Supervised laser induced breakdown spectroscopy classification for prehistoric chert provenance: A methodological framework

The sourcing of lithic artefacts, and in particular chert, is a key proxy for archaeologist to better understand hunter-gatherer populations. The heterogeneous structure of chert samples, low trace element content, and variability of outcrops make the geochemical characterisation a methodological challenge. Laser Induced Breakdown Spectroscopy (LIBS) can overcome the issues of variability by enabling fast and low-cost and nearly non-destructive analysis of samples. This paper presents a protocol for chert sourcing using LIBS, by comparing several supervised classification models and signal pre-processing with two different approaches: a selection of features or the use of broadband spectra, with an example application on marine flysch cherts from the central Pyrenes (France) presenting similar micropaleontological and textural features. • LIBS enables fast and low-cost classification of chert samples with converging geologic features. • Classification performance is better than previously investigated methods (ED-XRF, LA-ICP-MS). • The classification performance is highly dependent on the data processing used, comparing models is necessary. • Selection of features via peak fitting is more robust than broadband spectra analysis.