Debasement of silver throughout the Late Bronze - Iron Age transition in the Southern Levant: Analytical and cultural implications

摘要

The study of silver, which was an important mean of currency in the Southern Levant during the Bronze and Iron Age periods (similar to 1950-586 BCE), revealed an unusual phenomenon. Silver hoards from a specific, yet rather long timespan, similar to 1200-950 BCE, contained mostly silver alloyed with copper. This alloying phenomenon is considered here for the first time, also with respect to previous attempts to provenance the silver using lead isotopes. Eight hoards were studied, from which 86 items were subjected to chemical and isotopic analysis. This is, by far, the largest dataset of sampled silver from this timespan in the Near East. Results show the alloys, despite their silvery sheen, contained high percentages of Cu, reaching up to 80% of the alloy. The Ag-Cu alloys retained a silvery tint using two methods, either by using an enriched silver surface to conceal a copper core, or by adding arsenic and antimony to the alloy. For the question of provenance, we applied a mixing model which simulates the contribution of up to three end members to the isotopic composition of the studied samples. The model demonstrates that for most samples, the more likely combination is that they are alloys of silver from AegeanAnatolian ores, Pb-poor copper, and Pb-rich copper from local copper mines in the Arabah valley (Timna and Faynan). Another, previously suggested possibility, namely that a significant part of the silver originated from the West Mediterranean, cannot be validated analytically. Contextualizing these results, we suggest that the Bronze Age collapse around the Mediterranean led to the termination of silver supply from the Aegean to the Levant in the beginning of the 12th century BCE, causing a shortage of silver. The local administrations initiated sophisticated devaluation methods to compensate for the lack of silver - a suspected forgery. It is further suggested that following the Egyptian withdrawal from Canaan around the mid-12th century BCE, Cu-Ag alloying continued, with the use of copper from Faynan instead of Timna. The revival of long-distance silver trade is evident only in the Iron Age IIA (starting similar to 950 BCE), when silver was no longer alloyed with copper, and was imported from Anatolia and the West Mediterranean.