Chlorine as a Discriminant Element to Establish the Provenance of Central Mediterranean Obsidians

Abstract

Chlorine is a minor element present in obsidians in quantities greater than in average igneous rocks. The chlorine concentration in obsidians is generally low, of the order of tenths of wt %, but it exhibits an appreciable differentiation among geological sources. Despite these characteristics, chlorine has rarely been taken into consideration as a possible indicator of obsidian provenance and it does not appear in the chemical analytical tables accompanying the geochemical characterisation of obsidian samples.

Keywords

• chlorine geochemistry
• central mediterranean obsidian
• epma analyses
• obsidian-sources discrimination