In 2012, archaeological teams associated with the Ecole Francaise d'Extreme-Orient (EFEO) were able to uncover previously unknown bronze workshops at the ceremonial center of Angkor Thon in Siem Reap, Cambodia. Radiocarbon dating has confirmed the workshops were actively used during the 11th to 12th centuries at the height of Angkor civilization under King Jayavarman VII. Excavations for this project are now aimed at identifying the degree of metalworking (for both bronze sculptures and leaded roof tiles) at the ceremonial center of Angkor Thom during this important period. As a result, 251 soil samples were taken from 64 soil probes (and several test pits) in 2016 from across the ceremonial complex for processing and analysis by inductively coupled plasma-mass spectrometry (ICP-MS) at the Smithsonian Museum Conservation Institute in Suitland, MD. While in the field, portable X-ray fluorescence (pXRF) was used to determine in-situ heavy metal content for each soil core at the depth most commonly associated with excavated bronze workshops (at 100 cm depth when possible). Preliminary ICP-MS results reveal concentrations of Cu and Pb in several areas in excess of 1000 ppm, far exceeding expected environmental levels. P-XRF was found to precisely predict locations of suspected bronze workshop activity across the site of Angkor Thom. Examples of six soil probes demonstrating elevated and trace levels of Cu (as quantified by ICP-MS), demonstrating the ability of p-XRF to determine the presence/absence of a Cu-enriched area of the site.
For more information: Little, Nicole and Brice Vincent. 2021. Identification of Bronze Workshops using p-XRF and ICP-MS in Angkor Thom, Cambodia, Microscopy and Microanalysis, 27(S1): 2554-2555.