RAM SETHU, AS seen from the air. This picture was taken while flying over Sri Lanka looking west.
(Photograph by : PlaneMad, 2005. Creative Commons Attribution ShareAlike 2.5 License.)
SCIENCE and rationality have taken a beating in the unfolding of the recent events surrounding the controversial mega marine project called the Sethusamudram Ship Channel Project (SSCP) of the Government of India. The project envisages the dredging of the shallow ocean region in the south-eastern Bay of Bengal to create an artificial 167-kilometre-long, 300-metre-wide and 12-metre-deep channel-like passage for (10,000-12,000 gross tonnage) ships across the island formations called Adam’s Bridge or Ram Sethu.
The bridge, or sethu, is a discontinuous chain of sandbars dotting a 30-km stretch in the east-west direction between the southern tip of the Rameswaram island in India and Talaimannar in northwestern Sri Lanka, creating a geographical divide between the Palk Bay and the Gulf of Mannar, which form part of the southern Cauvery basin. The rationale for the project is that such a channel would avoid circumnavigation of Sri Lanka (of an additional distance of over 400 km) in the voyage between the east and west coasts of India.
Ram Sethu and Adam’s Bridge are names derived from Hindu and Islamic mythologies respectively, the former from the epic Ramayana wherein Rama (venerated as God by Hindus) is supposed to have built this bridge with the help of his allies (the Vanara Sena) to reach Lanka and rescue his abducted wife Sita, thus giving rise to the belief among Hindus that the island chain is man-made. The sea separating India and Sri Lanka is, therefore, referred to as Sethusamudram, from which the project derives its name. According to the Islamic account, Adam used the bridge to reach Adam’s Peak in Sri Lanka where he stood in repentance for 1,000 years.
The proposal for a channel linking the Palk Bay and the Gulf of Mannar actually goes back to the British in 1860 and since then several proposals have been made and six distinct alignments for the passage to go across Ram Sethu have been put forward. But only in 1998, Atal Bihari Vajpayee, the Prime Minister of the previous National Democratic Alliance (NDA) government, finally launched the project. It was only inaugurated during the United Progressive Alliance (UPA) regime in 2005 by Prime Minister Manmohan Singh.
The protests by the BJP currently in evidence against cutting Ram Sethu, as the channel alignment chosen in 2002 would require, on the grounds that any structural change to Ram Sethu would hurt the religious sentiments of the Hindu millions of the country, is clearly dictated by political expediency with the agitation to “preserve Ram’s heritage” being now spearheaded by Hindu fundamentalist organisations such as the Vishwa Hindu Parishad (VHP) and the Hindu Munnani.
Political expediency, given the distinct possibility of early general elections, has dictated the government’s responses to the opposition to the project as well. They reflect obvious communal vote politics, meant not to lose Hindu votes. Following the Supreme Court’s judgment restraining the SSCP from carrying out any dredging that could damage Ram Sethu on the petitions filed by Janata Party leader Subramanian Swamy, among others, the Centre’s responses have been less than rational. It has decided not only to withdraw the counter-affidavit filed by the Archaeological Survey of India (ASI) but also to redefine the project by choosing another alignment that does not cut through Ram Sethu.
The affidavit’s statement that mythological texts such as the Ramayana “cannot be said to be historical record to incontrovertibly prove the existence of the characters, or the occurrence of events depicted therein”, was perhaps unnecessary and unwarranted for arguing that Ram Sethu is not a man-made structure as contended by the petitioners, but the statement itself cannot be faulted given the scientific evidence.
Be that as it may, the decision to withdraw a well-argued affidavit in its entirety has only resulted in giving primacy to religious beliefs over a whole body of scientific evidence on which the affidavit was based to show that Ram Sethu is a natural geological formation.
The move, which was made notwithstanding the fact that two senior civil officers of the ASI had drafted the affidavit (they have since been inexplicably suspended), also seriously undermines the autonomy of a scientific agency like the ASI and the concept of tackling important national issues through a science-based approach.
In fact, by playing the same game of communalised politics as the Sangh Parivar, the UPA government has left no room or forum for raising real, serious issues expressed by many people concerning the project, issues such as the techno-economic viability of the project and its long-term ecological impact on the region. The irrational religious opposition has unfortunately clouded these.
It all began in 2002 when the National Aeronautics and Space Administration (NASA) of the United States released some satellite images taken at various times of the chain of sandbars or shoals in the Palk Bay area. These were picked up by various Hindutva-espousing websites, which interpreted them as evidence of the remains of the mythical bridge built by Rama.
These websites further claimed that NASA had concluded that the bridge was man-made from the “bridge’s unique curvature and composition by age”. They claimed that archaeological studies had revealed that first signs of human inhabitants in Sri Lanka dated back to 1.75 million years ago as did the age of the bridge, and contended that the age matched the age of events described in the Ramayana. They protested that the holy site of Rama’s heritage would thus be damaged by the SSCP.Fresh ammunition
This was fresh ammunition for fundamentalists and the Sangh Parivar to launch a nationwide “Ram sethu ke hetu (for the cause of Ram Sethu)” campaign. NASA’s clarifications and rebuttals to these claims have clearly been of no avail because even some of the petitions being currently heard in the courts continue to claim that the NASA pictures are evidence for a man-made Ram Sethu.
NASA official Mark Hess had then stated: “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.” Hess further stated that NASA had been taking pictures of these sandbars for years. Its images had never resulted in any scientific discovery in that area. “The images reproduced on websites may well be ours but their interpretation is certainly not ours.”
The Sangh Parivar’s claim that the first inhabitants in Sri Lanka dated back to 1.75 million years is clearly bogus and patently unscientific. Human evolution studies have unequivocally established that modern humans (Homo sapiens sapiens) came into existence only about 200,000 years ago. Further, humans arrived in the Indian subcontinent not before 100,000 years ago. Clearly, the age of Treta Yuga (1.7 million years ago), when Rama is supposed to have reigned, belongs to mythology and so would be the other characters and events in the Ramayana, including Ram Sethu.Geological studies
Two independent scientific agencies, namely the Geological Survey of India (GSI) and the Space Applications Centre (SAC) of the Indian Space Research Organisation (ISRO), and individual geologists have conducted detailed studies on the geological formations associated with Ram Sethu and all have established conclusively that Ram Sethu is not a man-made structure. Interestingly, soon after the release of the NASA images and when the related news items began appearing, it was Uma Bharati, the then Union Minister for Coal and Mines, who initiated a study by the GSI to establish the palaeogeography of the sethu terrain. Ironically, today she is actively involved in the “save Ram Sethu” campaign in Tamil Nadu.
The GSI carried out a special programme called “Project Rameswaram” between December 2002 and March 2003, which, according to the GSI’s newsletter of September 2003 annexed in the government counter-affidavit, included: (i) reconnaissance survey; (ii) drilling the Dhanushkodi Foreland (the eastern projection of the Rameswaram island); (iii) offshore surveys involving depth measurements; (iv) seabed samples and side scan sonar images of the seabed; (v) drilling in one of the islands within the Exclusive Economic Zone, or EEZ (which is about 10 km from the Dhanushkodi tip); and (vi) radiocarbon or C-14 dating and thermoluminescence (TL) dating of samples.
Four boreholes, roughly 4 km apart, were drilled to collect subsurface sediment/rock samples to generate geological data towards determining the geological history of Dhanushkodi Foreland and Adam’s Bridge/Ram Sethu. Samples from different locations off Mandapam (located on the mainland coast across the Rameswaram island) were taken for TL dating.
Important among the GSI’s conclusions, based on the geological investigations of its marine wing, are the following:
There are no indications or evidence of man-made structures in the present-day seabed or in the sub-surface level between Dhanushkodi tip and Adam’s Bridge islands within India’s EEZ limits. Age data of corals indicate that the Rameswaram island has evolved since 125,000 years ago.
A combination of various natural coastal processes such as sea level positions in the historical past, wind-borne activity, new tectonic movements, wave action, etc., have led to the evolution of the coastal areas around Mandapam, Rameswaram and Adam’s Bridge/Ram Sethu, which has led to the formation of beach rocks, coral growth, vast stretches of coastal dunes, series of islands (of Ram Sethu) and subsidence of the erstwhile Dhanushkodi township.
Palaeogeographic studies suggest that the sea level in the region has oscillated significantly over historical time scales exposing the seabed between India and Sri Lanka periodically. Around 6,000-7,000 years ago the sea level was 17 m below the present level, resulting in partial exposure of the seabed. About 10,000 years ago, sea level may have been even 60 m below. Radiocarbon dating suggests that during the last glacial maxima (about 20,260 years ago) when sea level is at its minimum, the level may have been as low as 118 m. The domain between Rameswaram and Talaimannar may have thus been exposed sometime between 18,000 and 7,000 years ago, the ASI has concluded. Since then sea level has been rising gradually with minor periodic fluctuations.
Analysis of samples from drilling of boreholes between Dhanushkodi and the third island of Ram Sethu suggests that there were three sedimentation cycles dominated by clay, limestone and sandstone. The growth of the Dhanushkodi sand spit (narrow coastal formation) itself is a feature of coastal processes and shoreline emergence and its orientation seems to be along the dissipation of wave energy patterns of the Palk Bay and the Gulf of Mannar.
The Dhanushkodi sand spit and the five islands of Ram Sethu (that lie within India’s EEZ) change their shape and size owing to monsoon activity. TL dating suggests that the sand dunes of Dhanushkodi to Ram Sethu began to be deposited only about 500-600 years ago.
The Marine and Water Resources Group of SAC/ISRO also carried out space-based investigations, using satellite remote sensing imagery, in 2003 to establish if Ram Sethu is man-made or coralline in nature, using Indian Remote Sensing Satellite (IRS) data. Ocean Colour Monitor data of the satellite IRS-P4 of April 18, 2002, and LISS-III camera data of IRS-1D of May 6 and March 21, 2000, were used. The recognition of features, say the authors of the investigation, was based on experience with the Indian coral reefs and well-established methodology.
The authors concluded that Adam’s Bridge is not man-made but 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 linearity of the sethu was interpreted to be due to the old shoreline – implying that the two landmasses of India and Sri Lanka were once connected – from where coral reefs evolved. Continuing investigations on the reef system, which they have identified as Ribbon reef Type, have shown that the orientation and size of the sand cays have changed during 1990-2000 and again during 2000-2005, thus indicating their dynamic nature.
According to V. Ram Mohan of the Centre of Natural Hazards and Disaster Studies of the University of Madras, island chains, including seamounts, are frequent in the ocean and could be the result of various geological processes. The chains in the Philippines and Japan have, for example, been formed because of subduction related volcanism.
In the Hawaiian islands, it is owing to the movement of lithospheric mantle over hot spots. It can also be owing to the opening of the sea during seafloor spreading along mid-oceanic ridges, as it is in Iceland, or along transform faults, as in St. Helena.
Island chains in the Caribbean and on the southern tip of the South American continent consist of sediments of marine origin formed by coastal processes, which cover the basaltic stratum and serve as substrate for coral reefs, which are exposed above sea level. Though the features of these are similar to the Adam’s Bridge system, the latter has not revealed any evidence for basaltic basement, which results from volcanic mechanism.Adam’s Bridge chain
A PROTEST IN Jammu on September 12 by activists of the Rameswaram Ram Sethu Raksha Manch.
The geological information on the Adam’s Bridge chain is scanty as part of the chain falls in international waters, says Ram Mohan. “Trying to reconstruct the geological evolution of the island chain is a challenging task and has to be carried out with circumstantial evidence,” he adds, writing in a paper titled “Geological Evolution of Adam’s Bridge”.
He argues that the possibility of formation of shoals in the shallow continental shelf as barrier bars (sandbars that may have formed during the period of high water level following sand deposition but remain exposed during low mean sea level) appears to be the most plausible explanation for the evolution of Rameswaram and Adam’s Bridge.
This formation may have been initiated when the sea level was 125 m below the present level, around 18,000 years ago, and was building up when the sea level continued to rise. The continuous sand deposition and the natural process of sedimentation have led to the formation of a chain of barrier islands, which are very dynamic, and this is not unique to Adam’s Bridge, notes S. Ramachandran, Vice-Chancellor of the University of Madras. The formation of barrier islands, which are common in the Atlantic coast, probably began around 25,000 years ago, he says.Geological imprints
Dredging work near Adam’s Bridge in Rameswaram. A file picture.
Based on available data, N. Ramanujam, Head of the Department of Geology of V.O. Chidambaram College, Tuticorin, has attempted to reconstruct the geological evolution of the region and its significant features. According to him, block faulting, subsidence and formation of elongated depressions with ridge separation are the characteristic imprints of the early geological history that are recorded in the Palk Bay and the Gulf of Mannar.
This, he points out, are characteristic of Precambrian basement rock before the Indian plate separated from East and West Gondwanaland about 150 million to 70 million years ago. The northward migration of the Indian plate and its collision with the Eurasian plate and the transfer of stress in the northern converging zone towards the weaker triangular crustal end and the lateral forces enhanced the plume activity (mantle upwelling) at the southern peninsular side. The Cauvery basin, he argues, has thus been formed by the down-warping of the crust and the block faulting of the basement over millennia, resulting in the formation of several elongated depressions separated by ridges.
These ridges became centres of coral reef growth, resulting in atoll-like formations, which in turn acted as “sand trappers” attracting peculiar sandy deposits called salient formation in the region. What was originally a paleosea between Mandapam and Rameswaram thus became a sandy deposit (the salient) extending about 40 km in the east-west direction. This altered the shoreline in the Mandapam-Rameswaram region and acted as an offshore obstruction wall for the littoral currents which transported sediments from the northeast and southwest directions and directed them towards the east and southeast (see diagram). The diversion of ocean currents contributed to the accretion of deposits from both the Dhanushkodi spit and the Talaimannar spit resulting in the formation of sandy barrier islands, which forms Adam’s Bridge or Ram Sethu.
All the independent studies discussed above seem to suggest a consistent picture of the natural processes that led to the formation of Adam’s Bridge or Ram Sethu. It is this combined scientific evidence that the ASI submitted to the apex court, stating that “Adam’s Bridge formation can be classified as a series of shoals or a series of barrier islands, both of which are naturally occurring formations caused by tidal action and sedimentation.”
It further stated: “In the light of the scientific study conducted, the said formation cannot, therefore, be said to be a man-made structure. The same is merely a sand and coral formation, which cannot be said to be of historical, archaeological or artistic interest or importance…[and] the question of construing Adam’s Bridge as an ‘ancient monument [as demanded by the petitioners] and declaring it as a protected monument [under the Ancient Monuments Archaeological Sites and Remains Act, 1958] does not arise”.
By withdrawing this submission, the government has clearly yielded to the communal forces at work and thrown science by the wayside.
(Letters to the Editor should carry the full postal address)
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