Other names

• Adam's Bridge

Historical naming

• Ibn Khordadbeh's Kitāb al-Masālik wa-l-Mamālik referred to it as "Set Bandhai" or "Bridge of the Sea."
• Al-Biruni's Tārīkh al-Hind (c. 1030) introduced the name "Adam's Bridge,".

Location

• Between Pamban Island,  off the south-eastern coast of Tamil Nadu and Mannar Island, off the north-western coast of Sri Lanka.
• Separates the Gulf of Mannar (southwest) from the Palk Strait (northeast)

Length

• 48 km

Structure  

• Some of the sandbanks are dry and the sea in the area is very shallow, being only 1 to 10 metres deep in places.
• According to temple records it was completely above sea level until it broke in a cyclone in 1480.

Geological evolution

• Limestone shoals.
• Series of parallel ledges of sandstone and conglomerates.
• Indian Space Research Organization (ISRO) concludes that Adam's Bridge comprises 103 small patch reefs lying in a linear pattern with reef crest, sand cays and intermittent deep channels.

Cays, also known as keys, refer to low-elevation islands situated on surfaces made of coral reef.

Transport Corridor

• In 2005, the government of India approved Sethusamudram Shipping Canal Project.
• Aims to create a ship channel across the Palk Strait by dredging the shallow ocean floor near Dhanush Kodi.
• Underwater exploration project earlier done through vessel named Sindhu Sadhana.

Sindhu Sadhana is an indigenous exploration vessel which can stay underwater for up to 45 days.

Biosphere reserves

• The coral reef platforms between Thoothukudi and Rameswaram in the Gulf of Mannar were notified as a marine biosphere reserve in 1989.

Religious significance

• Hindu believers hold it as the structure that Lord Rama and his army built to reach Lanka.
• Muslim tradition holds that Adam's Bridge was crossed by Adam following his expulsion from the Garden of Eden.

Recent Mapping and Findings

• Map reveals the bridge's continuity from Dhanushkodi to Talaimannar, with a staggering 99.98 per cent of it submerged in shallow waters.
• Discovered 11 narrow channels that allowed water to flow between the Gulf of Mannar and Palk Strait, playing a crucial role in preserving the structure from sea waves.

Technology Used

• The researchers used NASA's ICESat-2 data from October 2018 to October 2023 to generate a 10-meter resolution map of the full length of the submerged ridge.

PRACTICE QUESTION

Q. The Ram Setu carries the unique geological imprints of an eventful past and needs to be preserved. Justify. 150 words.