Refining Chert Provenance Methods: Evaluating Laser Ablation Spot Size and Reproducibility

Summary

This is an abstract from the "Current Methods and Applications to Chert Sourcing: Case Studies from Across the Americas" session, at the 90th annual meeting of the Society for American Archaeology.

This study evaluated the effectiveness of minimum spot sizes for laser ablation on chert artifacts to determine the trace element information required for accurate geologic source provenance. Using an NSF-funded excimer 193 nm laser and an inductively coupled plasma triple quadrupole mass spectrometer (ICP-QQQ-MS), laser ablation was conducted on NIST 610, 612, and 614 standards. Samples included chert from Edwards Plateau, Fort Payne, and Golden Valley, with three nodules sampled per formation and 10 flakes per nodule. A projectile point from each formation was also tested to simulate source attribution. Laser ablation spot sizes ranged from 1 to 150 microns, with each size replicated three times to assess variance and reproducibility.

This study incorporated internal standardization with isotopic ratios of silica (29Si/28Si) to correct for signal drift and matrix effects, and Ultra-High-Purity (UHP) gases to reduce nitrogen oxide interferences. Laser-induced fractionation effects and depth profiling were evaluated to ensure data integrity. Principal Component Analysis (PCA) and Random Forest Classification analyzed geochemical signatures to determine the optimal and smallest spot sizes for accurate source attribution. The research aims to refine analytical techniques in chert sourcing by maximizing data resolution and preserving artifact integrity through minimally invasive practices.

This Resource is Part of the Following Collections

• Society for American Archaeology 90th Annual Meeting, Denver, CO (2025)   •
• Current Methods and Applications to Chert Sourcing: Case Studies from Across the Americas

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Record Identifiers

Abstract Id(s): 52228