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Travel log – The Kenya rift

Travel log – The Kenya rift

Topographic map of the Kenya rift and surroundings. Dark red lines indicated faults from the GEM database. Dotted blue lines separate the northern, central and southern Kenya rift. In green circles the discussed locations.

A little over a year ago, I was lucky enough to join a field trip to the Kenya rift organized by Potsdam University and Roma III. This rift is part of the active East African Rift System, which I introduced in a previous blog post. With a group of 25 enthusiastic participants from Roma Tre, Potsdam University, Nairobi University and GFZ Potsdam (we somehow always managed to make the 20-person bus work), we set out to study the interaction between tectonics, magmatism and climate and their link to human and animal evolution. Based on several pictures, I’ll take you through the highlights.

 

 

 

 

Basement foliation and fault orientation

Two numerical modellers looking at rocks… Gneisses of the Mozambique belt with steeply dipping foliation – I think. Courtesy of Corinna Kallich, Potsdam University.

Although this first picture might not look so impressive (I promise, more impressive ones will come), this road outcrop shows the structure of the basement that is responsible for the orientation of the Kenya rift’s three western border faults. Here in particular, we are slightly west of the Elgeyo escarpment, the scarp of the major east-dipping Elgeyo fault. It reactivated the steep foliation of the Mozambique belt gneisses that formed during the Pan-African orogeny (550-500 Ma; Ring 2014). Changes in foliation orientation are mirrored by changes in fault orientation from NNE to NW upon going from the Northern to the Southern Kenya rift (see map). The Elgeyo fault itself displaced the 14.5 My old massive extrusion of phonolite lavas that can be seen throughout the Kenya rift area, marking the start of the current rift phase. From the differences in basement level between the western shoulder and the rift centre, the total offset along the fault is ~4 km!

Rift axis volcanism

Lunch overlooking the Menengai caldera that collapsed 36,000 yr ago. Courtesy of Corinna Kallich, Potsdam University.

With on-going rifting, the tectonic and magmatic activity localised in the centre of the Kenya rift. One massive central volcano is the Menengai volcano, whose view we enjoyed over lunch. This 12 km wide caldera collapsed 36,000 yr ago; the ash flows of the eruption can be found throughout the whole of Kenya. Within the caldera, diatomite layers alternating with trachyte lava flows indicate the presence of lakes 12 and 5 ky ago. These lakes were fed by the neighbouring Nakuru basin overflowing into the Menengai crater. The volcano itself was responsible for the earlier compartmentalization of the larger Nakuru-Elmentaita basin. At the moment, freshwater springs are being fed by the groundwater, and 40 geothermal wells are being constructed to benefit from the groundwater being heated by the magma chamber at 3-3.5 km depth.

Lunch at Hell’s Gate

Looking along Hell’s Gate Gorge – cut into the white diatomite and pyroclastic layers – towards feeder dikes of the remaining core of a volcano. Courtesy of Corinna Kallich, Potsdam University.

Watching the wildlife and beautiful scenery is usually the reason people visit Hell’s Gate National Park, but we studied the flow structures in a highly viscous, silica-rich lava flow. We then scrambled our way through Hell’s Gate Gorge that cut into mostly diatomite lake sediments (these algae are very helpful) alternated with pyroclastic layers. Most impressive however, were the crosscut basaltic intrusions that we could trace back to the centre of an otherwise eroded volcanic dome. The well-deserved lunch was a rather frustrating affair, as Vervet monkeys took every chance at stealing our food, not even shying away from distracting us with their adorable babies.

Monkey enjoying my lunch. Courtesy of Corinna Kallich, Potsdam University.

 

 

 

 

 

Wishing the lake was back

The white diatomites of the Olorgesailie Formation, indicating the presence of a lake. Courtesy of Corinna Kallich, Potsdam University.

The Olorgesailie basin is where paleoanthropologist Louis Leakey and his wife palaeontologist Mary Leakey (Wikipedia) unearthed a score of Acheulean hand axes in the 1940s. The 600-900 ky old tools were used to dig for roots, cleave, hammer and scrape meat and can be seen in the Kariandusi museum site. Besides the hand axes (made from all the trachyte found in the area), we marvelled at the Olorgesailie Formation that contains them, which was deposited between ~1.2-0.5 Ma. The formation consists of repetitions of wetland, river and lake sediments and paleosols (fossil soils, indicating dryer conditions). As we stand baking in the sun on top of the dusty, white diatomite, the vision of a lake sure is very alluring.

A not-so-fresh lake

On our way to a tiny hotspring along the edge of the slightly pink waters of Lake Magadi. In the foreground the white evaporates the lake is mined for. Courtesy of Corinna Kallich, Potsdam University.

While we mostly stayed in resorts, our only campsite (proper “glamping” with a shower and bathroom in the tent) was close to Lake Magadi, one of the lakes along the rift axis. This saline, alkaline lake gave its name to magadiite, a sodium hydro silicate, that when dehydrated forms chert (i.e. flint). The lake is also mined for its sodium carbonate, known as trona. During the African Humid Period (15,000-5,000 yr ago; Maslin et al. 2014), Lake Magadi was about 40 m higher, a lot fresher and connected to Lake Natron further south. Fun fact from Wikipedia: elephants visit the Magadi Basin to fill up on their own salts supplies as well. From my own experience, I can tell you, it does not taste very good.

 

 

My trusted companions for over a decade did not survive Kenya’s heat and volcanics… Serves me right for not taking them out often enough!

And then there were the hippos, neptunic dikes, dancing Maasai, a boat trip to the hydrothermal vents on Ol Kokwe Island, giraffes outside our cabin, midnight stargazing… too much to capture in one blog post. I had a wonderful time in Kenya exploring the geology, admiring the wildlife and getting to know its people. My only regret? Losing my shoes…

 

 

 

 

References:

Maslin, M. A., Brierly, C. M., Milner, A. M., Shultz, S., Trauth, M. H., Wilson, K. E. (2014). East African climate pulses and early human evolution, Quaternary Science Reviews 101, 1-17.

Ring, U. (2014). The East African Rift System, Austrian Journal of Earth Sciences, 107, 1.

Strecker, M. R., Faccenna, C., Wichura, H., Ballato, P., Olaka, L. A. and Riedl, S. (2018). Tectonics, seismicity, magmatic and sedimentary processes of the East African Rift Valley, Kenya, Kenya Field School Field Guide.

Personal communication with Strecker, M. R., Wichura, H., Olaka, L. A. and Riedl, S.

Holiday recommendations – blog break summer 2018

Holiday recommendations – blog break summer 2018

Even dedicated workaholics such as the editors of your EGU GD Blog Team sometimes deserve a break! Let me clarify that by saying ‘an intentional break’ (because uploading every Wednesday is hard!). We will be ‘on holiday’ during August, so there won’t be any new blog posts then. But don’t worry: we will be back stronger than ever in September and we already have a lot of very good blog posts in the pipeline for you. To start the holidays properly and to get you in the holiday spirit as well, the EGU GD Blog Team shares their geodynamical holiday recommendations with you. Enjoy & relax!

Iris van Zelst – Edinburgh

Hutton’s Section with a very young me (in 2012) for scale

Go. To. Edinburgh. Seriously: Edinburgh is the place to be for anyone who has an affinity with the Earth sciences. In this beautiful, historic city, James Hutton – the founder of modern geology, who originated the idea of uniformitarianism – lived and died. Everywhere in the city you can find little reminders indicating this iconic scientist lived there. You could, for example, visit his grave, and hike to his geological section on Edinburgh’s Salisbury Crags. There are also little plaques spread around the city that mark significant James Hutton places and events. The city itself is also steeped in a mix of geology and history: Edinburgh Castle, situated on the impressive volcanic Castle Rock, boasts an 1100-year-old history and towers over the city. Directly across from the castle, connected by the charming Royal Mile is Holyrood Palace, where you can soak up even more history – Mary Queen of Scots lived here for a while. Nearby, there is Holyrood Park where you can find the group of hills that hosts Hutton’s Section and a 350 million year old volcano named Arthur’s Seat. Climb it when the weather is nice and you will have the most amazing view of Edinburgh. The whole park is perfect for day hikes and picknicks.
Even if you (or your travel buddy) are not that into Earth Sciences (or history), Edinburgh has plenty of other attractions. It is the perfect place for book and literature lovers with the large International Book Festival every August and a very rich literary history with iconic writers such as Walter Scott (Ivanhoe), Robert Louis Stevenson (Strange Case of Dr Jekyll and Mr Hyde; Treasure Island), Arthur Conan Doyle (Sherlock Holmes), and – more recently – J. K. Rowling (Harry Potter). Theatre fans will also love Edinburgh, particularly during August when it hosts the Edinburgh Festival Fringe – the largest arts festival in the world.
I totally should’ve booked a trip to Edinburgh this year… Learn from my mistakes and enjoy it in my stead!

The view of Edinburgh when you’re standing on top of Arthur’s Seat: a more than 300 million year old volcano. Pretty epic.
Picture by me in 2012 (also: proof that the weather can be good in Scotland!)

Luca Dal Zilio – Aeolian Islands

My recommendation? I vote for the Aeolian Islands! Smouldering volcanoes, bubbling mud baths and steaming fumaroles make these tiny islands north of Sicily a truly hot destination. This is the best place to practice the joys of “dolce far niente“: eat, sleep, and play. The Aeolian Arc is a volcanic structure, about 200 km long, located on the internal margin of the Calabrian-Peloritan Arc. The arc is formed by seven subaerial volcanic edifices (Alicudi, Filicudi, Salina, Lipari, Vulcano, Panarea, and Stromboli) and by several volcanic seamounts which roughly surround the Marsili Basin. The subduction-related volcanic activity showed the same eastward migration going from the Oligo-Miocene Sardinian Arc to the Pliocene Anchise-Ponza Arc and, at last, to the Pleistocene Aeolian Arc. My favourite island, Stromboli, is one of the few volcanoes on earth displaying continuous eruptive activity over a period longer than a few years or decades. I like Stromboli because it conforms perfectly to one’s childhood idea of a volcano, with its symmetrical, smoking silhouette rising from the sea. Most of this activity is of a very moderate size, consisting of brief and small bursts of glowing lava fragments to heights of rarely more than 150 m above the vents. Occasionally, there are periods of stronger, more continuous activity, with fountaining lasting several hours, violent ejection of blocks and large bombs, and, still more rarely, lava outflow. I can’t quite explain what made it so special to me. It may be because Stromboli itself is an island, and all the time during the hike I enjoyed splendid sea views (with a beer in my hand). It may be the all encompassing experience, where I could see, hear and literally feel the lava explosions. It was simply fantastic.

Credit: Flickr

Anne Glerum – Montenegro

In case you don’t make it to Montenegro/Serbia this summer, it’s fun in winter too. And yes, it’s fun in spring too – there’s snow, mountains and a younger me on a tiny sled. Photo courtesy of Cyriel de Grijs

My geo-holiday-destination: Montenegro!
A summer without beach-time is not a summer to me (already got one beach-day in this year, phew). Being Dutch, a proper holiday also requires some proper mountains – or hills at least. And no trip is complete without cultural and culinary highlights to explore.
Montenegro is a country that ticks all the boxes. Situated along the Adriatic Sea it hosts a score of picture-perfect beaches; quiet or taken over by the jet-set, intimate coves or long stretches of white sand, take your pick.
Further inland, you reach the Dinarides orogenic chain, the product of 150 My of contractional tectonics and later collapse during the Miocene. Traversing the chain into neighboring Serbia will lead you past complete ophiolite sequences, syn-orognic magma intrusions and major detachment zones of the extensional orogenic collapse.
Visit the centuries old fortified coastal cities of Budva or Kotor or one of the many churches and frescoed monasteries spread around the countryside. For more bodily sustenance, enjoy the fresh fish dishes, rich meats or the regional cheeses and yoghurts. Seasonal fruits are eaten for dessert or, even better, turned into wine and rakija. Ehm, why I am not going there again this year – this time in summer?

Not-so-sunny spring view from St. John’s fortress onto Kotor along the Bay of Kotor. Photo courtesy of Cyriel de Grijs

Diogo Lourenço – CIDER Summer School

This year, my favourite geodynamical destination is CIDER 2018! It’s far from holidays… but it’s really cool! For the last three weeks (one week to go), we have been intensely learning about heterogeneity in the Earth, and trying to understand it in an interdisciplinary perspective with contributions from geochemistry, geodynamics, and seismology. Quite an intense schedule and a lot of information to process, but I think we are all learning a lot, and hopefully in the future we will use more constraints coming from other fields into our own work. Oh, and did I mention that it is happening in Santa Barbara? Great Californian weather, beautiful coastal landscapes, barbecues by the beach, and swimming in the ocean, all sprinkled with scientific discussions! Quite the geodynamical destination, no?

Just had to cross the street from the KITP building where the conference is happening to take this photo…

Grace Shephard – Svalbard

Geoscientists are no strangers to travelling to exotic places and many of us take the opportunity to turn a work-related trip into potential holiday scouting. My suggested destination is most probably the northernmost point you can quite easily travel to on this planet – Svalbard.
Svalbard is an Arctic archipelago located around between 74-81°N latitude. It is sometimes confused with Spitsbergen, which is actually the name of the largest island where the main settlements, including Longyearbyen and Barentsburg, are situated. The islands are part of Norwegian sovereignty, though with some interesting taxation and military restrictions (the Svalbard Treaty of 1920 makes for some pretty interesting reading). Svalbard is host to a stream of tourists and scientific researchers year-round, and this week I will travel back to Longyearbyen as a lecturer for an Arctic tectonics, volcanism and geodynamics course at the University Centre in Svalbard (UNIS).
Geologically speaking, Svalbard makes for a very interesting destination. It offers a diverse range of rock ages and types; having experienced orogenic deformation events, widespread magmatism, and extensive sedimentary and glacial processes.
If you’re after a more usual tourist package amongst the draw cards are of course iconic polar bears (though please keep your distance), stumpy reindeer, arctic foxes, whales, birds and special flora. There are many glaciers – in fact around 60% of Svalbard is covered in ice – as well as fjords and mountains, former coal mining settlements… the list goes on. You are even spoilt for choice between midnight sun or midday darkness, depending on the time of year, so prioritise your activities wisely. Plus, did I mention those miles and miles of unvegetated, uninterrupted rock exposures to keep any geology enthusiast happy?… if you’re lucky you might come across some incredible fossil sites.

Itinerary recommendation, tried and tested: Whale watching and fjord cruising to a Russian mining ghost town (Pyramiden) followed by an important sampling of the world’s northernmost brewery.

The rock whisperers…

The rock whisperers…

The Geodynamics 101 series serves to showcase the diversity of research topics and methods in the geodynamics community in an understandable manner. We welcome all researchers – PhD students to professors – to introduce their area of expertise in a lighthearted, entertaining manner and touch upon some of the outstanding questions and problems related to their fields. This month, Manar Alsaif, PhD student at Université Montpellier, discusses actual rocks and field work!

In a discipline increasingly shaped by models, what can the rocks still tell us?

Flicking through your typical geodynamics bodies of work, most of the papers are on some kind of modelling – be it analogue, numerical, or something using seismic data. This is hardly surprising considering that geodynamics is all about the depths of the Earth, where we cannot make direct observations. But at some point, we need to check the results of these models, and checking them means looking for the observables. This is ok for the global scale – we can measure gravity and magnetism and the like, but what about smaller scales? And more detail? And the kind of complexity we cannot yet model? Our observations are restricted to the Earth’s surface – but this is actually not a bad place start. There is still a lot that we can learn from good old fashioned field work. And in fact, a lot of the motivation for models comes from an observation of something not understood, or not previously thought of.
So if you need a little inspiration for your next research project, I implore you to literally take a hike!

Apart from a source of inspiration, where does field work fit into a geodynamics workflow? I’d say it fits on top (no pun intended), since all geodynamic processes have a surface expression (at least to some degree).
Take plate motion, for example. Whether a plate moves laterally or vertically, that motion is recorded in the rocks. Palaeomagnetism will trace lateral motion, while thermochronometry will give you a vertical history of the rocks. More often than not, it will reveal a complex history of the rocks and the plate in which they lie. This complexity includes a myriad of processes e.g. fluid action, metamorphism, deformation, diagnesis, etc. These are all processes that are still not fully understood but which we can address by picking up a rock and looking at its mineralogy, its texture, its veins, its contact with its surrounding rocks, its P-T history, its fractures, their strain patterns, etc.

This is by no means an exhaustive article on field methods, I merely mention some examples of how field methods can be useful. So if field geology can be so useful, why are there fewer and fewer scientists doing it? Well, there’s the popular misconception that field geology is only geological mapping, and that the world’s geological surveys have more or less taken care of that already. In reality, some geological surveys have done a marvellous job at mapping out the rock units, but half of a geological map is actually interpretation. This interpretation will constantly change with new understanding of processes and with new data, especially where rock exposures are few and/or flighty.

Apart from the misconception that all field geology has ‘been done’, there are some practical reasons why geodynamicists veer away from field studies. Firstly, there is a mismatch of scales. Generally, the smallest scale a geodynamicist will deal with is a plate – that is already a scale which is too large for field work in practice. But as we argued above, field studies can tell you so much, so what do you do? Go strategic! Pick a few practical locations on your plate, where you might find the products of the processes you’re looking at. For example, if you are looking at obduction, go look around the high pressure rocks, which have probably already been mapped – thank you, local geo survey. If you’re looking at active faulting, use topography and satellite data to help guide you, and then a little thermochronometry can go a long way. If you’re looking at processes behind magmatism, look around your magmatic rocks, and then let the powers of geochemistry come to your aid. There are so many other examples that field geologists do and new tricks that we could start to do with a little creative thinking.

Drone field geology, bridging geo-scales. Tectonic study of Northern Scandinavia by CEED U. Oslo researchers Hans Jørgen Kjøll and Torgeir Andersen. Picture provided by Hans Jørgen Kjøll.

This is all made much easier by using satellite data as a first line of attack. Never before have we had such fine satellite data to simply strategising as we do now.
So maybe it’s also time to move on from old fashioned geological mapping – especially where pretty good maps already exist- and move on to more comprehensive, strategic field campaigns. And remember, technology can be our friend, we need not shy away from it. The photo here is not merely a gorgeous landscape, it is a drone picture by Hans Jørgen Kjøll and Torgeir Andersen of CEED, U. Oslo (seen as the people-looking lines in the middle of the photo). They are seen here flying a drone to get high resolution field data in rugged, inaccessible northern Scandinavia, while simultaneously bridging the scale of typical field work to large scale tectonics.
Similar advantages can be had by using LIDAR, various GPS methods, shallow logging techniques, etc. Perhaps it’s time to stop thinking of geologists as the hammer-hand lens people, and of geophysicists as the gadget people, and of geodynamicists as the code people. Perhaps it’s time to blur the lines, work together and learn from each other.

All of this might eventually give us more real data to plug into our models, perhaps refine some of the parameterisation, or at the very least, give us something against which to compare our model predictions.

After all, George Michael said it best: “Let’s go outside”!

Let’s talk about disability in geosciences

Let’s talk about disability in geosciences

Climbing towards outcrops during fieldwork for your undergraduate studies simply isn’t doable for everyone. However, this doesn’t mean that there are adequate alternative solutions available. This week, Katy Willis, PhD student on strain-localisation in the continental lithosphere at the University of Leeds, UK, discusses disability in the geosciences, because regardless of who you are a career in geosciences should be available to you.

On June 4th, 2018 at The Geological Society in London, the UK branch of the International Association for Geodiversity (IAGD) was launched under the name DiG-UK (Diversity in Geosciences, UK), and I was one of those in attendance. The IAGD focuses on the inclusion of people with disabilities within the geosciences, and DiG-UK has incorporated this aim along with championing a better representation of black, Asian, and other ethnic minority groups. Here, I am going to focus on the disability inclusion.

Before I go on – and it’s a shame that I have to type this in the 21st century – let me point out that just because a person has a mental or physical handicap it in no way detracts from their ability to study geosciences or advance in a career in either academia or industry. What hinders them is the barriers that are erected by others before their careers even start. There are a range of disabilities. Anyone may experience a temporary one, like a broken leg restricting your mobility. Some people may experience longer term issues, for example depression triggered by the death of a parent. It may be a health issue that has intermittent effects, such as Crohn’s disease. Or it could be a lifelong issue, such as partial blindness or complex mental health issues.

Geosciences is a broad term for anything from geology to paleo-climate, right up to geodynamics. The one thing that unites such studies, especially at an undergraduate level, is fieldwork. In the UK, an accredited geology degree requires a component of fieldwork, and graduation above a certain level may demand an extended independent fieldwork experience lasting weeks. This is all well and good if you are physically and mentally capable of doing such work, but each year a small proportion of students find themselves unable to go on fieldwork. The old “solution” was to give them a desktop study while the rest of the year went off to Cyprus, Scotland, or Spain. The field group would form close friendships while away, so that those left searching dusty library shelves felt partially excluded from their year group. Hardly an acceptable solution.

The inaugural DiG-UK meeting brought together academia and industry to discuss disability inclusion. An open session looking at how different organisations have got people thinking about disability inclusion and how to practically implement it got us all chatting and sharing ideas. I was delighted to see the approach the Open University had taken regarding fieldwork. It acknowledges that not all field locations are accessible to those with physical disabilities, but there is no need to prevent such students attending field trips because there will remain a number of locations that can be readily visited. For the inaccessible locations they set up a local WiFi network and use iPads so an able bodied person can stream a live image to those who can’t reach that particular outcrop. Genius!

Manchester Metropolitan University has developed a “Diversity Dash” game to help groups understand the many barriers that all students and staff can face. Each team is allocated a character, and a range of scenarios are presented (lab work, unexpected meeting on the top floor, taking notes in lectures). The teams then have to find realistic ways in which their character can take part in the scenario. The characters cover a range of people, from someone who has a pregnant partner through to the rich student that seems to have everything but certain issues are causing increased complications.

If universities automatically allow for the provision of disabled people in their fieldwork plans, then it allows students to continue their studies should they suffer a mild injury such as a sprained ankle. During my undergraduate time, I saw two people fail to finish their course because the university was unable to accommodate their disability needs. They were intelligent people, who knew that beyond graduation lay geoscience careers that did not rely on fieldwork, but they could not pass that barrier of obtaining the appropriate degree. In both cases a few simple adjustments would have allowed them to finish.

It behoves any institute to set up a framework that encourages practical and workable disability inclusion in the geosciences. Organisations such as DiG-UK and the IAGD can provide valuable information on how to do this. Our area of study – geodynamics – sees many of us sat in front of a computer, but a lot of us were required to carry out field studies at some point in our education. It added to our knowledge and experience and in my case it inspired me into the direction of geodynamics and the desire to understand the broader picture.

In September I am taking part in a field trip to Anglesey UK. There will be a range of people going and we aim to discover which methods assist inclusion and accessibility in the field (and which don’t!). Then the findings will be shared so real and practical ways of being inclusive can be implemented for geoscience fieldwork across the UK (and hopefully internationally).

So, go on. What are you going to do this month to help people with disabilities become more involved in geosciences?

Follow DiG-UK on twitter: @DiG_UK_IAGD