The secret world of Antarctica’s volcanoes

Renowned for its desolate and unforgiving landscape, Antarctica is the driest, coldest, windiest continent on the planet. Immortalized as a world of glittering glaciers and huddling penguins, the barren tundra hides a very big secret … numerous volcanoes. Perhaps the very antithesis of the frozen desert, one of our latest Memoirs explores these volcanoes. Production Editor Jo Armstrong and Commissioning Editor Bethan Phillips had the opportunity to speak with the Chief Editor of the volume, Professor John Smellie of the University of Leicester, about his research and time spent in Antarctica.

Why should people read your book?

The Memoir is the most up-to-date, in-depth description and assessment of volcanism right across Antarctica, going back 200 million years. It is based on research by volcanologists and petrologists from multiple nations going back decades and the lead authors of the chapters are internationally acknowledged experts in their fields. Most people (including many scientists) are unaware that Antarctica has volcanoes. Yet they are common and include some of the largest in the world. Of course, most are almost completely covered by the Antarctic ice sheet. Only a few are still active and include Deception Island in northern Antarctic Peninsula, and Mt Erebus on the opposite side of the continent. Erebus is distinguished by a permanent lava lake, one of only a handful worldwide. Antarctica’s volcanism also includes unimaginably voluminous flood basalt lavas and associated explosively generated rhyolites, formed during the fracturing and initial disintegration of the Gondwana super-continent. It was an episode that also caused multiple mass extinctions globally. But most of Antarctica’s volcanoes show evidence for interaction with the ice that surrounded them when they were active and they preserve an unrivalled record of the terrestrial environment over the past 30 million years. Documenting and understanding the history of the Antarctic ice sheet, which is the largest ice mass on Earth and which may be a dominant influence on world climate, is clearly critical if we are to understand and mitigate climate change. Additionally, due to atmospheric circulation patterns, some of Antarctica’s volcanoes have the potential to have an immediate impact far outside of the region (e.g. on aviation) and the Memoir also includes the results of investigations into all of Antarctica’s active volcanoes.

Why Antarctica? What makes it a good place to study volcanism?

Antarctica is the coldest driest place on Earth, so all forms of life find it extremely hard to survive there. Humans too. But the benefit to volcanologists is that the rocks are exceptionally clean because most plants can’t colonize the surfaces. Therefore, the rock is essentially pristine and that helps us to record details about past eruptions that are hard or impossible to see in most other parts of the world. Antarctica also hosts the world’s largest and longest-lived glaciovolcanic province on Earth and it is characterized mainly by many very large, long-lived volcanoes. Other provinces (e.g. Iceland, British Columbia) are dominated by very small glaciovolcanoes that individually give only single snapshots of the environmental conditions. By contrast, Antarctica’s volcanoes typically have lifetimes of a few million years, so the record of environmental change and, particularly, of the ice sheet, is much more extensive as well as uniquely important. It provides a vital counterbalance to our knowledge of environmental change that is otherwise mainly based on the more distal marine record.

Antarctica contains several active volcanoes, one of which is Mt Erebus, could you tell us a bit more about Erebus and its lava lake?

When the Antarctic continent was discovered, in the 1840s, the explorer who first observed Mt Erebus fortuitously saw it in eruption, with lava pouring down its flanks. That means that the lava lake was present 200 years ago, at least. We also know that the lake has been present continuously since the late 1960s and subsequent monitoring and comprehensive volcanological—geophysical investigations have become a byword for understanding lava lake dynamics and eruptive processes of an open-vent volcanic system. Heat from the magma has also created numerous fumaroles under the capping ice, which has created substantial ice caves within the summit caldera. Together with other examples in the region, they have been cited as likely refugia that, going back millions of years, may have helped terrestrial life on the continent survive multiple pan-Antarctic glaciations.

What’s your favourite image from the volume?

They’re all favourites but, if I was pushed, I might choose the cover image. I spent three long field seasons camping and working on Deception Island, Antarctica’s most active volcano, so I got to know the island very well. It was where I first practised volcanology professionally and where I learned a lot of my skills, so it has a special place in my affections. The photo was taken in the 1960s (not by me – I was still at school!) and shows a trio of small scoria cones (you can only see two in the view) that together constructed a tiny new island following their eruption in 1967. The new island is situated within the huge caldera of Deception Island. The caldera, an immense collapse structure, is flooded by the sea. On the snow-covered part of the island in the background, you can also see volcanic steam rising from a tuff cone or ring, which also erupted at the same time as the trio of cones. The eruption began the destruction and abandonment of two of the three scientific stations on the island. The new island lasted only 3 years before it was partly destroyed during another eruption in 1970, when it also became joined to the coast, illustrating how ephemeral many volcanic features can be. To me, the view nicely combines my passion for volcanoes with my love of ice-clad Antarctica.

How has the research on volcanism in Antarctica changed over the years?

Like all science in Antarctica, it has become much more focused, evolving from ‘what’s there and where is it?’, i.e. a frontier science associated with initial exploration, to ‘why is it there, what processes were involved and what are the global implications?’. Access to Antarctica has also become much simpler. Whereas in the past you had to spend many months and sometimes years in Antarctica because of the operational costs and time-consuming logistics, you can now plan on making short visits of maybe just a few days, although field seasons for most volcanologists are a few weeks. Previously, with such long time commitments, a lot of the research was conducted by scientists employed by dedicated research institutions, such as the British Antarctic Survey, which I worked for during most of my career. Now, by contrast, the much better logistics and shorter visits means that most of the research is carried out by scientists based in universities. Thus, the science has also migrated into highly specialized research topics, such as glaciovolcanism (i.e. the interaction between volcanoes and ice), itself a very young science (essentially

What’s it like to do fieldwork there?

As you would expect, it is very cold and that means you are clothed in multiple insulating layers and end up fighting the restrictive clothing as much as the environment. So you can get exhausted quite quickly. UV levels are also much higher, partly because of the ultra-clean air but also because of the ozone hole which is prevalent during the Antarctic Spring. So your skin can burn badly. However, you generally keep all of your skin covered up so UV damage isn’t serious. Avoiding frostbite is a perennial problem, and sunglasses are essential to prevent snow blindness. Volcanology is a field-based science so the fieldwork involves camping, with its own particular issues associated with a very cold climate. For example, inland, where temperatures are much lower compared to the coast, it is usually impossible to get the frost-line inside the tent below 30 cm from the tent floor. However, the atmosphere is so dry that the frost doesn’t melt, it sublimes (i.e. changes directly to vapour), so it doesn’t make your sleeping bag wet. At one large static field camp in the Transantarctic Mountains a few hundred kilometres from the South Pole, I once watched a scientist hang out a hand-washing at minus 20°C. It froze stiff as a board within seconds but was bone dry in less than 30 minutes.

If you had your time over again would you still be a volcanologist?

Yes, no question. I decided to be a geologist when I was 11 years old and my passion and drive, which were quickly channeled almost exclusively into volcanology, have never gone away. They still consume me. I often stop and think how lucky I have been to have forged almost an entire career working in Antarctica, one of the most beautiful places in the world, but also to be studying volcanoes in Antarctica, some of the most remote in the world. What a combination and how cool is that! There are significant downsides, however, mainly to home-life and family, and I have missed very many Christmases and New Years at home. You need a supportive and accommodating family. However, with that important caveat, it has been a privileged and intellectually rewarding professional life.

What is it like being part of the volcanism community?

This is not an easy one to answer. The community is very scattered, although with several prominent volcanological centres such as at Bristol University and Clermont-Ferrand. We tend to meet up mainly at international meetings, particularly those run by the International Association for Volcanology and Chemistry of the Earth’s Interior (IAVCEI), which is the premier forum for volcanologists. Field trips attached to those meetings are particularly useful, especially for early-career researchers, helping them to understand the scientific deduction process and for networking in an informal setting, both essentials in any science. Like many parts of geology, the volcanological community is also very diverse scientifically, with multiple subdivision into specialties such as (in my case) glaciovolcanism. Those specialties also tend to organize themselves into fora or discussion groups for like-minded individuals (the one I participate in is the IAVCEI/IACS Volcano—Ice Interactions Commission). None of this is peculiar to volcanology but affects all sciences.

What are the most important unanswered questions? Where do you see the research going now?

Currently, with the world focused on global warming, the most exciting development in my own field is the application of glaciovolcanological investigations to documenting and understanding variations in the Antarctic ice sheet. At present, we are almost totally reliant on the results of marine sedimentary investigations using expensive drilling platforms (constructed on sea ice and ice shelves in Antarctica’s case), and the oxygen isotope record of benthic foraminifera. But only volcanological studies can give us the complementary terrestrial record. The volcanoes are also situated in ultra-proximal locations, unlike the marine and del¹⁸O record. They provide us with remarkably detailed information such as ice thickness, thermal regime, surface elevation etc., much of it quantifiable and unobtainable any other way. New investigations in Antarctica are acquiring exciting and hitherto-unimagined information that shall help us to understand the causes and consequences of past variations in the Antarctic ice sheet. For example, how did the basal thermal regime (a measure of ice sheet stability) evolve over time, a question that impacts directly on the global climate system? Established thinking has suggested a sudden unidirectional change from a dynamic to a stable ice sheet but volcanological studies are suggesting that the picture is much more nuanced and involved a patchwork mosaic of polythermal ice, making precise predictions of global sea levels more difficult. Such a result, if validated, shall ultimately help us to predict much better future ice sheet behaviour.

We’re really excited to have published a memoir of this breadth and with so many expert-contributors. Did you a feel a GSL Memoir was the ideal home for Volcanism in Antarctica?

Of course, I talked with many publishers about creating this volume. But ultimately the Geological Society Memoir series proved to be the best vehicle for ‘Volcanism in Antarctica’. It was a hard-nosed decision but the Memoir series is world-renowned and highly respected amongst all geological communities, not just volcanologists. What swayed the decision were important features such as the large A4 format (hence ability to publish more information), the opportunity to include large datasets as an integral online resource, publication in full colour throughout, and a projected competitive price for the volume. And, from past experience publishing with the Geological Society, I knew I’d have excellent support from the staff. Having finally seen the fruits of the labours of everyone involved, I feel we have collectively created a true landmark publication that shall last for decades.

Volcanism in Antarctica: 200 Million Years of Subduction, Rifting and Continental Break-up, edited by J.L. Smellie, K.S. Panter and A. Geyer was published in June 2021 and is available to buy in the Online Bookshop at www.geolsoc.org.uk/M0055