Beyond the Bulk: Interpretations of Multi-Temporal Pyrostratigraphies through Integrated Micro-Contextual and Geochemical Proxies

Pyrostratigraphic records often represent high-entropy systems where overlapping combustion events and diagenetic pathways obscure the original anthropogenic signal. To resolve these palimpsests, we adopt a comparative assessment of selected archaeological deposits characterized by complex fire-related evidence through a multi-scalar integration of high-resolution field stratigraphy, and sediment geochemistry and micromorphology. Bulk sediment samples were analysed using X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), Raman spectroscopy, and Fourier-transform infrared spectroscopy (FT-IR); the study also involved FT-IR analysis of a selection of bone fragments recovered from the deposits. These datasets are complemented by micromorphological analysis in thin section, including micro-FT-IR, to resolve the spatial averaging of bulk signals and enable the micro-contextual characterization of combustion residues and associated diagenetic processes. The multi-proxy approach allows for the identification and quantification of key mineralogical and geochemical transformations, including phosphate enrichment linked to organic waste inputs, clay mineral alteration, and crystallinity index of calcite, aragonite and apatite [1]. The focus is on diagnostic microfacies, including rubified substrates, vesicular and platy microstructures, charcoal-rich aggregates, dung-derived elements, and calcitic ash diagenesis pathways. These proxies are used to reconstruct the thermal history of the deposits, combustion temperatures and site-use intensity. The case studies span diverse environmental and chronological contexts: Riparo Mochi (Liguria), preserving a dense succession of Proto-Aurignacian and Aurignacian combustion features; Riparo Gaban (Trentino), characterized by Early Neolithic fumier deposits associated with penning, burning, and organic accumulation cycles; and Baratti - Centro Velico (Tuscany), a coastal site dated to the 12th-11th centuries BCE, representing an exceptionally well-preserved briquetage workshop for salt production [2, 3]. The results highlight the analytical and interpretative potential of an integrated geoarchaeological framework for deconstructing the formation processes of anthropogenic sedimentary facies and for refining behavioural and environmental reconstructions in pyrotechnological contexts. By deconstructing these complex sequences, the study demonstrates that geoarchaeological proxies are indispensable for identifying subtle shifts in site-use intensity and pyrotechnological efficiency. This approach transforms static stratigraphic units into dynamic records of human decision-making and environmental adaptation across different cultural stages.