Did you know that the Godavari once flowed northward into an ocean, and that the river is thus older than the subcontinent? That “stupendous” volcanic activity once blocked rivers in peninsular India, creating swamps in and around which all sorts of ancient species lived, died and were squashed into the soil? That the Deccan once stretched from Kachchh to Rajahmundry and even to land now 1.5 km below the Arabian Sea? That whales were once wolf-sized land-based carnivores? That all sorts of interesting things are going on in the ground beneath the industrial belt of Jharkhand? That — and this was a real surprise — a hill near Vadodara “comprises a unique succession beginning with ankaramite at the base, followed upwards successively by mugearite, hypersthene-basalt, olivine-basalt, andesite with rhyolite and tuffs at the top”?
All right, that last one was unfair. But I am currently enthralled by this book I can barely understand. It’s called The Making of India: Geodynamic Evolution, and it’s a newly published textbook of Indian geology for college students and teachers — though author K S Valdiya adds, somewhat incredibly, that he was also aiming for “non-specialist readers”.
Non-specialists, if they do pick up this book, will probably read for thought-provoking and retailable snippets like the ones above. My own favourite takeaway is the absolutely electrifying notion of “cratons”.
We all know that India has been moving around, in geological terms, like a beauty at a ball. For a long time she was attached to Gondwana. Then she split up with it and (over 70 million years) raced off — abandoning Madagascar and the Seychelles — to nuzzle Eurasia. She is, they say, the fastest continent. (I wonder if that is geological humour.)
So, cratons. Cratons (from the Greek for “strength”) are those parts of tectonic plates that, being located at the centre, are hardly changed at all. At a craton the crust is thickest, and the rocky roots go deep into the Earth’s mantle. They are the very oldest bits of land.
India has four or five cratons, named after the areas where they are oldest — 3 billion-plus years. There is the Dharwar Craton, the Bundelkhand Craton, the Bastar Craton and the Singhbhum Craton. In the interstices are the Narmada, Godavari and Mahanadi river valleys. And Meghalaya sits atop its own little craton.
Apart from being romantic and satisfying, the idea of cratons — slow-changing, coherent rafts of rock — is also portable. For example, visualising the city of Delhi as a continent, I live on the boundary of two cratons. That is, I live where the Connaught Place commercial craton meets the Lutyens’ Delhi power craton. This is not to say that these zones are unchanging, rather that the locally dominant human activities have a reliable continuity.
Other cratons are the dense dormitory suburbs of east Delhi, separated from the Lutyens craton by the Yamuna bed; the dry western suburbs marked off by the Ridge; ex-colonial north Delhi, centred on the University; south Delhi from Badarpur to Vasant Vihar; and Old Delhi, which may be an offshoot of the Connaught Place craton.
At one level, this is a reworking of the familiar notion of the city as an organism, with organs for various functions (where is Delhi’s heart?) and a circulatory system moving the lifeblood of people and commerce around. But at another level — and thinking in the longer, if not quite geological, term — the idea of cratons is a way to view our future history.
What if, to take one example, India’s climate warms 3 degrees C in this century. Will Delhi then be too extreme to support a global capital and its attendant population? Will Lutyens’ power craton then migrate into the Himalayan foothills? The form and structure of government may not change that much, but its location could.
Another example: the smug idea that a services economy is a durable economy has lately been proved mistaken. Manufacturing is critical, and it is becoming less polluting by the day. Will the industrial cratons of Gujarat and Maharashtra now migrate towards the cities? With SEZs, the process has already begun.
A third: with easier and cheaper long-distance travel, and with better broadband access, will certain salubrious portions of the country begin to attract an urban middle-class population, as Mysore, Pune and Bangalore once pulled in retirees? I can imagine a colony of flexible service-sector workers forming a loose social-economic craton in southern coastal Maharashtra, or around Bhopal, or (give it some time) in the neighbourhood of Darjeeling.
And so on. With human history one is usually looking back at the past. It is geology that calls to mind fate and the far future.