~na, J.C., Roberts, A.P., Rohling, E.J., Winklhofer, M., Wehausen, R.,

2003. Three million years of monsoon variability over the northern Sahara.

Clim. Dynam. 21, 689e698.

Lotter, A.F., Sturm, M., Teranes, J.L., Wehrli, B., 1997. Varve formation since

1885 and high-resolution varve analyses in hypertrophic Baldeggersee

(Switzerland). Aquat. Sci. 59, 304e325.

Mandel, R.D., Simmons, A.H., 2001. Prehistoric occupation of late Quaternary

landscapes near Kharga Oasis, Western Desert. Geoarchaeology 16, 95e

117.

McBrearty, S., Bishop, L., Kingston, J., 1996. Variability in traces of middle

Pleistocene hominid behaviour in the Kapthurin Formation, Baringo,

Kenya. J. Hum. Evol. 30, 563e580.

McBrearty, S., Bishop, L., Plummer, T., Dewar, R., Conard, N., 1998. Tools

underfoot: human trampling as an agent of lithic artifact edge modifica-

tion. Am. Antiq. 63, 108e129.

McBrearty, S., Brooks, A.S., 2000. The revolution that wasn’t: a new interpre-

tation of the origin of modern human behaviour. J. Hum. Evol. 39,

453e563.

McCauley, J.F., Schaber, G.G., Breed, C.S., Grolier, M.J., Haynes, C.V.,

Issawi, B., Elachi, C., Blom, R., 1982. Subsurface valleys and geoarchaeol-

ogy of the eastern Sahara revealed by shuttle radar. Science 218, 1004e1020.

Moreno, A., Targarona, J., Henderiks, J., Canals, M., Freudenthal, T.,

Meggers, H., 2001. Orbital forcing of dust supply to the North Canary

Basin over the last 250 kyr. Quatern. Sci. Rev. 20, 1327e1339.

Nicoll, K., 1996. Deposition and diagenesis of freshwater spring-deposited

travertines from Oklahoma, Arizona, and Egypt. Master’s Thesis, Bryn

Mawr College.

Nicoll, K., Giegengack, R., Kleindienst, M., 1999. Petrogenesis of artifact-

bearing fossil-spring tufa deposits from Kharga Oasis, Egypt. Geoarch-

aeology 14, 849e863.

Pedley, H.M., 1990. Classification and environmental models of cool freshwa-

ter tufas. Sediment. Geol. 68, 143e154.

Petit-Maire, N., Fontugne, M., Rouland, C., 1991. Atmospheric methane ratio

and environmental changes in the Sahara and Sahel during the last 130

kyrs. Palaeogeogr. Palaeoclimatol. Palaeoecol. 86, 197e204.

Polyak, V., Asmerom, Y., 2001. Late Holocene climate and cultural changes in

the southwestern United States. Science 294, 148e151.

Prell, W.L., Kutzbach, J.E., 1987. Monsoon variability over the past 150,000

years. J. Geophys. Res. 92, 8411e8425.

Rossignol-Strick, M., 1983. African monsoons, an immediate climate response

to orbital insolation. Nature 304, 46e49.

Schild, R., 1998. Comment on Van Peer, ‘The Nile Corridor and the Out-of-

Africa model’. Curr. Anthropol. 39 (Suppl.), S134eS135.

701J.R. Smith et al. / Journal of Human Evolution 52 (2007) 690e701

Schwarcz, H., Morawska, L., 1993. Uranium-series dating of carbonates from

Bir Tarfawi and Bir Sahara East. In: Wendorf, F., Schild, R., Close, A.

(Eds.), Egypt During the Last Interglacial. Plenum Press, New York.

Smith, J.R., Giegengack, R., Schwarcz, H.P., McDonald, M.M.A.,

Kleindienst, M.R., Hawkins, A.L., Churcher, C.S., 2004a. A reconstruction

of Quaternary pluvial environments and human occupations using stratig-

raphy and geochronology of fossil-spring tufas, Kharga Oasis, Egypt. Geo-

archaeology 19, 1e34.

Smith, J.R., Giegengack, R., Schwarcz, H.P., 2004b. Constraints on Pleisto-

cene pluvial climates through stable-isotope analysis of fossil-spring tufas

and associated gastropods, Kharga Oasis, Egypt. Palaeogeogr. Palaeocli-

matol. Palaeoecol. 206, 157e179.

Sonntag, C., Klitzsch, E., Lohnert, E.P., El-Shazly, E.M., Munnich, K.O.,

Junghans, C., Thorweihe, U., Weistroffer, K., Swailem, F.M., 1979. Palae-

oclimatic information from deuterium and oxygen-18 in carbon-14-dated

north Saharan groundwaters. In: Isotope Hydrology 1978. International

Atomic Energy Agency, Vienna, pp. 569e581.

Sturchio, N.C., Du, X., Purtschert, R., Lehmann, B.E., Sultan, M.,

Patterson, L.J., Lu, Z.-T., Mueller, P., Bigler, T., Bailey, K.,

O’Connor, T.P., Young, L., Lorenzo, R., Becker, R., Alfy, Z.E.,

Kaliouby, B.E., Dawood, Y., Abdallah, A.M.A., 2004. One million year

old groundwater in the Sahara revealed by krypton-81 and chlorine-36. Geo-

phys. Res. Lett. 31, 1e4.

Sultan, M., Sturchio, N., Hassan, F.A., Hamdan, M.A.R.,

Mahmood, A.M., Alfy, Z.E., Stein, T., 1997. Precipitation source in-

ferred from stable isotopic composition of Pleistocene groundwater

and carbonate deposits in the Western Desert of Egypt. Quatern.

Res. 48, 29e37.

Szabo, B.J., Haynes, C.V.J., Maxwell, T.A., 1995. Ages of Quaternary pluvial

episodes determined by uranium-series and radiocarbon dating of

lacustrine deposits of eastern Sahara. Palaeogeogr. Palaeoclimatol. Palae-

oecol. 113, 227e242.

Szabo, B.J., McHugh, W.P., Schaber, G.G., Haynes Jr., C.V., Breed, C.S.,

1989. Uranium-series dated authigenic carbonates and Acheulian sites in

southern Egypt. Science 243, 1053e1056.

Van Peer, P., 1998. The Nile Corridor and the out-of-Africa model. Curr.

Anthropol. 39, S115eS140.

Van Peer, P., Vermeersch, P.M., 1990. Middle to Upper Palaeolithic transition:

the evidence for the Nile Valley. In: Mellars, P. (Ed.), The Emergence of

Modern Humans: An Archaeological Perspective. Edinburgh University

Press, pp. 139e159.

Wendorf, F., Schild, R.A., 1980. Prehistory of the Eastern Sahara. Academic

Press, New York.

Wendorf, F., Schild, R., Close, A.E. (Eds.), 1993a. Egypt During the Last

Interglacial: The Middle Paleolithic of Bir Tarfawi and Bir Sahara East.

Plenum Press, New York.

Wendorf, F., Schild, R., Close, A.E., 1993b. Summary and conclusions. In:

Wendorf, F., Schild, R., Close, A.E. (Eds.), Egypt During the Last Intergla-

cial: The Middle Paleolithic of Bir Tarfawi and Bir Sahara East. Plenum

Press, New York, pp. 552e573.

Wiseman, M., 1999. Late Pleistocene prehistory in the Dakhleh Oasis. In:

Churcher, C.S., Mills, A.J. (Eds.), Reports from the Survey of the Dakhleh

Oasis, Western Desert of Egypt, 1977e1987. Oxbow Books, Oxford, pp.

109e115.

Zouari, K., Chkir, N., Causse, C., 1998. Pleistocene humid episodes in south-

ern Tunisian chotts. In: IAEA (Ed.), Isotope Techniques in the Study of

Environmental Change: Proceedings of an International Symposium on

Isotope Techniques in the Study of Past and Current Environmental

Changes in the Hydrosphere and the Atmosphere. STI/PUB/1024. Interna-

tional Atomic Energy Agency, pp. 543e554.