Dating surface archaeological sites in Tibet and Australia

The project, Out in the open: Dating open archaeological sites in Tibet and Australia using luminescence-based dating techniques, will make significant contributions to the fields of archaeology and geochronology. Because stone is so resilient, the most common and obvious remains of Palaeolithic material culture are stone tools, quarries, and stone arrangements and megaliths. However, it is difficult to determine when humans made these kinds of sites, which are, thus, difficult to understand relative to the archaeological and palaeoenvironmental records. This project has two general aims that will address this problem. First new approaches for dating very common archaeological site types will be developed that will add significant tools to the quiver of archaeological scientists. We will apply existing and recently developed methods based on optically stimulated luminescence (OSL) in novel ways to develop approaches that can be used to date the use of lithic quarries, the construction of stone arrangements and megaliths, and the accumulation of surface artefact scatters. The second aim of this project is to apply these approaches to resolve two questions in contexts where more classical approaches have failed: when was the high altitude core of the Tibetan Plateau permanently colonised by Palaeolithic humans and how did continent-wide Australian stone arrangement culture develop temporally? The innovation and originality of this project underscores its international significance to the disciplines of archaeology and geochronology. The new approaches developed in this project will enable archaeologists to research accessible and new types of sites. Likewise, the numerical chronologies for central-Tibetan occupation and Australian stone arrangement construction will be valuable contributions to regional- and global-scale archaeological discussions.

The most resilient, common, and obvious remains of Palaeolithic material culture are made from stone: scatters of stone tools, lithic quarries, and stone arrangements and megaliths. However, it has been difficult to use classical methods to determine when humans made these kinds of sites, which makes them difficult to understand in the context of the archaeological and palaeoenvironmental records. In this project, we succeeded in addressing this problem by developing and testing new methods for dating these site types using the luminescence signal from mineral grains. During the course of the project, we developed and applied new techniques for dating (i) when fresh rock surfaces were first exposed, (ii) when stone tools were discarded by their makers, and (iii) when boulders were emplaced in stone arrangements. We performed and published the first laboratory validations of the OSL-Surface Exposure Dating method, which we used date a stone tool quarry in Tibet. We developed a new method for dating the discard of stone tools, which we applied to artefacts at the Tibetan stone tool quarry site. We used a systematic, new approach to date the construction and maintenance of a stone arrangement complex in Australia, showing pulses of maintenance and eventual abandonment of the site. These newly developed methods have the potential to give us a much more precise understanding of human prehistory by directly dating human use of the landscape.