Monday, August 13, 2007

Adam's Bridge

This topic has generated a lot of controversy. Between Pamban, Southern tip of Tamil Nadu, India and Mannar, northern tip of Sri Lanka is the Palk Strait. Adam's Bridge is a chain of sand shoals and coral islands which appear as stepping stones along the Palk Strait . Everyone accepts that these are natural features. The controversy is whether there is a causeway linking these islands. Proponents of the causeway say that recent "studies" prove the presence of an artificial structure. This lends credence to the story in the epic Ramayan that Shri. Ram's army built a causeway in order to invade Sri Lanka and rescue Shri Ram's wife Sita. This causeway known as Ram Sethu, according to the proponents has since been submerged due to a sea level rise. Satellite pictures showing a milky white line connecting India and Sri Lanka have appeared in Wikepedia and also in the Indian blogosphere. The one above, of the Palk Strait is the NASA image that has contributed to the controversy. The perception of continuity is however an illusion caused by a combination of cloud cover and suspension of white calcium carbonate sediment along the length of the coral islands. The next image shows a close up of the Palk Strait. The discontinuous nature of the islands is clearly seen. The images are inconclusive on the issue of the causeway.

In the online magazine Rediff, there was an interview (July 31 2007) with Dr. Badrinarayanan, former director of Geological Survey of India and former coordinator of the survey division of the National Institute of Ocean Technology (NIOT), Ministry of Earth Science, in Chennai. NIOT recently drilled boreholes and recovered cores along the island chain. This has produced data more informative that satellite pictures. The cores are more than 10 metres thick and according to Dr.Badrinarayanan

"we found marine sands on top and below that was a mixed assemblage of corals, calcareous sand stones, and boulder like materials. Surprisingly below that up to 4-5 metres, again we found loose sand and after that, hard formations were there".

Dr. Badrinarayanan is clearly puzzled by this inter-layering of sand, boulder and coral and concludes that the boulders have to be artificially placed there, since there is no way they can appear on top on a marine sand layer. As a geologist who specializes in limestones, I can say that this sequence of sediment is exactly what you would expect from such a setting. The coral animal secretes a skeleton of calcium carbonate. Corals are colonial organisms, so hundreds of millions of such animals aggregate and secrete calcium carbonate skeletons. This, over time results in large structures which produce topographic highs on the sea bed. Such coral aggregates which show topography are called reefs. The shapes of these structures range from delicate branching types to more massive aggregates of carbonate material, some of which look like giant brains. As these structure grow upwards from the sea bed they encounter shallower water and start getting battered by waves. Particularly during storms, pieces of corals break off from the main reef.It is common for reefs to have an apron of debris composed of small and large boulders sitting on top of the sandy sea floor. In reef systems, sand is everywhere. The natural disintegration of coral skeletons upon death of the coral animal produces sand, erosion by waves produces sand, and additional sand can be transported from the surrounding continental shelf. In this case much of the sand is being brought by currents from coastal areas of India (Rameshwaram to Vedaranniyam coast) and Sri Lanka (Jaffna penninsula). This sand infiltrates the cracks and crevices of the coral structures and also blankets the sea floor.

Now, here is the crucial property of such very shallow water systems. They produce such vast amounts of sediment that they force a local change in sea level along with changes in currents. This means a certain type of sedimentary environment may in response to a shift in sea level encroach upon and bury an adjoining sedimentary environment. Corals can encroach and bury sand, just as sand can shift and bury adjacent coral and boulders. Over long periods of time such migrating and shifting environments will create a geological section, such as the one observed in Dr. Badrinarayanan's cores, a complex sequence of inter-layered sand, coral and boulders.

I suspect the sand shoals and the coral complexes represent a geologic history spanning the late Pleistocene to Holocene epochs (the last hundred thousand years). During the Pleistocene "ice-age" period, glacial buildup and melting forced fluctuations in sea-level by tens of meters , setting up the conditions for several episodes of coral reef and sand shoal formation. During periods of large sea-level drops in the Pleistocene, there would have been a land connection between India and Sri Lanka. But at the end of the last Wisconsin glaciation, the sea-level began to rise world-wide. This period of global sea level rise beginning around 10-12 thousand years ago marks the beginning of the Holocene epoch. The Palk strait became deeper as sea-levels rapidly rose by several ten's of meters in the early part of the Holocene. By mid-Holocene sea-level stabilized, and thereafter minor fluctuations in sea-level changes have been dictated by local geological processes more than any global control. It is important to understand where the Ramayan fits in within the context of all this history of sea-level changes. Mainstream historians place the Ramayan around 100-500 B.C, while the fringe historians place it as far back as 3000 B.C. Both parties though place it firmly within the mid-late Holocene, by which time the Palk Strait was certainly a few to ten's of meters deep. Dr. Badrinarayanan interprets the entire sequence in his cores as having formed in the mid Holocene, specifically from about 5800 to 4000 years ago. He bases this on coral reefs terraces on Rameshwaram island which give carbon dates ranging from 5400 to around 2600 years B.P. (before present). There is also recent coral in the low tide shorezone of Rameshwaram island. According to him, the causeway was built during a sea-level fall sometime in the last few thousand years, i.e in the mid Holocene, the boulders brought in by quarrying exposed coral rock in Rameshwaram. This may conjure up images of Pleistocene style sea-level falls of several ten's of metres, exposing much of the Palk strait sea-bed, leaving only few deeper patches to be filled up to form a causeway. But the coral reef terraces at Rameshwaram may be telling a different story. Reef growth track sea level change. So the successive reef terraces can be taken as an indicator of sea level change. The Rameshwaram reef terraces are about 1 to 1.5 meters above present sea level. This suggests that Holocene sea-level falls were probably not extensive enough to have exposed large parts of the basin. Plus there is the question of the timing of sea-level falls. I am not sure if there is an exposure surface between the older and younger terrace which would indicate that sea -level fell, exposed the sea bed and then rose again drowning the area and leading to the growth of the younger coral terrace. That would be an interesting find as it would give a solid date to the sea level fall and would provide more reliable evidence of the extent of Holocene sea level falls. At the moment the best we can say is that sea-level has been dropping sometime after the youngest dated exposed terrace around 2600 B.P. In any case I doubt if any sea level fall in the Holocene would have lead to any significant lowering of sea-level. Large stretches kilometers long would have remained under water metres deep, making causeway building an impossible exercise. In contrast, processes of coral reef formation in the Palk strait would have provided an in situ source for the natural formation of the debris and boulders found in the cores.

This is a controversial issue involving the religious sentiments of millions of Indians. I feel though that any detailed geological investigation of the Palk strait sediments will be able to explain Adam's bridge as a natural consequence of sand shoal formation and coral reef dynamics.

There are other natural processes by which boulders can appear on the sea floor. But that is a topic for another blog.

15 comments:

  1. At the end we still aren't sure about the bridge (Whether it was man made or natural). With such a lot of research how come we still have a question mark?

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  2. The core materials have a perfectly natural geological explanation. But it is hard to overturn deep religious beliefs. Having said that it is a mistake to think that a lot of research has been done. A few core samples doesn't give you enough information. But will any scientific evidence however pursuasive be accepted?

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  3. Prehistoric Event of Ramayana - Atleast 18 Milion Years.
    Stricking ways how Ancients showed the Modern people on Forces Of Universe which current day Scientists are wondering about the Universe!.

    That God in the form of Man came down to show the virtue of how Human should conduct and behave. It was Lord Rama in advent manifestation along with all the natural forces of the universe in the Tretha Yuga(2nd among 4 time spans of universe). Universal Natural forces like Mysterious " Dark Energy " which makes 75% of the Universe had manifested in human form as Lord Rama, Nature's -Wind took form of Humanam, Nature's Evolutionary Design Life force came down as Bharatha-Lord Own Brother(Sanghu-Conch), The milky way galaxy which is in form of Chakra - Mighty Disc took human form as Younger brother Satrugna, The mighty Solar Sun came down as Sugreeva and the Geo Electromagnetic Force took form of Vaali(Indra) and so on. So called "Modern" Science of the present day human begin is still trying to understand these Natural forces and they have been searching externally while the Ancient Seers of this part of world have comprehended and has left us vast knowledge, heritage monuments(like Rama Sethu) and temples to help the human being to realise the universe's Nature. They wanted us to learn the Love universe radiates and showed ways attain the blisfull state of union with natural forces. During the advent of Dark Energy/Lord Rama, It's the " Dark Matter "/Pure Love which the form of Seetha, Wife of Rama.

    Like all epic of ancient India(Bharatha) continent, Srimad Ramayana is a epic which has to be researched for such universal concepts which unifies different facts of nature.

    Dark Matter/Dark Energy of our universe has been so Mysterious not only for current day scientists but also for al the ancient seers and sages of Continent Bharatha(India). Now this Bharatha became a Sub continent merging with Jumbu(Asia). Leading to Rise of Mighty Himalayaas and this whole movement of the continent was engineered by the King Baagiratha to bring down everlasting water sources to Current day India and south east asia.

    These are very Pre Historic Events and showcasing the determination of such people. These Prehistoric events described in Valmiki Ramayana or other Puranas(Pre Historic History) like moving of Indian(Bharatha Continent) land mass, Constructing Bridge by Natural forces in human/monkey form go closely with modern day scientist findings. Like We all know Humans came from Monkeys and this is exactly reflected in prehistoric Ramayana narrating the intellectual evolution of Homosapiens from intellectual Monkeys, The Ramayana intellectual monkeys were nothing but the 33 crores(330 million) forces of energy form of natures in our universe. From Agni deva or Heat energy(Lowest form in Thermodynamics energy transformation principles) to Lord Indra - GeoElectricity(Comparatively higher form) to Highest form of Dark Energy(which is a Puzzele to many Scientists, which can be felt and never be explained off :) )

    Further The Prehistoric epics like Ramayana describes the ages of Jurassic Park Dinosaurs and descends as semi evolved after the mighty catastrophe wiping away the massive Dinosaurs population. Those survived semi intellectually evolved creatures survived until 18 million years and King of Lanka Vibhishana, Brother of Ravana, had to fight with these less intellectually evolved Dinosaurs to protect the human civilisation, which is described in Vamiki Ramayana.

    Currently age according to Kali yuga(Span of 432000 yrs) progression is 5108th year. Georgian calendar starts 3000 years later and we count today at 2007 AD, Christians Believe world was created 5000 years ago and it is partially right, Last Age ended at 5000 years ago and this world recovered from the deluge of Dwapara yuga and it was altogether creation once again. However nature choose to protect many people from Dwapara yuga to come into Kaliyuga, for that the ever lasting cycle of birth/death and in-between enjoyment should continues as it has been ALWAYS. Kaliyuga was preceded by Dwapara yuga(Span of 864000 years) which was preceded by Treta Yuga(span of 1296000) during which Advent of Dark Energy / Lord Rama Happened. !!!!!!By simple calculations the construction of Bridge (Rama Sethu) to Lanka was some time before 1869100 years. At least 18 million years its been since the Bridging of Lanka with India by the natural forces of universe in human form !!!!!!!


    Our Prehistoric EPICS are Treasure for the world capturing the advances of ancient humans and their connected living with Nature's forces. Many such People living in india has been surviving continuously thought-out there has been serious catastrophes of ancient times and passed on the knowledge/Artefacts/ monuments etc. to the modern day human civilisation, for us to learn, protect and pass it down to the civilisation that is yet to come.

    Our prehistoric text has been a bigger research tool for westerners always!, to find new technology and dominate the world. While knowing all technologies far beyond what we know, Lord Rama Dominated and ruled the seven continents of world with technology of LOVE. And in memory of Lord Rama there are artefacts across the world.


    Moment INDIA takes on ancient Indian epics seriously, India would start leading the world in technology front. I am already benefiting by and many more like me. It wont take 2020 just 2012 to realise the vision.

    RAMA BRIDGE TO LANKA WAS BUILT 18 MILLION YEARS AGO!!

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  4. Is this guy anywhere near serious!!

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  5. Hi Suvrat Kher,

    Thank you for your well written post. I have linked it in my Tamil blog to show that it is natural formation. Hope that is ok.

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  6. Hi Suvrat,

    Just wanted to share something with you.....would like to confess upfront that I don't know ABCD about Geology :-)

    What detailed studies has the Govt undertaken to conclusively prove that the Setu is a natural formation?

    I'm quoting what Dr Badrinarayanan and his colleagues have recommended as next steps in order to determine whether or not the Setu is manmade: "In order to understand the true nature of this central zone it is recommended to do large scale pitting to 20 m depth till the second loose marine sand zone is reached in RS/AB feature and to carry out detailed underwater videography and close spaced sampling of all the 4 walls and the base of the pits for determining the composition and age of rocks and sediments."

    Dr Badrinarayanan and his colleagues go on to say that, "UNLESS ALL OF THE ABOVE INVESTIGATIONS AND STUDIES ARE CARRIED OUT, THE EXISTENCE OF THE REMNANTS OF RAMA'S BRIDGE OVER THE RS/AB FEATURE CANNOT BE CONCLUSIVELY DISPROVED."

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  7. The post talks about the geological feature in Gulf of mannar. It does not discuss the physical structure on this feature. How come history records 20 villages on the bridge and that the bridge was used as a land-bridge between India and Srilanka for thousands of years, unlike the Great Barrier Reef which is always called a reef? The next blog should talk on this. best wishes, k

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  8. I really enjoyed this article and i think it's great that in life we have beauty that "just is" as remarkable as it appears.

    I stumbled upon this article after writing an entry totally unrelated to this however one thing does lead to another if one lets it.

    thank you

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  9. Ramayana was around 10-15000BC and Mahabharata around 3000BC. They werent millions of years ago as is popularly accepted, they are gross misinterpretations by Vedic scholars..read mor in the book Holy Science by Sri Yukteshwar were he gives a good account of the various yugas etc. Ram Sethu is 100% real, and not matter how many big-sounding words these amateur wannabe scientists use, they are just blind men trying to show way to others. And the worst are these new breed of wannabe modern pseudo-liberals in India. I am an Indian residing in the US, and have done all kinds of research on Hindu heritage and will attest to the validitiy of its majorty beliefs, and align with Paramhansa Yogananda's belief that the Gita is one of the most divine books in the world. It is sad to see Indians doubting their own rishis and saints.

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  10. Excellent post. I do not know much about geology but your arguments against the existence of a man-made structure is pretty good. It is good to see some Indian scientists providing a balanced version rather than get carried away by religious rantings.

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  11. Today skepticism almost always appears to resemble intellectuality and progressive thinking!

    I think the question should not be whether we can prove the existence of Rama or not, or whether the bridge is natural or man-made. The simple question is whether or not it is right to ignore the religious sentiments of many believers. If we began to debate sentiments and beliefs of all people we could ask if Jesus existed? or if Moses existed or did Prophet Muhammad(pbuh) really talk to Angels?
    Be that it may that the bridge is proven to be a natural formation and stories later developed around it, I still think going ahead with a project which does have alternatives, marginalizes the emotions and beliefs of our people.

    There is still a question left unanswered - Why do such structures exist in such rarity? Why do many other straits in similar latitudes not have such coral formations?

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  12. there is no rama and ramayana is a story written by fool.

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  13. Well,sayng Ramsetu is natural,it means valmiki hrishi wrote fiction ,but he knew there was real natural formation between india and srilanka tht time,so he used that location as fiction.ok then,how pushpak viman idea came from?just by watching birds,he thot there can b flying machine ? or had he saw one? see this link abt ancient flying machine.http://www.vigyanprasar.gov.in/comcom/vimana.htm

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  14. http://itihaasafindings.blogspot.com/2009/08/ramayan-proof.html

    Hindu itihaas is not myth

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