Non-destructive in-situ classification of sandstones used in the Angkor monuments of Cambodia using a portable X-ray fluorescence analyzer and magnetic susceptibility meter

The Angkor monuments were built between the 9th and 15th centuries using gray to yellowish brown sandstone, red sandstone, and greywacke, which are petrologically classified as feldspathic arenite, quartz arenite, and feldspathic to lithic wacke, respectively. Gray to yellowish brown sandstone was generally used in all of the Angkor monument temples. Red sandstone was used as the main building material in the Banteay Srei temple but was also occasionally mixed with gray to yellowish brown sandstone in temples built in and after the late Bayon period. Greywacke was the main building material in the five sanctuaries atop the Ta Keo temple and was also used for statues and Linga-Yoni pedestals. To distinguish these sandstones using a non-destructive and in-situ approach, measurements were performed using a portable magnetic susceptibility meter and portable X-ray fluorescence analyzer. The obtained Rb, Sr, and Y contents and magnetic susceptibility values were used to effectively classify the above three rock types. The results show differences in the magnetic susceptibility, Rb and Y contents between the greywacke used in the Ta Keo temple, that used in statues, and that used in Linga-Yoni pedestals, which demonstrates different source locations.