Between a Rock and a Hard Place

sandstone

Science Snap (#19): Angkor Wat, Cambodia

Sorcha McMahon is a third year PhD student in the School of Earth Sciences at the University of Bristol. Sorcha is investigating how strange igneous rocks called carbonatites may have formed, using both natural samples and high-pressure experiments.

The word Angkor is derived from the Sanskrit term Nagara meaning “Holy City”, and was the capital city of the Khmer. It consists of successive city foundations and temples constructed by the kings of three dynasties over a period of about 600 years. The site is most famous for Angkor Wat, the largest religious monument in the world, which has been a part of the Cambodian national flag since the first version was introduced circa 1863.

View of Angkor Wat, Cambodia. The temple is part of the Angkor World Heritage Site, established in 1992.

View of Angkor Wat, Cambodia. The temple is part of the Angkor World Heritage Site, established in 1992. Photo credit: Sorcha McMahon

Angkor Wat was constructed under the rule of King Suryavarman II (reigned AD 1113 – 1150), and built in the form of Mount Meru, home of the Hindu gods. The main temple incorporates 5 towers, representing the peaks of Mt Meru, and is surrounded by ~1×1 km walls (‘mountain ranges’) and a moat (‘ocean’). The temple was built as a place to worship ancestors and as a mausoleum to receive the cremated remains of individual kings.

The temple beautifully displays the classical style of Khmer architecture. Over 5 million tons of sandstone was used in the temple’s construction. Rocks were transported by raft along the Siem Reap river from Mount Kulen, ~ 40 km to the north east. Laterite, a clay formed by weathering of rocks in the tropics, was also used for internal structure. Large blocks were laid without mortar, and it’s likely that elephants, ropes, pulleys and bamboo scaffolding were all employed in the construction. Today, holes in the blocks can be seen (~2.5 cm diameter and 3 cm deep), probably used to aid lifting the blocks into place using metal rods. Angkor Wat was completed in around 40 years (the duration of the king’s reign), although a modern engineer estimated that it would take 300 years to complete Angkor Wat today!

Much of Angkor Wat’s sandstone surface was apparently once covered in gold, and other temples in the area were originally red (painted using tree resin). Bas-relief friezes (low relief images typical of Hindu-Buddhist arts in India and SE Asia) dominate the decoration. Imagery includes the king, his court, and iconographic scenes drawn from the Hindu religion. Apsaras (female spirits of the clouds and waters in Hindu and Buddhist mythology) and devatas, from the Hindu term for ‘Deva’ meaning deity, are abundant; there are more than 1796 depictions of devata in the present research inventory.

Intricate bas-relief on the ceiling and walls inside Angkor Wat. Remnants of the original red colour has been partially preserved.

Intricate bas-relief on the ceiling and walls inside Angkor Wat. The original red colour has been partially preserved. Photo credit: Sorcha McMahon

Sandstone carving of devata at Angkor Wat. Credit: Sorcha McMahon

Sandstone carving of devata at Angkor Wat. Photo credit: Sorcha McMahon