Investigation of tin, arsenic and lead concentrations in prehistoric arrowheads

Abstract

Copper arrowheads discovered inside burial sites at Jabal al-Buhais were analyzed using X-ray fluorescence spectrometry to reveal the elemental composition and to quantify the concentrations of tin, arsenic and lead. Archaeological analysis of the various artifacts found in the tombs reveals different chronological eras from the late stone-age (5000 BC) to the Hellenistic period (200 BC); thus determination of the arrowheads' copper alloys will improve the archaeological information pertaining to dating and provenance. Analysis of 39 arrowheads revealed that 19 are made of pure copper, whereas tin, arsenic and lead are present in trace amounts. The remaining 20 arrowheads are made of bronze (all, except two, were found in burial sites 51 and 64), with high concentrations of tin (min 1.79%, max 22.94% and average 8.9%). The elemental composition of the arrowheads strongly suggests that they were locally manufactured, most probably from raw copper smelted nearby at Wadi al-Hilo. Since there are no records of local tin mines, most probably it was imported from outside the region, from mines as far away as Afghanistan.