Wednesday, December 26, 2007


Adam's Bridge

From Wikipedia, the free encyclopedia

Coordinates: 9.1210° N 79.5217° E

Landsat 5 image of Adam's Bridge
Landsat 5 image of Adam's Bridge

Adam's Bridge, also known as Rama Setu[1] meaning "Rama's Bridge", is a chain of limestone shoals, between the islands of Mannar, near northwestern Sri Lanka, and Rameswaram, off the southeastern coast of India. Hindus believe that this bridge was built by Rama incarnation of Lord Vishnu to rescue his consort Sita who was abducted to Lanka by Ravana, as mentioned in the Ramayana. Many historical inscriptions, coins, old travel guides, old dictionary references, old religious maps indicate that this structure is considered sacred by Hindus.[2][3] Geological evidence indicates that this bridge acted as former land connection between India and Sri Lanka.[4]

The bridge is 30 miles (48 km) long and separates the Gulf of Mannar (southwest) from the Palk Strait (northeast). Some of the sandbanks are dry and the sea in the area is very shallow, being only 3 ft to 30 ft (1 m to 10 m) deep in places, which hinders navigation.[4] There are controversies about whether this structure is natural or manmade. Few scientists have claimed that this structure is natural one whereas others including former Geological survey of India director S.Badrinaryanan claims that this structure is man made. The Madras high court, the highest court of law in Tamil Nadu (the state where this bridge lies) has said that this bridge is man-made.[5][6]

In 2001, the Government of India approved a controversial multi-million dollar Sethusamudram Shipping Canal Project that aims to create a ship channel across the Palk Strait by dredging through a portion of this causeway. Some organizations oppose this project using current alignment based on religious, economic and environmental grounds and suggest implementation of the same through one of the 5 alternative alignments considered earlier[7][8] without damaging this structure.


Famous 12th century venetian traveller Marco Polo's travel map shows that he has travelled around Rama's bridge area. His travel book calls this area as Setabund-Rameswara.[[8]] which means bridge constructed by Rama.
Famous 12th century venetian traveller Marco Polo's travel map shows that he has travelled around Rama's bridge area. His travel book calls this area as Setabund-Rameswara.[[8]] which means bridge constructed by Rama.

The name Rama's Bridge or Rama Setu (Sanskrit; setu: bridge) for the shoal of islands derives from the Sanskrit epic Ramayana (written versions dated from 500 BCE to 100 BCE), in which a bridge from Rameswaram was built by allies of Rama that he used to reach Lanka and rescue his abducted consort Sita from the asura king, Ravana.[9] The sea separating India and Sri Lanka is called Sethusamudram "Sea of the Bridge". Maps prepared by Netherland cartographer during 1747 which is available in Tanjore Saraswathi mahal library shows this area as Ramancoil, a colloquial form of the Tamil Raman Kovil (Rama's Temple). Another map of Mogul India prepared by J.Rennel in 1788 retrieved from same library gives indications that this area would have been called as Rama Temple or Ramar Bridge. Many other maps in Schwartzberg's historical atlas and other sources call this area with various names like Koti, Sethubandha, Sethubandha Rameswaram etc. All these names are connected with names in Hindu scriptures.[10] Valmiki Ramayan calls this bridge built by Lord Rama as Setu Bandhanam in verse 2-22-76[11]. The earliest map that calls this area as Adam's bridge was prepared by British cartographer in 1804.[12] Various travel guides, books, dictionary prepared during the 18th and 19th centuries, including translations of Marco Polo's account of his travels, call this area as Setabund Rameswara or Ramar Bridge.[13]

The name first appears in the 11th century, mentioned by Alberuni; Ibn Khordadbeh in his Book of Roads and Kingdoms (ca. 850 AD) calls it Set Bandhai or "Bridge of the Sea".[14]


Map of Adam's Bridge and environs

Adam bridge starts as chain of shoals from Dhanuskodi tip of Rameswaram Island of India and ends at Mannar Island of Srilanka. Rameswaram Island is connected to Indian mainland by 3Km long Pamban bridge. Ramasetu and areas adjacent to it like Rameswaram Dhanushkodi, Devipattinam and Thirupullani are connected with various legends in Ramayana. [9] [10] [11].

Geological evolution and age

According to V. Ram Mohan of the Centre of Natural Hazards and Disaster Studies of the University of Madras "reconstruction of the geological evolution of the island chain is a challenging task and has to be carried out based on circumstantial evidence".[15] The lack of original evidence explains much of the uncertainties regarding the nature and of Adam's Bridge, which consists of a series of parallel ledges of sandstone and conglomeration, that is hard at the surface and grows coarse and soft as it descends to sandy banks. Considerable diversity of opinion and confusion exists about the nature and origin of this structure. In the 19th century, there were two prevalent theories explaining the structure. One considered it to be formed by a process of accretion and rising of the land, while the other surmised that it was formed by the breaking away of Sri Lanka from the Indian subcontinent.[16] The friable calcerous ridges are broken into large rectangular blocks, which perhaps gave rise to the belief that the causeway is an artificial construction.[17]

Recent studies have variously described the structure as chain of shoals, coral reefs, ridge was formed in the region owing to thinning of earth's crust, a double tombolo[18], sand spit, and barrier islands. It has been reported that this bridge was formerly world's largest tombolo before it is split as chain of shoals due to the change in mean sea level few thousand years back.[19]The geological process that gave rise to this structure has also been attributed to crustal downwarping, block faulting, and mantel plume activity by one study[20] while another theory attributes it to continuous sand deposition and the natural process of sedimentation leading to the formation of a chain of barrier islands related to rising sea levels.[15] Yet another theory affirms the origin and linearity of the Ram setu may be due to the old shoreline – implying that the two landmasses of India and Sri Lanka were once connected – from where coral reefs evolved. Marine and Water Resources Group of Space Application Centre, ISRO based on satellite remote sensing data, without actual field verification concluded that Adam’s Bridge comprises 103 small patch reefs lying in a linear pattern with reef crest (flattened, emergent – especially during low tides – or nearly emergent segment of a reef), sand cays (accumulations of loose coral sands and beach rock) and intermittent deep channels. The coral reefs are designated by the different studies variously as ribbon and atoll reefs.

The origin of the structure has been explained due to long shore drifting currents which moved in an anti-clockwise direction in the north and clockwise direction in the south of Rameswaram and Talaimannar.The sand was supposed to be dumped in a linear pattern along the current shadow zone between Dhanushkodi and Talaimannar with later accumulation of corals over these linear sand bodies. In a diametrically opposing view another group of geologists propose crustal thinning theory, block faulting and ridge formed in the region owing to thinning and asserts that development of this ridge augmented the coral growth in the region and in turn coral cover acted as a `sand trapper'. The tombolo model on the other hand affirm a constant sediment source and a strong unidirectional or bi-directional (monsoonal) long shore current. One study tentatively concludes that there is insufficient evidence to indicate eustatic emergence and that the raised reef in south India probably results from a local uplift.[21]

The scientific age determination of the structure is also mired in confusion. A team from the Centre for Remote Sensing (CRS) of Bharathidasan University, Tiruchi, led by Professor S.M. Ramasamy dates the structure to 3,500 years.[22] They also claim that the carbon dating of some ancient beaches between Thiruthuraipoondi and Kodiyakarai show the Thiruthuraipoondi beach dates back to 6,000 years and Kodiyakarai around 1,100 years ago. Another study suggests that the appearance of the reefs and other evidence indicate their recency, and a coral sample gives a radiocarbon age of 4020+-160 years B. P.[21] The GSI carried out a special programme called “Project Rameswaram” concluded that age data of corals indicate that the Rameswaram island has evolved since 125,000 years ago. Radiocarbon dating suggests that the domain between Rameswaram and Talaimannar may have thus been exposed sometime between 18,000 and 7,000 years ago.[15] Other studies also conclude that during periods of lowered sea level over the last 100,000 years, Adam's Bridge has provided an intermittent land connection between India and Sri Lanka, which according to famous ornithologists Sidney Dillon Ripley and Bruce Beehler supports the vicariance model for speciation in some birds of the Indian sub-continent.[23]Thermoluminescence dating by GSI however concludes that the sand dunes of Dhanushkodi to Ram Sethu started forming only about 500-600 years ago.[15]

The heavy mineral rich beach sands of the coastal stretches of Kerala, Tamil Nadu, Andhra Pradesh and Orissa in west and east coasts of India are estimated to have around 25% -31% of world's Thorium reserves.[24][25]Some of the heavy mineral placer deposits of Kanyakumari, Tirunelveli and Thuthukudi disticts of Tamil Nadu are situated south of the coast adjoining Adam's Bridge.

Tsunami expert Prof Tad S Murty feels Rama's bridge might have acted as a protection wall during the Indian Ocean Tsunami event, 2004, due to its elevation and prevented damage to South Kerala. He states that however that this view is not based on his own original research, nor he is aware of any such studies being carried out by anyone.[26]

Early surveys and dredging efforts

Adam's Bridge seen from above the Mannar island, Sri Lanka.
Adam's Bridge seen from above the Mannar island, Sri Lanka.

Government of India has constituted 9 Committees before Independence and 5 committees after Independence for suggesting alignments for Sethusamudram canal project. Most of them have suggested land based passage across Rameswaram island. None of them have suggested alignment across Adam's bridge. [12].[27]Due to shallow waters, Adam's Bridge presents a formidable hindrance to navigation through the Palk strait. Though trade across the India-Sri Lanka divide has been active since at least the first millennium BCE, it has been limited to small boats and dinghies. Larger ocean going vessels from the West have had to navigate around Sri Lanka to reach India' eastern coast.[28] Eminent British geographer Major James Rennell, who surveyed the region as a young officer in the late eighteenth century, suggested that a "navigable passage could be maintained by dredging the strait of Ramisseram [sic]". However little notice was given to his proposal, perhaps because it came from "so young and unknown an officer", and the idea was only revived 60 years later.[29]

In 1822, Sir Arthur Cotton (then an Ensign), was entrusted the responsibility to survey the Pamban channel, which separates the Indian mainland from the island of Rameswaram and forms the first link of Adam's Bridge. Geological evidence indicates that this was at one point bridged by a land connection, and some temple records suggest that the connection was broken by violent storms in 1480. Cotton suggested that the channel be dredged to enable passage of ships, but nothing was done till 1828, when some rocks were blasted and removed under the direction of Major Sim.[30][31]

A more detailed marine survey of Adam's Bridge was undertaken in 1837 by Lieutenants F. T. Powell, Ethersey, Grieve and Christopher along with draughtsman Felix Jones, and operations to dredge the channel were recommenced the next year.[30][32] However these, and subsequent efforts in the 19th century, did not succeed in keeping the passage navigable for any vessels except those with a light draft.[4]

Sethusamudram shipping canal project

Adam's Bridge as seen from the air
Adam's Bridge as seen from the air
Opposition parties are demanding implementation of Sethusamudram canal project using one of the 5 alternative alignments considered by Government earlier without damaging Ramsetu structure. Sethusamudram project committee in 1956 also strongly recommended to union government to use land passages instead of cutting Adam's bridge due to several advantages of land passage.
Opposition parties are demanding implementation of Sethusamudram canal project using one of the 5 alternative alignments considered by Government earlier without damaging Ramsetu structure. Sethusamudram project committee in 1956 also strongly recommended to union government to use land passages instead of cutting Adam's bridge due to several advantages of land passage.[33]

In 2001, the Government of India approved a multi-million dollar Sethusamudram Shipping Canal Project that aims to create a ship channel across the Palk Strait by dredging the shallow ocean floor near Dhanushkodi. The channel is expected to cut over 400 km (nearly 30 hours of shipping time) off the voyage around the island of Sri Lanka. This proposed channel's current alignment requires dredging through this causeway.

Political parties including the BJP, AIADMK, RJD, JD(S) and some Hindu organizations oppose dredging through the shoal on religious grounds — Rama's Bridge is popularly identified as a causeway described in the Ramayana — and suggest using an alternate alignment for the channel that avoids damage to Adam's Bridge.[34][35] The state and central government have opposed such changes, with Union Shipping Minister T R Baalu saying the current proposal was well scrutinised for economic viability and environmental sustainability and that there were no other environmentally feasible alternatives.[36][37][38]

Opposition to dredging through this causeway also stems from concerns over its impact on the area's ecology and marine wealth, potential loss of thorium deposits in the area, and increased risk of damage due to tsunamis.[39]. Some organizations are completely opposing this project on economical and environmental grounds and claims proper scientific studies were not conducted before undertaking this project.[40]


NASA satellite photo of Rama's Bridge—oblique, Sri Lanka to the left
NASA satellite photo of Rama's Bridge—oblique, Sri Lanka to the left

Vaishnava News Network and some other U.S.-based news services suggested that it had discovered the remains of the bridge built by Rama and his Vanara army, that is referred to in the Ramayana, and that it was not a natural formation, basing their claim on 2002 NASA satellite footage.[41] Some archaeologists and geologists have presented differing estimates. Thus, a team from Centre for Remote Sensing (CRS) of Bharathidasan University, Tiruchi led by Professor S.M. Ramasamy in 2003 claimed that the, "Rama's bridge could only be 3,500 years old" and, "as the carbon dating of the beaches roughly matches the dates of Ramayana, its link to the epic needs to be explored".[42]

Geological Survey of India's former director, S. Badrinarayanan claims that such a natural formation would be impossible, He justifies the same by the presence of loose sands layer under corals for entire stretch. Corals normally form above rocks.."[43] [44]. He feels that thorough analysis was not conducted by Geological Survey of India before undertaking SSCP project. In connection with the canal project, the Madras High Court in its verdict, stated that the Rama Sethu is a man-made structure. [45].Geological and archaeological findings of Teri formations, rich assemblage of Mesolithic-Microlithic tools and human fossils found on both sides of the bridge by Department of Earth-Science in March 2007 are also quoted as evidence for manmade structure.[46][47][48][49]

NASA distanced itself from the claims saying that what had been captured was nothing more than a 30 km long, naturally-occurring chain of sandbanks.[50]. It also clarified that, "The images reproduced on the websites may well be ours, but their interpretation is certainly not ours. Remote sensing images or photographs from orbit cannot provide direct information about the origin or age of a chain of islands, and certainly cannot determine whether humans were involved in producing any of the patterns seen"[51] Prof. N. Ramanujam, Head, Post Graduate Department of Geology and Research Centre, V.O. Chidambaram College, astrophysicist Jayant Narlikar and a group of professors of Madurai Kamaraj University (which is in the state of Tamil Nadu and is directly under the control of the state ministry of education) stated that Rama's bridge is a natural geographical feature which formed some 17 million years ago.[41][52]. In addition, Archeological Survey of India has said that the structure is not man-made. A government publication from National Remote Sensing Agency, which was recently tabled in the Indian Parliament, says that the structure "may be man-made".[53][54]

See also


  1. ^ also transcribed as Ram Sethu, Ram Setu, Ramarsethu and variants.
  2. ^ [1]
  3. ^ [2]
  4. ^ a b c Adam's bridge. Encyclopædia Britannica (2007). Retrieved on 2007-09-14.
  5. ^
  6. ^
  7. ^ 5 Alternative alignments without damaging Ramar bridge
  8. ^
  9. ^ Room, Adrian (2006). Placenames of the World. McFarland & Company, p. 19. ISBN 0786422483.
  10. ^ Various maps of the ancient period indicate this area as Ramancoil, Ramar Temple, Sethubandha Rameswaram and Koti which are names connected with Hinduism or Hindu scriptures
  11. ^ Valmiki Ramayan calls mythological bridge built by Lord Rama as Setubandhanam
  12. ^ [3]
  13. ^ [4]
  14. ^ Horatio John Suckling, Ceylon: A General Description of the Island, Historical, Physical, Statistical, London (1876), p. 76.
  15. ^ a b c d Frontline, Myth and Reality, September 22 - October 5, 2007
  16. ^ Tennent, James Emerson (1859). Ceylon: An Account of the Island Physical, Historical and Topographical. Longman, Green, Longman, and Roberts, p.13.
  17. ^ Suess, Eduard; Hertha B. C. Sollas (translator) (1906). The Face of the Earth (Vol. II). Oxford: Clarendon Press, p. 512-513.
  18. ^ Double Tombolo reference by NASA
  19. ^ Adam's Bridge World's largest Tombolo
  20. ^ Crustal downwarping, block faulting, and mantel plume activity view
  21. ^ a b Raised Reefs of Ramanathapuram, South India D. R. Stoddart, C. S. Gopinadha Pillai Transactions of the Institute of British Geographers, No. 56 (Jul., 1972), pp. 111-125 doi:10.2307/621544
  22. ^ CRS study point Ram Setu to 3500 years old
  23. ^ Ripley, S. Dillon; Beehler, Bruce M. (Nov. 1990). "Patterns of Speciation in Indian Birds". Journal of Biogeography 17 (6): pp. 639-648.
  24. ^ Beach Sand Deposits of India
  25. ^
  26. ^ Prof Tad S Murty's interview
  27. ^ Most of the earlier committees have suggested land based passage across Rameswaram Island. None of them suggested Adam's bridge
  28. ^ Francis, Jr., Peter (2002). Asia's Maritime Bead Trade: 300 B.C. to the Present. University of Hawaii Press. ISBN 082482332X.
  29. ^ Rodd, Rennell (April 1930). "Major James Rennell. Born 3 December 1742. Died 20 March 1830". The Geographical Journal 75 (4): pp. 289-299.
  30. ^ a b Hunter, Sir William Wilson (1886). The Imperial Gazetteer of India. Trübner & co., pp. 21-23.
  31. ^ Digby, William (1900). General Sir Arthur Cotton, R. E., K. C. S. I.: His Life and Work. Hodder & Stoughton, pp. 15-16.
  32. ^ Dawson, Llewellyn Styles (1885). Memoirs of hydrography. Keay, pp. 52.
  33. ^ "Use land based channel and do not cut through Adam bridge:Sethu samudram project committee report to Union Government", September 30, 2007. Retrieved on 2007-10-15. ""“In these circumstances we have no doubt, whatever that the junction between the two sea should be effected by a Canal; and the idea of cutting a passage in the sea through Adam’s Bridge should be abandoned.”"
  34. ^ Ram Setu a matter of faith, needs to be protected: Lalu. (September 21, 2007). Retrieved on 2007-09-24.
  35. ^ Rama is 'divine personality' says Gowda. (September 22, 2007). Retrieved on 2007-09-24.
  36. ^ [5]
  37. ^ [6]
  38. ^ [7]
  39. ^ Thorium reserves to be disturbed if Ramar Sethu is destroyed. The Hindu (August 5, 2007). Retrieved on 2007-09-24.
  40. ^ [ Karunanidhi or T.R.Baalu's arguments are not based on scientific studies claims coastal action network convenor
  41. ^ a b "Hanuman bridge is myth: Experts", Times of India, October 19, 2002. Retrieved on 2007-09-18.
  42. ^ "Rama’s bridge is only 3,500 years old: CRS", Indian Express, February 2, 2003. Retrieved on 2007-09-18.
  43. ^ "Debate shifted over Ram from Ram Sethu",, September 15, 2007. Retrieved on 2007-09-18.
  44. ^ Ram sethu should be manmade says former Geological survey of India director
  45. ^
  46. ^
  47. ^
  48. ^ Evidence found for human habitation in Ramsethu area by Department of Earth Science
  49. ^
  50. ^ Kumar, Arun. "Space photos no proof of Ram Setu: NASA", Hindustan Times, September 14, 2007. Retrieved on 2007-09-18. ""The mysterious bridge was nothing more than a 30 km long, naturally-occurring chain of sandbanks called Adam's bridge," [NASA official Mark] Hess had added. "NASA had been taking pictures of these shoals for years. Its images had never resulted in any scientific discovery in the area."
  51. ^ Kumar, Arun. "Space photos no proof of Ram Setu: NASA", Hindustan Times, September 14, 2007. Retrieved on 2007-09-18.
  52. ^ Kumar, R.Vimal. ""It's not a man-made structure"", The Hindu, March 17, 2007. Retrieved on 2007-09-18. "" "Adam's Bridge, nothing but a geological formation""", The Hindu, March 21, 2007. Retrieved on 2007-09-18.
  53. ^ Ram Sethu 'man-made', says government publication
  54. ^'man-made'%2c+says+Govt+publication

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