Our use of cookies

Myself, my field assistant, the driver, his mate, all our gear, and assorted other accoutrements deemed essential for travel in India,  squeeze into the bulging underpowered ancient yellow and black vehicle that in India passes for a serviceable taxi, and in any other country would draw the swift attention of any even half-asleep traffic cop.

My ears are assaulted by the continual blaring of horns – in India, whilst any other part of a vehicle, including tyres or steering wheel, is likely to be far from roadworthy, the horn is always in fine working order, mingling nicely with the high-decibel distorted “music” emanating from the low quality car stereo.

It’s going to be a long journey to the road head, from where we depart for the field site, no doubt filled with the usual trials and tribulations of working in this chaotic country, and I love it.

 The joys of India

I love the milling mass of over-curious people, with their characteristic head wobbling, followed by the word “acha”, which I used to think meant, “OK, I agree” but now I realise can equally well mean “OK, I am hearing you, but I have absolutely no intention of acting on what you have just requested”…. which can be a touch frustrating when, for example, you leave someone in charge of shipping your hard-won rock samples, and come back three hours later to discover they have made no progress out of the door.

I love the chaos and the lack of rules, providing continuous mental challenges: the mechanism by which my rock samples exited the country last time, permitted and packaged, will almost certainly not work this time and I’ll need to find another solution. The patience of a saint, coupled with the mental dexterity of a gymnast, as one ducks and dives the bureaucracy, are skills that I am still working on.

And I love the mountains – the beauty and serenity and the magnificence of the Himalayas. They’re the reason why I work here: to try to understand how these most beautiful creations formed.

Formed by the gods, or by colliding plates

According to Hindu mythology, the Himalaya were formed after the god Vishnu created Mother Earth by swallowing a large ocean. Whilst Vishnu then slept, the demon Hirantanksha seized the opportunity to assault the defenceless Mother Earth and the resulting breakages and contortions formed the Himalaya. 

According to western scientific thought, the Himalaya formed when the Indian and Asian continental plates, previously separated by a large ocean, collided. The force of the collision forced rocks from the bottom of the ocean 8000 metres up in to the air, and that is why sea shells and marine fossils are found at the top of Mt. Everest.

My research focusses on trying to determine when this collision occurred. Current estimates range from 65 to 30 million years ago.

My approach involves searching for evidence of the earliest material which was eroded from the Asian continental plate now lying on the Indian continental plate. This material must have been carried by rivers and this could only have happened once the two plates were joined.  So if I find the oldest such material, I’ll know the time of the collision. Easy? Not quite.

Zircon offers an answer

First, how does one recognise Asian material as distinct from Indian material? The answer is provided by a mineral called zircon.

Before collision, from approximately 130 million years ago, the oceanic plate which previously separated India and Asia was being pushed under the margin of the Asian plate. This heated the crust of the Asian margin, and the crust started melting. 

When the melting crust cooled, zircon was formed. This melting, cooling process happened on the Asian plate between 130 and 40 million years ago, but did not occur on the Indian plate during this period. Thus, zircons formed during those years must be originally from Asia, not India.

But even when we find Asian-derived zircon in river sediment on the Indian plate, how do we know when it was deposited there? Fortunately, there are fossils in these sedimentary rocks, and these fossils are of animals that lived at specific times, of short duration, and in this way we can date the rock.

Collecting the samples

So, going back to my taxi ride, what am I doing? I am searching for Asian-aged zircons on the Indian plate. First I take the taxi to the road head. Then, when the road runs out, I transfer to foot, with a fleet of horses , a guide, a cook, and a field assistant.

We huff and puff ever higher into the mountains searching for potential zircon containing rocks - ones on the Indian plate which look like they were deposited from rivers in the past, and have fossils of a suitable age. 

When we’ve found them, we collect many kilograms, load them on to the backs of our beasts of burden, return to the road head, into the groaning taxi, through Indian bureaucratic export hurdles (yes, we do indeed want to pay hundreds of dollars to export material which we claim is of no commercial value, we explain to incredulous customs officers), and into the lab.

The final analysis

Painstaking separation of the mineral zircon from the rock – there is usually only a few milligrams of zircon processed from five kilograms of rock – transfer of each individual tiny grain (less than the size of a pin head) to a mount without sneezing at the wrong moment, photograph each grain under a microscope to make sure we are analysing the correct part of the grain, and finally radiometric dating of each grain.

The result? I find grains of Asian origin in Indian plate rocks which were deposited by rivers 55 million years ago and, in this way, date the time that Vishnu swallowed the ocean, and the Indian and Asian plates collided.

For more information see:

The Himalayan consortium, an international research group funded by the EU.

The National UK lab facility where we analyse our zircons:

Details of my other Himalayan research and more photos