Microstratigraphic Laboratory-Based Excavation of an LGM Hearth From Shizitan 29 (North China Loess Plateau): Challenges and Opportunities

The deeply stratified, open-air site of Shizitan 29 (Shanxi Province, China; ca. 28–13 ka cal BP) provides crucial, diachronic evidence for hunter-gatherer adaptations to the severe global cooling of the Last Glacial Maximum (LGM), including a rare, well-dated sequence for the development of microblade technology [1, 2, 3]. During the original salvage excavations of the 50 × 30 m site in 2009–2010, time constraints led to the lifting of over 160 undisturbed sediment blocks (~1 m³ each) containing distinct combustion features to preserve their spatial and stratigraphic integrity. This forward-looking conservation strategy presents both challenges and opportunities, and we discuss here how state-of-the-art methodologies are allowing us to analyse these ephemeral LGM traces today in ways that were difficult to implement or unavailable during the initial excavation. As researchers will increasingly face the methodological challenges of investigating such complex features, we present our choices and experiences in a pilot ex-situ laboratory-based micro-excavation conducted in November 2025. We focus on the methodological framework applied to Box 47, containing a well-preserved hearth (5H4). To manage the spatial complexity of the deposit, the volume was subdivided into elongated north–south-oriented blocks (STRIPs) and excavated through ~3-cm artificial spits. This spatial control, supported by 3D modelling, enabled highly precise sampling tailored for contemporary high-resolution geoarchaeological approaches, including soil micromorphology, geochemistry, and microbial DNA analyses. While Box 47 preserves a single combustion feature, integrating these high-resolution sedimentary and biomolecular data can yield profound insights into LGM fire use, pyrotechnology, and hunter-gatherer activities. Crucially, these data allow us to retrospectively recontextualise the evidence from this feature within the site’s broader original stratigraphy and palaeoenvironmental contexts. Ultimately, this initial micro-excavation attempt will serve to develop a robust methodological protocol for more efficient excavation of the remaining boxes. This ex-situ approach maximises data recovery from vulnerable deposits and provides a viable, forward-looking geoarchaeological strategy that can be successfully applied to other prehistoric contexts. This study is conducted within the framework of the Italian project “Modern Behaviour among the last foragers and first farmers in Eastern Asia” partially funded by the Italian Foreign Ministry (MAECI, DGCE XIII), the Italian Institute of Human Palaeontology and MIST Project (Fondazione CARITRO, SIME 2024.0578). D. Cohen’s work is funded by Taiwan National Science and Technology Council grant 114-2410-H-002-110-MY2.