Geostatistical modelling of chemical residues on archaeological floors in the presence of barriers

Maps representing the distribution of chemical residues over anthropogenic floors are the main diagnostic tools used by archaeologists for addressing the identification of geochemical signatures of past actions. Geostatistics models these kind of phenomena with spatial variation, but restricted to homogeneous prediction regions. The presence of barriers, such as the inner walls of domestic units, introduces discontinuities in prediction areas. In this paper, we investigate how to incorporate information of a geographical nature into the process of geostatistical prediction. In this way, we propose the use of cost-based distance to quantify the correlation between locations, a solution which has proved to be a practical and competitive option for archaeological intrasite analysis. Thus, the cost-based approach produces more reliable results avoiding the assumption of certain unrealistic premises about the homogeneity of the study area. As a working example, a case study regarding the distribution of Calcium in domestic floors is presented within a controlled ethnographical context in Northern Gujarat (India). On a broad disciplinary scale, the benefits of using our approach include improved estimates in regions with complex geometry and lower uncertainty in the kriging predictions