The Pleistocene geoarchaeology and geochronology of Con Moong Cave, North Vietnam: Site formation processes and hominin activity in the humid tropics

This paper presents the results of geoarchaeological and geochronological investigations at Con Moong Cave, North Vietnam. Beneath the published, terminal Pleistocene sequence, recent excavations have uncovered a ~5 m stratigraphic sequence containing flaked stone artifacts and sedimentary features that indicate extensive post-depositional change. As the effects of tropical conditions on Pleistocene cave sediments are poorly resolved, a range of complementary techniques was selected to reconstruct the nature of on-site sedimentation and occupation, while assessing the taphonomy of archaeological and palaeoecological materials. Our approach incorporates microstratigraphic, geochemical and sedimentological analyses, using optically stimulated luminescence (OSL) dating to estimate the time of sediment deposition in the cave. This case study has broad application to tropical zones worldwide. Sedimentation began in early Marine Isotope Stage (MIS) 4, while micromorphologically observed human occupation commenced before 42 thousand years ago (ka). By placing our results within the context of published, high-resolution regional records of climate, we demonstrate that on-site rhythms of Pleistocene occupation correlated with environmental changes in the region. During MIS 3, episodic abandonment of the site coincided with periods of drier conditions, while rapid climate fluctuations in MIS 2 corresponded with short-lived occupation events and a switch to predominantly geogenic deposition in the cave.