Accepted Manuscript

Title: Site formation processes in caves: the Holocene sediments of the Haua Fteah,Cyrenaica, Libya

Authors: Chris Hunt, John Davison, Robyn Inglis, Lucy Farr, Tim Reynolds, DavidSimpson, Graeme Barker, Hwedi el-Rishi

PII: S0305-4403(10)00026-9

DOI: 10.1016/j.jas.2010.01.021

Reference: YJASC 2417

To appear in: Journal of Archaeological Science

Received Date: 11 September 2009

Revised Date: 8 January 2010

Accepted Date: 14 January 2010

Please cite this article as: Hunt, C., Davison, J., Inglis, R., Farr, L., Reynolds, T., Simpson, D., Barker,G., el-Rishi, H. Site formation processes in caves: the Holocene sediments of the Haua Fteah,Cyrenaica, Libya, Journal of Archaeological Science (2010), doi: 10.1016/j.jas.2010.01.021

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Site formation processes in caves: the Holocene sediments of the Haua Fteah, Cyrenaica, Libya Chris Hunt1, John Davison1, Robyn Inglis2, Lucy Farr3, Tim Reynolds4, David Simpson1, Graeme Barker 2, Hwedi el-Rishi5 1. School of Geography, Archaeology, and Palaeoecology, Queen’s University of Belfast, UK

2. Department of Archaeology, University of Cambridge, UK

3. McDonald Institute for Archaeological Research, University of Cambridge, UK 4. Faculty of Continuing Education, Birkbeck College London, UK 5. Department of Geography, Garyounis University, Benghazi, Libya Abstract Caves have yielded some of the most globally important archaeological sequences, but often their interpretation has suffered from assumptions about cave sedimentary processes. Caves contain distinctive sedimentary environments: this has major implications for the understanding of contained archaeological materials. This paper describes and analyses the Holocene sediments in the Haua Fteah, a sequence regarded as essentially continuous by the original excavator. 50 years after it was first excavated the Haua’s Epipalaeolithic to post-Classical chronological range and rich finds make it still the key Holocene archaeological site in North Africa. The reassessment shows, however, that the sequence is strongly discontinuous and this has major implications for the reinterpretation of the site, as the highly-resolved archaeological record is thus likely to reflect a series of brief occupations, rather than continuous human activity. As with many caves, the sedimentary record in the Haua Fteah is an extremely sensitive indicator of environments and processes in the wider landscape. Secure understanding of sedimentary process, from analysis of the highly individual records found in caves, is essential for full understanding of their contained archaeology. Keywords Cave archaeology, North Africa, Libya, Holocene, Facies Analysis, Radiocarbon Dating Introduction Caves are often key archaeological sites because people used them over extended periods and because caves are known to preserve long and often critical archaeological and environmental records (e.g. Bar-Joseph & Meignen 2008; Bertran et al. 2008; Barker et al. 2007; Chase et al. 2009; Farrand, 2001; Hovers 2009; Hunt et al. 2007b; Laville et al. 1980; Mc Burney 1967). Yet caves are not simple repositories – they are dynamic sedimentary environments with their own complex taphonomic processes which shape the nature of the archaeological record (Hunt & Gale 1986). Understanding of taphonomic processes – the processes of site formation – are critical to the evaluation of the archaeological record from caves. Previous generations of cave archaeologists had only very limited understanding of sedimentary and taphonomic processes in caves, and this limited understanding of process had significant repercussions in their interpretation of the cave record. Typical early archaeological models of cave sedimentation often involve the concept of the build-up of ‘a steady drizzle’ of sediment (e.g. Harrisson 1959a,b; McBurney 1967), resulting in archaeologists regarding cave deposits as containing continuous archaeological records. Modern re-evaluation of this early work, utilising sedimentological and stratigraphic studies of cave sediments (e.g. Woodward & Goldberg, 2001; Gilbertson et al. 2005; Bertran et al. 2008; Ghinassi et al., 2009), and taphonomic evaluation (e.g. Hunt & Rushworth 2004), is in

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some cases providing dramatic new results (e.g. Woodward & Goldberg, 2001; Gilbertson et al. 2005; Barker et al. 2007; Bertran et al., 2008) diametrically at odds with the earlier interpretation. Caves contain highly complex sequences, laid down by a wide variety of processes (Gillieson, 1996; Gilbertson et al., 2005; Bertran et al., 2008; Ghinassi et al. 2009). Sedimentation rates vary by many orders of magnitude, both spatially and chronologically (Bailey & Galanidou, 2009). Deposition is often discontinuous and sometimes catastrophic. Erosion and recycling of materials occurs frequently. Yet in spite of the difficulty and complexity of cave records, it is clear that they are as significant archaeologically as ever. It has become increasingly evident, however, that the archaeological record from any cave is only as good as the understanding of the local depositional environment (Farrand, 2001; Butzer, 2008). In this paper we re-evaluate using a facies-analysis approach (Walker, 1992; Ghinassi et al., 2009) the Holocene depositional sequence in the Haua Fteah, Cyrenaica, Libya, as an example of how the re-evaluation of the cave sediments affects the understanding of the archaeological record. Here, the original interpretation (McBurney, 1967) was of a continually-deposited archaeological sequence, with sudden dramatic changes in the archaeology being thought to reflect major cultural events. This interpretation resulted from the interpretation of the sedimentary record as reflecting the more-or-less constant accumulation of the deposits, and thus that the archaeological sequence was virtually complete. Our re-evaluation shows a rather different pattern, which has major implications for our understanding of the nature of the contained archaeological record. Materials and methods The Haua Fteah, in the Gebel Akhdar, Cyrenaica, Northeast Libya (Fig. 1, 2), has remained one of the foundations of North African archaeology since the seminal publication of McBurney (1967). The Haua is technically a tafoni (a granular disintegration feature) on the side of a doline (a depression caused by solution and/or collapse common in limestone areas). The Haua Fteah has small relict phreatic features in places in its roof and small vadose conduits in its roof and floor which are active under very high rainfall, suggesting that the tafoni formed in an area already subject to cave formation. McBurney (1967) excavated to a depth of 14 m in the fill of this enormous feature during the 1950s, and discovered a highly stratified record which he suggested might reach back to the later part of the last interglacial period, perhaps 80000 years ago. McBurney’s excavations produced what is still regarded as the longest sequence of human activity in North Africa. The site – and the prehistoric archaeology of the region - has been largely untouched by research since this time, and McBurney’s findings are now in urgent need of revision. [Figs 1, 2 about here] The Cyrenaican Prehistory Project (CPP) is, therefore, carrying out a programme of archaeological fieldwork and science-based archaeology (Barker et al. 2007, 2008), with the aim of reassessing McBurney’s work and integrating it with modern archaeological paradigms. It is clear from initial work (Barker et al. 2007, 2008, 2009, Simpson, Hunt 2009) that the Haua Fteah contains a high-resolution record, where changing environments and patterns of human activity can be discerned. It is also showing that many of McBurney’s findings require re-evaluation in the context of modern techniques and understandings. In this account, we consider the sediments exposed in McBurney’s ‘Upper Trench’, which is a ~2 m deep, ~10 m by ~10 m excavation unit. This contained a Holocene sequence beginning with the ‘Libyco-Capsian’ Mesolithic (his Layers X, IX) dated using some pioneering

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radiocarbon determinations by McBurney to c.8000-5000 BC, followed by the Neolithic (his Layers VIII-VI, 5000-2700 BC), and then the Graeco-Roman (his Layer III). The upper part of the trench (his Layers II, I) was referred to recent centuries. McBurney’s (1967) conception of the sedimentary processes operating seems to have been of the then-prevailing ‘drizzle of sediments’ model, with aeolian dust-fall augmented by various quantities of roof collapse. He therefore argued that the archaeological sequence in the cave was essentially complete. At the end of the 1955 season, the excavation was backfilled. Subsequently, local informants tell us that the Libyan authorities dumped gravel in the cave to provide a hardstanding for vehicles. During a high rainfall event around 1997-1998, considerable surface runoff entered the cave from the doline outside. During this event “…mud and water ran into the cave and I feared that I would be drowned…” (Mr Salim Hussein, pers. comm. 2007). The same informant described the traditional use of the cave as a place to manage and pen goats. Until recent years, the cave was used as part of a transhumant land-use pattern, with goat herds pastured at low altitude near the coast at the Haua during the winter, then moving inland to higher altitudes in the Gebel Akhdar for the spring flush of grazing and the summer. The build-up of ticks and other pests necessitated the burning of the accumulated guano on the cave floor at the end of the occupation season every one or two years. In April 2007 we removed the backfill of the ‘Upper Trench’ to establish the robustness of the original faces and their suitability for renewed investigation. All of McBurney’s surviving section pins and labels were recorded and the original faces were cleaned back substantially to expose fresh sediment. Detailed running sections (Figs. 3-4) were constructed on the western (East-facing) and southern (North-facing) faces and charcoal samples were taken from these sections for 14C dating. All radiocarbon dates were on well-preserved, angular charcoal roundwood pieces selected for their good preservation and lack of rounding as least likely to be recycled and without appreciable old carbon effects. Unpublished preliminary work on the sedimentary organic matter in the Holocene deposits by Simpson and Hunt shows that there is no appreciable movement of organic material through the sediments as the sedimentary organic matter profile is highly stratified and coherent. Hard water effects in this limestone region were avoided by selection of identified woody terrestrial taxa. Radiocarbon dates were by Accelerator Mass Spectrometry at the Oxford Laboratory for Archaeology and the history of Art. They were calibrated using Calib 5.02 and are documented in detail in Barker et al. (2008) and in Table 1. Selected profiles were cleaned further back, then samples taken from the East-facing section for sediment and other analysis: the work on these samples other than sediment analysis will be reported elsewhere. In this paper, determinations of magnetic susceptibility and of organic carbon by loss on ignition follow Gale & Hoare (1992). In the 2008 season we again cleaned the sections for investigation of the Holocene sediments in the Haua Fteah to establish the major depositional processes and post-deposition history, with a programme of intensive recording of sediment characteristics, sedimentary structures and pedogenic features, using drawing, photography, clast roundness and hand-texturing in the field. Krumbein roundness follows Krumbein (1941), using the procedure of Gale & Hoare (1992), and is expressed as minimum range value (mode) maximum range value, since means should not be calculated for ordinal data. The cave deposits The cave deposits are heterogeneous and analysis of the sections showed that they occur in unconformity-bounded units. Major changes in lithofacies (sedimentary characteristics

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recording depositional environments) between and within beds are distinguishable. Lithofacies for sedimentary units in the two exposed faces (the East-facing and North-facing sections of the Upper Trench) are set out and interpreted below. Their occurrence is summarised in Tables 2 and 3, with their locations on the sections shown in Figs 3 and 4. Typical lithofacies are shown in Figs. 5-13, and sedimentary properties are shown graphically in Figs. 14 and 15. This lithofacies analysis omits pedogenesis and pedogenic features in the sediments, which will be dealt with elsewhere. [Figs 3-4 and Tables 1 and 2 about here] Diamicts, poorly mixed (D1) Diamict, unsorted, silty sand to gravel matrix, with clasts mostly subrounded (Krumbein roundness for Context 147 is 0.2(0.7)0.7: n=9) and randomly orientated. Also contains clods of calcreted riverine sediments, lumps of charred material, ashy lenses, dispersed carbonised and uncarbonised goat guano (Fig. 5). This layer is made ground: it in-fills the top of the McBurney trench above the primary fill. Local informants suggest that this layer was introduced into the cave and bulldozed into position during the 1980s and it’s textural qualities suggest derivation from local fan gravels. [Fig. 5 about here] Diamicts (D) Matrix to clast-supported diamicts, which consist of angular to subangular cobbles to small boulders in a silty matrix. Clasts mostly subangular (Krumbein roundness for Context 153 is 0.2(0.4)0.7: n=37; for Context 126 is 0.1(0.3)0.6: n=38) Clast ‘lines’ lie at the base of the deposit and also line scour-like features (Fig. 6). Clast long-axis imbrication is weak and predominantly horizontal, north-south orientated or slightly southward-dipping. The diamicts usually infill existing topography and wedge out southward. The matrix- and clast-supported, poorly sorted nature of these deposits, the basal stone ‘line’ and the stone lines at the base of the scour-like features, together with the horizontal long axis orientation of clasts is consistent with these being mudflow deposits. Comparison with the field soils on the doline floor outside the cave, which are characterised by being predominantly silty with similar subangular clasts (Krumbein roundness 0.1(0.3)0.5: n=17), suggests that this is the sediment source. [Fig 6 about here] Clast-supported cobbles and boulder gravels (Gc) and Openwork cobbles and boulder gravels (Goi) Clast-supported and openwork gravel of cobble to small boulder size with angular-subangular clasts disorganised or showing a weak horizontal fabric which is north-south orientated (Fig. 7). Partly infilling some voids in what was originally openwork gravel are laminated silts, clayey silts and ash layers. This layer contains abundant carbonised goat guano. This layer is intimately related to the underlying diamicts - some large clasts in this layer are partly embedded in the diamict. The horizontal imbrication of some clasts in this openwork deposit is perhaps suggestive of deposition from rather turbid water flows, or watery mud-flows, probably at the end of the event which laid down the underlying diamict. Some of the silty void-fills probably relate to the settling of fines after the gravel was deposited. Later, other openwork voids were in-filled with waterlain ash and silts.

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[Fig. 7 about here] Gravels (G) Clast to matrix-supported gravel, with subangular clasts in a silty-sand matrix. Clasts mostly subangular to angular (Krumbein roundness for Context 125 is 0.1(0.3)0.7: n=20, for Context 152 is 0.1(0.2)0.4: n=14) The horizontal long-axis imbrication of the clasts is strong. The sediment bodies occupy scours which are ‘V’-shaped in cross-section, incised into older deposits (Fig. 8). The clast-to matrix-supported gravels with clear horizontal clast long-axis imbrication is suggestive of rapid deposition from relatively turbid flowing water. The morphology and sediment characteristics of these deposits are consistent with them being a waterlain gully-fill. [Fig. 8 about here] Silts (Si/Sil) Silts, sometimes with some fine sands, occasional small stones. The deposits are massive (Si) or indistinctly to distinctly southward-dipping cross- and plane-laminated (Sil). The clasts are subangular to angular (Krumbein roundness for Context 135 is 0.1(0.2)0.4: n=35; for context 136 is 0.1(0.3)0.4: n=10; for Context 132 is 0.1(0.2)0.2: n=6) The layers usually infill existing topography and wedge out southward. The generally well-sorted nature of these deposits and their southward dips is consistent with them being waterlain from shallow surface wash and rills originating on the doline floor outside the cave. [Fig. 9 about here] Laminated silts and clays (SiCl) Clayey silts, plane-laminated, with the laminations typically being silt-clay fining upward couplets (Fig. 10). The silt-clay fining upward couplets are consistent with these deposits being settling-out deposits from quiet water [Fig. 10 about here] Openwork breccia (Bo) Openwork breccia, with very angular clasts (Fig 11). Clast roundness for context 173 is 0.1 (n=25). The general depositional dip and clast long axes dip northward. In cross-section the sediment bodies are lenticular. The openwork texture and clast morphology of these deposits is consistent with them being debris-avalanche deposits resulting from rockfall. Breccia (B) Clast to matrix-supported breccia (Fig. 11). The matrix is silty, with some ash in places. The clasts are angular (Krumbein roundness for Context 144 is 0.1(0.2)0.4: n=25), with long axes conforming to the depositional dip. There is some size-sorting of clasts. Depositional dips are generally northward. The angular clasts and imbrication of these deposits are consistent them being debris-avalanche deposit resulting from rockfall, with a minor admixture of silty or ashy substrate which became entrained in the debris-avalanche. Ashy Breccia (Ba) Clast-supported to matrix supported breccia (Fig. 11). The matrix is mostly silt and/or ash and it contains artefacts, bone, shell and charcoal. The clasts are angular (Krumbein roundness for Context 131 is 0.1(0.1)0.5: n=24; for Context 161 is 0.1(0.1)0.4: n=21; for Context 172 is 0.1(0.1)0.4: n=10; for Context 167 is 0.1(0.2)0.4: n=20; for Context 168 is

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0.1(0.2)0.4: n=10) Clast long-axis orientation and depositional dip is generally northward. The sediment bodies are lenticular in cross-section, wedging out northward. The poorly-sorted nature of these deposits, the general angularity of the clasts, the morphology of the sediment bodies all suggest that these are debris-avalanche deposits. The high content of anthropogenic material may be because debris avalanches incorporated this material from the substrate, or that it was anthropogenic material which collapsed to produce the debris-avalanches. [Fig. 11 about here] Tabular-bedded ash (At) Ash, silty and with occasional stones, containing artefacts, shell, and bone. The deposits are crudely and indistinctly tabular-bedded and usually very compact. Clast roundness is quite variable, probably reflecting a variety of parent materials: (Krumbein roundness for Context 133 is 0.1(0.1)0.8: n=11) The nature of these deposits, with their high anthropogenic content and compaction, suggests that they are occupation horizons. [Fig 12 about here] Tabular-bedded ash and goat guano (Atg) Ash, stony ash and carbonised goat pellets, containing occasional to frequent artefacts, bone and shell. The layers typically are tabular in form, with a sharp upper contact and a gradational lower contact, often with ‘fingers’ of ash infilling small burrows (Fig. 5). Clasts are angular (Krumbein roundness for Context 175 is 0.1(0.1)0.3: n=23). Discussion with local informants, together with the characteristics of the deposits - which are extremely rich in goat guano - suggest that these layers are ‘stable-burning’ horizons, where the floor of the cave was either deliberately or purposefully fired to eliminate ticks and other pests. Laminated ash (Al) Laminated or cross-bedded silty ash, containing occasional artefacts, bone and shell (Fig. 13). The layers infill depressions in the underlying topography and load-casts and water-escape structures are sometimes present. The clear laminations in these deposits are consistent with the accumulation of ash in quiet water following surface wash. [Fig. 13 about here] Synthesis: lithofacies assemblages in the Holocene sediments of the Haua Fteah A number of major sedimentary facies assemblages are present in the Holocene deposits of the Haua. The lower part of the sequence, from McBurney’s (1967) layers X-IV, can be assigned to two major facies assemblages, and the upper part to two further facies-assemblages. Lithofacies-assemblage 1 In the lower part of the northern half of the East-facing section, the dominant facies is silty and massive (structureless) or more-or-less laminated or cross-laminated (lithofacies Si, Si/Cl). The depositional dips in layers allocated to this facies are consistent with derivation from the doline floor, to the north. It may be suggested that these deposits result from shallow wash and rill-flow and the dominantly silt-grade sediments are most probably derived from ultimately aeolian sources, with comparatively little pedogenic alteration of the material prior to redeposition in its present location. The Krumbein roundness (Fig. 14)

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is consistent with the clasts in these layers losing some of their angularity through transport in a flowing medium. Lithofacies-assemblage 2 In the lower parts of the north-facing section and the southern half of the east-facing section, the predominant facies association consists of more-or-less ashy breccias (lithofacies B, Bo and Ba) and occupation deposits (lithofacies At). Clasts in these breccias are characteristically very angular (Fig. 14) and have A-axis dips towards the north. The non-clastic component typically includes a high proportion of cultural debris. These can be assigned to rockfall (when predominantly limestone breccia: lithofacies B, Bo) and debris-avalanche processes (when containing significant ash and cultural material: lithofacies Ba), most probably in a dry state. It is hypothesised that the ashy breccias reflect cultural material spilling forward from an occupation area usually located on a slightly higher area of the cave floor, to the south of the cave, into a ‘sump’ area where the McBurney trench is located. Lithofacies-assemblage 3 This facies assemblage is distributed throughout the upper parts of the North-facing section and the East-facing section. This facies-assemblage, consisting of reddish clayey silts (lithofacies Si), diamicts (lithofacies D) and gravels (lithofacies G), results from mudflows and surface wash of field soils from the doline. This is inferred from the strong reddish-brown colours, sedimentary structures and clast morphology. Water-escape and loading structures suggest that the underlying sediments were in a wet state when some of these diamicts arrived. One major mudflow (contexts 126 and 153, correlating with McBurney’s Layer III) most probably arrived shortly before the building of the Graeco-Roman structure, but the major wash event which frightened our informant seems to have left little discernable trace in the sedimentary record. Lithofacies-assemblage 4 This facies assemblage is distributed throughout the upper parts of the North-facing section and the East-facing section and interdigitates with the third facies-assemblage. It consists of ashy deposits containing abundant carbonised goat pellets, derived from stabling, mostly of goats, and the burning of the resulting guano (lithofacies Atg and Al). Facies change in the Haua and it’s causes The major sedimentary change below McBurney’s layer III, from the first two of these facies-associations to the second pair, points to significant changes both inside and outside the cave. Inside the cave, the dominant process changes from debris–avalanche of occupation debris, to deposition of sediments resulting from goat-penning and stable-burning. It is probable that occupation by a residential group who kept their domestic animals elsewhere to the cave gave way at this point to shepherding communities predominantly using the cave for animal-keeping. There is also a change in the nature of the materials entering the cave at this time and the processes concerned. Small-scale wash of sediment derived from aeolian sources characterises the externally-originating layers in the earlier Holocene, before McBurney’s unit III. From David Simpson’s unpublished pollen analysis, the earlier Holocene vegetation of the area round the Haua was extremely open and of a rather arid aspect. This would chime with evidence for aeolian sedimentation outside the cave and a lack of pedogenic alteration of the materials entering the cave. This scenario is replaced in Historic times (McBurney’s Unit III) by wash and mudflow of doline soils, most probably resulting from relocation of ploughsoil under extreme rainfall events. It is noteworthy that the major mudflow (contexts 126, 153) happened very shortly after the change in land-use outside the

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cave and before the Graeco-Roman structure was built. It presumably reflects the relocation of easily-eroded stored sediment from the doline at a time when there was no vegetation cover, maybe as a result of ploughing, and once this had occurred, the quantity of sediment available for movement into the cave was substantially less. The rather uniform sedimentary properties throughout the Holocene (Fig. 14) reflect the rather similar, ultimately aeolian sources from which the Haua sediments have derived, but the switch between facies-associations 1 and 2 in the Libyco-Capsian and Neolithic layers and facies-associations 3 and 4 in the Historic layers is visible as a general decline in magnetic susceptibility. This decline most probably reflects changes in magnetic mineralogy. as low-temperature smouldering of goat guano during the Historic period generally higher temperatures reached by domestic fires during the Neolithic and Libyco-Capsian. The broad coincidence between these changes and the start of the Greek occupation in Cyrenaica around 621 BC may suggest that there were changes in residential location and land use associated with the incoming of the Greeks. The community previously resident in the cave was relocated and it would appear that the present-day pattern of cultivation of the doline and goat-herding in the cave started around this time. There is no trace of habitation activity in the sediments relating to the Graeco-Roman sanctuary. The vegetation on the Cyrenaican littoral in the Graeco-Libyan period consisted of forests with some cleared and grazed or cultivated areas (Hunt et al. 2002) but it was not as degraded as it became during the Roman occupation, or subsequently during the Little Ice age (Barker et al. 2008), but this increasing degradation in the wider landscape does not seem to have resulted in major sediment accumulation in the Haua Fteah. Re-evaluation of the McBurney model of sedimentation This re-examination of the Holocene deposits in the Haua Fteah is only the first stage of the complete re-evaluation of this important depositional sequence. It provides a framework for detailed micromorphological, geochemical, palaeobotanical and palynological studies, and for the re-evaluation of the archaeology. The new dating evidence and the facies analysis can be used to suggest that a re-evaluation of McBurney’s (1967) model of continuous sedimentation is overdue. Layers seem, on the whole, to have accumulated extremely rapidly, with significant hiatuses between depositional episodes (Table 3). In the Holocene layers underlying the 1980s made ground there are probably 24 significant depositional events, some of which probably took no more than a few minutes to occur, and few of which lasted more than a few years. This is particularly the case for the mudflow, debris-avalanche and rockfall deposits, which would have accumulated virtually instantaneously, but it is also likely to be the case with the waterlain layers, which most probably accumulated in single wet seasons. This pattern of episodic deposition has been reported widely in other recent high-resolution studies of cave sedimentation (e.g. Otte et al., 2003; Gilbertson et al., 2005; Lundberg & McFarlane, 2007; Pickering et al. 2007; Bertran et al., 2008; Ghinassi et al. 2009). There are also a few instances of significant recycling – the date for layer X of 12761-12131 BC is far older than would be expected from the other dates associated with this layer both from McBurney (1967) and from Barker et al. (in press), who have calibrated dates of 8806-8615 BC and 9294-8951 BC from lower in layer X deposits. This is a phenomenon increasingly to be expected from caves and many other types of archaeological sites as technological advance enable the taking of smaller radiocarbon samples and more cost-effective protocols lead to increases of the average number of dates per site.

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A new model of sedimentation for the Haua Fteah would thus be of long periods of hiatus separated by extremely rapid and often catastrophic sedimentation events incorporating, on occasion, materials from older levels. This change in the interpretation of the sequence do not negate its archaeological significance, but they do require a re-evaluation of their contained archaeology, which would now perhaps be reinterpreted as highly-resolved ‘snapshots’ of archaeological events rather than a continuous sequence. A further corollary is that (as the excavated locality is the topographic low in the cave and thus where virtually all material might be expected to accumulate) the history of human activity in the Haua Fteah was extremely discontinuous, with short phases of activity separated by many years of abandonment. This may be the reason that McBurney (1967) documents a series of highly distinctive artefact assemblages in these horizons - conceivably people were gradually modifying their technology during the episodes of non-deposition, but the artefacts we see come only from short, well-separated periods of activity in the cave and thus are likely to be typologically distinct. An alternative (but by no means completely mutually exclusive) viewpoint (e.g. Bailey & Galanidou, 2009) would hold that these assemblages are time-averaged palimpsests derived from the accumulation of many years human activity on a stable surface. At present, the un-abraded and pristine nature of the lithics and the extremely good preservation of bone, molluscs and charred plant debris recovered by the deep section cleaning and the first of the new excavations in the cave inclines us against this hypothesis, since in time-averaged palimpsests there is a strong tendency for degradation of archaeological materials by passing feet, weathering and animal activity. These viewpoints will be tested further over the coming years by highly-controlled test-excavations. It is clear that the full significance of the archaeological record at the Haua will not be apparent until tests of the coherence of layers, such as lithic refitting and fluorescence microscopy of pollen grains (Hunt et al. 2007a) have been carried out. [Table 3 about here] Conclusions: cave geoarchaeology and the quality of the archaeological record The example of the Haua Fteah confirms many indications from the recent literature. In many cases, caves do not contain simple sedimentary systems, but extremely complex and variable ones. The deposition of sediment in caves is intimately related to the processes occurring at any given point in time and space: these processes will vary in time, and across the cave floor, with distinctive facies relating to the geography and geometry of the cave, the location and types of inputs of sediment and the transport mechanisms involved. People may further complicate these patterns by their activities, and the location and type of human activity is governed by cultural issues, the geography and geometry of the system, the stability and dryness of the cave floor and the cave microclimate. Also of considerable significance are periods of non-deposition, where successions of cultural activities may occur over considerable periods. Caves, during times when they are accumulating archaeologically-important deposits, are intimately related to the outside world, and the processes which transport sediment into and deposit it within caves are often, but not always, manifestations of processes which are operating outside. Sediment supply also is likely to vary through time, so that even if processes are constant, the nature and rate of sediment accumulation may vary. Caves thus mirror the outside world in many ways - that is part of their value to the geoarchaeologist and to the wider archaeological community. And - as with the outside world - transport, depositional and erosional processes will vary with

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time and with changes in the outside climate and environment. Also significant will be changes in the morphology of the cave itself. The geoarchaeologist wishing to interpret cave sequences has a series of key issues to address. First and possibly most important is the identification of the sedimentary mechanisms involved in the formation of the cave record. The variety of processes involved is considerable, but facies analysis offers a powerful tool for their identification. Second, the recognition of changing sedimentation rate and of periods of non-deposition is critical to the interpretation of the sequence and it’s contained archaeology. This has resonance in the recognition of - on one hand - instantaneous ‘snapshots’ or lagerstaten and - on the other, -palimpsests and time-averaged deposits. Without secure geoarchaeological understanding, the cave archaeological record is meaningless. Acknowledgements We would like to particularly acknowledge the permission and support of the Department of Antiquities of Libya to undertake the project; the financial support of the Society for Libyan Studies, the Leakey Foundation, and the University of Cambridge, for the fieldwork; and the significant help in kind provided by the Department of Antiquities in Tripoli and Cyrene. The personal support of the President of the Department of Antiquities Dr Giuma Anaag and the Controllers of Antiquities for Cyrene Achmed Sabar and Abdulgader al Mulzeni has been vital to the success of the project. Further invaluable support for the project was provided by Paul Bennett (former Chair of the Society for Libyan Studies), Mustapha Turjman (Department of Antiquities, Tripoli), Ibreike Quinhe (Inspector of Antiquities, Apollonia), Mohammed Twati and Fathallah Khalifa (Department of Archaeology, Omar Mukhtar University al-Baeida), and Ahmed Buzaian (Department of Archaeology, Gar Yunis University, Benghazi). We thank the many members of the Cyrenaica Prehistory Project for support in the field and discussion. An early version of this paper was read at the World Archaeological Congress, Dublin, 2008. References Bailey, G., Galanidou, N. 2009. Caves, palimpsests and dwelling spaces: examples from the Upper Palaeolithic of south-east Europe, World Archaeology,41:2 ,215 — 241. Bailey, G. N., Woodward, J. 1997. The Klithi deposits: sedimentology, stratigraphy and

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McDonald Institute for Archaeological Research, pp. 61–94.

Barker, G., Hunt, C., and Reynolds, T., Brooks, I., el-Rishi, H. 2007. The Haua Fteah, Cyrenaica (northeast Libya): renewed investigations of the cave and its landscape, 2007. Libyan Studies 38: 93-114. Barker, G., Basell, L., Brooks, I., Burn, L., Cartwright, C., Cole, F., Davison, J., Farr, L., Grün, R., Hamilton, R., Hunt, C., Inglis, R., Jacobs, Z., Leitch, V., Morales, J., Morley, I., Morley, M., Pawley, S., Pryor, A. Reynolds, T., el-Rishi, H., Roberts, R., Simpson, D., Stimpson, C., Touati, M., van der Veen, M. 2008. The Cyrenaican Prehistory Project 2008: the second season of

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investigations of the Haua Fteah cave and its landscape, and further results from the initial (2007) fieldwork. Libyan Studies 39, 175-221. Barker, G., Antoniadou, A., Barton, H., Brooks, I., Candy, I., Drake, N., Farr, L., Hunt, C., Abdulhamid Ibrahim, A., Inglis, R., Jones, S., Morales, J., Morley, I., Mutri, J., Rabett, R., Reynolds, T., Simpson, D., Twati, M. & White, K. 2009 The Cyrenaican Prehistory Project 2009: the third season of investigations of the Haua Fteah cave and its landscape, and further results from the 2007-2008 fieldwork. Libyan Studies 40, 55-94. Bar-Yosef, O. Meignen, L. (eds.) 2008. Kebara Cave, Mt Carmel, Israel. The Middle and Upper Paleolithic Archaeology. Part I. Harvard, Harvard University Press Bertran, P., Caner, L., Langohr, R., Lemée, L., d’Errico, F. 2008. Continental palaeoenvironments during MIS 2 and 3 in southwestern France: the La Ferrassie rockshelter record. Quaternary Science Reviews 27, 2048–2063. Butzer, K. W. 2008. Challenges for a cross-disciplinary geoarchaeology: The intersection between environmental history and geomorphology. Geomorphology 101, 402–411. Chase, P.G., Debenath, A, Dibble, H.L.. McPherron, S.P. 2009. The Cave of Fontechevade. Recent Excavations and Their Paleoanthropological Implications. Cambridge, Cambridge University Press Farrand, R. 2001. Sediments and stratigraphy in rock shelters and caves: a personal perspective on principles and pragmatics. Geoarchaeology 15.5: 537-557. Gale, S. J., Hoare, P. G. 1992 Quaternary Sediments: Petrographic methods for the study of unlithified rocks. London, Belhaven. Ghinassi, M., Colonese, A. C., Di Giuseppe, Z., Govoni, L., Lo Vetro, D., Malavasi, G., Martini, F., Ricciardi, S., Sala, B. 2009 The Late Pleistocene clastic deposits in the Romito Cave, southern Italy: a proxy record of environmental changes and human presence. Journal of Quaternary Science 24, 4, 383-389. Gilbertson, D. Bird, M. Hunt, C. McLaren, S. Mani Banda, R. Pyatt, B. Rose, J., Stephens, M. 2005. Past Human activity and geomorphological change in a guano-rich tropical cave mouth: initial interpretations of the Late Quaternary succession in the Great Cave of Niah, Sarawak. Asian Perspectives 44, 1, 16-41. Gillieson, D. S. 1996. Caves, development, processes and management. Oxford, Blackwell, 324 pp. Harrisson, T. 1959. New archaeological and ethnological results from the Niah Caves. Man 5: 108. Hovers, E. 2009. The Lithic Assemblages of Qafzeh Cave. Oxford, Oxford University Press. Hunt, C. O., El-Rishi, H. A., & Hassan, A. T. 2002 Reconnaissance investigation of the palynology of Holocene wadi deposits in Cyrenaica, Libya. Libyan Studies 33, 1-7

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Hunt, C. O., Rushworth, G., Dykes, A. P. 2007a UV-fluorescence microscopy and the coherence of pollen assemblages in environmental archaeology and Quaternary geology Journal of Archaeological Science 34, 4, 562-571. Hunt, C. O., Gilbertson, D. D., Rushworth, G. 2007b Modern humans in Sarawak, Malaysian Borneo, during Oxygen Isotope Stage 3: palaeoenvironmental evidence from the Great Cave of Niah. Journal of Archaeological Science 34, 1953-1969. Hunt, C. O., Rushworth, G. 2005 Airfall sedimentation and pollen taphonomy in the West mouth of the Great Cave, Niah. Journal of Archaeological Science 32, 465-473. Laville, H., Rigaud, J.P., Sackett, J., 1980. Rock Shelters of the Perigord: Geological

Stratigraphy and Archaeological Succession. Academic Press, New York. 371pp.

Lundberg, J., McFarlane, D.A. 2007. Pleistocene depositional history in a periglacial terrane: A 500 k.y. record from Kents Cavern, Devon, United Kingdom. Geosphere 3, 4, 199-219. Krumbein, W. C. 1941 Measurement and geological significance of shape and roundness of sedimentary particles. Journal of Sedimentary Petrology 11, 64-72. McBurney, C.B.M. 1967. The Haua Fteah in Cyrenaica. Cambridge: Cambridge University Press. Otte, M., López Bayón, I., Noiret, P., Bar-Yosef, O., Yalçınkaya I., Kartal, M. Jean-Marc Léotard, J.-M., Pettitt, P. 2003 Sedimentary Deposition Rates and Carbon-14: the Epi-paleolithic Sequence of Öküzini Cave (Southwest Turkey). Journal of Archaeological Science 30, 325–341. Pickering, R., Hancox P. J., Lee-Thorp, J. A., Grün, R., Mortimer, G. E., McCulloch, M., Berger, L. R. 2007. Stratigraphy, U-Th chronology, and paleoenvironments at Gladysvale Cave: insights into the climatic control of South African hominin-bearing cave deposits. Journal of Human Evolution 53, 602-619. Simpson, D.J., Hunt, C. O. 2009 Scoping the past human environment: a case study of pollen taphonomy at the Haua Fteah, Cyrenaica, Libya. Archaeological Review from Cambridge 24, 2, 27-46. Walker RG. 1992. Facies, facies models and modern stratigraphic concepts. In Facies

Models: Response to Sea Level Changes, Walker RG, James NP (eds). Geological Association

of Canada: St John’s; 1–14.

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CAPTIONS TO THE FIGURES Fig. 1. Map of the central Mediterranean showing the location of the Haua Fteah. Fig. 2. The Haua Fteah before re-excavation in 2006, showing also the cultivated field in the doline in front of the cave. The site of the McBurney excavation is visible as a large crater-like depression in the cave fill. Fig. 3. The East-facing Section in the re-excavated Upper Trench in the Haua Fteah, showing the McBurney layers, the contexts identified by the CPP, and the locations of the new radiocarbon dates obtained by the CPP. Modified from Barker et al. (2009). Fig. 4. The North-facing Section in the re-excavated Upper Trench in the Haua Fteah, showing the McBurney layers and the contexts identified by the CPP. Fig. 5. Detail of the East-facing section, showing D1 diamict of context 147 overlying Atg ash with carbonised goat pellets of context 135 and then Si clayey sitls of context 138. Divisions on scale are 0.1 m. Fig. 6. Detail of the North-facing section, showing D diamict of context 153 with large clasts ‘floating’ in a silty matrix and with a basal line of clasts. To the left of the photograph, a scour-like features is lined with clasts. Divisions on scale are 0.1 m. Fig. 7. Detail of the East-facing section showing context 125 - Gc clast-supported gravel (darker matrix) passing up into Goi openwork gravel subsequently infilled with waterlain sandy silt (lighter matrix). Divisions on scale are 0.1 m. Fig. 8. Detail of the junction between the East-facing and North-facing sections showing a gully-fill with basal G imbricated clast-supported gravel of context 152. Divisions on scale are 0.1 m. Fig. 9. Detail of the East-facing section showing context 135 with massive and cross-laminated silts Sim and Sil. Divisions on scale are 0.1 m. Fig. 10. Detail of the East-facing section showing weakly laminated very clayey silts SiCl of context 138. Divisions on scale are 0.01 m. Fig. 11. Detail of the North-facing section showing strong brown silty diamict D of context 153 (at top of picture) overlying dark grey ashy breccia Ba of context 161, overlying light brown openwork breccia Bo of context 173 (in middle of picture) overlying light brown clast to matrix-supported breccia B (in lower part of picture). Divisions on scale are 0.1 m. Fig. 12. Detail of East-facing section, showing shelly tabular silty ash At occupation horizon, overlain by cross-bedded and massive silts Si of context 132. Divisions on scale are 0.1 m. Fig. 13. Detail of East-facing section, showing crudely-laminated silty ash Al in context 140, with carbonised goat pellets in the lower part of the picture. Divisions on scale are 0.1 m. Figure 14. Sedimentary properties of the sample profile of Holocene deposits in the East-facing section of the Upper Trench in the Haua Fteah.

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Figure 15. Krumbein roundness histograms for contexts in the Holocene sediments of the Haua Fteah. Context 173 (lithofacies Bo) is excluded from the diagram since a sample of 25 clasts all had a Krumbein roundness of 0.1.

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Table 1. Details of CPP and McBurney (1967) Holocene radiocarbon dates from the Haua Fteah, modified after Barker et al. (2009). McBurney (1967) states his dated material only as ‘charcoal’ and his records do not enable attribution to CPP contexts. Sample and species CPP

Context McBurney Layer

Phase Lab no. Radiocarbon age

Cal. BC/AD

(2σ)

190 (Juniperus sp.) 126 III Historic OxA-18710 1688±25 259-416 AD

243 (Zygophyllum sp.) 129 VI Neolithic OxA-18675 5759±28 4692-4534

BC

243 (Zygophyllum sp.) 129 VI Neolithic OxA-18676 5462±30 4356-4259

BC

243 (Zygophyllum sp.) 129 VI Neolithic OxA-18794 5521±32 4451-4331

BC

Charcoal na VI top Neolithic NPL-40 5800±108 4932-4375 BC

Charcoal na VI Neolithic NPL-41 4860±97 3936-3375

BC

209 (Rhus cf. tripartita) 131 VIII Neolithic OxA-18673 6917±31 5877-5729

BC

244 (Suaeda sp.) 131 VIII Neolithic OxA-18667 6115±31 5208-4949 BC

238 (Ephedra sp.) 132 VIII Neolithic OxA-18674 6505±33 5533-5376

BC

380 (Rhus cf. tripartita) 132 VIII Neolithic OxA-19028 6413±32 5471-5326

BC

Charcoal na VIII Neolithic W98 6800±350 6400-5001 BC

Charcoal na VIII Neolithic NPL-42 6370±103 5526-5065

BC

254 (Juniperus sp.) 136 X Capsian OxA-18678 12360±50 12762-

12130 BC

317 (Juniperus sp.) 176 X Capsian OxA-19184 9425±40 8806-8615 BC

319 (Juniperus sp.) 176 X Capsian OxA-19158 9740±45 9294-8951

BC

Charcoal na X Capsian GrN-3167 8400±150 7729-7061

BC

Charcoal na X Capsian W89 7300±300 6822-5570 BC

Charcoal na X Capsian Grn-3541 7000±110 6062-5673

BC

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Table 2. Lithofacies identified in the Holocene sediments of the Haua Fteah.

Lithofacies code

Description Interpretation Context

D Matrix to clast-supported diamicton consisting of subangular cobbles to small boulders in a silty matrix. Weak clast long-axis imbrication is predominantly north-south. In the upper part, laminated silts, clayey silts and ash layers between clasts. Layers usually infill existing topography and wedge out southward.

Mudflow deposits originating on the doline floor outside the cave during heavy rainfall events. Infiltration deposits between clasts in the upper part of the units.

126, 142, 146, 149, 153

D1 Diamict, unsorted, clasts mostly rounded and randomly orientated, clods of calcreted riverine sediments, lumps of charred material, ashy lenses, dispersed carbonised and uncarbonised goat guano.

Made ground: layer of fill introduced into the cave and bulldozed into position during the 1980s.

147, 148

G Clast to matrix-suported gravel, clasts subrounded-subangular, long-axis imbrication follows depositional dip, silty matrix. Sheets of gravel or lenticular sediment bodies occupying gullies.

Gravel deposited from sediment-rich flows at end of mudflow, waterlain gully-fill gravel.

125, 152 (lower part)

Si Silts, sometimes with fine sands, massive or indistinctly to distinctly southward-dipping cross- and plane-laminated, occasional small stones. Layers usually infill existing topography and wedge out southward.

Wash and rill deposits originating on the doline floor outside the cave during heavy rainfall events.

132, 135, 136, 138, 150, 154, 155, 156, 400

Sil Silts, sometimes clayey, well laminated.

Settling-out deposits from quiet water

128, 134

Bo Openwork breccia, clasts very angular, general depositional dip and clast long axes dipping northward. Clast long-axis orientation and depositional dip generally northward. Lenticular sediment bodies in cross-section.

Debris-avalanche deposits resulting from rockfall.

173

B Breccia, clast to matrix-supported, silty, some ash in places. Clasts angular, with long axes conforming to depositional dip. Some size-sorting. Depositional dips generally northward.

Debris-avalanche deposit resulting from rockfall. Minor admixture of cultural material.

144, 169, 170, 176, 177

Ba Breccia, clast-supported to matrix supported, matrix mostly silt and/or ash and containing artefacts, bone,

Occupation debris, rockfall and aeolian silt relocated in small debris

129, 130, 131, 143, 151, 159,

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shell and charcoal. Clasts angular to slightly subangular, clast long-axis orientation and depositional dip generally northward. Lenticular sediment bodies in cross-section, wedging out northward in long section.

avalanches. 161-168, 172, 401

At Ash, silty and with occasional stones, containing artefacts, shell, bone, crudely and indistinctly tabular-bedded.

Occupation debris 133, 402

Atg Ash and carbonised goat pellets, occasional to frequent artefacts, bone and shell.

Burning of goat guano layers.

135, 137, 145, 158, 159, 175, 176

Al Laminated or cross-bedded silty ash, containing occasional artefacts, bone and shell.

Accumulation of ash in quiet water.

17, 127, 139, 140, 141, 146, 152 (upper part), 157

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Table 3. Stratigraphic relationships, depositional environment and CPP dates from layers in the Haua Fteah

Layer code no.

McBurney layer

Lithofacies code

Facies-assemblage

Depositional environment

Date

148, 147

Post 1955 D1 Made ground 1980s AD

154 Si Gully-fill ashy silt 1955-1980s AD 155 Si Gully-fill ashy silt

152 G Gully-fill gravel

137 I–II Historic

Atg 4 Goat penning and stable-burning

138, 146, 156, 157

Si 3 Wash and rill, silt with ash

149 Al 4 Ash accumulating in quiet water

145, 158, 159

Atg Goat penning and stable-burning

125, 144, 143, 145, 139

III Historic Sil, G 3 Settling out deposits from quiet water, silts and ash, infilling openwork gravels

126, 142, 153

IV Historic D 3 Mudflow originating in doline floor

259-416 AD

128, 400

Sil Settling out deposits from quiet water

129 VI Neolithic

Ba 2 Debris avalanche relocating occupation debris and fallen rock

4692-4534 BC, 4356-4259 BC, 4450-4331 BC

130, 161

Ba 2 Debris avalanche relocating occupation debris and fallen rock

131, 172

Ba 2 Debris avalanche relocating occupation debris and fallen rock

5877-5729 BC 5208-4949 BC

132 VII Neolithic

Si 1 Wash and rill deposits originating in doline floor

5533-5376 BC 5471-5326 BC

402 At 2 Occupation layer

162, 163

Ba Occupation debris relocated from the

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south by debris avalanche

164, 166, 165

Ba Occupation debris relocated from the south by debris avalanche

167 (pars)

VIII Neolithic

Ba 2 Occupation debris relocated from the south by debris avalanche

133 IX Libyco-Capsian

At 2 Occupation layer

134 SiCL 1 Settling out deposits from quiet water

404 Si Wash and rill deposits originating in doline floor

143, 168

Ba 2 Occupation debris relocated from the south by debris avalanche

144, 169, 170, 177, 176

B Rockfall breccia

135, 172

Si/Ba Occupation debris relocated from the south by debris avalanche, grading into wash deposits from the doline floor

175 B Rockfall breccia

167 (pars)

Ba Occupation debris relocated from the south by debris avalanche

136 X Libyco-Capsian

Ba/Si 2 Occupation debris relocated from the south by debris avalanche, grading into wash deposits from the doline floor

12760-12130 BC (probably recycled: see Table 1)

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