Fig 1.
(A) Location within the 12th c walled enclosure of Angkor Thom (adapted from Angkor GIS map data of Pottier [8] and Evans [9] for illustrative purposes only). (B) Details of the eastern façade. (C) Plan showing location of the Reclining Buddha outlined in red (plan of Baphuon similar but not identical to the original image from Royère [10] and is for illustrative purposes only). (D) Details of the modification of the western façade.
Fig 2.
Location of bow-tie crampons from the original structure (BPN-30001, BPN-30002, BPN-30006) and the u-shaped crampon behind the head of the Reclining Buddha modification (BPN-30009) that could have been dated.
Section of Baphuon is similar but not identical to the original image from Royère [17] and is for illustrative purposes only.
Fig 3.
Documentation of the dated specimens.
Sampled parts within each crampon are shown in white. Schematic drawings of the microscopic metallographic observation on the cross-section after Nital etching enlighten the distribution of the carbon content within the metal. The black marks within the metal of the most carburized samples, selected for the radiocarbon measurements, indicate the fingerprint of the drill samples. 2 dates were obtained for each crampon BPN-30001 and BPN-30002. Both samples BPN-30009(1) and BPN-30009(2) from BPN-30009 could be dated therefore providing 2 dates for the crampon.
Fig 4.
Treatment of SI measurements for BPN-30009 (BPN-30009(1) and BPN-30009(2)) for which numerous welding lines were identified.
(A) Localisation of the hyperspectral maps performed on representative zones of each artefact BPN-30009(1) and BPN-30009(2). (B) (left) BPN-30009(1) and BPN-30009(2) SI subcompositional ratios (noted Xij NRC) projected onto the first two PC axes. The PCA conducted on the standardized Xij NRC (in this case, the only detectable NRCs are Al2O3, SiO2, MgO, CaO) and a hierarchical cluster analysis [21] reveals 6 groups (one color per group). Comparing group projections and loading structure (right), “black and grey” group is identified as smelting slag; red group seems to be derived from or contaminated with silica flux; green, blue, brown and orange groups derived from or contaminated with fuel ash. For more information [21]. (C) (left) X-ray map of an analyzed zone at O Kαline and spotting of the contaminated SI identify by the statistical analysis. (Right) The SI colored in green are representing SI from green group. It is not possible to identify various groups within the group identified as smelting slag evidencing that the Xij NRC and therefore the chemical signatures are comparable for the different parts of BPN-30009(1) and BPN-30009(2) and between them. No case of recycling was detected for BPN-30009.
Fig 5.
Calibrated (95.4% probability ranges) and modelled radiocarbon dates obtained for iron crampons from the Baphuon temple and from the reclining Buddha of the western side.
The dotted gray box denotes the two sub-samples for each crampon. Results from the Baphuon temple are compared with the reigns of kings Jayavarman V (968–1000 CE), Suryavarman I (1010–1050 CE) and Udayadityavarman II (1050–1065 CE). Results from the Reclining Buddha are compared with the period of Ayutthayan occupation at Angkor.
Table 1.
Radiocarbon dating results for the crampons from the original structure (BPN-30001, BPN-30002, BPN-30006) and Reclining Buddha modification (BPN-30009).