and site formation processes

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Journal of Anthropological Archaeology 30 (2011) 89–101

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Making time: ‘Living floors’, ‘palimpsests’ and site formation processes – A perspective from the open-air Lower Paleolithic site of Revadim Quarry, Israel Ariel Malinsky-Buller a,⇑, Erella Hovers a, Ofer Marder b a b

Institute of Archaeology, The Hebrew University of Jerusalem, Mt. Scoups, Jerusalem 91905, Israel The Israel Antiquities Authority, P.O. Box 586, Jerusalem 91004, Israel

a r t i c l e

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Article history: Received 17 June 2010 Revision received 22 November 2010 Available online 1 February 2011 Keywords: Site formation processes Palimpsests Living floor Lower Paleolithic Revadim Quarry

a b s t r a c t The recognition of the dynamic role of site formation processes led archaeologists to recognize a behavioral dichotomy between ‘living floors’ and palimpsests’, Yet the archaeological proxies of ‘living floor’ and ‘palimpsest’ were never defined formally, and therefore have been used variably. We use archaeological criteria mentioned in the archaeological literature to model types of formation processes. The case study of the Lower Paleolithic open-air site of Revadim Quarry, Israel is used to test the model. Two types of palimpsests, differing in the rate of accumulation and thus in their effects on the anthropogenic remains, were discerned. Based on these results we review some other Lower Paleolithic instances. A sliding scale of formation processes provides a much needed middle ground between the scales of coarse, time-averaged formation processes and short, ‘‘near real-life’’ behavioral episodes and is an appropriate archaeological frame of reference. Ó 2010 Elsevier Inc. All rights reserved.

Introduction Over the last three decades site formation studies have played a major role in changing the epistemology of paleoanthropology. Simplistic and at times uncritical perceptions of the archaeological record have changed due to the recognition of the dynamic cultural and natural agents which affect the formation of archaeological sites (e.g., Binford, 1977, 1980, 1981b; Schiffer, 1972, 1983, 1987). Paleoanthropologists have come to recognize that, with rare exceptions, the amount of material and its spatial distribution at prehistoric sites can often be altered before and after human occupation. This shift in understanding of the forces that affect the formation of sites has particular relevance for perceptions of temporal resolution. On a more practical level, such studies showed that notions about prehistoric sites being unaltered, fossilized manifestations of human behaviors were less plausible. Rather, an effort to recognize non-anthropogenic background noise is required before behavioral models are constructed. Two key concepts, ‘living floor’ and ‘palimpsest’, epitomize the range of complexity inherent in site formation processes and its role in shaping the archaeological record. The term ‘living floor’ was adopted from ethnographic research and was quickly incorporated into archaeological thought as a reference to a short-duration single episode of hunter-gatherer occupation in a given site (Clark, ⇑ Corresponding author. Address: Institute of Archaeology, The Hebrew University of Jerusalem, Mt. Scopus Jerusalem 91905, Israel. Fax: +972 2 5825548. E-mail address: [email protected] (A. Malinsky-Buller). 0278-4165/$ - see front matter Ó 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.jaa.2010.11.002

1954; Leroi-Gourhan and Brézillon, 1966, 1972). Neither Clark nor Leroi-Gourhan and Brézillon advocated a general use of the term ‘living floor’ nor did they support the notion that sites represented undisturbed spatial configurations of remains left by prehistoric groups. Yet the concept of an archaeological ‘living floor’ became rooted in archaeological research and was used as the interpretative model for sites from various periods (Clark, 1967, 1968; de Lumley, 1969, 1975; Stekelis, 1966). This led to many unfounded interpretations of the term ‘living floor’. Assuming that a given archaeological manifestation represented a discrete and brief time interval, researchers disregarded the problematic nature of direct analogies across large temporal and contextual distance (e.g., Gifford-Gonzalez, 1991; Juthe, 2005; Wylie, 1985). In contrast, the concept of ‘palimpsest’ emerged from within the field of site formation research, using a term borrowed from conservation studies. This term denotes multiple, temporally sequential depositional episodes, caused independently by humans and/or non-human agents (Bailey, 1981; Binford, 1981a,b, 1987; Villa, 1976, 1982, 1983, 2004). When overlapping in space, later episodes of deposition variably obliterate the initial configurations of previous deposits. The term ‘palimpsest’ is not a monolithic concept. Bailey (2007) identified several ‘‘types’’ of palimpsests based on their epistemological as well as practical implications for our understanding of the past. Such typologies are important because they require explicit definitions of time and space relationship as expressed in the archaeological deposits. Both terms, ‘living floor’ and ‘palimpsest’, were quickly incorporated into paleoanthropological research and became widely used

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as two categories that encompass the full range of site formation processes. However, the archaeological proxies of ‘living floor’ and ‘palimpsest’ were never defined formally. These two categories are being used by different authors but their meanings are not always the same or, for that matter, not always made explicit (see also Dibble et al., 1997). In this paper we construct accumulation models for Lower Paleolithic occupations, based on strictly archaeological characterizations of the two concepts. We use the test implications of the models to investigate formation processes in the Late Lower Paleolithic open-air site of Revadim Quarry, Israel (hereafter Revadim). Thus we purposefully avoid assigning specific behavioral meanings (e.g., ‘‘base camp’’, ‘‘butchery site’’) to the archaeological phenomena under discussion. We then use the Revadim case study to show that not all palimpsests are the same, and that the term conflates and therefore masks several temporal scales of formation processes. Unpacking ‘palimpsests’ enhances the resolution of complex archaeological sequences and helps create more nuanced frames of reference for human behavior in its immediate environmental context. Models of accumulation In the present paper we model types of formation processes. For the purpose of model building, we rely on the definitions and assumptions of previous research. This allows us to discuss our results in comparison to earlier works on these issues (Table 1). The ‘living floor’ model The original understanding of the ‘living floor’ concept draws heavily on ethnographic analogies. This implies that activities were contemporaneous. The attributes of this model as they appear in Table 1 are based on Villa’s (1976) archaeological criteria. She specified that a ‘living floor’ should be a thin layer of medium artifact density, but never defined these two properties in quantitative terms. Leakey (1971) was the only researcher who specified the thickness of what she identified as ‘living floors’ (ca. 3 in.), which we follow here. Villa (1976) further noted that because a living floor represents human activities in highly restricted space and time dimensions, more or less contemporaneous activities are carried out in spatially distinct areas of the occupation. It follows that a ‘living floor’ should be a stratigraphically discrete layer with distinct boundaries. Assuming that activities were spatially differentiated, activity areas should be distinguishable through the uneven spatial distribution of artifacts, faunal remains, hearths and other anthropogenic elements. We perceive the term ‘living floor’ as a temporal construct, the defining criterion being that of a single episode of site use.

Pristine living floors are expected to be preserved where depositional processes involve fast burial of the surface without preceding erosion. Such specific depositional circumstances are expressed archaeologically in the nature of the sediments overlying the living floor. Additionally, lithic artifacts on a living floor are expected to be fresh and unrolled, without signs of re-use or re-distribution. Bones, being more susceptible to mechanical and chemical modifications, are more likely to be damaged even as activities are still taking place. Villa (1982, 2004) suggested that the level of contemporaneity of finds on a putative ‘living floor’ can be tested through refitting of lithic and faunal elements. The ‘living floor’ scenario predicts discrete activity areas, identified by specific spatial associations of various find categories (e.g., Alperson-Afil et al., 2009; Delagnes et al., 2006). Knapping will be manifested through refitting, overlap of the distribution of artifacts and micro-artifacts, and spatial co-occurrence of flaked pieces with hammer stones (Isaac, 1981). The ‘rapid-accumulation palimpsests’ model Bordes (1975; Bordes et al., 1972) questioned the validity of analogies between the archaeological and ethnographic records, as well as the ability of archaeologists to achieve the resolution needed to identify the prehistoric analogues of ethnographic ‘‘sol d’habitat’’. He argued that ethnographic analogues constituted a short-lived surface with an exclusively human signature, while a typical archaeological layer encompasses several ‘‘sols d’habitat’’ that were altered by synchronous or sequential natural processes and human activities. Bordes’ emphasized explicitly the diverse temporal scales reflected by archaeological sites. Our model of ‘rapid-accumluation palimpsest’ is based essentially on Bordes’s approach (1975; Bordes et al., 1972). The model posits that a series of living floors resulting from repeated and frequent short visits of human groups were rapidly buried and/or super-imposed on one another, merged together into what appears to be a single occupation horizon by any combination of postdepositional mechanisms (e.g., biological, hydraulic, or chemical processes; Bocek, 1986; Gifford-Gonzalez et al., 1985; McBrearty et al., 1998; Petraglia and Potts, 1994; Schick, 1987; Schiegl et al., 1996; Villa, 1982; Villa and Courtin, 1983). In this scenario, the accumulation would tend to be less discrete spatially. Behaviorally meaningful spatial patterning is likely to have become less notable or even completely obliterated. Because the model posits short exposure of each pristine occupation, most artifacts would appear fresh. The model of a ‘rapid-accumulation palimpsest’ predicts a spatial distribution in which several anthropogenic clusters (as described above for the ‘living floor’ model) can still be observed. Such clusters may occur on a single horizon but may not be

Table 1 Accumulation models and corresponding archaeological signatures. Living floor (Villa, 1976; Leakey, 1971)

‘Rapid-accumulation palimpsest’ (Bordes et al., 1972; Bordes, 1975)

‘Slow-accumulation palimpsest ‘ (Binford, 1981a)

Occupation

A single confined episode

Time scale

Short duration- anthropological time frame

Several confined episodes joined together by postdepositional processes. Intermediate between anthropological and geological time scales

Multiple episodes, the boundaries of which are blurred by post-depositional processes Long; only the geological scale can be detected

The layer is more than 10 cm and not bounded laterally

The layer is more than 10 cm and not bounded laterally Discrete clusters cannot be identified

Archaeological test implications Layer Spatial distribution Condition of artifacts

Clear boundaries vertically and horizontally (ca. 10 cm) Uneven spatial arrangement with clear discrete activity areas The anthropogenic material should demonstrate contemporaneity. The artifacts should be in mint condition

Anthropogenic clusters detected yet represent more than one episode or are masked by non-human agents Most of the artifacts are fresh

Mixed preservation (fresh and abraded)

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contemporaneous. Alternatively, the clusters may be super-imposed and clearly belong to different times of occupation. The ‘slow-accumulation palimpsests’ model Following his taphonomic analysis of some of Olduvai’s ‘living floors’ Binford (1981a, 1987) argued that causal associations (suggesting synchrony) between different types of archaeological finds should not be presumed due to spatial proximity. Rather, they should be demonstrated through the assessment of a site’s resolution and integrity. The present model of ‘slow-accumulation palimpsest’ derives from Binford’s insights. In this scenario the remains of many episodes of human activities are accumulated over a stable surface, where low rates of natural deposition lead to extended exposure of each occupation surface. This results in slow mixing of the anthropogenic remains with those from earlier ones as well as with the remains left by non-human agents (either biological or geological). Due to the extended time frame invoked by this model, the likelihood grows that artifacts and other material items will be deposited on-site but also removed post-depositionally (e.g., Isaac, 1984: fig. 5.9). Because of the longer time of exposure on the stable surface, a higher proportion of patinated and abraded (i.e., mechanically damaged) artifacts are expected to become mixed with more pristine elements. The model of a ‘slow-accumulation palimpsest’ predicts a homogenous distribution of artifacts (Table 1) without discernable anthropogenic clusters, due to taphonomic effects. The site of Revadim Revadim is located on the southern coastal plain of Israel (Fig. 1). It is situated on a hillock at an elevation of 71–73 m above sea level, some 300 m north of a confluence of two tributaries of Nahal Timna, which is itself a small wadi in the drainage basin of Nahal Soreq. The geological sequence at the site is paleomagnetically normal, indicating that it post-dates the Brunhes-Matuyama boundary of 780,000 years BP (Gvirtzman et al., 1999; Marder et al., 1999). Preliminary U–Th dating of carbonate coatings on flint artifacts yielded dates between 300,000–500,000 years BP and possibly older, setting the minimal age estimate for human occupation of the locality (Marder et al., 2010). Given the characteristics of the lithic assemblages, the entire anthropogenic accumulation is ascribed to the Late Acheulian techno-complex (Marder et al., 2006, 2008). Fieldwork at the site focused mainly on two excavation areas (B and C), correlated stratigraphically by two geological trenches (T12 and T23; Fig. 1). Seven archaeological layers were exposed in the two areas. Details of the geological stratigraphy and archaeological sequences as well as spatial correlations between the excavated areas are given in Marder et al., 2006, 2010). The present analysis focuses on the eastern part of Area C (hereafter C East). Area C was excavated over a total area of 44 m2 (Fig. 1) and was divided into two separate sub-areas, designated C East and C West, which were located 8 m apart (Fig. 1). In area C West, extending over 33 m2, five archaeological layers were discerned, labeled (from top to bottom) C1–C5. Layers C1–C4 were encountered within a Quartzic Gray-Brown Paleosol (Marder et al., 2006). Area C East was excavated over an area of 11 m2. The archaeological sequence in this area consists of a single layer, ca. 40 cm thick which is a continuation of Layer C3 in Area C West. The sandy silt matrix in the upper 20 cm contains more manganese oxides compared to carbonate nodules, whereas in the lower 20 cm the reverse proportion is encountered. This layer contains dense continuous horizontal and vertical distributions of lithics and bones, with the majority of items (70–80%) lying in a horizontal position. While in the stratigraphic profile of Trench 12 only a single pebbly

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horizon was noted, extension of the lateral excavation revealed two archaeological horizons (C3a and C3b, from top to bottom) as well as another assemblage that comprised all artifacts above the archeological horizons (‘‘above C3’’; Fig. 2). It also became clear during excavation that the thickness of the pebbly horizons differed between grid units, and that in some cases they were thicker than a single item, without clear separation by sterile sediments. The most conspicuous characteristic of Layer C3 in Area C East is the high frequency of unmodified cobbles that co-occur with artifacts and faunal remains (Fig. 3). Morphologically, this archaeological feature resembles the ‘Ubeidiya ‘living floors’ and has raised questions about the behavioral significance of such an association. We aim to distinguish the roles of geogenic processes and human actions on the formation of these assemblages and elucidate the temporal relationship between depositional episodes in Area C East. Methodology In order to approach the question of site formation processes in Area C East, we describe the sequential deposition using the various parameters of the accumulation models presented in Table 1. In order to be able to compare the thickness of the sequence (40 cm) to the thickness of a ‘living floor’ (10 cm; Leakey, 1971), the section was divided into four levels (levels I–IV from top to bottom), ca. 10 cm thick each. This division is not arbitrary because it takes into account the appearance and arrangement of lithic specimens, so that level boundaries do not ‘‘truncate’’ cobbles or artifacts. The ‘‘assemblage’’ from each level was divided into large-size and small-size components, using the threshold value of 20 mm in maximum dimension common in the analyses of Lower and Middle Paleolithic lithic assemblages. The study of the lithics from the various levels was conducted using an attribute analysis (Clark, 1967, 1968; Isaac, 1977; Bar-Yosef and Goren-Inbar, 1993). In this study we emphasize attributes of the lithic assemblages that are significant in the context of site formation studies (e.g., Dibble et al., 1997) and are therefore meaningful for testing the models discussed in Table 1. The mass and size, as well as sphericity and roundness of large unmodified items (i.e., larger than 20 mm, hereafter LUM) are informative about the magnitude of fluvial processes (Folk, 1965: 3–14; Wadell, 1935) and thus were documented in levels I–IV of Revadim C East. We used the statistic of kurtosis to assess the degree of size sorting of cobbles (following Inbar, 1990). The distribution of the mass of small-size components of both modified and unmodified items is a sensitive measure of fluvial processes (e.g., Petraglia and Potts, 1994; Schick, 1986). Thus small unmodified (smaller than 20 mm, hereafter SUM) as well as modified items smaller than 20 mm (henceforth micro-artifacts) were counted and weighed. The taphonomy of large modified pieces (henceforth artifacts) reflects the degree of disturbance by natural agencies. Here it is described by reference to edge damage, wear of the ridges of dorsal face scars, and patination. Each of these categories reflects different natural mechanisms. The condition of artifacts may be affected by water action, which damages artifacts by abrasion of the scars and edges (Shackley, 1974; Schick, 1986; Petraglia and Potts, 1994; Burroni et al., 2002) and trampling or pedoturbation which may cause breakage and edge damage (Villa and Courtin, 1983; Gifford-Gonzalez et al., 1985; Pryor, 1988; McBrearty et al., 1998). Specific patina formation rates depend on PH values and presence of water in the surrounding soil as well as vegetation cover (Rottlander, 1975). Several case studies have shown that in the Mediterranean region patina forms rapidly (from 2 weeks to 6 months after discard and exposure to atmospheric conditions (Nadel and Gordon, 1993; Friedman et al., 1994). The effects of

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Fig. 1. Map of the excavation areas at Revadim (after Marder et al., 2010).

human activities were studied through documentation of burning and breakage patterns. Since one of the goals of the study was to distinguish between the anthropogenic and non-human accumulation of the artifacts, a major focus concerned distinctions between LUM and modified nodules. We therefore restricted the technological analyses presented in this study to the distinctions between detached vs. flaked pieces (as defined by Isaac et al., 1981, 1997a; see Table 2). A full analysis of the lithics will be published elsewhere (Malinsky-Buller et al., in prep.).

Results Eco-facts or manuports? One of the characteristics of the assemblage in Revadim Area C East is the significant component of large flaked pieces and LUM. Three possible hypotheses can explain this phenomenon. The first suggests that the LUM were brought to the site by hominins (Leakey’s [1967: 420] ‘‘manuports’’). The second scenario is that natural accumulation (e.g., through hydraulic action) of the

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Fig. 2. Stratigraphy of Layer C3, Area C East. View from Trench 12 to the south, Squares BG16-BJ15. In the trench profile, only a single pebbly layer was observed, whereas two such layers were documented during excavation of the adjacent area C East (see text for details and discussion).

unmodified lithics preceded human occupation(s). The third option is that the LUM were part of the sediments that buried the remains of hominin activities after abandonment of the site. The alternative hypotheses are tested by looking at differences of mass, metrics and damage patterns of artifacts vs. LUM. LUM may have reached the site through hominin activities, as potential raw material (e.g., Potts, 1988). In this case they are expected to be of the same raw materials as the artifacts and of the same size or larger than the nodules reduced by flaking. Lithic artifacts, as well as the majority of hammerstones, are modified exclusively on flint. Most of the LUM are of flint (70% in level I, 80% in level II, 69% in level IV and only 54% in level III), followed by hard limestone. It is possible that flint was selected for flaking out of the raw materials available on-site. However, the size relationship between the LUM and the flaked pieces does not support this notion. In each of the four levels LUM items are on average smaller than the pieces in the respective level, although the difference is not statistically significant (Fig. 4). This is true even with regard to tested nodules (i.e., nodules with three or fewer removals), which exhibit minimal reduction of their original volume. Two such items appear in level II, five in level III and 10 in level IV. Their mean dimensions (level III: 92 mm length, 79.8 width

and 39.6 thickness; level IV: length 67.8, width 57.1 mm, thickness 35.5 mm) are larger than those of the LUM in the respective levels. These results do not support the hypothesis that LUM were transported into the site by hominins as a stock of raw material for anticipated flaking activities. The difference between levels I and II on the one hand, and III and IV on the other, is statistically significant (Fig. 4). Differentiating episodes of accumulation The accumulation of unmodified items appears to be largely due to natural causes. Two alternative hypotheses invoked natural on-site deposition and accumulation of the LUM at Revadim C East, either prior to or contemporaneous with/postdating the human occupation(s) (the two latter possibilities are not readily distinguishable). If LUM were part of post-occupation sediment accumulation through hydraulic transport, it is expected that this late event(s) would similarly affect the mass distribution of both the LUM and large modified components. If the weight distributions of the two components diverge, it is likely that this reflects separate, at least partly independent accumulation processes (Dibble et al., 1997: 636–637).

Fig. 3. View of Area C East. The lithics seen in the photo are both artifacts and unmodified clasts. Note the thickness of the accumulation.

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Table 2 Frequencies of generalized lithic categories in the four levels of Area C East. Level I N Debitage

366

Core

41

Tools

72

Debris

1562

Sub-total Unmodified >2 cm Unmodified