Thursday, 28 January 2016

Adam's Bridge

Everyone now accepts that the World is not set in stone: chunks of the planet lumber about the surface of the globe grinding past each other or colliding directly and heaving up mountain ranges. 400 million years ago, during the Caledonian Orogeny [Scottish mountain-building in normal-speak] in the Devonian Period, the NW and SE sections of what is now Ireland came together with a rock-melting clunk. The fractal nature of geology suggests that if an island like Ireland was once in two parts, a smaller area can be joined up too.  The Blob has discussed two examples [Middle Island and its penguins; and Peñón de Vélez de la Gomera in not-Morocco] of once-upon-an-islands that have become more or less joined to the mainland in my lifetime.  It cuts both ways: the South and East coasts of Wexford in the extreme Sunny SE of Ireland are disappearing quite rapidly due to coastal erosion. Land-loss and erosion is a central metaphor in Colm Tóibín's brilliant novel about the  history of our Republic The Heather Burning. The Scilly Isles were once a more substantive chunk of dry land and Scillonians can still walk or wade between some of the current islands at low Spring tides.

Sri Lanka / Ceylon is, like Ireland, an island nation which has been riven by sectarian strife since the Brits left. It is about 3/4 the size of Ireland but has 3-4x as many people living there.  It wasn't always so crowded, at independence in 1948, the populations were about the same [7m Sri Lanka: 3m RoI + 1.3m NI = 4.3m Ireland] but the number of Lankans has tripled to about 20 million now.  3/4 of the people are ethnic Sinhalese, 11% are Tamils, 9% are 'Moors' / muslims and the rest a bit of everything else. The Northern part of the island hosts most of the ethnic Tamils who are closely related to Tamils on the other side of the Palk Strait [R 80km wide sat-view; and below] in India.

If you look closely at the coastal geology the Palk Strait is bisected by a string of coral reefs, cays and sand-bars extending between Pamban Island, which is connected to the Indian railway system and Mannar Island on the Lankan side.  That too used to be connected to Colombo by the railway system until a disastrous cyclone washed out the line in 1964. Indeed an Indian train full of 150 people was swept into the sea just short of Dhanushkodi by a storm surge killing everyone aboard. Dhanushkodi was inundated by the water and those that survived the night lost the will to live there and moved away. When the sea receded before the 2004 Indian Ocean tsunami, parts of the old town were revealed for the first time in 40 years. Adam's Bridge is acknowledged in the map above and in my 1938 era map of Southern India in The New Universal Atlas.  Hindu legend says that the bridge was passable by gods and the peculiar square slabs of surface limestone have had people imagining that it was man-made. Actually in the legends, the bridge was constructed not by men but an army of apes led by Nala. Temple records suggest that the whole string was traversable on foot as late 1480 when another cyclone scoured at least one channel too deep to ford. We live indeed on a Restless Earth.

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