Statistical discrimination of Guatemalan jadeitite sources using LA-ICP-MS trace element and petrological data

Abstract

While tracing the geological provenance of Maya jadeitite-jade is key to understanding Mesoamerican exchange and extraction, distinguishing between the north (NMM) and south (SMM) Motagua sources presents significant challenges. This difficulty is due to shared mineralogical traits and the limitations of applying bulk whole rock trace element determination to invaluable archaeological objects. This study proposes an integrated statistical framework combining existing whole rock reference data with new Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) trace element measurements. We characterized 39 geological reference samples from both NMM and SMM, as well as 16 archaeological fragments from seven Maya sites. Despite complex multi-generation growth and local geochemical heterogeneities revealed by cathodoluminescence and LA-ICP-MS, a Partial Least Squares Discriminant Analysis (PLS-DA) model successfully discriminated between NMM and SMM sources 91.4% accuracy using eleven key trace elements (Th, Zn, La, Hf, Lu, Ce, Ni, Tm, Yb, Sr and Pr). Application of this model to archaeological samples suggests a predominant exploitation of NMM sources across the Maya Highlands, Lowlands, and Pacific coast. This approach validates LA-ICP-MS as a robust tool for jade provenance studies, overcoming the biases of accessory minerals inherent in whole rock analyses and offering a transferable strategy for archaeometric research.