This study presents an integrative geoarchaeological and microarchaeological case study of combustion features,
employing a multi-method analytical approach incorporating archaeomagnetic, rock magnetic, and soil micromorphological
methods, alongside Quantum Diamond Microscopy (QDM). The case study focuses on a combustion
feature from the Middle Palaeolithic site of El Salt (80 to 45.2ka). The primary aim is to reconstruct the
depositional and post-depositional history of this combustion feature, identifying human activities and environmental
processes using high-resolution magnetic and micromorphological data.
The combustion feature H89/90 was studied as part of the research into a large palimpsest of combustion
features located within Unit XI. Archaeomagnetic and rock magnetic microarchaeological analyses of the combustion
feature demonstrates that it is relatively well-preserved and in situ. This integrative approach reveals
clear evidence of anthropogenic behaviours, including hearth maintenance, the use of grass-based fuels, and
potentially the active sustaining of fire through the successive addition of these fuels. Furthermore, the study
highlights maghemite as the primary magnetic carrier within the combustion feature. This mineral is not
commonly reported as a dominant magnetic phase in archaeological hearths. Its presence suggests either previously
unrecognized burning conditions, microenvironmental factors unique to this feature, or a broader need to
improve the resolution at which hearth mineralogy is studied.
These interpretations are possible through high-resolution rock magnetic analysis, enhanced by QDM's
micrometer-scale magnetic field mapping. Representing the first known application of QDM in archaeological
science, this method allows researchers to visualize internal magnetic fabrics directly within thin sections,
enabling the identification of specific microfacies and magnetic structures that are typically invisible to traditional
micromorphological analysis. As a result, this method not only deepens our understanding of the magnetic
architecture of the hearth but also strengthens behavioural interpretations of its formation and use. Overall, the
study demonstrates the value of a deeply integrated magnetic microarchaeological approach for investigating
human behaviour associated with fire use.
