Resumen
Remote sensing in archaeology has grown to become a large and varied field nowadays. In the recent years, a strong emphasis has been put on the use of high precision and accuracy tools to achieve a more detailed documentation of archaeological elements (drones, LIDAR, etc.). Satellite remote sensing has also benefited from the increase in the spatial and spectral resolution of the sensors, an improvement that is allowing the discovery and documentation of new archaeological features and sites worldwide. While there is no doubt that a lot is being gained with those “site detection” approaches, there still remains a large potential to be explored of remote sensing methods as tools to analyse archaeological problems, especially at large geographic scales. In this paper, we discuss that potential by focusing on one common archaeological problem: the mapping of environmental resources used in the past, and in particular the procurement of lithic raw material by hunter-gatherer groups. Geological studies since the 1970’s have tested the capacity of satellite remote sensing for lithological mapping in different environmental contexts, highlighting the ability of spectral analysis to discriminate between the diverse rock and soil units, thus complementing and improving the accuracy of the data provided by conventional geologic maps. However, these techniques have received only little attention by archaeologists concerned with the procurement of lithic resources in the past, despite the remarkable advantages they represent for addressing this problem at a large spatial scale. We argue that a remote sensing and GIS-based approach holds the potential to overcome some of the major limitations of traditional archaeological methodologies when faced with questions about resource catchment in massive and harsh study areas that lack detailed baseline data. To illustrate our points, we will show how the combined use of freely accessible Landsat 8 images and “ground-truthing” through focused field studies has allowed identifying in a vast area of the Atacama desert, encompassing 22.500 km2, a discrete number of potential sources of silex, the major lithic resource used in coastal archaeological sites spanning from 12.500 to 1.500 cal. BP. This is a large scale approach that takes full advantage of the natural conditions of the study area and also of the information contained in the “grey literature” provided by spatially discrete and dispersed CRM reports, offering a cost-effective methodology which can easily be replicated in other contexts.The benefits and drawbacks of the methodology will be discussed, stressing the need of “ground-truthing” through VIS/NIR and FTIR reflectance spectroscopy for further refinement in the spectral satellite imagery processing and also to conduct lithic provenance studies with a high level of geographic resolution. Finally, we will discuss the strength of remote sensing techniques in addressing archaeological questions that comprise large spatial scales, and the key role that they can play in the detection and study of specific environmental resources, such as lithic source areas within challenging physical settings.