Plants vs. Stone Tools: A Protocol for Controlled Experiments and Correlative Microscopy for Traceological Studies in Island Southeast Asia

Riczar Fuentes1*, Joao Marreiros2,3, Ottmar Kullmer4,5, Walter Gneisinger2, Alfred Pawlik1,6,7, Rintaro Ono8, Nasrullah Aziz9, Sriwigati9, Merlyn Geromiano10, and Ivan Calandra2

This paper presents a protocol that was developed specifically for the identification of prehistoric plant processing in lithic assemblages of Island Southeast Asia (ISEA). This objective is not only important in terms of verifying or refuting the so-called ‘bamboo hypothesis’ – i.e. the assumption that tools made from bamboo may have replaced stone tools – but also for identifying other aspects of prehistoric technology in ISEA that relied on plant working. The experimental setup and analysis were conducted to test the working of bamboo in particular, using chert flakes in a controlled setting. The analysis of the stone tools prior to and following the experiments was conducted using a combination of 3D scanning, laser-scanning confocal microscopy, and optical widefield microscopy, supported by a correlative microscopy system. Our results indicate the role and influence of changes in chert material and surface texture, as well as bamboo species and size, on the resulting traces. The combination of the chert type and the original surface topography of the tool, and bamboo species particularly influenced micropolish formation. Further development of the respective experimental protocol is therefore needed to assess the mechanics of use-wear formation in controlled experiments relating to plant processing, prior to its application to archaeological questions. The results of our experimental use-wear analysis and the applied framework may be useful in obtaining additional diagnostic features for the differentiation of traces from different bamboo species and could contribute to filling the gaps in our understanding of prehistoric plant processing in the region.