New insights into the Pleistocene archaeology of North Vietnam: understanding tropical cave sediments through microstratigraphic investigations and geo-ethnoarchaeological experiments

The Pleistocene archaeological record of mainland Southeast Asia (MSEA) is difficult to interpret, due to a sparsity of dated sites and a lithic record that is ill-suited to typological analysis. These challenges are compounded by the poorly constrained effects of tropical environments upon the deposition, preservation and degradation of archaeological cave sediments. These uncertainties restrict the interpretative potential of archaeological investigations, but the development of a rigorous, geoarchaeological framework of interpretation that is tailored to tropical cave sites offers an opportunity to improve research outcomes in MSEA and in tropical zones worldwide. Con Moong Cave (henceforth CMC), a Pleistocene archaeological site in North Vietnam, provided a small-scale example with which to explore the effects of tropical conditions upon archaeological site formation processes, and the potential of micro-geoarchaeological methods to overcome the difficulties of site interpretation in tropical zones. Research at CMC produced a depositional history for the site that revealed a correlation between sedimentation, the intensity of human occupation and changes in regional precipitation, as recognised in speleothem records in the published literature. Mineral suites from CMC’s guano deposits did not conform to established models of guano-driven diagenetic change and suggested that fluctuating hydrological conditions had led to diachronous episodes of mineral authigenesis. A shortage of reference data relevant to these processes meant it was not possible to conclusively relate these results to sedimentary palaeoenvironments or to understand their effects on assemblage taphonomy. Geo-ethnoarchaeological experiments were conducted to generate such a dataset, to enable hypothesis testing of the models of environmental changes at CMC and provide an assessment of the effects of tropical climates on sediment diagenesis