Análisis arqueomagnéticos como herramienta para evaluar procesos postdeposicionales en fuegos arqueológicos

Abstract

Identify and evaluate post-depositional processes in prehistoric fires has important implications both from the archaeological and archaeomagnetic viewpoints. Formation and burial processes in archaeological cave fires have been almost exclusively studied from the geochemical perspective. However, the potential mechanical alterations undergone are usually evaluated from macroscopic observations. In this paper, we study the record of the archaeomagnetic direction in two Holocene cave fires from the Mirador Cave (Sierra de Atapuerca, Burgos, Spain), one apparently “in situ” and the other clearly bioturbated. This detailed paleomagnetic study allows establishing the magnetic features of an in situ archeological fire: i) in ashes, univectorial and high intensity NRM orthogonal demagnetisation diagrams; ii) Koenigsberger (Qn) ratio values higher than unity indicate of an undisturbed thermoremanence or partial thermoremanence and iii) a good clustering of characteristic directions defining an statistically representative mean archaeomagnetic direction. The concurrence of these observations can be used as criterion to determine when an archaeological cave fire preserves its primary position, thus allowing a correct interpretation of the archaeological record.