Lithotheques, interdiscipline and common language among Archaeologists and Geologists. An example from Patagonia (Argentina)

FERNÁNDEZ, VICTORIA; ALBERTI, JIMENA

Simposio; 5th Arheoinvest Symposium "Stories Written in Stone" International Symposium on Chert and other Knappable Materials; 2013

Lithic technology research was the first systematic approach to the archaeological record of Patagonia (Argentina), and has a long trajectory in the investigation of different aspects on the issue: techno-morphological analyses, use-wear analyses, lithic raw materials provenance, geometric morphometrics, use-residues, among others. Many of these investigations have been reinforced with the creation of lithotheques, of local or regional scale.Although these lithotheques aim to make comparisons with the archaeological record, they fail on the extent of their use. This may be due to the lack of unified criteria to classify and name lithic raw materials, probably because of the short time that archaeologistsand geologists have been working together, in spite of the long trajectory of the lithic analyses in Patagonia. This interdisciplinary research, which implies a considerable effort, is conditioned in Argentina by the different theoretical frameworks in geology, thespecialization areas of geologists, objectives of the archaeological investigations, as well as different analyses, methods and identification criteria that have been applied.In relation to the queries arrived at in our investigations, we have noticed that this lack of consensus regarding the classification and denomination of rocks makes it difficult to communicate and compare our observations with those of our colleagues in other areasof Patagonia, which implies that lithotheques are, in the end, not useful when the research aim is to achieve comparisons at the supraregional level. For example, in the case of Patagonia, we have found that sometimes a term that refers to a texture of a certainrock (e.g., porphyric) is used as a rock type (e.g., porphyric rhyolite) or that the same term is used to talk about different type of rocks (e.g., ignimbrite). This constrains the exploration of some of the most relevant issues of provenance analyses, e.g., human group mobility, lithic raw material circulation, exchange of information and people, among others. Because of this, we believe that a unification of the terms used to classify and name rocks that archaeologists use is necessary to transform lithotheques into useful and powerful tools to make comparisons at different scales of analyses and not only at the local level.In order to achieve our goal, we have made an exhaustive bibliographical review in a macroscale approach (Patagonia, Argentina) in order to detect the different nomenclatures and criteria employed to identify and classify rocks. To accomplish this task we haveworked along with Geologists specialized in Petrography, Mineralogy and Sedimentology. We think this interaction is fundamental to establish any classification of rocks. In this paper we propose a general classification for rocks and that are useful to lithic artifacts manufacture in Patagonia, based on current geological criteria. We want to highlight that this proposal is for macroscopic lithic raw materials identification (i.e. naked eye or a 10x lens). It seeks to create wide categories that include different types of rocks and which do not go against more precise identifications made using a petrographic microscope. This classification is based on the consideration of possible situations from which we could create a framework that includes them. Our intention is to give an example of the generation of a geologically based common language from an archaeological perspective, which we expect can be useful among Patagonia lithic analysts.