Why the Indian subcontinent is a geological museum like no other

January 15, 2018 09:47 am | Updated 09:47 am IST - Chennai

It is challenging to tell an engaging story on the life of rocks, but Pranay Lal has looked at enough mountains, basalt and fossils in the Indian subcontinent over 22 years to come up with fascinating stories.

Far from being lifeless, his rocks enliven the story of how India has a unique geological history that should make it one vast museum, with colourful remnants of volcanic eruptions going back hundreds of millions of years.

In an illustrated talk titled ‘Indica: A Natural History of the Indian Subcontinent,’ on day one of The Hindu Lit for Life, the biochemist-turned-geology researcher delved deep into the exciting origins of this part of the world, based on his book on the subject.

His story for the fest was a voyage that starts in Jodhpur, which stands on a mountain created by a volcanic event 750 million years ago, and ends in Jaisalmer in Rajasthan where he stumbled on foot-fossils of chicken-sized dinosaurs that existed an estimated 90 to 70 million years ago.

These are just anecdotes in a long sweep that covers the formation of the earth, early meteor strikes, the gift of water, the many eruptions of volcanoes and the formation of magnificent rocks. Finally, we have monumental events triggered by staggering volcanic eruptions that separated present-day continents from much bigger masses of land, which were covered by ice in early epochs.

Indica traverses these epochs right from the birth of the earth about 4.5 billion years ago, to the more recent events around 170 million years ago, when a channel was created between West Gondwana, which was today’s Africa and Latin America together, and East Gondwana, containing India, Madagascar and Australia. Look at rocks in Brisbane in Australia and Rajmahal in eastern India, and note that they are nearly identical. Then, 68 million years ago, a massive Deccan volcano eruption set India off on a fast northward course that culminated in its impact with Asia and the formation of the Himalayas and the Ganga.

Mr. Lal’s talk had many anecdotes that would, he hoped, provoke the curiosity of the itinerant traveller to wander around more mindfully - look carefully at the ancient history of rocks, at the wealth of fossils that hide in plain sight, the geological oddities such as phosphorus and iron combinations that impart a golden hue to rocks in some parts, and so on. “The next time you look outside the train window, notice the many layers of different rock that tell the story,” he says. His own travels turned up fossils of custard apples, indicating that they are not really exotics introduced to India by the Portuguese, and coconuts in the north-western areas.

Does India appreciate its exalted status in the history of the earth in natural history terms? Mr. Lal answers the question himself, asking why there are no museums for Gondwana, for the Deccan and the Himalayas in the country. He is also saddened by the lack of curiosity in the school education system, something that should be addressed “by de-schooling policy and encouraging critical thinking.”

One immediate dilemma is whether the locations of rare fossils, such as the chicken-dinosaur find, should be widely publicised, risking their destruction either due to the resulting unsustainable tourism, or left unmarked with the hope that they would not be built over by property developers.

As a researcher, Mr. Lal is also concerned that the role of the Ganga and the Himalayan rivers in combating climate change is not being given due attention. In his view, the Ganga must be saved to avert dangerous climate change more than any other reason, because it is a massive carbon burial mechanism thanks to unique silica sediments, but there are commercial forces ranged against such a simple remedy.

A visitor wanted to know whether humans would be able to control the way future evolution takes place, or face massive cataclysmic events as in the past. Mr. Lal’s response is that nature has never witnessed a species like humans, who are conducting a rapid assault on natural systems, with consumption and introduction of synthetic elements like plastics into the environment, for which there is no known handling mechanism. Ultimately, though, “nature will take its own course.”

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