Natural Arch at Tirumala Hills
Natural Arch, Tirumala hills is a distinctive geological wonder located 1 km (0.6 mi) North of the Tirumala hills temple, near the Chakra Teertham in the state of Andhra Pradesh, India. The Arch is also called Silathoranam(శిలాతోరణం)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). The arch measures 8 m (26.2 ft) in width and 3 m (9.8 ft) in height, and is naturally formed in the quartzites of Cuddapah Supergroup of Middle to Upper Proterozoic (1600 to 570 Ma) due to natural erosive forces.
The arch is one of the few natural arches or bridges in Asia. But there are many others in other continents, such as the Rainbow Bridge (Arch) and Arches National Park in Utah, USA which depicts 2000 sandstone arches, theDurdle Door arch in Dorset and the Arch of Cut Through in UK, Pravčická brána in Bohemian Switzerland, in Czech Republic, Pont d’Arc in Southern France, Rainbow cave arch in the Galilee Israel, El Arco de Cabo San Lucasin Mexico and London Arch in Australia
According to one version, the arch resembles the hood of a serpent, a conch (Sanskrit: Shank) and a discus (Sanskrit: chakra) – all symbols of worship in Hindu religion – and considered to be the source of the Idol of Lord Venkateswara or Lord Balaji at the Tirumala hill temple.
The second version is that the main deity in the Tirumala temple is of the same height as the height of the arch.
The third version is that Lord Vishnu (Hindu God) called as Balaji or Venkateswara (the Central deity of Srivaishnava tradition) at the Tirumala temple town, is supposed to have put his first foot down at a place called Padalu or Sreevaripadalu (శ్రీ వారి పాదాలు)(Telugu language: Divine foot prints) which is the highest point of Tirumala hills, the second step at the location of the arch. Thereafter, the next step is stated to have been placed where his idol is now worshipped in the temple at Tirumala.
The natural geological arch has two distinct physiographical regions – southwest upland and northeast lowland. The Tirupati hills situated at the foot of a picturesque range of hills are known by several names such as ‘Seshachala’, ‘Venkatachala’ and ‘Balaji’. The geological formations are categorized under four heads namely, the (1) Archeans (the gneisses), (2) the Eparchean unconformity (Quartzose sandstones Overlying the granite with a distinct unconformity), (3) Puranas (formation of Cuddapah group well developed in the valley) and (4) Quaternary deposits. The Tirumala hills essentially of precambrian period are composed of sedimentary rocks –quartzites and intercalated shales, which are given the geological, stratigraphical nomenclature of Nagari quartzites.
The hill ranges of the Tirumala rise to a height of 900 m (3,000 ft) (at Tirumala) from the average height of 150 m (490 ft) in the plains at Tirupati. The steep scarp of the hill ranges depicts unconformity in its topographic, structural and denudational features, which is the Eparchian Unconformity.
The sedimentary thickness of the Cudappa basin is of the order of 12 km (7.5 mi) with volcanic sequences in the form of sills and dykes. A prominent Eparchaean Unconformity of the formation resting on the Archaean peninsular gneissic complex is noted. Rocks of Cuddapah Supergroup including Kurnool Group are the prominent feature of the basin.
Specifically, the arch’s origin is attributed to two schools of thought namely, a) it could be the effect of a wave action from oceanic transgression or intensified climatic settings and corrosion and b) it may have been naturally carved out of quartzite.