Mineralogy, geochemistry, and stable isotopes of Guatemalan jadeitites: A new method to determine the provenance of Mesoamerican jade artifacts.

摘要

The only known jadeitite source region utilized by Mesoamerican peoples lies in the Motagua Fault Zone (MFZ) in Guatemala. Petrologic diversity of jadeitites within sub-regions north and south of the MFZ makes artifact provenance identification difficult using current methods. Major- and trace-element characterization using LA-TOF-ICP-MS and stable isotopes, paired with traditional petrologic studies, discriminate jade sources near the MFZ, refining a previous sourcing method utilizing only mineralogy. Oxygen isotope data deviates between jadeites found north and south of the MFZ by approximately 0.5 to 4.0‰, overlapping between +8.6 and +9.1‰. delta18O values of jade artifact samples from a Classic Maya jade workshop at Cancuen span the range of both groups. Stable isotope data paired with elemental enrichment and depletion trends relative to chondrites correlate source samples from the same sub-regions. Thus, stable isotopic overlap between North- and South-MFZ jadeites may be distinguished by jadeite elemental composition.