Identification of Ceramic Traditions on the Prehistoric Mines of Gavà (Barcelona, Spain)

1 Introduction

The study of prehistoric pottery vessel production methods in the Iberian Peninsula has witnessed a significant increase in recent years (Calvo, Bosch, Gómez, & Molist, 2021; Cámara, Clop, García, Pons, & Saña, 2021; Cámara, Clop, García Roselló, & Pons, 2021; Clemente, Mazzuco, Mozota, & Díaz, 2019; Clop & Álvarez, 2009; Díaz, 2019; Díaz et al., 2020; Dorado, 2019). This research demonstrated the significant gap in the existing bibliography regarding the ceramic strategies and production techniques. However, the evidence shows a volume of information about typological, morphological, and decorative analyses. This type of study transforms shreds into direct fossils that contribute to data chronology and the definition of cultural groups (Gibson & Woods, 1990; Orton, Tyers, & Vince, 1993).

Since the beginning of the twentieth century, numerous researchers have emerged, developing a series of approaches that integrate archaeological and ethnographical data within laboratory analysis. These methodologies have allowed a more comprehensive understanding of the technical phenomena involved at different stages of ceramic vessel production (Balfet, 1953; García Rosselló, 2008; Gosselain, 1992, 2002, 2008; Rice, 1981, 1987; Roux, 1990, 2016; Shepard, 1980).

The concept of Chaîne Opératoire in relation to ceramic assemblage has become a frequent presence in contemporary archaeological literature, particularly in the context of Neolithic studies, providing almost unpublished information in many of the archaeological contexts. However, despite the significance of these works, they are often facing challenges regarding their recognition and impact, being undervalued and, in some cases, ignored.

The concept Chaîne Opératoire related to pottery studies is commonly found. It originated in ethnology through field work that observed the diverse fabrication processes of objects and their implication for social and symbological systems. This concept serves as evidence of the cultural and social dimension of the processes and, therefore, the technical aspects (Mauss, 1947).

From this point, a new school of anthropology and archaeology emerged, focused on the study of techniques, with notable contributions from A. Leroi-Gourhan and R. Cresswell, as key researchers.

In 1964, the concept of Chaîne Opératoire was introduced explicitly for the first time in archaeological literature by Leroi-Gourhan (1964, p. 164). It was defined as: “La technique est à la fois geste et outil, organisés en chaîne par une véritable syntaxe qui donne aux séries opératoires à la fois leur fixité et leur souplesse.”

This definition transformed the concept into a fundamental tool needed to describe the gestures and operational processes performed and adopted by different groups. On this basis, Cresswell (1976) developed the concept as: “a series of operations that transforms a raw material into a final product, which will be an object of consumption or tool.” It is Cresswell’s definition that serves as the foundation for the work presented in this article.

Numerous studies have been developed both as methodological proposals (Arnal, 1976; Berg, 2008, 2009; García Rosselló & Calvo, 2013; Manem, 2016) and as practical studies across different chronologies and geographical regions around the world. These include research on the Early Neolithic periods in southern Europe (Gomart et al., 2017); the Chasséen group in northern areas (Colas, 2007); Late Neolithic assemblages in central–western France (Ard, 2014); the valleys of Senegal (Gelbert, 2000, 2003); French Middle Bronze age assemblages (Manem, 2008), contexts in the Ecuadorian Andes (Lara, 2017); and in sites in the Orinoco Valley in Venezuela (Lozada, 2020).

This study is developed from the theoretical and methodological framework of Chaîne Opératoire as described by Roux (1990, 1994, 2003, 2010, 2011, 2013, 2014, 2016, 2019). The selection of this approach for analyzing our pottery set is guided by several factors: 1. the extensive body of work by Roux on different areas (ethnographical, experimental archaeology, and archaeology sets) has established a robust methodology for exploring social aspects through a technological overview; 2. the structured methodology recognized for the different stages of pottery production allows one to understand the different strategies employed by artisans; and 3. this methodology can be adapted to be applied on the pottery set related to its characteristics. Therefore, a lot of bibliography with different strategies on the study of the pottery technology and reconstruction of the Chaîne Opératoire is available (Ard, 2013, 2014; García Rosselló & Calvo, 2013; Gosselain & Livingstone-Smith, 1995; Martineau, 2002; Vuckovic, Filipovic, Stojanovic, & Risch, 2021).

Based on Roux’s approach, the objective of this study focuses on the manufacturing process of part of the ceramic production recovered from the Mines Prehistòriques de Gavà (Barcelona – Spain – Figure 1). This will be achieved through the identification of macro-traces of manufacture, since they provide valuable insights into the technological solutions employed during the time/work investment processes.

Figure 1

Location map of the site Mines Prehistòriques de Gavà (Author: S. Calvo).

The Mines Prehistòriques de Gavà is a well-documented site that has been recognized as a mining center focused on the extraction of variscite. The site has an extensive bibliography available since its discovery in the late 70s of the twentieth centuries. This mineral was transformed into personal ornamentation and distributed throughout the western Mediterranean region (Bosch & Santacana, 2009; Bosch, Gómez, Calvo, & Molist, 2020).

One of the most remarkable aspects of the archaeological complex is the network of mining structures formed by shafts, chambers, and galleries developed at various depths interconnected with each other. Once mineral extraction was completed, each mine was filled with residues of daily life, including fauna and botanical remains, ceramic fragments, lithic industries, bone industries, as well as remnants of mining activities and fragmented slate that allowed the creation of this network (Bosch & Borrell, 2009; Borrell & Bosch, 2012; Gimeno, Fernández, Villalba, Edo, & Blasco, 1996; Villalba, Bañolas, Arenas, & Alonso, 1986). This type of closure has led to a remarkable conservation of archaeological material, particularly ceramic remains, allowing the recovery of complete profiles and, in some cases, more than 50% of the ceramic vessels, which facilitates technological studies (Calvo, 2019).

The radiocarbon dates indicate the intensity of the extraction during the first quarter of the fourth millennium BC and the beginnings of the second quarter (Borrell, Bosch, & Vicente, 2009; Borrell & Orri, 2009; Borrell & Bosch, 2012; Calvo, 2019 – Table 1). During this period, the Catalonia region, where the Mines de Gavà are situated, was inhabited by a population belonging to a culture known as Sepulcres de Fossa. This homogeneous cultural group was associated with the consolidation of the agricultural and breeding practices in Catalonia.

The materials examined in this study originate from two mining structures identified as 5/11 and 16 (Figures 2 and 3). Both structures were selected for analysis among the numerous known mines due to materials recovered in well-defined contexts, with the availability of radiocarbon dating enabling the identification of a chronological framework of the Catalan Middle Neolithic period (Table 1); this period represents a peak in mining exploitation (Bosch & Borrell, 2009; Borrell & Bosch, 2012; Bosch, 2012; Oliva, 2015; Villalba, Bañolas, & Arenas, 1990; Villalba, 2002). The second factor influencing the selection of this site was the excellent preservation of the set of ceramic vessels recovered, something that is not usual in archaeological contexts.

Figure 2

(a) Ground plan mine 11 and (b) section mine 5 (Author: Villalba et al., 1986 modified by: S. Calvo).

Figure 3

Section mine 16 (Author: Bosch, 2010 modified by S. Calvo).

2 Methodology

The methodology applied in this work is based on the identification of macro-traces of manufacture left on the ceramic vessels, using both macroscopic observations (naked eye) and microscopic observations (Dino-Lite digital microscope).

The recognition of these macro-traces allows the reconstruction of the Chaîne Opératoire, which is characterized by a specific sequence of operations comprising three main parts: the base, body, and neck/lip. Each part of the vessel’s manufacture consists of two phases: first roughing out, which involves creating a homogeneous volume without the final geometric shapes, and performing, consisting of the sequence of operations that give the vessel its final geometric shape before finishing and surface treatment operations. Only the vessels produced using the mold technique are documented in a single phase (Roux, 1990, 2016).

Once the reconstruction of the Chaîne Opératoire of the ceramic vessels is achieved, the procedure to follow is to classify the ceramic assemblage using the same process, based on the technical processes and objects. This classification aims to identify the technical traditions present in the ceramic assemblage and, consequently, the social groups associated with them (Roux, 2016).

The procedure involves creating hierarchical techno-stylistic trees (of the dendrogram type), obtained through both the technological and typological classifications of the vessels. This approach enables the description of the technical processes and the objects produced offering an understanding of the different traditions comprising the ceramic assemblage. This analysis will be both qualitative and quantitative, allowing us to know the distribution of vessels and their belonging to each branch of the tree.

For the construction of this tree, two principles can be applied: either division or unification. In this study, groups are formed through division, according to the criteria that unifies all the vessels based on the type of clay mass we are working with and the sketching technique employed. As the reconstruction of the Chaîne Opératoire progresses, the groups are further subdivided until they reach a level where they can no longer be divided (such as finishes and surface treatments). This hierarchical tree reveals multiple Chaînes Opératoires rising from its branches, providing an overview of the technical traditions comprising the whole assembly. Through this observation, it is understood that each technical group represents a set of technical operations that make it possible to characterize the elements that distinguish them from another. This interpretation suggests that each technical group along with the specific aspects describing each branch of the tree enables the characterization of certain Chaînes Opératoires (Roux, 2016). The nodes, representing the bifurcation points in the tree’s branches, serve as indicators of the diversity of operational sequences and the artisans’ selection of techniques (Manem, 2008).

In summary, these trees facilitate the description of both the technical steps and the objects produced according to these processes, providing an understanding of the different traditions that build the ceramic assemblage. The obtained results indicate the distribution of vessels among the branches of the tree. Once the techno-stylistic tree is defined, it becomes possible to examine whether the technological variability is linked to functional and social factors, as well as to determine the complexity of the sociological composition (Roux, 2016).

Based on this approach, the vessels (total: 63 vessels) included in this study allow for typological recognition. By incorporating these data, we can gain insights into the production techniques employed within the ceramic assemblage, establish clearer delineation of technical traditions, and assess the significance of each tradition within the pottery set and the mining center context.

3 Results

Through the analysis of technical procedures and objects, the ceramic set is classified to identify the technical traditions and associated social groups. This classification provides a global view of the different traditions, both qualitatively and quantitatively. These traditions are represented through techno-stylistic trees, which help distinguish between functional and social variables (Roux, 2016).

In this study, the initial classification is based on the modeling technique applied to each vessel: assembled elements or clay mass. The results are classified in three different trees: vessels made from clay mass, vessels produced by assembling elements, and vessels created using a combination of both techniques named as mixed techniques (when the vessel was produced with these two types).

The first tree assembled element vessels (Figure 4) reveal 14 different production methods that originate from 12 different nodes. Each node indicates the diversity of operational sequences and the technique selection applied by the craftsmen (Manem, 2008). Although the coiling technique is consistent across the ramifications, there are variations in the application strategy: spreading in the A/B ramification, pinching in the A/I ramification, and drawing in the A/K ramification (Figure 5). Most cases exhibit a series of fingerprints, continuous over thicknesses and fissures.

Figure 4

Techno-stylistical group from assembled elements potteries (Author: S. Calvo).

Figure 5

Traces of assembled elements potteries: (1a) coils by drawing junction; (1b) fingerprints; (2c) coils by pinching junction; (2d) fingerprints from coils by pinching; (2e) coil organization in spiral; (3f) fingerprints from coils by spreading; (3g) fissure junction; (3g) coils by spreading junction (Author: S. Calvo).

From a border perspective, these Chaînes Opératoires can be differentiated into two main groups based on the vessel’s production methods, represented by the A/B and A/I ramifications. In these two variations, we observe important variability of typologies. The third group is characterized by a lower variability in production methods with techniques adapted to a specific typology. Within each group, the existence of variabilities between each production responds to the vessel’s morphology (first group) and by the functional option (second group).

The second tree represents mass clay vessels, which reveals the existence of two ramifications divided by one node (Figure 6). All vessels in this category were produced using pinching as a modeling technique. The node that divides this tree in two Chaînes Opératoires was detected by variations on the performing techniques. The first branch documents the scraping technique, while the second branch involves the production based on shaving techniques (Figure 7). In this case, it is possible to observe a technical difference between vessels. This first case includes small-sized vessels presented with noticeable traces and fingerprints in its fabrication (Figure 8). The second case features medium- to large-sized vessels showcasing a higher level of specialization artisan. The differentiation in techniques is characterized by functional aspects related to a variation in the vessel’s dimensions.

Figure 6

Techno-stylistical group from mass clay potteries (Author: S. Calvo).

Figure 7

Fingerprints by pinching technique from different points of view (Author: S. Calvo).

Figure 8

Fingerprints by pinching technique (Author: S. Calvo).

Finally, the third tree representing vessels using mixed clay techniques displays seven different ramifications by four nodes (Figure 9). This tree exhibits a higher level of complexity compared to the other two cases. All ramifications share a common base produced using the modeling technique with clay mass. However, two types of techniques are documented: on the first branch, A/B involves percussion techniques, while in the second branch, the vessel was produced using direct pressure.

Figure 9

Techno-stylistical group from mixed techniques potteries (Author: S. Calvo).

In this case, the first branch is the most interesting. Within this branch, some vessels exhibit a base production using molding techniques (B/C), while other vessels show hammering techniques (B/D). Beyond node “C,” various Chaînes Opératoires emerge, showcasing a wide range of techniques employed during the roughing-out stage, such as coiling technique by spreading, molding technique, and modeling by pinching. Additionally, different performing techniques are documented, including beating, pressure technique for the lip, scraping, and shaving techniques (Figure 10). The major evidence is the presence of a fissure between both techniques along with the presence of fingerprints.

Figure 10

Traces of mixed techniques: (a) flat prints from beating technique; (b) coils junction and flat prints; and (c) junction between coil technique and molding (Author: S. Calvo).

From a broader perspective, these six Chaînes Opératoires can be categorized into three principal groups of technical traditions distinguished by cultural features. In the first group, the morphological characteristics determine the different techniques used for its fabrication. Similarly, in the second group, the morphological characteristics play a crucial role in differentiating the techniques employed.

As an initial observation, it is possible to observe the existence of a great variability on the ways of production. While roughing-out techniques are more prevalent, the variability of techniques increases during performing and finishing techniques. It is acknowledging the artisan’s capacity to find technical solutions within the ceramic set to produce vessels with consolidated typologies specific to their social group.

4 Discussion

Once the technological analysis has been conducted, a comparative approach is applied to examine the social variations among the three different techno-stylistic groups. This comparison reveals the existence of six technical tradition groups at the site, each characterized by specific techniques and gestures, despite a homogeneous typological set. These six groups are described as follows:

1. Technological group 1: constituted by six pottery vessels; this group exhibits variations in the roughing-out stage, employing techniques such as coiling by spreading and molding (Figure 11). Some of the vessels are produced using both techniques. Although there are differences in the first stage, the most important characteristic is the use of percussion techniques on the pre-forming stage, as a beating, with occasional modeling by lip pressures. And finally, the use of burnishing as a principal surface treatment. The different manufacturing strategies that are documented in these groups respond to functional aspects of the vessel related to its size and typology: semi-spherical vessels and spherical vessels with medium dimensions and carinated open vessels.

2. Technological group 2: this group is significant due to the quantity of documented vessels (29 vessels) and the typological variability observed. All vessels within this group were produced using coiling by spreading as a technique on the first stage of its production. In this case, the most important techniques include performing by pressure (scraping technique), and all vessels documented in this group undergo a surface treatment of burnishing (Figure 12). In this group, it is important to mention the presence of the Venus de Gavà (Figure 13). This feminine figure presents the same technical procedure as the vessels of this group, and it is considered part of this technical group (Calvo et al., 2021). The technological variability observed within this group appears to be related to functional aspects, particularly in the manufacturing of the lips and surface treatment. In terms of lip modeling, the choice of a particular technique may depend on whether reinforcement is desired to prevent easy fracturing in that area. This suggests the presence of technical solutions integrated within this specific technical tradition to address potential issues during vessel modeling. Regarding surface treatment, the decision to apply a specific type of treatment seems to be influenced by the vessel’s dimensions, particularly in relation to their volume capacities. Therefore, the technological variabilities in this group respond in the first place to technical solutions developed during the manufacturing process or because of vessel use. Additionally, the dimensions of the desired containers also play a role in shaping the technological variations within this group. The most typological vessels documented in this group are carinated and spherical (both open and closed) with medium dimensions and containers with big dimensions.

3. Technological group 3: this group is characterized by a low presence of vessels with only ten documented examples. This low variability is documented on typological variation too. However, technological variability is significantly high, offering diverse technical possibilities considering the dimensions of the vessel. Techniques such as hammering, coils by pinching, and coils by spreading are frequently combined. The presence of flat prints, fingerprints, or overthicknesses indicates the use of these techniques. All vessels within this group show burnishing as a surface treatment (Figure 14). Notably, a unique vessel in this group features as a distinctive decoration: two diagonal lines on the base displaying an atypical morphology on the Catalan context (Figure 15). The other vessels associated in this group are spherical and big-dimension vessels, and open and closed carinated vessels with medium dimensions.

4. Technological group 4: Like technological group 2, this group has a significant number of potteries produced with this technical tradition (25 vessels). The typological variation within this group is considerable, while the technical gestures employed throughout the Chaîne Opératoire remain consistent in each phase. The documented differences in all procedures have minimal variability and are dependent on the type of the vessel. All of them were fabricated by coils by pinching technique; however, the carinated vessels combined this technique with molding. It can be observed in the presence of the junction fissure (Figure 16). Principally, the technical variants respond to typological factors and, finally, to the size of the vessels. The different typologies documented are spherical open vessel and closed carinated vessels, both in medium dimensions.

5. Technological group 5: This group consists of only seven containers that can be related between them, resulting in a low typological variability and, consequently, being the least documented group within the set. Consequently, there are few changes observed in the Chaîne Opératoire. All the vessels presented the same techniques throughout the fabrication process with a slight variation on the junction of the coils. Traces such as overthicknesses, fissures, and/or disorganized sections are similar across all vessels (Figure 17). The main differences in the sequence are documented in the modeling of the lips and, as documented in other groups, appear to be related to technical solutions addressing potential issues that may arise during vessel modeling. Finally, the typologies are semi-spherical medium vessels, spherical medium vessels, and carinated open and closed medium vessels.

6. Technological group 6: Finally, this group stands out in the study due to its low variability in both typological and technological characteristics. It exclusively includes open and closed carinated vessels, all of which are manufactured using the molding technique, with slight variations in surface treatments. The most documented feature in this group is thin walls (Figure 18). The variabilities in the sequence of operation are influenced by functional aspects related to the sizes of the vessels.

Figure 11

Technological group 1 (Author: S. Calvo).

Figure 12

Technological group 2 (Author: S. Calvo).

Figure 13

Observed traces on Venus de Gavà ((a) fingerprints, (c) coil junctions, and (b) traces from burnishing) (Author: S. Calvo).

Figure 14

Technological group 3 (Author: S. Calvo).

Figure 15

Atypical vessel with diagonal decoration (Author: S. Calvo).

Figure 16

Technological group 4 (Author: S. Calvo).

Figure 17

Technological group 5 (Author: S. Calvo).

Figure 18

Technological group 6 (Author: S. Calvo).

One common aspect among all these groups is that the different technological strategies employed in vessel production are closely related to dimensions and the type of the vessels. This relation is evident in the variability of the surface treatment.

All groups exhibit a high degree of typological variability. Technological groups 2 and 4 have standing out due to their big volume of vessels compared to the rest of groups. These two groups not only exhibit a large number of vessels but also demonstrate homogeneity within their typological corpus.

In contrast, technological groups defined (1, 3, and 5) feature a small number of vessels per tradition, and the typological variations within these groups are limited. However, technological group 6, characterized by a single sequence of operation but a significant number of vessels in comparison with the other groups, raises the possibility of relating it to the technological groups 2 and 4.

5 Conclusions

This study aimed to approach the analysis of ceramic materials from the Mines Prehistòriques de Gavà in a new perspective, moving beyond the conventional morphological and decorative analyses that have predominated in previous research on the Neolithic period (Muñoz, 1965; Martí, Pou, & Carlús, 1997; Roig & Coll, 2010). The objective was to provide fresh and significant insights into the manufacturing techniques of the ceramic remains within the historical framework of agricultural societies in the northeast peninsular.

This information is particularly valuable considering the archaeological context of historical periods analyzed and characterized by short- and long-distance exchanges. Understanding the various methods of manufacturing can provide us with significant information.

Through the data analysis conducted in this study, and how it is defined in this work, the study focuses in the first half of the fourth millennium (4000–3400 cal ANE) and specifically on mines 5/11 and 16; a great variability in the ways of doing allows us to define six different technological groups that reflect different technical traditions.

An important aspect to highlight within the vessel manufacturing process is the surface treatments employed, particularly the presence of high-quality burnishing. This technique effectively eliminates most of the technical evidence from the performing and finishing stages. Experimental studies have indicated that burnishing requires significant time and effort (Calvo, Bosch, Molist, & Gómez, 2018; Díaz, 2019). The technical gesture applied at a given moment in which the paste in the leather-hard state is optimal to avoid deformations and technical intermittences, while the piece acquires the brightness and good quality that characterizes the archaeological piece.

The results obtained in this study allow us to formulate hypotheses regarding functional and sociological factors represented on the techno-stylistically trees. Following the principles defined by Roux (2016), the evaluation of the grade of complexity enables the interpretation of the sociocultural context and the characteristics of the site.

To address these issues, it was essential to consider the functionality of the site. The archaeological site Mines Prehistòriques de Gavà shows a purely mining character intended for the extraction of the variscite and, later, its transformation into beads to necklace and/or bracelets. Therefore, it is a reason to focus on the characterization of the degree of complexity shown by the ceramic set.

The ceramic forms showed a great heterogeneity of Chaînes Opératoires, which allowed the definition of six technological groups within the same area. A technological group is also understood as representing different approaches to produce archaeological vessels, regardless of the type or functionality of the container. This is associated with the fact that each technological tradition would be, therefore, the representation of different groups. In fact, we propose two main social groups in the Middle Neolithic, represented by technological groups 2 and 4 (57% of total set), which are separated by the number of containers that form part of each group and, by the typological variability of dimensions, covering a wide range of functionalities that respond to the different needs. These two social groups would share the same objectives within the mining activity, such as the extraction of the variscite or the elaboration of corporal ornamentation. Since their exchange, they would also participate in shared spaces, including settlements, agricultural areas, and livestock areas, and they would collaborate in shared waste management areas; grouping one to waste is subsequently occupied as filler mines closed, such as to the case of both the mines 5/11 and 16. We reinforce this idea through the radiocarbon dates (Table 1) that show us the same data for both mines.

The data obtained from the reconstruction of Chaînes Opératoires can be further supported by radio carbonic data recovered in the different sectors of the site (Serra de les Ferreres and Can Tintorer), allowing us to consider a simultaneous activity of the different areas. It is possible with the presence of the two or more groups on the site, as commented by Borrell and Bosch (2009). In fact, the mines studied in this work are situated in the same chronological range (Table 1). The large size of the mine structures indicates the need for a substantial workforce to operate at the same time. Moreover, the practice of refilling the mines with residues suggests the coexistence of multiple groups in the same area, sharing mining goals.

These social groups would not only share domestic spaces or economic goals but also share the manufacturing method for certain ceramic vessels. This hypothesis has technological group 6 as an empirical basis, with open and closed carinated vessels, which present a single sequence of operations, representing 19% of the total set (Figure 19). These vessels manufactured in a concrete way of doing shared by both technical traditions perhaps respond to a common need or related to mining.

Figure 19

Percentages of the different technological group (Author: S. Calvo).

The presence of technological groups 1, 3, and 5, which are documented from a few individuals and, in fact, have a 24% presence throughout the ceramic set, with little typological variability of the defined corpus, gives these ways of doing a minority character in the manufacture of containers within the mining complex. The presence of these groups is related to one of the most important aspects that characterizes the Catalan Middle Neolithic, and well known, such as exchange networks. The Mines Prehistòriques de Gavà are considered as a receptor and distributor of materials that circulated in these exchange networks. It is likely that the existence of these groups is due to the presence of other craft groups less linked to the extraction of variscite but related to obtaining variscite in the form of necklaces and bracelets and the contribution of exogenous elements such as silex bedouliense or obsidian and some typologies as a painted vessel.

It is important to emphasize the fragmentation of ceramic containers. The re-assembly of different fragments has allowed for the study of nearly complete vessels. It is at this point, where it has been able to observe that these fragments do not come from a single stratigraphic level; the great majority of these containers are made up of fragments that come from more than one of the levels and even sometimes, up to three levels.