Adam's Bridge
Adam's Bridge, also known as Rama's Bridge or Rama Setu, is a chain of limestone shoals, between Pamban Island, also known as Rameswaram Island, off the south-eastern coast of Tamil Nadu, India, and Mannar Island, off the north-western coast of Sri Lanka. Geological evidence suggests that this bridge is a former land connection between India and Sri Lanka.
The bridge is long and separates the Gulf of Mannar from the Palk Strait. Some of the regions are dry and the sea in the area rarely exceeds in depth, thus hindering navigation. It was reportedly passable on foot until the 15th century, when storms deepened the channel: temple records seem to say that Adam's Bridge was completely above sea level until it broke in a cyclone in 1480.
Historical mentions and etymology
The bridge was first mentioned in the ancient Indian Sanskrit epic Ramayana written by Valmiki, wherein the god Rama had his Vanara army construct it to reach Lanka and rescue his wife Sita from the Rakshasa king, Ravana.The western world first encountered it in Ibn Khordadbeh's Book of Roads and Kingdoms, in which it is referred to as Set Bandhai or Bridge of the Sea. Some early Islamic sources refer to a mountain in Sri Lanka as Adam's Peak, and described Adam as crossing from Sri Lanka to India via the bridge after his expulsion from the Garden of Eden; leading to the name of Adam's Bridge. Alberuni was probably the first to describe it in such a manner. The earliest map that calls this area by the name Adam's bridge was prepared by a British cartographer in 1804.
Location
The bridge starts as a chain of shoals from the Dhanushkodi tip of India's Pamban Island and ends at Sri Lanka's Mannar Island. Pamban Island is semi-connected to the Indian mainland by the 2-km-long Pamban Bridge. Mannar Island is connected to mainland Sri Lanka by a causeway. The border between India and Sri Lanka is said to pass across one of the shoals, constituting one of the shortest land borders in the world. Ramasetu and neighbouring areas like Rameswaram, Dhanushkodi, Devipattinam and Thirupullani are mentioned in the context of various legends in Ramayana.Geological evolution
Considerable diversity of opinion and confusion exists about the nature and origin of this structure. In the 19th century, two major theories were prominent in explaining the structure. One considered it to be formed by the process of accretion and rising of the land, while the other surmised that it was established by the breaking away of Sri Lanka from the Indian mainland. The friable calcareous ridges later broke into large rectangular blocks, which perhaps gave rise to the belief that the causeway is an artificial construction.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". The lack of comprehensive field studies explains many of the uncertainties regarding the nature and origin of Adam's Bridge, which mostly consists of a series of parallel ledges of sandstone and conglomerates that are hard at the surface and grow coarse and soft as they descend to sandy banks.
Studies have variously described the structure as a chain of shoals, coral reefs, a ridge formed in the region owing to thinning of the earth's crust, a double tombolo, a sand spit, or barrier islands. One account mentions that this landform was formerly the world's largest tombolo that split into a chain of shoals by a slight rise in mean sea level a few thousand years ago.
Based on satellite remote sensing data, but without actual field verification, the Marine and Water Resources Group of the Space Application Centre of the Indian Space Research Organisation concludes that Adam's Bridge comprises 103 small patch reefs lying in a linear pattern. The feature consists of the reef crest, sand cays and intermittent deep channels. The coral reefs are variously designated by other studies as ribbon and atoll reefs.
The geological process that gave rise to this structure has been attributed in one study to crustal down warping, block faulting, and mantle plume activity 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. Another theory affirms that the origin and linearity of Adam's Bridge might be due to the old shoreline from which shoreline coral reefs developed.
Another study attributes the origin of the structure to longshore drifting currents which moved in an anticlockwise direction in the north and clockwise direction in the south of Rameswaram and Talaimannar. The sand could have been dumped in a linear pattern along the current shadow zone between Dhanushkodi and Talaimannar with the later accumulation of corals over these linear sand bodies. In a diametrically opposing view, another group of geologists propose a crustal thinning theory, block faulting and a ridge formed in the region owing to thinning and asserts that development of this ridge augmented the coral growth in the area and in turn coral cover acted as a 'sand trapper'.
The tombolo model affirms a constant sediment source and a high unidirectional or bi-directional longshore current. One study tentatively concludes that there is insufficient evidence to indicate eustatic emergence and that the raised reef in southern India probably results from a local uplift. 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 Subcontinent.
Age
The studies under "Project Rameswaram" of the Geological Survey of India, which included dating of corals, indicate Rameswaram Island evolved beginning 125,000 years ago. Radiocarbon dating of samples in this study suggests the domain between Rameswaram and Talaimannar may have been exposed sometime between 7,000 and 18,000 years ago. Thermoluminescence dating by GSI concludes that the sand dunes between Dhanushkodi and Adam's Bridge started forming about 500–600 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 4,020±160 years BP.
Early surveys and dredging efforts
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 BC, it was limited to small boats and dinghies. Larger ocean-going vessels from the west have had to navigate around Sri Lanka to reach India's eastern coast. Eminent British geographer Major James Rennell, who surveyed the region as a young officer in the late 18th century, suggested that a "navigable passage could be maintained by dredging the strait of Ramisseram ". 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.In 1823, Sir Arthur Cotton, was assigned 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 a land connection bridged this in the past, and some temple records suggest that violent storms broke the link in 1480. Cotton suggested that the channel could be dredged to enable passage of ships, but nothing was done until 1828 when Major Sim directed the blasting and removal of some rocks.
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. 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.
Sethusamudram shipping canal project
The government of India constituted nine committees before independence, and five committees since then, to suggest alignments for a Sethusamudram canal project. Most of them suggested land-based passages across Rameswaram island, and none recommended alignment across Adam's Bridge. The Sethusamudram project committee in 1956 also strongly recommended to the Union government to use land passages instead of cutting Adam's Bridge because of the several advantages of land passage.In 2005, 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 off the voyage around the island of Sri Lanka. This proposed channel's current alignment requires dredging through Adam's Bridge.
Indian political parties including the Bharatiya Janata Party, All India Anna Dravida Munnetra Kazhagam, Rashtriya Janata Dal, Janata Dal and some Hindu organisations oppose dredging through the shoal on religious grounds. The contention is that Adam's Bridge is identified popularly as the causeway described in the Ramayana. The political parties and organizations suggest alternate alignment for the channel that avoids damage to Adam's Bridge. The then state and central governments opposed such changes, with the Union Shipping Minister T. R Baalu, who belongs to the Dravida Munnetra Kazhagam and a strong supporter of the project maintaining that the current proposal was economically viable and environmentally sustainable and that there were no other alternatives.
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. Some organisations completely oppose this project on economic and environmental grounds and claim that proper scientific studies were not conducted before undertaking this project.
Origin legends
Indian culture and religion includes legends that the structure is of supernatural origin.According to the Hindu epic, Ramayana, Ravana, the demon king of Lanka kidnapped Rama's wife Sita and took her to Lanka, doing this for revenge against Rama and his brother Lakshmana for having cut off the nose of Ravana's sister, Shurpanakha. Shurpanakha had threatened to kill and eat Sita if Rama did not agree to leave her and marry Shurpanakha instead.
To rescue Sita, Rama needed to cross to Lanka. Brahma created an army of vanaras to aid Rama. Led by Nila and under the engineering direction of Nala, the vanaras constructed a bridge to Lanka in five days. The bridge is also called Nala Setu, the bridge of Nala.
Rama crossed the sea on this bridge, and pursued Ravana for many days. He fired hundreds of golden arrows which became serpents that cut off Ravana's heads, but ultimately had to use the divine arrow of Brahma to slay Ravana.
Revisionist movement
In recent times, some groups have attempted to recast this religious legend as a historical event, with Adam's Bridge being the remains of the bridge built for Rama by the vanara, rather than having been created by natural processes. These groups include Tamil nationalists, Hindu fundamentalists, and Infotainment providers.Bharathidasan University was founded in 1982 in the Indian state of Tamil Nadu and named after Bharathidasan, a Tamil poet, social reformer, and political philosopher associated with the Dravidian movement, the Pure Tamil movement, and the resurgence of Tamil cultural identity generally. Professor S.M. Ramasamy's team from Centre for Remote Sensing at this university asserted that "as the carbon dating of the beaches roughly matches the dates of Ramayana, its link to the epic needs to be explored".
Ramasamy's team dates the structure to 3,500 years. The investigation determine that the land/beaches between Ramanathapuram and Pamban were formed due to the longshore drifting currents. About 3,500 years ago, the currents moved in an anti-clockwise direction in the north and clockwise direction in the south of Rameswaram and Talaimannar. In the same study, carbon dating of some ancient beaches between Thiruthuraipoondi and Kodiyakarai shows the Thiruthuraipoondi beach dates back to 6,000 years and Kodiyakarai around 1,100 years ago.
S. Badrinarayanan, a former director of the Geological Survey of India, said that it is impossible for Adam's Bridge to be a natural formation, because of the presence of a loose sand layer under corals for the entire stretch. Coral typically forms above rocks. He suggests that a thorough analysis was not conducted by the Geological Survey of India before undertaking the SSCP project.
In 2007, a publication of the National Remote Sensing Agency said that the structure "may be man-made".
In a 2008 court case, a spokesman for the government stated the bridge was destroyed by Rama according to the scriptures. this claim has been rejected by other observers. In connection with the canal project, the Madras High Court in its verdict stated that the Rama Sethu is a man-made structure.
The Science Channel had broadcast an episode in the series What on Earth?, which included a few minutes on Adam's Bridge and claimed that the ancient Hindu myth of Lord Ram building the structure could be true. Deutsche Welle rejected the conclusions noting that no actual evidence is offered beyond vague speculation, false implications, and the point that – as with many geological formations – not every detail of its formation has been incontrovertibly settled. Indian Geologist C. P. Rajendran described the broadcast as an "abhorrent" example of the "post-truth era, where debates are largely focused on appeals to emotions rather than factual realities".
Other scientists in India and elsewhere have rejected a supernatural explanation for the existence of the structure. NASA said that its satellite photos had been egregiously misinterpreted to make this point.
In 2007, the Sri Lankan Tourism Development Authority sought to promote religious tourism from Hindu pilgrims in India by including the phenomenon as one of the points on its "Ramayana Trail", celebrating the legend of Prince Rama. Some Sri Lankan historians have condemned the undertaking as "a gross distortion of Sri Lankan history".