History on the rocks
The mysteries of the earth’s fantastic past are hidden all around us — in rocks and caves, in stalagmites, even in plain sight. Travel back in time, as far back as 4.2 billion years, through ancient remnants still visible in and around some of India’s big
The earth’s been through a lot in its 4.54 billion 250 million years ago: Dinosaurs evolve anye d arbse .H gio n w tm od uco h meivnidaetn e ce Eaor f tha. t early tumult is still visible? What can traces of that time tell us about how we got here, and what next? It turns out, there’s evidence of prehistory hiding in plain sight, even within and around our largest cities. A peculiar stump rising out of the earth in the suburb of Andheri in Mumbai, now flanked by residential buildings and topped by two temples, dates back to a time when all of India was an island, floating towards Asia. That’s the soaring, 66-million-year-old Gilbert Hill.
In Meghalaya, a stalagmite was extracted from a cave, split open and studied, to reveal signs of a 200-year global megadrought that may have contributed to the decline of the Indus Valley Civilisation. The clear evidence of the megadrought observed in this stalagmite prompted the International Commission for Stratigraphy to name the period that began then, 4,200 years ago, the Meghalayan Age.
In Odisha, hair-thin zircon filaments found embedded in rocks date back to when the earth was an ocean of lava and was still being bombarded by asteroids, 4.2 billion years ago. The filaments also hold new clues to how (and when) the earliest rocks formed.
Not far from Bhopal, 550-million-year-old Dickinsonia fossils have been found at Bhimbetka. The fossils of a mysterious, soft-bodied organism believed to have been a kind of flatworm or lichen are the first Dickinsonia ever found in India.
Meanwhile, recently discovered rock paintings on the fringes of Delhi reveal that habitation in the Aravallis goes back a lot further than the Indus Valley Civilisation.
As dating technology improves, “India is now busy pushing its history back in time,” says SB Ota, retired joint director general of the Archaeological Survey of India.
Areas that need desperately to catch up are preservation, legislation and funding. Geologists Rajat Mazumder and Trisrota Chaudhuri, who discovered the zircon fragments in Odisha, had to beg labs around the world to test their samples, before a lab in China agreed to help. Mazumder is now struggling to secure funding to study the site further, and to preserve it.
Scientists across the country, meanwhile, have been pushing for a geo-heritage preservation law. “The wait is getting longer and geoheritage sites are being vandalized unabated in many parts of the country in the name of development,” Dhiraj Mohan Banerjee, INSA emeritus scientist and former professor of geology at the University of Delhi, wrote in an editorial in the journal Current Science, in July 2021. “India’s unique geological features are made by natural processes and cannot be repaired or replaced,” he added. “Once destroyed, they will be gone for ever.”
Gone with them would be clues to what the planet was like in its earliest years, the creatures that lived before us, the life and times of early man, even the causes, progressions and effects of previous phases of climate change. Wouldn’t that be a shame, to lose vital signs tucked away in the earth, of what a long strange trip it has been?