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Reading the Dezz

LiveMint logoLiveMint 14-04-2017 Pradip Krishen

I travel quite frequently in the Thar desert, four or five times a year, but I wouldn’t call my travelling “scientific”. I go looking for plants, seeds, soils, minerals, because the work I do is all about rewilding a rocky desert habitat. “Dezzing” for me is an adventure in a vastly delicious and only just-beginning-to-get-spoilt landscape. I am looking for unusual seeds, marvelling and peering (usually quizzically) at rock formations, crying out (excitedly) when my companions or I find something that looks even vaguely like a marine fossil. And the music—I mustn’t forget the magic of Manganiyars singing jaangdas late into the night.

Some of this may sound scientific. Perhaps it even skirts the hem of scientific territory. But I have learnt that one can travel in a landscape and “see” very little of it, barely lift the covers to take a peek at what lies inside. It needs special skills and the confidence of deep knowledge to read a landscape like…well, like a Manganiyar knows how to draw divine music from his gaj (bow). This is what I learnt on a journey I made in the December of 2015.

I had two extraordinary travel companions. Prof. Ashok Sahni—“Proff”—is a paleontologist. He is not just a towering figure in his field, he is one of those scholars who makes you feel you’re in the presence of a glowing richness of thought. “Top Dada Man,” my friend Hussain would have said.

Proff was there thanks to Pranay Lal: biochemist, virologist and super-keen autodidact paleontologist. He was the one who said that the best way to begin to understand the Dezz was to invite Proff on a journey. No slouch himself, Pranay recently set our natural history world alight with Indica, his first book. This trip was to be my initiation into the world of fossils and deep time in the western marches of the Great Thar Dezz.

We headed north-east from Jodhpur towards Nagaur, familiar backstreets for me. Along this route I had found (quite by chance) a clonal forest of 100 or so indrokh trees growing around a small, seasonal pond, or naadi, some years before, and I showed it to Proff and Pranay with the air of a tour guide. Clonal forests are giant organisms made up of hundreds—sometimes thousands—of what may appear to be separate trees though they are all in fact the same creature, with identical DNA. Because they occupy stressed habitats where the chances of their seeds germinating are low, they resort to sending out “suckers” or “runners” underground which grow over time into entire tree-like extensions (if someone asks you what the largest creatures on earth are, it’s not whales or sequoias—just say “clonal forests” to get full marks). Indrokhs pay a price for eschewing sexual reproduction—because they’re all the same creature, they’re vulnerable to the same pathogens. One noxious virus would knock them all out at once. That’s the price you pay for not inheriting a different set of chromosomes from each parent.

"I learnt that my ‘indrokh’ forest owed its existence to a long-gone beach which probably lay exactly where we were standing…to a backstory of millions of years of shelled sea creatures living and dying in briny waves that broke on this beach."-

Proff seemed impressed. Well, sort of. Because he was looking around thoughtfully, reading invisible signs that led back in time. He picked up a pale irregular nodule of kankar lime from a nullah and started telling me how calcrete is characteristic of arid lands, and especially so in the Thar. “This naadi is a miniature playa (a flat, dried-up desert basin from which water evaporates quickly),” he said. “Probably a relic of an ancient drainage system that would have stopped flowing when the climate changed.” All the various kinds of carbonates in the desert, he said, have their origin in sea creatures that have extracted dissolved carbonates from seawater to make their shells.

Corals are particularly rich contributors to the formation of marine limestone. So are molluscs, gastropods, brachiopods, everything with shells made of calcium carbonate. When they die, all that calcium from these creatures gets incorporated in the rocks which build up as sediments in shallow seawater. My tour-guide mien was fading rapidly by now, changing into that peculiar smile that tourists have when they are learning more than they can possibly take in all at once.

I learnt that my indrokh forest owed its existence to a long-gone beach which probably lay exactly where we were standing…to a backstory of millions of years of shelled sea creatures living and dying in briny waves that broke on this beach. And that long, long after all this calcium carbonate was buried deep below the earth, it would have travelled slowly, inexorably upwards through the soil, drawn up by osmosis in a new arid landscape. It was all about time. I hadn’t thought about it like that. It hadn’t even occurred to me.

On our way to Bikaner, I was introduced to dolostone near Nagaur and to luminous bands of gritty purple gravel in China clay deposits near a lignite mine. No one seemed as impressed as I was with the intercalated bright colours. Pranay the chemist had this way of accepting that this is the way things behave. Crystals, lattices, ions, protons…. It’s what they do, the way they are.

Proff pointed out a “junction” between Cambrian formations (some 500 million years old) and much younger Eocene rocks (a mere 40-50 million years old). By now Pranay and he were both “reading” the rockscape the way musicians follow notations. Junctions of two different rock types sometimes display what earth scientists call an “unconformity”. At some point in time, something that lay interposed between the two layers of rock has disappeared and left no trace. In this delicious sense, an unconformity is like a piece of missing time!

A short while later we stopped at a somewhat higgledy-piggledy exposure of ochre-coloured Fuller’s earth and Pranay explained how this fine mixture of clay minerals—“montmorillonite”! Can’t forget that name—originates in shallow lagoons where an uncommon set of geological processes results in volcanic ash deposits being altered by seawater.

Fuller’s earth, absolutely chock-full of tiny forams, single-celled marine creatures.

“You see these rocks?” Proff said a little later. “Early Jurassic. Probably a foreshore not far from a tidal zone….” The rest of that stop was all about dinosaurs and all that we know about why they died out (mired in controversy, of course).

Then we talked about sponges, somehow. Amorphous, asymmetric, simple creatures (let alone backbone, no stomachs or nervous systems) that “decided” to band together in ancient seas to become a foundational experiment in complex life forms. Different kinds of sponges with little lattices of cells that support them like skeletons—with “spicules” made of all kinds of interesting substances like calcium carbonate, even silica.

I don’t remember everything I learnt that day. I couldn’t understand how Proff and Pranay were able to divine the kind of detailed understanding they had of everything they saw. Didn’t they need instruments? Or tests in laboratories? Perhaps it had all been mapped and studied before and these two remarkable men were simply introducing me to things that were now the common coinage of earth history in the Thar.

We were driving towards Jaisalmer late on the evening of Day 2, approaching a tiny village called Thaiyat about 12km before Jaisalmer. The sun had set and we knew we didn’t have more than 45 minutes or so of daylight left. We were on the trail of dinosaur footprints, or, more accurately, one single footprint that had been found the previous year on a low ridge close to the village. Neither Proff nor Pranay knew exactly where the footprint was, so we asked at a tea stall on the highway. “Do you know of some place nearby where lots of er, people from universities come here searching for something on the ground?” we asked.

“Dyna-sorrr! Dyna-sorr!” one man cried out brightly, pointing to some sedimentary rocks not far away. “Look, there! Everybody goes there!” We wondered what pictures he had in his mind about what a dinosaur is. Probably a T.Rex, or at least something toweringly huge and ferocious.

We didn’t find the dyna-sorr footprint after all. In the dying light we moved around in tightening circles looking for a telltale pattern in the rock, any organized shape that stood out from the random nicks and scratches in the worn sandstone. Nothing. We gave up. Maybe it had gone, expertly filched with precise tools by an unscrupulous collector. Perhaps the Geological Survey of India had taken it away to keep it safe. Unlikely! Or we had just simply failed to spot it. It was poor light, after all.

We gave up our search as darkness gathered around us and we felt the first nip in the air. I’ll admit it now—I was relieved. Not by the nip—by not finding the dinosaur footprint! It was just a tiny blemish in an amazing journey, but it put everything in perspective. Listening to Proff and Pranay all day, I wanted so much to turn into a palaeontologist and chemist rolled into one.

Prof. Ashok Sahni after giving up the search for the dinosaur footprint near Thaiyat.

But you know what? That missing Saurian footprint made me glad we don’t know everything there is to know and can’t find every footprint and fossil and ancient spicule hiding in the dust. That the world will always be full of secrets and surprises and discoveries, for ever and ever.

Pradip Krishen is the author of Trees Of Delhi and Jungle Trees Of Central India: A Field Guide For Tree Spotters.

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