TS
Tectonics and Structural Geology

Tectonics and Structural Geology

Meeting Plate Tectonics – Mathilde Cannat

Meeting Plate Tectonics – Mathilde Cannat

These bi-weekly blogs present interviews with outstanding scientists that bloomed and shape the theory that revolutionised Earth Sciences — Plate Tectonics. Stay tuned to learn from their experience, to discover the pieces of advice they share, to find out where the newest challenges lie, and much more!


Meeting Mathilde Cannat


Mathilde Cannat started her career at the early age of 26 when she obtained her Doctorate in Geology at the University of Nantes, France. After a PostDoc at Durham University, England, she took a position at the National Center of Scientific Research (CNRS). She researched at the University Paris 6 since 1992 and obtained her present position at the Institut de Physique du Globe de Paris (IPGP), France, in 2001. She was awarded with the ‘Médaille d’Argent’ of the CNRS in 2009.

Scientist should be able to take time to produce publications, even if this means that there would be fewer publications

Mathilde, could you share with us your research interests and the methods you use to solve your research questions?

I work on the processes of oceanic accretion. I want to understand how new oceanic domains are created at mid-ocean ridges. My focus lies on the specific case of slow-spreading ridges, where tectonic processes are prevalent, and I unravel the interactions between tectonics, magmatism and hydrothermalism. I’m primarily a geologist, but in addition to submersible studies and rock sampling I also use several geophysical methods, that include gathering time series data on active processes such as seismicity and the temperature of hydrothermal vent fluids.

That’s quite a lot different topics you address. What is the favourite part of your research?

Mathilde Cannat – Credit: ODEMAR scientific cruise

Participate in sea-going cruises is the best part of the job. In particular, the use of manned or remotely operated submersibles to explore the seafloor is a very exciting business. I also very much enjoy good collaborations with colleagues, and the last stages of writing a paper, when it is almost finished. Lastly I am also fond of working with and advising PhD students.

Creating new concepts and knowledge is highly relevant no matter the topic

What do you think makes your research relevant and connected to real world applications?

In my opinion, creating new concepts and knowledge is highly relevant no matter the topic. I completely disagree with the notion that creation of knowledge belongs to some other less real world. I even go further and believe that research is a fundamental part of our culture. In my view whether it can be applied to some material objective at short or longer term does neither increases or decreases its relevance.

After being in the field for quite some years now, what do you consider your biggest academic achievement?

In the ’90s, I proposed a new concept for the formation of seafloor that is partially made of tectonically uplifted rocks from the earth’s mantle. I was the principal proponent of this idea and until today it is still an accepted and commonly used concept.

What is the main problem that you solved during your most recent project?

I don’t believe that science problems are ever truly solved. It is more like conceptual hypotheses that are made based on our current understanding. These hypotheses can then be tested which in most cases results in updating the concept and so on. So for this question, I can say that in my most recent project I have been able to gather observations that appear consistent with the hypothesis that I made with a colleague a few years back concerning the formation of new seafloor at mid-ocean ridges that have a very low melt budget.

Scientist should be able to take time to produce publications, even if this means that there would be fewer publications

Over the years you have seen the system in which scientists manoeuvre their work being changed and adapted. What would you like to change to improve how science in your field is done?

I would definitely change science funding and general organisation to put the emphasis back on teamwork. Also, the pressure that scientists have on publishing their work should go down. Scientist should be able to take time to produce publications, even if this means that there would be fewer publications but these would have been more thought about!

Sauter, Cannat, et al., 2013. Nature Geoscience, 6, 314-320.

 

For the near future, what do you think are the biggest challenges right now in your field?

We should definitely look at plate tectonics in relation to a more global picture. This means that it would include the interactions and impacts between the solid Earth and the biosphere, the oceans, the atmosphere. This global picture should be regarded both in the present, with a better understanding of time variable processes, and in the past through the Earth’s history.

[To ECS] Do not become bitter when it seems to be so hard to get a stable position

One last question for the Early Career Scientists (ECS) that read this blog, when you were in the early stages what is the best advice you ever received and what advice would you give to them?

When I was an ECS myself, I saw myself staying in academia. The best advice that I was given at the time, I guess, was not to become bitter because it seemed to be so hard and take such a long time to get a stable position during my postdoc years. And so to ECS, I would definitely suggest not to hesitate to contact people, even senior people, if you like their work. Don’t be afraid to ask them questions, explain your own ideas and get into a scientific discussion with them.

Interview conducted by Anouk Beniest

Minds over Methods: What controls the shape of oceanic ridges?

Minds over Methods: What controls the shape of oceanic ridges?

In this edition of Minds over Methods, Aurore Sibrant, postdoc at Bretagne Occidentale University (France) explains how she studies the shape of oceanic ridges, and which parameters are thought to control this shape. By using laboratory experiments combined with observations from nature, she gives new insights into how spreading rates and lithosphere thickness influence the development of oceanic ridges. 

 

Credit: Aurore Sibrant

What controls the shape of oceanic ridges? Constraints from analogue experiments

Aurore Sibrant, Post-doctoral fellow at Laboratoire Géosciences Océans, Bretagne Occidentale University, France

Mid-oceanic ridges with a total length > 70 000 km, are the locus of the most active and voluminous magmatic activity on Earth. This magmatism directly results from the passive upwelling of the mantle and decompression melting as plates separate along the ridge axis. Plate separation is taken up primarily by magmatic accretion (formation of the oceanic crust), but also by tectonic extension of the lithosphere near the mid-ocean ridge, which modifies the structure of the crust and morphology of the seafloor (Buck et al., 2005). Therefore, the morphology of the ridge is not continuous but dissected by a series of large transform faults (> 100 km) as well as smaller transform faults, overlapping spreading centres and non-transform offsets (Fig. 1). Altogether, those discontinuities form the global shape of mid-ocean ridges. While we understand many of the basic principles that govern ridges, we still lack a general framework for the governing parameters that control segmentation across all spreading rates and induce the global shape of ridges.

Geophysical (Schouten et al., 1985; Phipps Morgan and Chen, 1993; Carbotte and Macdonald, 1994) and model observations (Oldenburg and Brune, 1975, Dauteuil et al., 2002, Püthe and Gerya, 2014) suggest that segmentation of oceanic ridges reflects the effect of spreading rate on the mechanical properties and thermal structure of the lithosphere and on the melt supply to the ridge axis. To understand the conditions that control the large-scale shape of mid-ocean ridges, we perform laboratory experiments. By applying analogue results to observations made on Earth, we obtain new insight into the role of spreading velocity and the mechanical structure of the lithosphere on the shape of oceanic ridges.

 

Laboratory experiments

The analogue experiment is a lab-scale, simplified reproduction of mid-oceanic ridges system. Our set-up yields a tank filled from bottom to top by a viscous fluid (analogous to the asthenosphere) overlain by the experimental “lithosphere” that can adopt various rheologies and a thin surface layer of salted water. This analogue lithosphere is obtained using a suspension of silica nanoparticles which in contact with the salted water emplaced on the surface of the fluid causes formation of a skin or “plate” that grows by diffusion. This process is analogous to the formation of the oceanic lithosphere by cooling (Turcotte and Schubert, 1982). With increasing salinity, the rheology of the skin evolves from viscous to elastic and brittle behaviour (Di Giuseppe et al., 2012; Sibrant and Pauchard, 2016).

The plate is attached to two Plexiglas plates moving perpendicularly apart at a constant velocity. The applied extension nucleates fractures, which rapidly propagate and form a spreading axis. Underlying, less dense, fresh fluid responds by rising along the spreading axis, forming a new skin when it comes into contact with the saline solution. By separately changing the surface water salinity and the velocity of the plate separation, we independently examine the role of spreading velocity and axial lithosphere thickness on the evolution of the experimental ridges.

 

Figure 2. Close up observations of analogue mid-oceanic ridges and schematic interpretation for different spreading velocity. The grey region is a laser profile projected on the surface of the lithosphere: the laser remains straight as long as the surface is flat. Here, the large deviation from the left to centre of the image reveals the valley morphology of the axis. Credit: Aurore Sibrant.

 

Analogue mid-oceanic ridges

Over a large range of spreading rates and salinities (Sibrant et al., 2018), the morphology of the axis is different in shape. The ridge begins with a straight axis (initial condition). Then during the experiment, mechanical instabilities such as non-transform offset, overlapping spreading centres and transform faults develop (Fig. 2) and cause the spreading axis to have a non-linear geometry (Fig. 3). A key observation is the variation of the shape of the analogue ridges with the spreading rate and salinities. For similar salinity and relative slow spreading rates, each segment is offset by transform faults shaping a large tortuous ridge (i.e. non-linear geometry). In contrast, at a faster spreading rate, the ridge axis is still offset by mechanical instabilities but remains approximately linear.

Figure 3. Ridge axis morphology observed in the experiments and schematic structural interpretations of the ridge axis, transform faults (orange ellipsoids) and non-transform faults (purple ellipsoids). Measurements of lateral deviation (LD) correspond to the length of the arrows. For comparison, white squares represent the size of closeup shows in Fig 2. Credit: Aurore Sibrant.

We can quantify the ridge shape by measuring the total lateral deviation, which is the total accumulated offset of the axis, when the tortuosity amplitude becomes stable. For cases with similar salinities, the results indicate two trends. First, the lateral deviation is high at slow spreading ridges and decreases within increasing spreading rate until reaching a minimum lateral deviation value for a given critical spreading rate (Fig 4A). Then the lateral deviation remains constant despite the increasing spreading rate. Experiments with different salinities also present a transition between tortuous and linear ridges. These two trends reflect how the lithosphere deforms and fails. In the first regime, the axial lithosphere is thick and is predominantly elastic-brittle. In such cases, the plate failures occur from the surface downwards through the development of faults: it is a fault-dominated regime. In contrast, for faster spreading rate or smaller salinities, the axial lithosphere is thin and is predominantly plastic. Laboratory inspection indicates that fractures in plastic material develop from the base of the lithosphere upwards: it is a fluid-intrusion dominated regime.

 

 

Comparison with natural mid-oceanic ridge

In order to have a complete understanding of the mid-oceanic ridge system, it is essential to compare the laboratory results with natural examples. Hence, we measure the lateral deviation of nature oceanic ridges along the Atlantic, Pacific and Indian ridges. The measurements reveal the same two regimes as found in laboratory data. The remaining step consists of finding the appropriate scaling laws to superpose the natural and experiment data. This exercise requires dynamics similarity between analogue model and real-world phenomena which is demonstrated using dimensionless numbers (Sibrant et al., 2018). Particularly, the “axial failure parameter – πF” describes the predominant mechanical behaviour of the lithosphere relative to its thickness. Low-πF accretion is dominated by fractures in a predominantly elastic-brittle lithosphere: the lateral deviation of the ridges is tortuous, while at higher pF, accretion is dominated by intrusion in a predominantly plastic lithosphere: the shape of the mid oceanic ridges is mostly linear (Fig 4B).

 

Figure 4. (A) Lateral deviation values measured in the experiments in function of the spreading rate velocities and salinities. (B) Evolution of the lateral deviation of the ridge axis, normalized by the critical axial thickness (Zc) relative to the axial failure parameter. Dark grey is the laboratory experiments and the colored circles are the Earth data. Adapted from Sibrant et al., 2018.

 

Our experiments give insight into the role of axial failure mode (fault-dominated or intrusion-dominated) on the shape of mid-oceanic ridges. In the future, we want to use this experimental approach to investigate the origin of mechanical instabilities, such as transform faults or overlapping spreading centres. This experimental development and results are a collaborative work between Laboratoire FAST at Université Paris-Saclay and Department of Geological Sciences at the University of Idaho and involves E. Mittelstaedt, A. Davaille, L. Pauchard, A. Aubertin, L. Auffray and R. Pidoux.

 

 

References
Buck, W.R., Lavier, L.L., Poliakov, A.N.B., 2005. Modes of faulting at mid-ocean ridges. Nature 434, 719-723.
Schouten, H., Klitgord, K.D., Whitehead, J.A., 1985. Segmentation of mid-ocean ridges. Nature 317, 225-229.
Carbotte, S.M., Macdonald, K. C., 1994. Comparison of seafloor tectonic fabric at intermediate, fast, and super fast spreading ridges: Influence of spreading rate, plate motions, and ridge segmentation on fault patterns. J. Geophys. Res. 99, 13609-13631.
Phipps Morgan, J., Chen, J., 1993. Dependence of ridge-axis morphology on magma supply and spreading rate. Nature 364, 706-708.
Oldenburg, D.W., Brune, J.N., 1975. An explanation for the orthogonality of ocean ridges and transform faults. J. Geophys. Res. 80, 2575-2585.
Dauteuil, O., Bourgeois, O., Mauduit, T., 2002. Lithosphere strength controls oceanic transform zone structure: insights from analogue models. Geophys. J. Int. 150, 706-714.
Püthe, C., Gerya, T., 2014. Dependence of mid-ocean ridge morphology on spreading rate in numerical 3-D models. Gondwana Res. 25, 270-283.
Turcotte, D., Schubert, G., Geodynamics (Cambridge Univ. Press, New York, 1982).
Di Giuseppe, E., Davaille, A., Mittelstaedt, E., Francois, M., 2012. Rheological and mechanical properties of silica colloids: from Newtonian liquid to brittle behavior. Rheologica Acta 51, 451-465.
Sibrant, A.L.R., Pauchard, L., 2016. Effect of the particle interactions on the structuration and mechanical strength of particulate materials. European Physics Lett., 116, 4, 10.1209/0295-5075/116/49002.
Sibrant, A.L.R., Mittelstaedt, E., Davaille, A., Pauchard, L., Aubertin, A., Auffray, L., Pidoux, R., 2018. Accretion mode of oceanic ridges governed by axial mechanical strength. Nature Geoscience 11, 274-279.

 

Meeting Plate Tectonics – Peter Molnar

Meeting Plate Tectonics – Peter Molnar

These bi-weekly blogs present interviews with outstanding scientists that bloomed and shape the theory that revolutionised Earth Sciences — Plate Tectonics. Stay tuned to learn from their experience, to discover the pieces of advice they share, to find out where the newest challenges lie, and much more!


Meeting Peter Molnar


Active in different research areas of the Earth Sciences, Prof. Peter Molnar has been Professor of Geological Sciences at the University of Colorado at Boulder for more than a decade.

Set your own standards for excellence and don’t let other people decide them

You have come a long way in academia! How do you remember the beginnings of your career?

Peter Molnar (1984) – Credit: what-when-how, In Depth Tutorials and Information

I studied physics in the United States, at Oberlin College, where I took one semester in Physical Geology. I remember a friend of mine said “Molnar, you ought to take Geology. If you take Geology, you will look at the landscape completely differently from the way you do.” And I liked looking at the landscape, so I took that semester. Then, I worked one summer at the Harvard Cyclotron Laboratory, and I realized that I wasn’t cut out for that kind of physics… So, I thought of going to geophysics. I applied and I was a good enough student that I got in, in both Columbia and Caltech. I went to Columbia University. During my second year, I attended a talk by Lynn Sykes. He had studied earthquakes on fracture zones and demonstrated that transform faulting occurred. This was a moment that changed me. I remember thinking “Oh my God! Continental drift does occur!” I had been introduced to it back in college, but I didn’t believe any of it! I heard Sykes, and I suddenly realized there is something exciting going on. I got interested and turned my attention to it. While a student I took a “sabbatical,” went to East Africa with a bunch of seismographs to study earthquakes there.

 

 

I attended a talk by Lynn Sykes… This was a moment that changed me

I graduated in 1970. Then I was a PostDoc for two years at Scripps Institution of Oceanography. Afterwards, I went to the USSR for four months, because I thought earthquake prediction offered a bright future. Next, I took a job at MIT where I had the good fortune to get to know Paul Tapponnier. He really taught me more geology than I knew by a long shot. I stayed at MIT for 27 years, but I wasn’t a very good teacher. So I decided to quit, and I supported myself on grants from NSF and NASA. Late in the 90s, after supporting myself for more than 10 years, I wanted to change directions. So I looked into moving to a place where they would pay me a little a bit so that I did not have to depend on grants. And there was the choice between University of Washington and the University of Colorado. I had gotten interested in climate change, and then other things since then, and I have been here for 18 years.

 

After being active for several decades in this field, where does your main research interest currently lie? 

Right now my main interest is related to how geodynamics affects climate on geologic scales. There are two problems that attract me: how does the high topography of Asia affect Asian climate and how do islands in the ocean affect rainfall and large-scale atmospheric circulation. The ultimate goal of the latter is Ice Ages, since I think they are all tied together. I have been working on what you might call geodynamics now for most of the last 50 years, so I still do that. I no longer do much seismology.

It’s almost a religion that I don’t believe what I don’t understand

Peter Molnar (2014) – Credit: Oceans at MIT

 

How would you describe your approach?

My wife says that what I do is to look for problems where everybody believes something, but there is an inconsistency, and that I try to find that inconsistency and expose it, and then revel in the pleasure of that exposure. That’s her observation of watching me, I certainly do not do this consciously. 

A concern I have with a younger generation is that, for some reason, they have not been encouraged or they have not learned to ask important questions…

 

 What about your methods?

Molnar & England (1990). Late Cenozoic uplift of mountain ranges and global climate change: chicken or egg? Nature, 346, 29–34.

I seek simple physical explanations for things. I do not like big models because I don’t understand them, and it’s almost a religion that I don’t believe what I don’t understand. I use big numerical codes. I use them to carry out “simple numerical experiments” where you vary one parameter and see what you get. To me this is an experiment. It’s just not done in a laboratory but on a computer. The strategy is to understand the physical processes while bringing data to bear. Another central element, which I often seen missing today, is that I try to direct my research towards problems that are “important”. It seems to me that an important problem is one that when you solve it, it changes the way people think. Sometimes you have to make incremental steps forward. As an example, both Tapponnier and I, over the years, have tried to constrain the kinematics of Asian deformation by studying slips on faults, and determining slip rates. One could argue, those studies are incremental steps forward, but of course, the big goal is to put the whole picture together. I no longer do this.

There are many people who do this better than I do. So, it would be pointless for me to do that. But I compile their data continually. And the question that I am asking, in this case, is what are the underlying physical processes that determine how the deformation occurs?

A concern I have with a younger generation is that, for some reason, they have not been encouraged or they have not learned to ask important questions.  There’s too much of a tendency to work on incremental problems. 

While you are learning, you are alive

What would you say is the favourite aspect of your research?

Bringing two pieces together that don’t look like they fit, until you put them together. For example, I think that rainfall over the islands in Indonesia and the growth of Indonesia has made the Ice Ages in Canada. Now, who would have thought that? I have fun with this! You have to realize that when you do this type of things, most of the time you are wrong. So, I might be wrong about this one, but I am having fun. So it doesn’t matter. I’m learning. That’s the second favourite thing: learning. While you are learning, you are alive. And the third thing is fieldwork. I love being in the field. My head gets clear, I see things that I have not seen before, I learn about other cultures and people. I just have a wonderful time. I don’t think my own fieldwork contributed much to our field  – but it’s important to me.

I’m just having fun!

Why is your research relevant? What are the possible real-world applications? 

Peter Molnar – Credit: University of Colorado Boulder

I think my research is about as relevant as Goya’s paintings – Goya is one of my favourite artists. So if you think that Goya’s paintings are relevant, then maybe my research is relevant. And if you think his paintings are not relevant, then my research is not relevant either. And I shouldn’t be so pretentious as to equate my work to Goya’s paintings.

What would you say is the main problem that you solved during your most recent project? 

I don’t know if I solved any problem… that’s not a question I ask myself. I’m just having fun!

I wanted to ask what do you consider to be your biggest academic achievement, but perhaps I should ask you what is the one achievement that gave you the most fun?

I don’t spend time thinking about my biggest achievement. I prefer to look forward to what’s coming. You know, most people my age are retired, I can still work 50 or 60 hours a week. I love what I do. I rather look forward to the exciting stuff in the future.

…it troubles me when I see people worrying […] about artificial metrics

Looking back, what would you change to improve how science in your field is done today?

I see two aspects of the direction science is going that trouble me. One, can do nothing about, is the level of funding. Most of us struggle to get funded. I feel that back 50 years ago, it was much easier than it is now. Of course, we were fewer people. But in any case, limitations on funding really slow us down.

The other thing that troubles me is the focus on metrics. People counting the number of papers they write, worrying about their citations and not worrying about the quality of their work. These very poor measures of quality. So much today is focussed on these metrics, these indexes, that are meant to be a measure of your work. People are not thinking about the quality, they are thinking about how many people are going to cite it, where they are going to publish it, does the journal have a high -whatever it is called- impact factor. This is just crap, people should not waste time on this. This is just ridiculous! The focus should be on the quality of the work. We all have different ways of deciding quality. It is not something you measure, however; it’s something we determine in some subjective way. And it troubles me when I see people not worrying about the right thing, quality, and worrying instead about these artificial metrics. I am just so glad these things don’t matter to me. I am old enough, but I really don’t envy young people that have to cope with these sorts of artificial targets.

I don’t see anything like Plate Tectonics in the verge from happening.

But I do see still see very exciting stuff, but probably in different parts the science

What do you think are the biggest challenges right now in your field?

Some of the challenges are too hard for me even to pursue them. In the climate world, we don’t know about the role of clouds. And I don’t know how to pursue this, so I don’t pursue it. Do clouds have a cooling effect, and what is the response from clouds to warming? Will they slow or accelerate the warming? We don’t know. The role of clouds is certainly a big, big question. Although I do not work on this, I think about it, but I don’t see what to do.

One of the problems I do work on is what brought us Ice Ages. How did we go through 300 My years without much ice in the northern hemisphere and then suddenly, beginning 3My years ago or so, we had 5 big Ice Ages? Why? An easy answer is that now CO2 is higher. But it’s really hard to measure, determining CO2 in the past is a big question.

Another big question for me is how does the convection in the mantle connect with deformation in the lithosphere? How do these connect to one another?

Another one I work on is where is the strength within the lithosphere? We still argue about it. This is a 40 years old question, and the points of view haven’t changed. There are still those who put the strength in the crust, while others put it in the mantle. I don’t think we know. And of course it’s going to be different in different places, so it’s a more complicated issue.

Molnar (2015). Plate Tectonics: A Very Short Introduction – Credit: Amazon

I think the prediction of earthquakes is often dismissed as something that we ought not to spend time on. But the progress that has been made in understanding earthquakes in the past 20 years is huge. This came up in Paris and I agree completely with what Eric (Calais), Jean-Philippe (Avouac), and others said. The use of GPS to study co-seismic and post-seismic deformation, and the realization of slow earthquakes are big advances. That’s a big question that I think we might be close to solving.

Another question I got really excited about is understanding how the upper mantle and the lower mantle are connected. In fact, some of us have had a discussion about it in Paris. The evidence shows the lower mantle is really chemically different from the upper mantle; that’s obvious. But how are the two connected; that’s not obvious. I don’t see this the same way as a bunch of other people do. I see the connection between the two, and this takes us back to the question of the early history of the Earth. How is the chemical difference manifested? How has the slower convection of the lower mantle slowed the cooling of the Earth?

I think the answer to your question is: I don’t see anything like Plate Tectonics on the verge of happening. I do see still very exciting stuff, but probably in different parts the science.

…that way I was not going to get killed

When you were in the early stages of our career, what were your expectations? Did you always see yourself staying in academia? 

I don’t remember what expectations I had, I don’t think I was even aware enough to know what I wanted to do. When I decided to go into geophysics, people said to me “Oh, what’s geophysics?”, and I didn’t know. And “What would you do?” and I said, “Well, oil companies need people like that”. At that time I knew so little, that it never dawned on me that if I work for an oil company, I might be stuck having to live in Texas. And I can’t imagine living in Texas. What I did know is that if I did not go to graduate school, I would be sent to Vietnam. I was kind of trapped with having to go to graduate school and choosing a field that seemed possible and open to me. So, I just decided to go for the easy road. I stayed in school because that way I was not going to get killed. I stayed, and I thought about music and girls. But once I got excited about research, it was clear that that was the only place for me.

 What is the best advice you ever received?

Now, that’s a good question. One of them came from my father. He did not articulate this, but I sensed it in a conversation with him. And one of my three main advisors, Jack Oliver, emphasized this to me again, and that is to continuously ask yourself: What is the most important scientific question? As soon as you did something, Jack Oliver would say, “Ok. Now you have done this, what’s the next most important question?” Just because you ask it, it doesn’t mean that you have solved an important problem. But if you continue to ask yourself that question, you have a better chance of doing good science, than if you don’t ask that question.

Jack gave another piece of advice, which is almost counter opposite to this, and that was that when you can’t think of what to do, the worst thing you could do is to do nothing. Just because you can’t come up with the most important problem doesn’t mean you should do nothing. You should just keep going.

Another piece of advice is, set your own standards. None of us is Einstein. None of us is Newton (maybe not none of us, but very, very few of us are). So, if we set those standards, we fail. And the problem is that, if we let universities with low standards but counting and using metrics to set the standards, we will not do as well as we would, if each of us would set our own standards for excellence. We should strive on meeting our standards, rather than what others expect from us. Don’t let other people decide your standards.

 

Peter Molnar – Credit: David Oonk

Interview conducted by David Fernández-Blanco

Meeting Plate Tectonics – Xavier Le Pichon

Meeting Plate Tectonics – Xavier Le Pichon

These bi-weekly blogs present interviews with outstanding scientists that bloomed and shape the theory that revolutionised Earth Sciences — Plate Tectonics. Stay tuned to learn from their experience, to discover the pieces of advice they share, to find out where the newest challenges lie, and much more!


Meeting Xavier Le Pichon


Prof. Xavier Le Pichon is one of the pioneers of the theory of plate tectonics. He developed the first global-scale predictable quantitative model of plate motion. The model, published in 1968, accounted for most of the seismicity at plate boundaries. Among many substantial contributions to the field, he also published, together with Jean Francheteau and Jean Bonnin, the first book on plate tectonics in 1973.

 

Your contributions have led to great advancements of our understanding of Plate Tectonics as we know it today. What‘s your main interest and what motivates your research?

My interest is the Earth and how it behaves. Discovering what type of animal the Earth is. I think of the Earth as a living organism, and we have to understand it. It’s very interesting to take the Earth as something that evolves, that changes, and that you have to understand how it evolves. The whole thing about research is getting very intimate with it and knowing really its behaviour.

I think of the Earth as a living organism

What would you say is the favourite aspect of your research?

I do not have any favourite aspect, but I think that to explain the change in the Earth is captivating. For example, how did we pass from an Earth where there were a single continent and a single ocean, ~200 Ma, to something where the continents are as dispersed as they are now… This had a tremendous influence on many things, including evolution, biology, climate… We know, for example, that when all the continents were together the pace of the evolution was much smaller than when continents are dispersed. All this fascinates me. I believe that if there is something that is not understood, you have to understand it. The basic question that proves you are a human is, you always have the “why” in your mind as the main thing that is present.

Claude Riffaud and Xavier Le Pichon – Credit: Jean-Claude Deutsch/Paris Match

 

What do you consider is the main problem that you solved during research?

I have been interested in many different aspects… I’m best known by the fact that I’ve been one of those who promoted plate tectonics. I made the first global model of quantifying the motion of the plates, knowing everywhere what would be the motion absorbed in the plate boundary. Also, I made the first finite and precise reconstruction of the configuration of the Earth, for nowadays, 70 Ma, 200 Ma, and so on. I also think that I was the first that proved that the Earth’s expansion did not work. Because if you take the shortening that is absorbed in the trenches of the world, in the mountain belts, and you claim there is no shortening there, then you are left only with the expansion of the ridges. And the expansion is asymmetric, and it’s produced much more in the east-west sense than it is in the north-south sense. And if you have that going on for several tens of millions of years, then the Earth would have a shape which is completely non-hydrostatic. It would not respect what the Earth has to have to be a planetary body turning on itself. So the Earth’s expansion was clearly impossible.

I believe that science that is completely regulated

top-down is not efficient

Le Pichon, X. (1968). Sea-floor spreading and continental drift. Journal of Geophysical Research, 73(12), 3661–3697.

 

After being many years active in the academia, looking back, what would you change to improve how science in your field is done today?

I never worried about “what is done”, I worried about “what I do”.  I have always found a way to get money, to get a position and to get a lab. I changed labs quite a few times. I created a few labs… I think it is a question of adjusting. I believe that science that is completely regulated top-down is not efficient. I think there has to be a lot of freedom. At least for fundamental science. For applied science, I don’t know but I think it is probably about the same. The reason is very basic: what is the purpose of research? It’s to discover something that is totally unexpected. If it is expected, then it’s not a discovery. When the guy who does the planification says: “we will focus all our energy to find out about that”, how does he know “that” is the thing that is going to come out? The most important things in the evolution of research have been totally unexpected and came from people that had no planification whatsoever of what they should find.

The most important things in the evolution of research have been totally unexpected

Where do you see the biggest challenges in your field right now?

Le Pichon, Francheteau, Bonnin (1973). Plate Tectonics: Developments in Geotectonics, 6 – Credit: Amazon

The plate tectonic was really a revolution that changed completely the concept. And it took a few tens of years to adjust to this revolution. Actually, we are still in the phase of adjusting to that. For example, we are adjusting to the fact that to understand that plate tectonics is not only what happens at the surface, but that it implies things that happen in the interior of the Earth, in the mantle and below. This is not fully understood. And we do not understand one very important thing, which is that plate tectonics is a relatively new thing on the Earth. In the beginning, there was no plate tectonics as we know it nowadays. And I think that even the style of the plate tectonics has changed in the last was 200 Ma for example. It probably was not the same before Pangea… So we have still lots of things to understand, and to incorporate. And then, the main thing about discoveries, again, is that they are unexpected. So, I would not be surprised that major discoveries focus our energy in a completely new direction in the near future. I think we are approaching a time where it seems that we need to trigger something else to get into something new.

 I am very afraid of people who get specialized too early

When you were an Early Career Researcher, what was your motivation, what stimulated you most?

Riffaud, Le Pichon (1976). Expédition ‘Famous’ à 3000 m sous l’Atlantique. Paris: Albin Michel. – Credit: Amazon

The fact that strikes me the most when I think about Europe is that the student’s mobility has been greatly increased and I think that this is extremely important. The mobility I had was not too frequent in my time – I have moved a lot: I moved to the United States, where I was offered a professorship, and came back, then I was an invited professor in other places, Oxford, Tokyo… I have created three different laboratories, and I’ve been in many places in the world. I think this is very important because you change with time and you cannot get stuck in a given thing. I think this is very basic in research. I mean, you learn a lot by comparing. You have to move, and confront yourself to other laboratories, to other ways to teach… Otherwise, you get stuck in a certain frame and that can be very dangerous. Then you become more interested in promoting your position and the place where you are than in the discoveries. Or you end up trying to be what your professor was and trying to imitate the guy that taught you is certainly one of the worst things you can do. I think anything that promotes mobility and independence and possibilities to change is a very good thing.

I am very afraid of people who get specialized too early. Of course, it is easier to get a job if you have a narrow speciality, you are more immediately usable. But I think the result is quite bad, quite often. You first have to see the different possibilities and then progressively you find out that you best express yourself in a certain direction, in a certain field. And that requests time and several tries and so on.

 

When you were a young researcher, did you always see yourself staying in academia?

I always wanted to do research. I wanted the freedom to choose. And I always went to places where I was sure that I would decide myself what type of research I would do. If that was not anymore the case, I quitted and I changed. I was very firm about the fact that I wanted to choose myself my own research direction. This has been a problem with financing. I had to change my source of financing. Whenever I had a problem with the state and the administration, I would go to oil people and other types of European financing in order to be able to keep this freedom.

You have to go to a place where research is thriving

The last question for today’s Early Career Scientists: what advice would you like to give the ECS that would like to stay in science?

Xavier Le Pichon – Credit: Instituto De Estudios Andinos Don Pablo Groeberg (IDEAN)

Basically, I have been an autodidact. I have always learned, in contact with other people, but mostly by myself. I cannot give any advice about what is best… but it is clear that you have to go to a place where research is thriving. If you go to a place where nothing happens, you will not start by yourself something unless you are a real genius. But even then, you don’t have the resources and so on. So you first need to identify the place where things are moving, where things are happening.

And then you try to go to this place and then, if possible, you try another one. Don’t get stuck to one thing only. Try to see the world, try to see how it moves, try to contact people…

One of the most interesting things in research is the contact with other people. Academia is a place where you have a lot of cooperation and you learn to interact with others and having a wide network of people with whom you interact is one of the gifts of this type of life. One very interesting thing is wherever you go you will agree if you talk about good science. Because when proper science is made, everybody agrees. This is not true in any other field. In philosophy, for example, you will never find people with whom you totally agree, it’s impossible. In science it’s so restricted, the rules are so clear that you are sure to come to a common agreement. So you can work with anybody on Earth that has the proper mind to do research and you will cooperate very well.

Xavier Le Pichon – Credit: Xavier Le Pichon

Interview conducted by David Fernández-Blanco

Lisbon at the dawn of modern geosciences

Lisbon at the dawn of modern geosciences

Here, where the land ends and the sea begins...
Luís de Camões (Portuguese poet)

Lisbon. Spilled over the silver Tagus River, it is known by its beautiful low light, incredible food and friendly people. Here, cultures met, and poets dreamed, as navigators gathered to plan their journeys to old and new worlds. Fustigated by one of the greatest disasters the world has ever witnessed, Lisbon is intertwined with the course of Earth Sciences. For some, modern seismology was born here. For others, this might even have been the place where it all begun; what we now call geology.

On the morning of All Saints day of 1755, a giant earthquake struck the city of Lisbon. With a magnitude of ~8.7, the event was so powerful that it was felt simultaneously in Germany, as well as in the islands of Cape Verde. The main shock occurred around 9.40 am, when a significant portion of the population was attending the mass in churches. Lasting several minutes, many of the roofs collapsed and thousands of candles set fires that would last for days. While people were looking for safety at open areas near the river, three giant tsunami waves were on their way. Forty minutes after the main shock, the waves rose the Tagus River and flood the city’s downtown. The death toll in Lisbon reached up to 50,000 people, about one quarter of Lisbon’s population at the time. This event is known as the Great Lisbon Earthquake of 1755.

 

Painting depicting the day of the 1755 Great Lisbon Earthquake. Credit: Wikipedia.

 

The 1755 Lisbon Earthquake was a terrific natural disaster. A few years ago, the French magazine L´Histoire, considered this earthquake as one of the 10 crucial events that changed history. At the time, Lisbon was a maritime power in a maritime epoch. This was also the age of Enlightenment, when man started to realize that many events such as earthquakes, volcanoes and storms, had natural causes, and were not sent by gods.

Convento do Carmo, destroyed during the 1755 earthquake and kept as a ruin for memory. Credit: Flickr.

Lisbon was in the spotlight of the modern world and some of the most prominent philosophers like Kant, Voltaire and Rousseau focused on the destructive event of the 1st of November, 1755. In particular, Emmanuel Kant published in 1756 (yes, 1756!) three essays about a new theory of earthquakes (see Duarte et al., 2016 and the reference list below for two of the Kant’s essays). I recommend all geoscientists to read these documents. It is incredible how Kant understands and describes how earthquakes align along linear features that are parallel to mountain chains. Does this sound familiar? Moreover, he uses the then new physics of Newton to calculate the forces that were needed to set the seafloor off Lisbon in movement in order to generate the observed tsunami. He even refers to experiments with buckets full of water to explain how the tsunami formed (analogue modelling!?). And Kant was not alone…

The minister of the King of Portugal at the time, the Marquis of Pombal, sent an enquiry to all parishes in the country with several questions. While some of the questions were intended to evaluate the extent of the damage, it is now clear that the Marquis was also trying to gain (scientific) knowledge about the event (see Duarte et al., 2016 and references therein). For example, he asks if the ground movement was stronger in one direction than in other, or if the tide rose or fell just before the tsunami waves arrived. Today, we can reconstruct with rigor what happened that day because of the incredible vision of this man.

 

The center of Lisbon today. The statue of Marquis of Pombal facing the reconstructed downtown. Credit: Wikipedia.

 

Coming back to Lisbon. If you visit the old city by foot, you will realize that houses on the hills are closely packed, separated by narrow streets and passages, while in the flat downtown streets are wide and orthogonal. The hilly parts of Lisbon are an heritage of the Moorish and Medieval times. Mouraria and Alfama are the ideal neighborhoods to visit. The organized downtown was the area that was totally floored during the earthquake, due to ground liquefaction and the impact of the tsunami, and was rebuilt using a modern architecture (see Terreiro do Paço and the downtown area in the first figure in the top). The Grand Liberty Avenue is clearly inspired by the style of the Champs-Élysées. Going up the Liberty Avenue, from the downtown, you will find the statue of the Marquis of Pombal (see figure above). And if you are already planning to visit (or revisit) Lisbon, you should definitely stop by the Carmo Archeological Museum, a ruin left to remind us all of what happened on that day of 1755, and the Lisbon Story Centre.

The hills of Lisbon, with the Castle in the top left and the 25 de Abril bridge in the background. Credit: Flickr.

Rebuilding plan after the 1755 earthquake. Credit: Wikimedia Commons.

The 1755 Great Lisbon Earthquake was however not the only earthquake that hit the city. On the 28th of February 1969, another major quake, with a magnitude of 7.9, struck 200 km off the cost of Portugal, at 2 am in the morning. The earthquake generated a small tsunami but luckily, given the late hours, did not caused any casualties. This event also occurred in a particular point in history: The time of plate tectonics. The paper that inaugurated plate tectonics had been published only 4 years before, by Tuzo Wilson. And in 1969, geoscientists already realized that some continental margins were passive and did not generate major earthquakes, such as the margins of the Atlantic, while others were active and fustigated by major earthquakes, such as the margin of the Pacific (Dewey, 1969). It was somewhat strange that this Atlantic region was producing such big earthquakes, which therefore immediately resulted in scientists coming to study this area (see map below).

Fukao (1973), studied the focal mechanism of the 1969 earthquake and concluded that it was a thrust event. Purdy (1975), suggested that this could result from a transient consumption of the lithosphere, and Mckenzie (1977) proposed that a new subduction zone was initiating here, along the east-west Africa-Eurasia plate boundary (see the thinner segment of the dashed white line in the eastern termination of the Africa-Eurasia plate boundary, map below), SW of Iberia. Later on, in 1986, António Ribeiro, professor at the University of Lisbon, suggested that instead, a new north-south subduction zone was forming along the west margin of Portugal (yellow lines in the map), a passive margin transforming into an active margin. This could explain the high magnitude seismicity, such as the Great Lisbon Earthquake of 1755.

 

Map showing the main tectonic features in the SW Iberia margin. The Eurasia-Africa plate boundary spans from the Azores-Tripe Junction (on the left) until the Gibraltar Arc (on the right, with its accretionary wedge marked in grey). The yellow lines mark a new thrust front that is forming and migrating northwards away from the plate boundary and along the west Iberia margin. The smaller yellow line marks the approximate location of the 1969 earthquake. The 1755 Great Lisbon Earthquake might also have been generated in this region (see Duarte et al., 2013 for further reading on the tectonic setting of the region; the figure is adapted from this paper).

 

Today, we know that the SW Iberia margin is indeed being reactivated (Duarte et al., 2013). Whether this will lead to the nucleation of a new subduction zone is still a matter of debate, and we will probably never know for sure. Nevertheless, subduction initiation is one of the major unsolved problems in Earth Sciences, and the coasts off Lisbon might constitute a perfect natural laboratory to investigate this problem. It may be the only case where an Atlantic-type margin (actually located in the Atlantic) is just being reactivated, which is a fundamental step in the tectonic conceptual model that we know as the Wilson Cycle (see also Duarte et al., 2018 and this GeoTalk blog). In any case, we know that there are two other locations where subduction zones have developed in the Atlantic: in the Scotia Arc and in the Lesser Antilles Arc. How they originated is still being investigated; which is precisely what we are doing now in Lisbon. That is however a topic that deserves its own blog post.

 

Written by João Duarte

Researcher at Instituto Dom Luiz and Invited Professor at the Geology Department, Faculty of Sciences of the University of Lisbon. Adjunct Researcher at Monash University.

 

Edited by Elenora van Rijsingen

PhD candidate at the Laboratory of Experimental Tectonics, Roma Tre University and Geosciences Montpellier. Editor for the EGU Tectonics & Structural geology blog

 

For more information about the Great Lisbon Earthquake of 1755, check out these two video’s about the event: a reconstruction of the earthquake and a tsunami model animation

 

References:

Dewey, J.F., 1969. Continental margin: A model for conversion of Atlantic type to Andean type. Earth and Planetary Science Letters 6, 189-197.

Duarte, J.C., Schellart, W.P., Rosas, F.R., 2018. The future of Earth’s oceans: consequences of subduction initiation in the Atlantic and implications for supercontinent formation. Geological Magazine. https://doi.org/10.1017/S0016756816000716

Duarte, J.C., and Schellart, W.P., 2016. Introduction to Plate Boundaries and Natural Hazards. American Geophysical Union, Geophysical Monograph 219. (Duarte, J.C. and Schellart, W.P. eds., Plate Boudaries and Natural Hazards). DOI: 10.1002/9781119054146.ch1

Duarte, J.C., Rosas, F.M., Terrinha, P., Schellart, W.P., Boutelier, D., Gutscher, M.A., Ribeiro, A., 2013. Are subduction zones invading the Atlantic? Evidence from the SW Iberia margin. Geology 41, 839-842. https://doi.org/10.1130/G34100.1

Fukao, Y., 1973. Thrust faulting at a lithospheric plate boundary: The Portugal earthquake of 1969. Earth and Planetary Science Letters 18, 205–216. doi:10.1016/0012-821X(73)90058-7.

Kant, I., 1756a. On the causes of earthquakes on the occasion of the calamity that befell the western countries of Europe towards the end of last year. In, I. Kant, 2012. Natural Science (Cambridge Edition of the Works of Immanuel Kant Translated). Edited by David Eric Watkins. (Cambridge: Cambridge University Press, 2012).

Kant, I., 1756b. History and natural description of the most noteworthy occurrences of the earthquake that struck a large part of the Earth at the end of the year 1755. In, I. Kant, 2012. Natural Science (Cambridge Edition of the Works of Immanuel Kant Translated). Edited by David Eric Watkins. (Cambridge: Cambridge University Press, 2012).

McKenzie, D.P., 1977. The initiation of trenches: A finite amplitude instability, in Talwani, M., and Pitman W.C., III, eds., Island Arcs, Deep Sea Trenches and Back-Arc Basins. Maurice Ewing Series, American Geophysical Union 1, 57–61.

Purdy, G.M., 1975. The eastern end of the Azores–Gibraltar plate boundary. Geophysical Journal of the Royal Astronomical Society 43, 973–1000. doi:10.1111/j.1365-246X.1975.tb06206.x.

Ribeiro, A.R. and Cabral, J., 1986. The neotectonic regime of the west Iberia continental margin: transition from passive to active? Maleo 2, p38.

Wilson, J.T., 1965. A new class of faults and their bearing on continental drift. Nature 207, 343– 347

Meeting Plate Tectonics – Dan McKenzie

Meeting Plate Tectonics – Dan McKenzie

These bi-weekly blogs present interviews with outstanding scientists that bloomed and shape the theory that revolutionised Earth Sciences — Plate Tectonics. Stay tuned to learn from their experience, to discover the pieces of advice they share, to find out where the newest challenges lie, and much more!


Meeting Dan McKenzie


Prof. Dan McKenzie is one of the key actors empowering the Plate Tectonic Theory. He was Professor of Geophysics in Cambridge until he retired in 2012. He is mainly known to have published, together with Robert Parker, the first paper on Plate Tectonics. “The North Pacific: an example of tectonics on a sphere” describes the principles of plate tectonics, where individual aseismic areas move as rigid plates on the surface of a sphere.

The trick is to know what is tractable and also what is not understood.

You are known to have published the “very first paper” on plate tectonics. How did this contribution came about?

I was a Physics undergraduate in Cambridge. Then I became a graduate student of Teddy Bullard with whom I worked on the fluid dynamics of the mantle before it became at all understood. He got me to a conference in New York, where I heard for the first time all the works that Vine had done on, eventually, plate movements. While examiners were reading my PhD, I did the work of my first paper on plate tectonics. It was concerned with the thermal consequences of plate creation on ridges. In Summer 1967, I went to Scripps and there I was reading a paper by Teddy on fitting the continents. It occurred to me that the method he used, Euler’s theorem, actually was a way to describe all surface motions of the Earth. And so I did. I wrote, what then turned out to be the first paper on plate tectonics, which was published 1967. I don’t have priority. Jason Morgan gave a talk at the AGU in the Spring of 1967. But his abstract was completely different from the talk he gave. I had read his abstract not too long before he gave the talk, and I missed it. It made no impression at all on the AGU.

Since then, I worked a bit on Plate Tectonics, but it became quickly a dead end. I was intrigued by some observations from ocean Islands, which showed that their sources had been isolated from the convecting of the mantle for about a thousand million years. This seemed extraordinary to me! So I got interested in the whole question as how you generate melt. I worked on that for quite some time. I’m still working on that.

I have gone beyond my wildest dreams

I worked on a lot of areas in the Earth Sciences and I have gone beyond my wildest dreams (laughs). It never occurred to me that I would be given all this prices and funding –it is all very flattery!  But I am always amazed by the fact that my papers are read and cited.

 

Dan McKenzie (1976) – Credit: The Geological Society (Mckenzie Archive)

How do you remember the beginnings in your career, what was your main motivation?

I never had an overall plan about what to do for my career. I simply work on what I find interesting and what I think that I and other people might be able to understand. I put my mind to it. There is no point in working on things everybody understands, nor in working on something that is totally intractable, because eventually, you won’t catch it either. The trick is to know what is tractable and also what is not understood. I particularly watched the technology. Most of what I have done followed a change in technology. You have to have some feeling that you can do something new and interesting, otherwise you are just going to get lost. If hundreds or thousands of people do the same thing, that is not the sensible thing for me to do. I have nothing to add to that. They do much better than I would. But the data is marvellous, and I can use it to do all kinds of things. The best scientific problems are clearly interesting, clearly not known and not understood, but tractable. There is no point whatsoever, trying to attack problems that are not tractable.

[Plate Tectonics research] was frankly a bit of a disappointment

What would you say, has been the favourite aspect of your research? 

I think the one that had the most influence on my career was certainly plate tectonics. That was frankly a bit of a disappointment. It was so successful that it really needed no further work. I spent an enormous amount of energy in the 1960’s in trying to make the theory as simple and as obvious as I could. And I succeeded, and other people were part too, but we succeeded too well (laughs).  And it did become really routine. Since that time, there haven’t really been any changes. So, it isn’t my favourite at all!

My favourite is trying to understand the mantle convection (of which plate tectonics is one aspect). Trying to understand the fluid dynamics of mantle convecion is really the dominant aspect of the research I have done for fifty years.

I am driven by wanting to understand things, rather than by the uses that people make of my understanding

After all the time you have spent in science, where do you see the biggest challenges right now in your field?

Dan McKenzie (mid 1990s) – Credit: British Library (Voices of science)

The present surface of Mars is so thick that it isn’t actually moving, but it seems it did in the past. So probably, in the early history of Mars, it did have something like Plate Tectonics. And I am sure that, if and when we ever get good images, the works on fluid dynamics will actually give us a handle of what is happening on this and other planets. But you need extraordinary increased spatial resolution images to actually see what is happening on planets in the solar system.

 

You have contributed greatly to establishing the revolutionary Theory of Plate Tectonics. Still, one might wonder – what are the real-world applications of your research?

McKenzie & Parker (1967). Nature, 216(5122), 1276–1280.

The understanding of plate motions has completely changed our views on seismic risk. At present, I think GPS is an enormous step forward in our understanding of seismic risk. Now, you can actually see the elastic strain that accumulated on plate boundaries using GPS. For instance, Tibet is moving southwards with respect to India. But there have been no really big earthquakes along the Himalayan front in historical times. It is quite clear from the GPS that there have been huge but very infrequent earthquakes. What has been happening in Indonesia and also in Japan, is likely to happen here: it will unzip and there will be earthquakes. I wish the Indians would take it more seriously… My friends and I reckon that somewhere in central Asia this century there will be earthquakes which will kill millions of people. That is a frightful thought.

 

…somewhere in central Asia, this century there will be earthquakes which will kill millions of people, and that is a frightful thought

The thing  I have done that had the most economic impact is getting an understanding of how oil is produced in sedimentary basins. That is a paper in which I put together our understanding of how such basins were formed. Which is simply by stretching of the continental crust. It is not like Plate Tectonics, because the extension is not localised, but distributed. That was the key. It took us long to understand that because we were actually trying to think in terms of plate motions, or plate boundaries. The paper is six pages long but no one ever reads the second three pages (laughs). If I had written only three pages, it would have had the same impact…

What I am doing now doesn’t have the same impact… Understanding mantle convection beneath the plates is not going to be of nearly the same significance, frankly. It is fascinating to see how it works, but it is a different matter. I am driven by wanting to understand things, rather than by the uses that people make of my understanding.

Well,  it will come to a use eventually!

Yes, understanding can be always be used… for good and bad reasons… look at nuclear physics.

Rather than more support, there should be less support

After being many years active in the academia, what would you change to improve how science is done in your field now?

This is not a question I ever thought about… I think my answer to that will be a bit complicated…

The real danger, in all subjects, is that the bright young people have lots of opportunities to be a graduate student and to obtain a PhD. And then they get trapped. They are not really good enough to get a proper tenure position in a university. But they are basically good enough to get a postdoc. They discover quite late in their careers, sometime in their thirties, that this is not going to work, that they are not going to get any further. And then they have real crashes. I think there is too much encouragement, on the funding agencies particularly, to carry people to keep on doing postdocs. This is really quite unfair. These people are really clever and they could have a much better career. How do you stop people from doing this, I do not know. Rather than more support, there should be less support (laughs). Of course, the people employing the postdocs, the tenured staff, object very strongly to this. Scientists, once they get a tenured position, want someone to do the work. They got the grant to employ people. They get the credit.

Get out of [academia]!

So, taking this you just mentioned into account, what advice would you give to Early Career Scientists?

Get out of it! (laughs). Unless you have very good chances to get a good position, get out of it and do something else before you get too old! That is what I always tell.

My career is of no use whatsoever to anyone

When you were an Early Career Scientist, did you always see yourself staying academia? What were your career expectations in that sense?

To be honest I did not think about these things… My position was rather particular. I wrote the first paper on Plate Tectonics at age 25. And I reckoned I was going to get a job! (laughs). So, I did not worry too much about that. When I was offered a job, I was offered a position at Cambridge, a full professorship at Manchester and one of the grand professorships at ETH in Switzerland. All at the same time! (laughs). I chose to stay in Cambridge and got married. For some time I was very poor, but I reckoned that would change. And it did. I never really worried about money. My career was not in any way planned and is no guide to anyone. Nothing like Plate Tectonics has happened since, it was really singular. So my career is of no use whatsoever to anyone. Things were different. When I started, there were almost no postdoctoral positions…

 

Dan McKenzie (2014) – Credit: Cambridge University

 

Interview conducted by David Fernández-Blanco

Meeting Plate Tectonics

Meeting Plate Tectonics

The sixties brought us many moving moments: Woodstock, the civil rights movement, the moon landing… and the establishment of the plate tectonic theory.

Tectonic Smile – Credit: Google Earth

It is during the turbulent late sixties that scientists published groundbreaking manuscripts proving that pieces of the Earth’s outer layer are in a constant state of motion.

In Late 1967 to mid-1968, Dan McKenzie and Robert L. Parker, Jason Morgan and Xavier Le Pichon, amongst others, showed that crustal motions on Earth approximate rigid body rotations on a sphere and that plates conforming the Earth’s upper layer have rates of motion that can be calculated thanks to paleomagnetic data. Five decades have passed since the advent of the plate tectonics theory, and it might take many more decades to fully understand all its implications.

 

Here, at the Tectonics and Structural Geology ECS-team, we can’t help but wonder where are we standing today, what the biggest achievements have been and which aspects of the plate tectonic theory still escape our understanding. Fortunately, a commemorative conference celebrating the 50 anniversary of plate tectonics, held in Paris in June 2018 under the title “Plate tectonics: Then, Now & Beyond,” provided a unique opportunity to seek for answers. Initiator David Fernández-Blanco made his way to Paris and together with Anouk Beniest interviewed several researchers that greatly contributed and still contribute to the plate tectonics theory. This blog series presents bi-weekly the interviews (a total of 15) held with these outstanding minds, from which ECS have so much to learn!

Find the interviews here:

Mind Your Head #4: Job uncertainty in academia – know your strengths and possibilities!

Mind Your Head #4: Job uncertainty in academia – know your strengths and possibilities!

Mind Your Head is a blog series dedicated towards addressing mental health in the academic environment and highlighting solutions relieving stress in daily academic life.

In the three previous blog post of this ‘Mind your head’ series, we discussed the importance of communication with fellow ECS, time management, and a healthy relationship with your advisors. However, there is one big source of stress which we haven’t addressed yet: the insecurities regarding your future career, especially if you wish for an academic career. Unfortunately, this is also one of the most challenging stress factors to tackle.

How to decide if you are up for a career in academia, and if not, what to do next? And how can you increase your chances for a future academic position if there is often someone who has more experience, more publications, or simply better connections? And more often than not, this would involve a transfer to another country for a job, which can be a stress factor in itself – particularly when having a partner and/or a family to take care of.

Success rates in academia
To start with, let’s face reality. A study done by Nature last year has shown that worldwide, 75% of the PhD students think that it is likely that they pursue a career in academia. However, the large majority of these Early Career Scientists will end up somewhere else. In the United Kingdom for example, only 3-4% succeed in landing a permanent position at a university.

You probably already realized that the academic environment is very competitive, but numbers emphasize that it is in fact extremely difficult to maintain a career in academia. So how do we explain this apparent misconception that Early Career Scientists have? Why do so many wish to pursue a career in academia, despite the low success rates?

One important factor is probably the lack of examples of alternative career paths: in universities and research institutions we are only exposed to the academic success stories. Our advisors are senior scientists, or professors, who have successfully established their scientific career. Our colleagues might be post-docs, who have managed to find a position after their PhD that they like, or researchers who have written a successful grant proposal, which ensures them to work independently on their projects for several years.

However, where do the people go who do not find that post-doc after their PhD, or who write grant proposals which get rejected, maybe even more than once? Or the people who simply choose to leave academia after doing a PhD, after one or more post-docs, or even after tenure?

Transferable skills
Of course, where these people end up are excellent choices as well, even though there will always be people telling you that academia is the only path. Not choosing academia doesn’t mean failing! Besides having an academic career, there are many possibilities for people who obtained a PhD degree. And some of these careers might fit you even better than an academic career; you just have to know that they exist and how to make the switch! There are many articles that discuss the different career possibilities for Early Career Scientists, an excellent example being this EGU blog post. It introduces several current and former geoscientists who ended up outside academia, and who share their experiences.

Whether you’re already considering leaving academia, or whether you just want to have a back-up plan in case your desired academic career does not go as planned: it is important to know your possibilities, but more importantly your strengths, and how these can be useful in other careers. Are you aware of the many skills you acquire during a PhD that are extremely valuable to your future employers? All ECS have them! In sectors like industry, or consultancy, the exact topic of your PhD is usually of minor importance. It is the additional skills that you acquired that make the difference between hiring someone with a Master’s degree, or someone who obtained a PhD.

Examples of such transferable skills are your ability to work independently on a long-term project, problem-solving, time-management, communicating within an international community, or efficiently obtaining and transferring knowledge, through articles or oral presentations. When exploring future job possibilities, take a moment to identify your (strongest) transferable skills, and in which environments they might be most valuable.

Competencies
Many companies and institutions work with competencies, also called ‘key competencies’, or ‘core competencies’. These are specific personal qualities that recruiters use as benchmarks to rate and evaluate possible candidates for a job. There are many lists online, that display all different types of competencies, often grouped in categories like ‘dealing with people’, or ‘self-management’. Also the book ‘Competency-Based Interviews’, by Robin Kessler, features a list of core competencies and explains how they are used for job interviews. Using such an overview to identify your core competencies might be easier than trying to come up with them from scratch.

In the end, knowing  your core competencies and using them to ‘sell yourself’ (during an interview, in a motivation letter, or on your CV), will be useful for any type of career, also in academia! To learn more about increasing your chances in academia, check out this article about marketing for scientists.

Mind your head!
So, to wrap up this series: many Early Career Scientists are very passionate about pursuing an academic career and are willing to work very hard to achieve what they want. Of course, you shouldn’t let yourself be scared off by the statistics; if an academic career is what you really want, go for it! Be prepared for the hard work and strong competition, but don’t forget to have fun! In order to do that, it is important to know yourself, your strengths as well as your limits, to manage your time wisely and… to communicate with your colleagues and advisors!

If it turns out that academia is not for you, don’t panic! There are many wonderful careers outside academia, where you and your skills will be highly valued. However, it is important to get out of the ‘academia-only’ bubble and broaden your horizon. Alternative careers can provide many benefits, such as job certainty, more teamwork, short-term and diverse projects, and an office in the right geographical location! Explore other careers that might suit you, and identify your strengths that will help you land your dream job, inside or outside academia!

 

By Elenora van Rijsingen
Written with help and revisions from Anne Pluymakers

 

Resources

2nd workshop of the Marie Skodowska-Curie ITN project CREEP: Discussion sessions between senior- and early career scientists focused on reducing stress levels in academia.

PhD management training by Marie-Laure Parmentier from Belpaeme Conseil, France. 

Mind your head #3: A healthy relationship with your advisor

Mind your head #3: A healthy relationship with your advisor

Mind Your Head is a blog series dedicated towards addressing mental health in the academic environment and highlighting solutions relieving stress in daily academic life.

Besides the professional environment in general, the relationship between early career researchers and their advisors also plays an important role in the degree of stress researchers might experience. This relationship does not only depend on the type of advisor you have, but also on your own personality type. A tough supervisor for one person, might be a very good supervisor for someone else. The success of a healthy relationship therefore lies in the expectations you have for each other, and how you respond if those expectations are not met.

Different types of advisors
There are many different types of advisors, as there are many different types of people. A famous one is the ‘superbusy’ type, but also the ‘over-confident’ (“of course this never-tried method will work!”), or the ‘micro-manager’ (someone who checks every detail of your work), are common types.

The ideal advisor would be a supporting one, who cares about your future career, tries to teach you how to become an independent researcher and encourages you to do your work in a way that works best for you. The opposite would be someone who is interested in their own career and only sees you as someone who will simply take on some of their workload, whilst all the time keeping control on how you do that.

Generally speaking, advisors will fall in between these two extremes, and depending on their own stress levels, they might be easier to work with at some times than at others.

Expectations in both ways
The good news is that you can steer a little as well! So, how to make sure your situation will approach the ‘ideal’ situation, rather than the opposite? The first thing you need is probably a bit of luck; a good fit of characters might already be enough to obtain a healthy relationship.

If you’re not so lucky, then communication becomes key! Take the time to figure out what your advisor expects from you as an early career scientist and to think about what you expect from him or her. Advisors are all different, but students are too! Make sure to tell your advisor what you need in order to do a successful job. For example, does your advisor expect you to write your drafts mainly independent? Or does he or she prefer to work on it together, and check it after each section you’ve written? You both might have different preferences for this and it is important to discuss these and find a compromise.

If necessary, make an appointment once a year to simply discuss the process of decision-making and discuss what the best way of communication is for both of you. For example: some people prefer lengthy emails, some short, and some people you need to catch in person in order to work together. If you make it a habit to figure out what the best mode of communication is, it will definitely speed up any cooperation!

Most conflicts between PhD-students and supervisors arise in the final year of the PhD, since this is the point that the student thinks most independently. – Marie-Laure Parmentier (occasional consultant for Belpaeme Conseil)

When conflicts arise
When expectations are not met, a conflict may arise. An example is the case of the ‘superbusy’ advisor, who never has time to talk, whereas you would prefer to have regular short discussions (once in two weeks for example). This could lead to frustration on the students’ part, and even to giving up on trying to communicate at all.

A contrary situation could be an advisor who checks up on you daily to see how you are doing, probably with all the best intensions, whereas you prefer to work independently, and will only call your advisor when you are stuck. This situation could lead to the feeling of not working hard enough and not meeting expectations, which most likely is not the advisors intension.

Eventually these types of frustration will build up and slow down your work, so it is best to simply avoid it all together by discussing expectations clearly.

 

Albert Mehrabian’s 7-38-55 Rule of Personal Communication. Credit: www.rightattitudes.com

 

When a conflict arises, the most direct and understandable response is an emotional one; frustration, anger or quiet worry eating away at you. People often directly confront the person causing such an emotional response (which is very human!). However, as you probably know, this is not the smartest, nor the most professional way to deal with frustrations.

So, take a step back and calm down first, count to 10, briefly go to the gym, sleep on it, or go to a friendly colleague to shout out all your frustration; anything that works for you. Reflect on the situation, figure out what the main issue is, and then find a quiet moment during which you can discuss the problem in a calm and rational way. This will ensure your message is received and taken seriously.

In a direct conversation, the impact of your message is mainly determined by body language, while the contribution of the actual words is very little (only 7%). If your movements, space occupation, intonation and volume shout out your anger or your sadness, your conversation partner is likely to respond to the emotion, rather than the message, even if you manage to find the right words straight away.

To conclude: even when you have a different opinion than your advisor, when you are able to express your arguments carefully and clearly, it is much more likely that you’ll find a solution which works for both of you. Communication is key in becoming a better scientist, and will benefit you in any type of collaboration during your career!

By Elenora van Rijsingen
Written with help and revisions from Anne Pluymakers

 

Resources

2nd workshop of the Marie Skodowska-Curie ITN project CREEP: Discussion sessions between senior- and early career scientists focused on reducing stress levels in academia.

PhD management training by Marie-Laure Parmentier from Belpaeme Conseil, France. 

Minds over Methods: Linking microfossils to tectonics

Minds over Methods: Linking microfossils to tectonics

This edition of Minds over Methods article is written by Sarah Kachovich and discusses how tiny fossils can be used to address large scale tectonic questions. During her PhD at the University of Brisbane, Australia, she used radiolarian biostratigraphy to provide temporal constraints on the tectonic evolution of the Himalayan region – onshore and offshore on board IODP Expedition 362. Sarah explains why microfossils are so useful and how their assemblages can be used to understand the history of the Himalayas. And how are new technologies improving our understanding of microfossils, thus advancing them as a dating method?

 

                                                                          Linking microfossils to tectonics

Credit: Sarah Kachovich

Sarah Kachovich, Postdoctoral Researcher at the School of Earth and Environmental Sciences, The University of Queensland, Australia.

Radiolarians are single-celled marine organisms that have the ability to fix intricate, siliceous skeletons. This group of organism have captured the attention of artist and geologist alike due to their skeletal diversity and complexity that can be observed in rocks from the Cambrian to the present. As a virtue of their silica skeletons, small size and abundance, radiolarian skeletons can potentially exist in most fine-grained marine deposits as long as their preservation is good. This includes mudstones, hard shales, limestones and cherts. To recover radiolarians from a rock, acid digestion is commonly required. For cherts, 12-24 hours in 5 % hydrofluoric acid is needed to liberate radiolarians. Specimens are collected on a 63 µm sieve and prepared for transmitted light or scanning electron microscope analysis.

Animation of radiolarian diversity. Credit: Sarah Kachovich

Scale and diversity of modern radiolarians. Credit: Sarah Kachovich (radiolarians from IODP Expedition 362) and Adrianna Rajkumar (hair).

 

 

 

 

 

 

 

 

 

 

Improving the biostratigraphical potential of radiolarians

The radiolarian form has changed drastically through time and by figuratively “standing on the shoulders of giants”, we correlate forms from well-studied sections to determine an age of an unknown sample. A large effort of my PhD was aimed to progress, previously stagnant, research in radiolarian evolution and systematics in an effort to improve the biostratigraphical potential of spherical radiolarians, especially from the Early Palaeozoic. The end goal of this work is to improve the biostratigraphy method and its utility, thus increasing our understanding of the mountain building processes.

The main problem with older deposits is the typical states of preservation, where radiolarians partly or totally lose their transparency, which makes traditional illustration with simple transmitted light optics difficult. Micro-computed tomography (µ-CT) has been adopted in fields as diverse as the mineralogical, biological, biophysical and anatomical sciences. Although the implementation in palaeontology has been steady, µ-CT has not displaced more traditional imaging methods, despite its often superior performance.

Animation of an Ordovician radiolarian skeleton in 3D imaged through µ-CT. Credit: Sarah Kachovich

To study small complex radiolarian skeletons, you need to mount a single specimen and scan it at the highest resolution of the µ-CT. The µ-CT method is much like a CAT scan in a hospital, where X-rays are imaged at different orientations, then digitally stitched together to reconstruct a 3D model. The vital function of the internal structures provides new insights to early radiolarian morphologies and is a step towards creating a more robust biostratigraphy for radiolarians in the Early Paleozoic.

Linking radiolarian fossils to tectonics

Radiolarian chert is important to Himalayan geologists as it provides a robust tool to better document and interpret the age and consumption of oceanic lithosphere that once intervened India and Asia before their collision.The chert that directly overlies pillow basalt in the ophiolite sequence (remnant oceanic lithosphere) represents the minimum age constraint of its formation. In the Himalayas, over 2000 km of ocean has been consumed as India rifted from Western Australia and migrated north to collide with Asia. Only small slivers of ophiolite and overlying radiolarian cherts are preserved in the suture zone and it is our job to determine how these few ophiolite puzzle pieces fit together.

Another way I have been able to link microfossils to Himalayan tectonics is by studying the history and source of erosion from the Himalayas on board IODP Expedition 362. Sedimentation rates obtained from deep sea drilling can provide ages of various tectonic events related to the India-Asia collision. For example, we were able to date various events such as the collision of the Ninety East Ridge with the Sumatra subduction zone, which chocked off the sediment supply to the Nicobar basin around 2 Ma as the ridge collided with the subduction zone.

Left: Results from the McNeill et al. (2017) of the sedimentation history of Bengal Fan (green dots) and Nicobar Fan (red dots). Middle/right: Reconstruction of India and Asia for the past 9 million years showing the sediment source from the Himalayas to both basins on either side of the Ninety East Ridge.

 

 

 

 

 

 

 

 

 

 

 

 

Lastly, on board Expedition 362 we were able to use microfossils to understand how and why big earthquakes happen. We targeted the incoming sediments to the Sumatra subduction zone that were partly responsible for the globally 3rd largest recorded earthquake (Mw≈9.2). This earthquake occurred in 2004 and produced a tsunami that killed more than 250,000 people.

From the seismic profiles (see example below), we found that the seismic horizon where the pre-decollement formed coincided with a thick layer of biogenetically rich sediment (e.g. radiolarians, sponge spicules, etc.) found whilst drilling. Under the weight of the overlying Nicobar Fan sediments, this critical layer of biogenic silica is undergoing diagenesis and fresh water is being chemically released into the sediments. The fresh water within these sediments is moving into the subduction zone where it has implications to the physical properties of the sediment and the morphology of the forearc region.

The Sumatra subduction zone. The dark orange zone represents the rupture area of the 2004 earthquake. Also shown are the drill sites of IODP Expedition 362 and the location of seismic lines across the plate boundary.

Seismic profile: The fault that develops between the two tectonic plates (the plate boundary fault) forms at the red dotted line. Note the location of the drill site.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

Hüpers, A., Torres, M. E., Owari, S., McNeill, L. C., Dugan, & Expedition 362 Scientists, 2017. Release of mineral-bound water prior to subduction tied to shallow seismogenic slip. Science, 356: 841–844. doi:10.1126/science.aal3429

McNeill, L. C., Dugan, B., Backman, J., Pickering, K. T., & Expedition 362 Scientists 2017. Understanding Himalayan Erosion and the Significance of the Nicobar Fan. Earth and Planetary Science Letters, 475: 134–142. doi:10.1016/j.epsl.2017.07.019