Advances in using oxalate-rich mineral coatings as dating tools in Australian rock art shelters

Summary

This is an abstract from the "New approaches to the intractable problem of dating rock art" session, at the 90th annual meeting of the Society for American Archaeology.

Oxalate-rich, glaze-like mineral deposits are commonly found on low-angle surfaces in Australian rock art shelters. The synchronous growth of individual layers in these deposits across the Kimberley region of northwest Australia, suggests an environmental control, though the exact nature of this link is unclear. Some glazes, associated with Indigenous rock art, may serve as dating tools if oxalate biomineralization can be confirmed. This could link their formation to specific conditions and highlight their potential as paleoenvironmental archives when growth intervals are constrained by radiocarbon dating. Importantly, these deposits form on timescales relevant to the region’s rich rock art record, and a link between accretion formation and environmental conditions may provide opportunities to match regional scale change to transitions observed between styles in the detailed rock art sequence. In this study, gas chromatography-mass spectrometry, inductively coupled plasma-optical emission spectroscopy, and x-ray diffraction analysis, provide an improved understanding of the chemical and elemental composition of these materials and their potential sources. By identifying glaze-specific biomarkers and using metagenomic data, we propose a microbial formation mechanism for these deposits. This offers insights into the environmental conditions and processes influencing their formation and enhances their usability and reliability as dating and paleo archival tools.

This Resource is Part of the Following Collections

• Society for American Archaeology 90th Annual Meeting, Denver, CO (2025)   •
• New approaches to the intractable problem of dating rock art

Keywords

Record Identifiers

Abstract Id(s): 51392