Sila Thoranam, a naturally formed arch of rock is a distinctive geological wonder located about 1 km north of the Sri Venkateswara Temple, near the Chakra Teertham at Tirumala. The Arch is also called Silathoranam in local language (Telugu language: “Sila” means ‘rock’ and “thoranam” means a garland strung over a threshold, connecting two vertical columns or an ‘arch’ as in this case). Since the rock look likes and appears to be the hood of a serpent, a conch and a discus, it is conceived that this source is dedicated to Lord Venkateshwara idol.
The arch measures 8 m (26.2 ft) in width and 3 m (9.8 ft) in height, and the Geologists have identified the rocks on the hill as pre-Cambrian, and this arch formation suggests an antiquity of several million years to the Tirumala hill.
History of Silathoranam Tirumala
In the 1980s, during excavations for a geological fault in the Tirumala hills, geologists found this rare geological formation of the rock arch which has two dissimilar sets of rocks with a connecting thin link. The assessed geological age of the rock arch is 1.5 billion years. Formation of the arch is attributed to intensified weathering and erosion of stream action that has withstood the torque of nature. This is a rare geological fault which is technically called in the geological idiom as ‘eparchian unconformity’.