Lithic Tools Transportation: New Experimental Data **

The transportation of lithic tools has been an important issue in prehistoric studies. It has been mainly discussed as related to the ‘curation’ debate. In 1973 Lewis Binford defined a

‘curated tool’ as an instrument that has been manufactured and transported from one site to another in anticipation of future needs (Binford 1973). When Binford first developed the curation concept, he was interested in the study of the site formation process. He was analysing the Nunamiut Eskimo technology, focusing on the way in which they conceived different types of gear as appropriate to carry on trips of differing purpose, distance and duration. Even if later the curation concept assumed other significances, both linked to tool efficiency, tool recycling, tool maintenance and tool functionality, at first ’curated tools‘ were mainly conceived as a corollary of mobility (Andrefsky 1991).

In this context, transportation was considered a practice subsumed by curation. Tools were transported to one site to another to perform specific activities at the new locations, as well as a form of precaution, in the eventuality of the insurgence of unexpected needs (Shott 1996a). Moreover, transportation was considered a relevant behaviour as implicates a selection. Considering the constraints associated with mobility and transport loads, the transportation of stone implements requires prehistoric individuals to operate a selection over the lithic assemblages, favoring some tools over others (Shott 1996b, Close 1996).

In microwear studies, the analysis of the effects of the transportation of lithic tools has often passed unperceived. Published researches on the so-called ‘bagwear’ have been mainly developed in order to investigate ’non-use wears‘ (wears caused by external agents, unrelated to the use or management of the tool) as post-excavation damage produced by the archaeological recovery and storage of the findings (Odell & Odell-Vereecken 1980, Lewenstein 1981, Plisson 1985, Luedtke 1986, Gutierrez et al. 1988).

Until now, most efforts were mainly focused on a methodological level to create an experimental reference in order to distinguish ‘use-wears’ (wears produced by the use of the tool) from ‘treatment wears’ and ‘non-utilitarian wear1’ (wears caused by actions linked with the production, management or maintenance of the tool, but not directly caused by use; e.g.

hafting, prehension, manufacture or transportation wears) (Rots 2010). On the contrary, few studies have considered prehistoric transportation as a relevant action capable of producing substantial changes on lithic tools (for a first the recognition of transport traces see Gyria 2004).

2.3.2.1. Experimental Procedure

The experimental program was designed and realized during a field work in the Central Pyrenees, inside the National Park of Aigüestortes i Estany of Saint Maurici, during 2009-2010 campaigns. Aims of this experimentation were to:

** This work has been recently published on the proceedings of the 3rd International Congress of Experimental Archaeology (Banyoles, 17-19 October). I am thankful with the author that collaborated in the paper: Mazzucco, N. & Clemente, I. 2012. Lithic tools transportation: new experimental data. In:

Experimentación en arqueología. Estudio y difusión del pasado, Palomo, A., Piqué, R. & Terradas, X. (eds.) Sèrie Monogràfica del MAC, Girona, 2013: 235-243.

i. Prove the efficiency of different modalities of transportation;

ii. Individualize which types of wear transportation produces on flint implements;

iii. Evaluate if those wears are distinguishable from other types of wear;

iv. Analyse which effects transportation could have on previous use-wear traces;

Transportation was executed in a way which is plausible for prehistoric conditions. Most of the authors agree that prehistoric implements were possibly transported between sites using a leather bag, as it has been also attested ethnographically (Oldfield 1865, Balicki 1970, Kamminga 1982, Plisson 1985). Organizing the experimental practice, I followed part of the methodology already proposed and published by Rots (2010). Three different modes of transportation were tested experimentally. In each case a single person transported some freshly knapped blade together with some previously used instruments under the following circumstances: A) in a loose hanging leather bag; B) in a loose hanging leather bag, with each implement individually rolled in a leather wrapping; C) and tied together by a leather string in a loose hanging leather bag; D) in a loose hanging leather bag, with each implement individually rolled in a leather wrapping and tied together by a leather string (Fig. 2.3.6, a).

Transported artifacts were blades and flakes produced from the same chert types recognized in the archaeological assemblages, the Ebro Valley cherts (Fig. 2.3.6, b). These materials have been intensively exploited during the entire Neolithic period in the NE of Iberian Peninsula, representing the best-quality raw-material for the production of blades, which generally represent tools with a long use-life, more likely to have been transported from one location to another during prehistoric times. Moreover, raw-material sourcing analysis indicates that such materials were moved over considerable distances (Mazzucco et al. 2013b; Rojo et al. 2014).

Thirty elements were transported, of which 8 elements were previously used for cutting a soft vegetal substances, mainly wild grasses of various type. I decided to introduce this

a) b)

Fig. 2.3.6. a) Leather bag with the flint implements tied together (transportation mode D); b) Some of the transported tools.

variable into the experimentation as most of the blade scrapers, analysed from the archaeological contexts included in this work, present traces associated to herbaceous plant harvesting. Experimental tools have been used for a variety of actions and tasks in to order to produce polishes resembling the archaeological specimens: cutting wild grasses, cutting aquatic plants and cutting meadow. The main objective was to create a layer of silica gel on the tool surfaces (i.e. polishes) and successively observe which type of modifications occurred during transportation. Artifacts have been transported for different time intervals, from a minimum of 8 hours (1 day) to a maximum of 180 hours (22 days).

2.3.2.2. Results

2.3.2.2.1. Type of Wears

I distinguished five main types of alterations that could occur with transportation practices: 1) edge-damage; 2) striations; 3) abrasions; 4) surface sheen; 5) polishes. The two last points briefly examine the modifications produced by transportation on previous use-wears (6) and the influence of the transport duration on the development of the use-wears (7).

1) Edge-damage occurs mainly as a consequence of the mutual contact between flint implements within the bag. All the transported edges have been in some degree affected by transportation-damage, even after few hours of transportation. However, the size and invasiveness of the fractures vary notably from one transport mode to another. When instruments are not tied together, as in mode A and mode B, movement during transportation is greater and could produce deep notches and extensive fractures along the edges (Fig. 2.3.7, a-b). Otherwise, in mode C and mode D, edge-damage is reduced and fractures are generally smaller than 2 mm (Fig. 2.3.7, c-d).

Even if fractures could occur in patches of certain regularity, the overall damage produced by transportation is easily distinguishable. Scars are generally irregular both in morphology and directionality. Their distribution over the edges is discontinuous and random. In this sense, scarring caused by transport resemble more post-depositional damage than use-damage.

2) Striations are a consequence of the contact between flint implements within the bag.

They occur mainly in modes A and C, while in mode B and D the presence of the leather wrap partially protects implements from mutual contact. Striations produced by transportation do not show a clear directionality and distribution. They could be isolated on the surfaces, as well concentrated in little spots (Fig. 2.3.7, e-f). Generally, they are easily distinguishable from wears produced by use or hafting. Otherwise, they resemble striations produced by contact with mineral substances, as rubble or brash present in soils.

3) The friction between flint implements could produce extensive abrasions on the surfaces. Those wears are comparable to ‘polish G’ described by Moss (1987) or the

‘bright spots’ described by Gijn (1989). Abrasion spots occur randomly on the surfaces, even if they frequently appear in the most exposed areas, such as the extremities, the edges and the bulb. They could reach a diameter of about 2 mm and, under an incident light, they are often visible at the naked-eye. Such features, caused by an intense friction between the flint surfaces, mainly occur in mode C, where tools are constantly in mutual contact, and even if movements are reduced, as implements are tied

Fig. 2.3.7. a-b) Invasive damage produced in modes A-B (8X and 10X magnification); c-d) Light edge-damage produced in mode D-C (8X magnification); e) Striation produced by transportation (400X magnification); f) Scratches produced by transportation (200X magnification); g-h) Friction spots at different magnifications (400X and 100X magnification).

together, friction between them is high (Fig. 2.3.7, g-h). In mode A and mode B contact between implements is more discontinuous, occasional, and is more likely to produce scarring than abrasions. Finally, mode D also produces spots of ‘polish G’, but they are mainly caused by the friction between the leather wrapping and the lithic surfaces, because of the pressure exerted by the leather string that holds together the pieces.

4) One of the most characteristic wear caused by transportation is the formation of a macroscopic visible gloss all over the tool (Rots 2010). However, this surface sheen (Fig. 2.3.8, a) could not be considered a proper ‘wear’, as do not produce any real modification of the flint surfaces. The gloss is probably a greasy layer deposited on the surface as a consequence of the contact with the leather bag. To prove the consistency of this layer I immerged the implements in a H2O2 30% solution, for various time intervals (10, 30, 60, 120 minutes). After one hour of immersion, the gloss completely disappears, proving that is a thin layer of organic substances. After cleaning only those friction-spots produced by mechanical forces are visible on the surface (Fig. 2.3.8, b). I consider this “greasy sheen” very difficult to recognize in archaeological materials as similar glosses could be produced by other natural agents, e.g. soil.

5) Polishes are mainly the result of the contact between flint and the leather bag or the leather wraps. Hide-like polishes are mainly produced in transportation mode D, where leather and implements are tied together. In this case, the friction between the leather string and the flint surfaces causes a certain rounding of the ridges and of the edges, sometimes associated to tiny striations. Those kinds of wears can be distinguished from use-wear as they are isolated on the surface and limited to small portions of the tools not necessarily connected to use or hafting (Fig. 2.3.8, c-d). In other transportation modes, where leather and tools are not tied together, the contact is too weak and discontinuous to produce polishes. Finally, the friction between flint implements could produce polishes. I recognized, on the very edge of the tools, some flat and bright spots with tiny striations that resemble polishes caused by the contact with hard materials (Fig. 2.3.8, e).

6) Previous use-wears develop a series of modifications after being transported. Scarring is the most evident alteration of the used edges. In fact, during transport a series of small fractures are often produced all over the used area, interrupting the polish and revealing the original flint surface (Fig. 2.3.8, f-g). Transportation also produces striations overlapping with the underneath polish. Both elongated striations and tiny scratches are visible in mode A, B and C (Fig. 2.3.8, h). In transportation mode D modifications are limited and hardly detectable as the leather wrap protect edges from wear phenomena.

7) The amount of wears seems to increase in a linear manner over time. The longer the instruments were transported, the higher the number of stripes and bright spots, more intense the gloss on the surface and the scarring of the edges. Edge-damage and striations are the first alterations to be produced, as a first contact between tool surfaces is produced when implements are mounted together inside the bag. Polishes and abrasions develop gradually during transportation as friction between the surface is produced during movements. In mode A and B well-developed transportation wears are produced already after 10 hours of transportation, while in mode C and D at least 30 or 40 hours of transport are required. However it is difficult to properly estimate

Fig. 2.3.8. a) Gloss produced by transportation (400X magnification); b) Same surface after H2O2 treatment (400X magnification); c-d) Polishes caused by the contact with the leather wrapping (200x and 400x magnification); e) Polish spot that resemble contact with hard material (400X magnification); f-g) Transport-scars interrupting plant polish (400X and 100X magnification); h) Scratches overlapping plant polishes (400X magnification).

how the time affects transportation wears production, as traces are not intentionally produced on the flint surface, but casually - and their degree of development could vary notably from one tool to another depending on the movements and the stress that suffered.

2.3.2.2.2. Modes of Transportation

On the basis of this experimentation I consider that the only reliable modes for transporting lithic tools are modes C and D. If one assumes that the main concern in the long-distance transportation of stone tools is the preservation of the cutting-edge from accidental damage, then only the presence of a leather string holding together the implements against the stress and the motion caused by transport, represent a valid response.

In the other modes (mode A and B) transportation could destroy the potentially functional edges. Even the presence of a leather wrap inside the bag (mode B) is not sufficient to prevent edge-damage, as during the trip the stone implements tend to move from their original position, losing the protection of the leather and possibly crashing into each other.

However, this experimentation does not pretend to reproduce all the possible ways in which prehistoric transportation could have occurred. For the archaeological case in analysis I cannot make reference to any specific ethnographic source. So, I based the experimentation on the basis of data and results previously published by other authors and on the basis of my common sense. This consideration, does not implicate that this experimental practice reproduces correctly prehistoric modes of transporting lithic tools; I simply tried to reproduce some plausible ways to do it, assessing which of these are reliable and which are not.

2.3.2.3. Final Remarks

As already stated by other authors (Odell & Odell-Vereecken 1980, Rots 2010), transportation produces quite different wears, mostly in terms of distribution and recurrence, from hafting and use-wear traces. However, scholars rarely wondered if it is possible to distinguish such wears from other sort of modifications, as depositional or post-excavation damage. Indeed, all of these wears involve similar physical forces (as compressive stress and sliding contact between siliceous materials, friction with organic matter, etc.).

Moreover, both transportation, post-depositional or post-excavation alterations, are involuntary, not deliberately produced by humans, as happen in use-wears, where the contact between the tool and the worked material is intentionally sought. Thus, is not surprising that the result will be a set of broadly comparable kinds of wear phenomena. In particular, post-excavation damage (e.g. the storage of lithic materials all together in a plastic bag) completely mimics, and consequently cancel, prehistoric transportation wears.

In my view, the main relevant difference between transportation traces and other post-depositional modifications is the absence of an extensive rounding all over the lithic surfaces.

Erosion natural forces, because of the size of the soil particles, can lead to changes at a microscopic level, polishing and rounding down to the most microscopic high-points of the lithic surfaces. Transportation does not produce such extensive rounding, as the contact between the lithic implements, the wrap, the string and the bag, is always limited to some specific points, never involving the entire surface.

In this sense, assuming that the modalities that I adopted for transporting lithic tools are

plausible for prehistoric conditions, my experimentation has permitted to advance in the understanding of the type of wears that transportation practices can produce on chert surfaces. On the basis of the distribution pattern of the wears and on the basis of the concurrence of two or more types of the previously described traces (edge-damage, striations, bright friction spots, hide-like polishes, alteration of pre-existence use-wears, absence of extensive rounding) it may be possible to determine if a lithic tool has been or not transported.

However, I still consider the detection of transportation wears a controversial issue. Even if use- and transportation-wears can be confidently distinguished, both post-depositional and post-excavation alterations can largely overlap those traces. In my view, prehistoric transportation could be confidently detected on flint tools through microscopic analysis only on well-preserved materials. Moreover, the microscopic analysis of wears should be integrated by other sources of information. Important data about prehistoric transportation directly from the archaeological context. Indeed, the analysis of the procurement and reduction strategies of the lithic materials could offer important indications in that sense. It is fundamental, more than ever for the interpretation of transportation modes, to integrate functional data in the overall context.

2.3.3. Tools for Ceramic Production and Maintenance: a