Groundbreaking technologies in the Middle Paleolithic of the Levant : high resolution and multi-scale functional analysis of Ground Stone Tools

Abstract

The study of Ground Stone Tools (GST) is a powerful topic of research to understand key elements related to the evolution of human behavior across time and space. As a clear and direct evidence for past human daily tasks such as percussive activities, these artifacts are a testimony of the oldest, most persistent and durable technological strategy in human evolution. Their origin stretches from the earliest evidence of human activity to the present day, across a wide geographic distribution. By definition, this group includes any stone item that was primarily manufactured through mechanisms of abrasion, polish, or impact, or itself used to abrade, polish, or impact (Adams, 2002). In the archaeological record, Ground Stone Tools diachronic and spatial distributions during the Middle Paleolithic of the Levant (ca. 250- 47 Ka BP) are mainly limited to mainly open-air sites, while their presence in caves and rock-shelters deposits is very rare. The reasons for these distribution patterns are still unknown. These patterns may be related to a research bias due to the difficulties in identifying these artifacts, or it can be related to the specific function that this material represented in each of the different location and type of site. From these contexts, in the literature a wide range of possible uses has been suggested for Ground Stone Tools, including the processing of organic materials (e.g., plants; faunal) and mineral products (e.g., ochres and bipolar lithic production). However, the correlation between different tool types, motions, and the processed material, and how these are represented in each site is still unknown. In order to contribute to identify and characterize Ground Stone Tools in the Levantine Middle Paleolithic record, two main problems need to be resolved: a) the development of analytical units that, via experiment-based actualistic studies, aim to improve the identification and characterization of the different types and scale of damage patterns presented on the surfaces of these materials, and b), through this approach, recognize and understand the specific function/s of these materials and its correlation with the rest of the site assemblages. To address these questions, this project follows a dedicated workflow characterized by 2 main research avenues: 1) technological and functional analysis using a high-resolution multi-scale approach, and 2) controlled experiments. The experimental program includes different types of Ground Stone Tools activities using limestone tools in a controlled environment. With the help of a mechanized system, a large number of variables can be controlled, resulting in numerical data to facilitate both the comparison of results and the replicability of the experiments. Functional analysis combines a high-resolution and multi-scale low and high magnification approach, as well as an integrated approach focused on both qualitative and quantitative analysis. This allows the acquisition of multi-scale 3D data, which aims to qualitatively assess and quantify different types of use-wear traces. In sum, this study presents groundbreaking research, contributing to the characterization of Middle Paleolithic populations behavior, addressing questions related to subsistence (e.g., food processing), technology and, possibly, symbolic behavior. The project also contributes to the methodological improvement of experimental and functional studies, by presenting a unifying methodology that contributes data for the comparison of Ground Stone Tools across time and space.