Carving out context; strengthening the case for an early human presence at archaeological sites in Asia and Australia

In the last few decades, the regions of Asia and Oceania have played a major role in the debate over human origins. These regions represent a ‘hotbed’ of hominin discoveries: new species (H. luzonensis, H. floresiensis, H. denisova), new genetic evidence of their interactions, and new H. sapiens early arrival sites (Lida Ajer, Fuyan Cave, Madjedbebe). This novel evidence has challenged conventional beliefs regarding the exit times out of Africa and the timing of dispersal through the region. However, establishing an early human presence in Asia and Oceania can be challenging. The analysis of human bones has had an immense impact on our origin story, but the context of the discovery and site is paramount to a secure interpretation of human remains and evidence. The two most vital contexts are the ‘when’ and the ‘where’, i.e., the timing and environmental setting. Environmental changes have forced human migration and it is widely acknowledged that despite Asia and Oceania’s importance in human history, the region’s environmental history is poorly understood due to a fragmentary record. Furthermore, the dating of human evidence is crucial for interpretation, but has been problematic in these regions due to criticism of association, provenance, and methodology.

In this research, a multi-disciplinary approach is used to develop a temporal and environmental context to establish an early hominin presence within sites in Asia and Oceania. An initial review highlights the under-utilised potential of faunal stable isotopes and clumped isotope thermometry to reconstruct the environmental context within these regions. The temporal context is explored within a site in Parramatta, Sydney, Australia, establishing a pre-last glacial maximum (LGM) human presence within the Sydney Basin. This represents the earliest continuous occupation in the region starting at ~32 ka and continuing through the LGM. The environmental context of Chinese hominin site Baxian Cave is explored using faunal stable isotopes and is directly compared to faunal stable isotopes from Lang Trang Cave in Vietnam. This revealed that hominins at Baxian were present in a dense C3 forest from 210-156 ka. For the first time, clumped isotope thermometry was applied to an archeologically relevant breccia from Baxian Cave and nearby Ma Feng Cave to reconstruct a paleo air temperature of 12º C alongside a wet climate.

These reconstructed temporal and environmental contexts provide vital details on climates at defined time periods, which strengthens the case for a human presence. Furthermore, they support evidence for human adaptions over time, from cold wet forests to extreme dry and dusty habitats. This provides valuable insights into hominin behaviour within Asia and Oceania.