Polar Podcasts

02: Brian Upton: “Ilimaussaq is magic” – beginnings of a lifelong passion for alkaline rocks

August 04, 2020 Julie Hollis Season 1 Episode 2
Polar Podcasts
02: Brian Upton: “Ilimaussaq is magic” – beginnings of a lifelong passion for alkaline rocks
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Polar Podcasts
02: Brian Upton: “Ilimaussaq is magic” – beginnings of a lifelong passion for alkaline rocks
Aug 04, 2020 Season 1 Episode 2
Julie Hollis

In this episode, we hear from Brian Upton, Emeritus Professor of Geology at the University of Edinburgh, about starting out in South Greenland with the Geological Survey of Greenland in 1955, and what became a lifelong passion for researching and understanding the unique rare earth element-rich rocks of the Gardar Province, on which Brian would become a world expert, still publishing his research on their remarkable geology more than 60 years later.

Show Notes Transcript

In this episode, we hear from Brian Upton, Emeritus Professor of Geology at the University of Edinburgh, about starting out in South Greenland with the Geological Survey of Greenland in 1955, and what became a lifelong passion for researching and understanding the unique rare earth element-rich rocks of the Gardar Province, on which Brian would become a world expert, still publishing his research on their remarkable geology more than 60 years later.

Transcript

02: Brian Upton: “Ilimaussaq is magic” – beginnings of a lifelong passion for alkaline rocks

Based on interviews held on January 14–15, 2020 in Edinburgh, Scotland

Note: Polar Podcasts are designed to be heard. If you are able, please listen to the audio, which includes emotion and emphasis that is not evident in the transcript.

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Brian 0:01

Some of the world’s most extraordinary rocks, very, very rich in rare earth elements, also rich in uranium, thorium, niobium, tantalum. Ilimaussaq is magic.

Julie 0:11

Welcome to Polar Podcasts, where you’ll hear stories from geologists who’ve spent their careers, their lives, exploring and studying the remarkable and remote geology of Greenland. Why did they become fascinated with Greenland? What were the problems and the discoveries that drove them? And what was it like working in these remote places, where few people venture, even now? I’m Julie Hollis.

In this episode, we hear from Brian Upton, Emeritus Professor of Geology at the University of Edinburgh, about starting out in South Greenland with the Geological Survey of Greenland in 1955, and what became a lifelong passion for researching and understanding the unique rare earth element-rich rocks of the Gardar Province, on which Brian would become a world expert, still publishing his research on their remarkable geology more than 60 years later.

Brian 1:10

Right, well I was born in 1933. I’ve got an older sister, about four years older than me, and she was a great influence on my life because she taught me a hell of a lot about natural history of all sorts and first showed me fossils and stones. And I became interested in Iceland. And when I was eighteen, I managed to get onto one of the British school’s exploring society trips to central Iceland. I fell in love with the country and I didn’t particularly like the people I was with. But I determined to get back as quickly as I could with more congenial company. And when I got back to Oxford, I met Professor

Julie 1:51

That is Professor Bill Wager.

Brian 1:53

half way down the stairs one day and he said, “Brian, are you interested in working in the north?” And I said, “Yes, well do ducks like swimming?” And he said, “Would you like to go to Greenland?” I said, “Yes.”

I’m going to digress for a moment to talk about my boss, Lawrence Wager, Bill Wager. He was a great climber. He held, for a long time, the record of the highest solo ascent of Everest, 28 000 feet without oxygen. He found Mallory’s ice axe. He got involved in the British East Greenland Air Route Expedition, 1931 or thereabouts. And Britain had had two famous long-distance um, sledging expeditions, Captain Scott and er then er Shackleton. The third longest, which is not known about, which was in 1932-33, putting a man up on top of the Greenland ice sheet at 11, 12 000 feet, just an awful long man-haul, involved in that. And it was, he subsequently then found the Skærgaard intrusion. 

Julie 02:57

The Skaergaard Intrusion is a remarkable layered gabbro intrusion in east Greenland, which is discussed by Emeritus Professor Kent Brooks in the next and later episodes.

Brian 03:07

and became a great enthusiast. After a very exciting wartime career, which I won’t go into, but after the war he wanted to get back to Skærgaard And he was well aware of NV Øssing’s work on Ilimaussaq, 1911.

Julie 03:23

The Ilimaussaq Complex is a very unusual layered rare earth element-rich magmatic intrusion that forms part of the Gardar Province in South Greenland, which Brian would later spend much of his career researching. This is how Brian summarises the complex and unique geology of the rifts in the crust that generated the extremely unusual alkaline rocks of the Gardar Province.

Brian 03:46

We can think of these as a continental rifts, in some ways at least analogous, let’s say, to the east African rift of Ethiopia and Kenya. And alkaline volcanoes erupted in connection with er, this rifting event. Then, about a hundred and forty million years when nothing of any note took place. And then another load of alkaline rocks were emplaced, almost certainly with superficial volcanoes on them, in conjunction with a great deal of faulting. All of these alkaline rocks we divide into the older Gardar and the younger Gardar. The name Gardar comes from the old Norse settlement in this area, which had been er formed by Erik the Red, So we’ve got a northern rift and a southern rift. They’re parallel to each other. They have a lot in common but the one down the axis of the mass of granite, the Julianehaab batholith, has far more exotic compositions associated with it. And all the interesting mineralization and all of the complex geochemistry is concentrated in the younger Gardar and the southern rift of the younger Gardar. It was defined by splitting down the middle with the emplacement of magmas as composite dykes, which started off more or less gabbroic but the later rocks in the central part were alkaline syenites of one sort or another,

Julie 05:23

A syenite is like a granite, but with little or no quartz.

Brian 05:27

followed by some much more silicic alkaline complexes, which cut across the giant dykes. One is the Tugtutoq central complex and the other one is referred to as the Narsaq complex. And then as the youngest event of any note in the Gardar, we get the Ilimaussaq Complex. First of all, we get massive emplacement of a syenitic rock, And that was essentially crystalline when another influx of alkaline magma was intruded, this time distinctly more evolved.

Julie 06:04

By which Brian means that the magmas were enriched in elements that do not easily fit into the crystal structures of minerals crystallising from the melt – elements such as the alkali elements, sodium, potassium, and more unusual elements such as the rare earth elements.

Brian 06:21

The augite syenite may have been superimposed by a volcano. We feel that the later one, had a thick lid on it but with the remains of the early volcano and was er, crystallised thereafter under a very, very  strong lid. As it did so, crystallization was, at first, largely from the base upwards, until it reached the stage when the very low density mineral, sodalite, was precipitating.

Now sodalite is able to float in the magma. And it forms a layer on the top of it, a very peculiar rock, unique in the world, which is called by the original discoverer of it, NV Øssing, he called it a naujiite. Naujiite is an extraordinary rock then, full of sodalite crystals, which have floated up. Sodalite has a very high chlorine content. It’s also an extremely sodic rock. If you like, you could consider a rock extremely just full of common table salt. It’s a rock extremely full of sodium chloride. The layer is of extraordinary thickness. It’s at least five hundred metres thick. Below this later of accumulated sodalite crystals, later magmas were reacting with the lower part of the naujiite. The belief is that this naujiite could amount to something like a total volume of sixty cubic kilometres of this extraordinary sodium-, chlorine-rich unique magmatic rock.

Beneath this, the magma, which we believe was very, very fluorine-rich, very rich in fluoride ions, which would reduce the viscosity. So you can think of it as an extremely low viscosity, very, very runny magma, which underwent further crystallization. The crystals now were denser than the melt from which they separately. They now sank to the bottom to form a floor cumulate. So we’ve now got a floor crystal cumulate rising upwards, trapping between it and the naujiite roof, a melt of persistently increasing concentration of all the rare elements. And they gave rise to some of the world’s most extraordinary rocks and er, very, very rich in er, rare earth elements. Also rich in uranium and thorium, niobium, tantalum and a whole host of other rare components. The rocks have sodium contents relative to the aluminium content. So instead of forming the usual sodium-aluminium silicates, like feldspars, they had to form sodium-rich minerals with ferric iron, forming the mineral aegerine. But thereafter with all sorts of rare elements like zirconium, forming the mineral er eudialyte

Julie 09:40

This is a rare earth element rich mineral with a beautiful deep red colour.

Brian 09:45

and a whole host of others. These rocks with this excess of sodium over aluminium are called agpaiites. It’s a name from one of the local Inuit localities. In some of the most extreme rocks, which have been distinguished as hyper-agpaiites, the mineralogy is really weird and extreme and gains high contents of uranium and thorium. These hyper-agpaiites constitute the largest magmatic concentration of thorium, I think anywhere on Earth. The rocks I’m talking about are rocks called lujavrites, which have a very, very odd mineralogy. 

Julie 10:32

Or to summarise more simply why the Ilimaussaq Complex is made of rocks of such unusual composition…

Brian 10:39

If you got a barrel full of apples and oranges and you keep taking out the apples, you concentrate the oranges. It’s a fractional extraction. And if you’ve got a, a molten material – it could be anything you like, any liquid, and you take out one component from it, you are going to concentrate everything else.

And why is Ilimaussaq extraordinary? Because fluorine is a wonderful polymer breaker. So a liquid with lots of fluoride ions in it, you can say it’s going to be runny and ionic migration, instead of being nanometers or millimetres can become metres.

Julie 11:24

By which Brian means that with so much fluorine, the magma can very easily separate into different chemical components – a process that is usually very slow and difficult in most magmas.

Brian 11:37

I can’t imagine there’s anywhere were it is so beautifully done. I don’t think there has ever been or ever will be a concentration of fluorine ever again on this planet, I’m going to say in the solar system, had such a concentration of that one element, ok, others but particularly fluorine. Ilimaussaq is magic.

Julie 11:57

And explaining why he regards these rocks as so precious…

Brian 12:02

Some of these are vesicular. With geodes in them,

Julie 12:06

Which means that the original magmas contained gas bubbles, which are now preserved as holes in the rock that have been partly filled with crystals that grew into those holes.

Brian 12:17

with feldspars and quartzes and amphiboles and zircons, and there’s nothing else in them. They’re just crystals sticking in. I think, these things, when you break them open and look at them, look at these quartz and feldspar crystals, you think, ‘what’ve I done? I have just broken a priceless Ming vase. I’m looking at something which has not been opened to fresh air for one thousand two hundred and eighty million years.’

I broke open a geode once on Ilimaussaq and there was a little tinkling noise and, ‘What have I done?’ These little aegerine crystals, little aegerine prisms had broken and fallen down. Those had been sitting there ever since they crystallised. Tutankhamun’s tomb is not a far-fetched analogy. These things have just been sitting there waiting, after one hell of a long time, to be looked at.

Julie 13:05

But to get back to that meeting on the stairs in Oxford in the 1950s, when Brian was first offered the opportunity to visit Greenland and the Ilimaussaq Complex by Professor Bill Wager…

Brian 13:17

And he said, “Would you like to work on Ilimaussaq?” So I said, “Yep.” And he had met Arne Noe-Nygaard, Danish professor, geology, again extraordinary war history with the Danish underground movement, which was largely based in the cellars under the geological museum.

Julie 13:38

In Copenhagen

Brian 13:39

Anyway, he and Wager got together through their work in east Greenland and became friends. So Wager said, “I will write to Noe-Nygaard and see if I could get you there, I’d love to get work on Ilimaussaq.” “Whoopee, yes”. It went to the Danish science committee and they said, “Mmm, no”. This was the height of the Cold War and, “no, there’s too much strategic importance in Ilimaussaq. We’d rather keep it for Danish folk. Would he like to work on Grønnedal-Ika, to the north of it, which is a nice carbonatite complex?”

“Yep, ok.” A few tears but still sounded fun.

No, again, they thought it had strategic importance, so no. There’s a mountain off to the west of that we don’t know anything about called Kunnatfjeld, which is er, granitic sensu-latu. And they sent me a photograph of it and I fell in love with it at first sight. I didn’t care if it was made of green cheese or concrete. And I did and that is one of the happiest accidents of my life, being sent to that anonymous heap of rock out in the way of things. Enormous fun.

Julie 14:50

I’m Julie Hollis and you’ve been listening to Polar Podcasts.

Julie 15:00

In the next episode we hear from Emeritus Professor Kent Brooks his fifty year career studying Greenland and his first field season in east Greenland in 1965.