Heat-retainer hearth identification as a component of archaeological survey in western NSW, Australia

Concentrations of heat-fractured rock are common in some areas of western New South Wales, Australia, and are frequently identified during archaeological surveys as the eroded remains of heat-retainer hearths, a type of earth oven used in the past by Aboriginal people to cook food. However, it can be difficult to consistently identify these features since heat-fractured rocks, like other clasts lying on the surface, can be dispersed or concentrated by a variety of geomorphic processes. In this paper, we describe a method we have developed for hearth identification and description to aid the consistent recording of these features. We recommend the use of a fluxgate gradiometer as a tool to verify that concentrations of heat-fractured rock are indeed the eroded remains of heat-retainer hearths. Using a gradiometer reduces observer variability and ensures that we are not overestimating the number of hearths present by including naturally occurring groups of stones not related to hearth activity. Adoption by others of a common method of hearth identification and classification would provide some degree of standardisation that will aid understanding of the patterns of Aboriginal occupation in the past.