The first insight to materiality of rock art pigments from Western Papua Region (Berau Gulf, Fakfak)

Abstract

This study represents the first investigation into the materiality of pigment samples from the rock art of Teluk Berau, Fakfak, West Papua, employing a suite of analytical techniques including optical observation, scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and X-ray absorption near-edge structure (XANES) spectroscopy. This comprehensive analysis provides nuanced insights into the material composition and cultural significance of these prehistoric artworks. The findings reveal that hematite is the primary component in red, brown, and purple pigments, while goethite is used for yellow pigments. Additionally, naturally occurring minerals such as quartz and clay minerals are also present in the pigments. The study further investigates the microstratigraphic layers of the rock surfaces, identifying a base of limestone composed of calcite, followed by gypsum layers, anthropogenic pigment layers, and surface crusts predominantly made of gypsum. The research also identifies the potential formation of whewellite on the rock art. XANES analysis sheds light on the oxidation states and chemical speciation of iron minerals, suggesting a complex interplay between iron oxides and/or iron oxy-hydroxides in the pigments. This study also indicates a similar pattern of the pigment utilization across Southeast Asia and affirm the continuity of pigment-use traditions, particularly the use of ferruginous minerals such as hematite and goethite throughout the region. The study enhances our understanding of iron oxide and iron hydroxide variability, providing new insights into prehistoric pigment characterization that have not been previously detailed. However, the source of the pigment materials used by prehistoric artists in the West Papua region remains unclear, highlighting the need for further field studies to pinpoint potential local sources and their relationship with the surrounding landscape. Overall, this research deepens our understanding of hematite and ochre use in prehistoric societies, reflecting their broader cultural and symbolic significance within the context of prehistoric West Papuan communities.