GD
Geodynamics
Grace Shephard / Tobias Meier

Guest

Find out more about the blog team here.

Let’s talk about plagiarism

Let’s talk about plagiarism

Hey you! Do you have 5 minutes to talk about plagiarism?
Have you ever wondered if some parts of a thesis that you have supervised are simply a copy-paste from another thesis or article? This week, an anonymous guest author will tell us about their personal experience with plagiarism in science and what can be done against it.

Granted, it is not the most fascinating topic. Until recently, I really thought there was nothing to say about it. Everybody agrees that plagiarism is bad, and one shouldn’t do it, right? Plagiarism is just for a pair of lazy bachelor students or maybe one or two entitled old professors who believe they are untouchable, right? Right?! Oh boy, was I naive!

For me, it all started with reading a few words that do ring a bell on a master student thesis that I had co-supervised. After some more investigation, I realized that this student did indeed copy and paste sentences and even paragraphs from my PhD thesis, as well as from other articles. He did also plagiarize in former assignments and in a scientific article he published in a journal at the beginning of the year. Uh uh.  At this point, the student had already defended his thesis and just got his master degree validated. In the process, the thesis had been evaluated by two independent reviewers and also had been read by my two PhD advisors. Nobody suspected anything. And this happened at THE top Earth science research institution of a country which is renowned for the quality of its research. No problem, I think, I contact the co-supervisor and the director of studies. For sure they’ll know what to do. Hahaha. I spare you the details, but, to sum it up, the master degree had already been awarded, so there was no way whatsoever to change anything about it.

I didn’t make friends this past few weeks by insisting and playing the self-righteous scientist card. The student still got his master and will soon be enrolled in the PhD program of the same institution. However, my complaining seems to have had some effect. In the institution in question, they will buy the rights to a plagiarism scanner software and create a special commission to deal with plagiarism cases. From now on, master students will have to include a declaration of originality for their master theses, and they will have a course on research integrity. If the same situation arises, there will be official tools to deal with it, and hopefully the education the students will receive will help prevent plagiarism.

So yes, sometimes it’s worth it to be (a bit) annoying. Here are a few other things you might want to consider in order to avoid this kind of situation.

Plagiarism and “self-plagiarism” (also called text recycling) are not allowed by most journals, however, there is quite a large part of the scientific community that does not see the problem with self-plagiarism and does it regularly in articles. Some copy whole paragraphs from former articles of theirs and, sometimes, these articles pass the plagiarism scan that journals generally do. So it is really worth it to scan for plagiarism every paper you receive to review. That’s how I gave my fastest peer review ever: 5 minutes to scan the article, 5 min to realize that a whole section was a copy and paste from another article, and 5 min to write a rejection message.

Check every thesis, every draft and every paper you receive with a plagiarism software. You might have some surprises. If you do so, you’re making students/co-authors a favour. Had I done that check with my student prior to his thesis submission, he could have had the chance to make things right, avoided cheating on an exam, and got his master degree fair and square. Instead of this, he has to walk around with a master diploma he didn’t really earn. Not a good start in one’s professional life. Same with co-authors:  if you catch their plagiarism, you save all your team the embarrassment of getting your paper rejected by a journal because of this.

It might be a good idea to check the policy of your institution on plagiarism before you’re faced with the situation I described earlier. If there is nothing planned, urge people in charge to set up some procedure. You don’t want to be in the situation of catching a student after his master has been validated and not being able to do anything about it.

Finally, to people who practice text recycling: if you want to copy a sentence from another article because it is the best sentence to describe your thoughts… Why not putting quotes? If you don’t, you’re just being dishonest.

 

The past is the key

The past is the key

Lorenzo Colli

“The present is the key to the past” is a oft-used phrase in the context of understanding our planet’s complex evolution. But this perspective can also be flipped, reflected, and reframed. In this Geodynamics 101 post, Lorenzo Colli, Research Assistant Professor at the University of Houston, USA, showcases some of the recent advances in modelling mantle convection.  

 

Mantle convection is the fundamental process that drives a large part of the geologic activity at the Earth’s surface. Indeed, mantle convection can be framed as a dynamical theory that complements and expands the kinematic theory of plate tectonics: on the one hand it aims to describe and quantify the forces that cause tectonic processes; on the other, it provides an explanation for features – such as hotspot volcanism, chains of seamounts, large igneous provinces and anomalous non-isostatic topography – that aren’t accounted for by plate tectonics.

Mantle convection is both very simple and very complicated. In its essence, it is simply thermal convection: hot (and lighter) material goes up, cold (and denser) material goes down. We can describe thermal convection using classical equations of fluid dynamics, which are based on well-founded physical principles: the continuity equation enforces conservation of mass; the Navier-Stokes equation deals with conservation of momentum; and the heat equation embodies conservation of energy. Moreover, given the extremely large viscosity of the Earth’s mantle and the low rates of deformation, inertia and turbulence are utterly negligible and the Navier-Stokes equation can be simplified accordingly. One incredible consequence is that the flow field only depends on an instantaneous force balance, not on its past states, and it is thus time reversible. And when I say incredible, I really mean it: it looks like a magic trick. Check it out yourself.

With four parameters I can fit an elephant, and with five I can make him wiggle his trunk

This is as simple as it gets, in the sense that from here onward every additional aspect of mantle convection results in a more complex system: 3D variations in rheology and composition; phase transitions, melting and, more generally, the thermodynamics of mantle minerals; the feedbacks between deep Earth dynamics and surface processes. Each of these additional aspects results in a system that is harder and costlier to solve numerically, so much so that numerical models need to compromise, including some but excluding others, or giving up dimensionality, domain size or the ability to advance in time. More importantly, most of these aspects are so-called subgrid-scale processes: they deal with the macroscopic effect of some microscopic process that cannot be modelled at the same scale as the macroscopic flow and is too costly to model at the appropriate scale. Consequently, it needs to be parametrized. To make matters worse, some of these microscopic processes are not understood sufficiently well to begin with: the parametrizations are not formally derived from first-principle physics but are long-range extrapolations of semi-empirical laws. The end result is that it is possible to generate more complex – thus, in this regard, more Earth-like – models of mantle convection at the cost of an increase in tunable parameters. But what parameters give a truly better model? How can we test it?

Figure 1: The mantle convection model on the left runs in ten minutes on your laptop. It is not the Earth. The one on the right takes two days on a supercomputer. It is fancier, but it is still not the real Earth.

Meteorologists face similar issues with their models of atmospheric circulation. For example, processes related to turbulence, clouds and rainfall need to be parametrized. Early weather forecast models were… less than ideal. But meteorologists can compare every day their model predictions with what actually occurs, thus objectively and quantitatively assessing what works and what doesn’t. As a result, during the last 40 years weather predictions have improved steadily (Bauer et al., 2015). Current models are better at using available information (what is technically called data assimilation; more on this later) and have parametrizations that better represent the physics of the underlying processes.

If time travel is possible, where are the geophysicists from the future?

We could do the same, in theory. We can initialize a mantle convection model with some best estimate for the present-day state of the Earth’s mantle and let it run forward into the future, with the explicit aim of forecasting its future evolution. But mantle convection evolves over millions of years instead of days, thus making future predictions impractical. Another option would be to initialize a mantle convection model in the distant past and run it forward, thus making predictions-in-the-past. But in this case we really don’t know the state of the mantle in the past. And as mantle convection is a chaotic process, even a small error in the initial condition quickly grows into a completely different model trajectory (Bello et al., 2014). One can mitigate this chaotic divergence by using data assimilation and imposing surface velocities as reconstructed by a kinematic model of past plate motions (Bunge et al., 1998), which indeed tends to bring the modelled evolution closer to the true one (Colli et al., 2015). But it would take hundreds of millions of years of error-free plate motions to eliminate the influence of the unknown initial condition.

As I mentioned before, the flow field is time reversible, so one can try to start from the present-day state and integrate the governing equations backward in time. But while the flow field is time reversible, the temperature field is not. Heat diffusion is physically irreversible and mathematically unstable when solved back in time. Plainly said, the temperature field blows up. Heat diffusion needs to be turned off [1], thus keeping only heat advection. This approach, aptly called backward advection (Steinberger and O’Connell, 1997), is limited to only a few tens of millions of years in the past (Conrad and Gurnis, 2003; Moucha and Forte, 2011): the errors induced by neglecting heat diffusion add up and the recovered “initial condition”, when integrated forward in time (or should I say, back to the future), doesn’t land back at the desired present-day state, following instead a divergent trajectory.

Per aspera ad astra

As all the simple approaches turn out to be either unfeasible or unsatisfactory, we need to turn our attention to more sophisticated ones. One option is to be more clever about data assimilation, for example using a Kalman filter (Bocher et al., 2016; 2018). This methodology allow for the combining of the physics of the system, as embodied by the numerical model, with observational data, while at the same time taking into account their relative uncertainties. A different approach is given by posing a formal inverse problem aimed at finding the “optimal” initial condition that evolves into the known (best-estimate) present-day state of the mantle. This inverse problem can be solved using the adjoint method (Bunge et al., 2003; Liu and Gurnis, 2008), a rather elegant mathematical technique that exploits the physics of the system to compute the sensitivity of the final condition to variations in the initial condition. Both methodologies are computationally very expensive. Like, many millions of CPU-hours expensive. But they allow for explicit predictions of the past history of mantle flow (Spasojevic & Gurnis, 2012; Colli et al., 2018), which can then be compared with evidence of past flow states as preserved by the geologic record, for example in the form of regional- and continental-scale unconformities (Friedrich et al., 2018) and planation surfaces (Guillocheau et al., 2018). The past history of the Earth thus holds the key to significantly advance our understanding of mantle dynamics by allowing us to test and improve our models of mantle convection.

Figure 2: A schematic illustration of a reconstruction of past mantle flow obtained via the adjoint method. Symbols represent model states at discrete times. They are connected by lines representing model evolution over time. The procedure starts from a first guess of the state of the mantle in the distant past (orange circle). When evolved in time (red triangles) it will not reproduce the present-day state of the real Earth (purple cross). The adjoint method tells you in which direction the initial condition needs to be shifted in order to move the modeled present-day state closer to the real Earth. By iteratively correcting the first guess an optimized evolution (green stars) can be obtained, which matches the present-day state of the Earth.

1.Or even to be reversed in sign, to make the time-reversed heat equation unconditionally stable.

Geodynamics in Planetary Science

Geodynamics in Planetary Science

It is a question that humankind has been asking for thousands of years:

Are we alone in the Universe or are there other worlds like our own?

As of today, it is unknown whether or not inhabited planets exist outside of our own solar system. With the discovery of the extrasolar planet 51 Peg b in 1992, it was confirmed that our sun is not the only star that hosts planets and therefore the search for extraterrestrial life has expanded beyond our own solar system.
However, before we look for an inhabited exoplanet, we must understand what makes a planet habitable.
Of course, the best example of an inhabited (and hence habitable) planet is our Earth and therefore it is a reasonable approach to first look for Earth-like planets. So, the question we should ask is

What makes Earth habitable?

  • The planet should be in the so-called habitable zone: the zone where the planet contains liquid water on its surface. One usually calculates this zone assuming an Earth-like atmosphere.  [e.g. Lammer et al., 2009]
  • The planet also needs to have an atmosphere that protects it from radiation but also keeps the planet warm with greenhouse gases. [e.g. Seager, 2013]
  • The planet should be made of rock and should have a molten core. A convective outer core gives rise to a magnetic field that protects the planet from solar winds and cosmic rays. [e.g. Shahar et al., 2019]

Interestingly, we can couple all three points: greenhouse gases in the atmosphere can heat a planet that is too far away from its host star and therefore make it habitable. On the other hand, they can also heat a planet too much such that it becomes inhabitable.
The third point (a planet made of rock with a molten core) brings geodynamics into play: plate tectonics and volcanic outgassing contribute to burial and recycling of atmospheric gases [Seager, 2013].
In our solar system, Earth is the only inhabited planet, and it is also the only planet we know of that exhibits plate tectonics (including exoplanets).
For example, Venus, our neighbouring sister planet, is very similar to Earth in terms of size, mass and composition. Some studies even suggest that Venus might have been the first habitable planet of our solar system [Way et al., 2016].
But present-day Venus is an inhospitable planet with a very thick carbon dioxide atmosphere (90 times denser than that of Earth) and an extremely hot surface temperature (up to 750K) which is mainly because of runaway greenhouse gases. But why did Earth become habitable and Venus did not?
To explain their different evolutionary paths, plate tectonics might play a major role. Through plate tectonics, Earth can efficiently recycle carbon back into its surface (deep carbon cycle) and this may help to prevent a runaway Greenhouse effect.

The importance of plate tectonics on the habitability of a planet is still being studied, and it is not yet fully understood how efficient this recycling is.

Plate tectonics also influences the generation of a magnetic field. Plate tectonics efficiently cools the mantle by subducting cold slabs into the deep interior, which leads to high heat flow out of the core. Therefore, the style of mantle convection controls the convection in the outer core. This then generates the magnetic field of a planet. The magnetic field acts as a protective shield from the solar winds, which otherwise might erode the planet’s atmosphere. As discussed above, the atmosphere controls the climate mainly through greenhouse gases. The resulting climate influences the tectonic regime: cool climates are favourable for plate tectonics because they facilitate the formation of weak shear-zones in the lithosphere [Foley et al., 2016].
This coupling between the climate, mantle and the core is called the “whole planet coupling” [Foley et al., 2016] and as a whole, it might explain why Earth and Venus have evolved so differently.

Whole planet coupling“: The atmosphere controls the climate which influences the tectonic regime. Subducting slabs cool the mantle which leads to high heat flow out the core. Therefore, the mantle convection controls the type of convection in the outer core which can generate a magnetic field. The magnetic field protects the atmosphere from solar winds and cosmic rays.

To understand the habitability of exoplanets, we therefore need to investigate all the components of the whole planet coupling. Most interestingly for geodynamicists, it is the interior dynamics of a planet’s mantle that couples all these different components!

In the past years, astronomers have discovered many exoplanets, and we expect many more to join this list. For some of them, astronomers and astrophysicists can measure its size, mass, and sometimes even the atmospheric composition and/or surface temperature.
This is very different from studying the Earth, where we can gather a lot of information about the interior through, for example, seismology. Geophysicists, Astronomers, Astrophysicists and many other research disciplines have to collaborate such that they can understand an exoplanet’s whole planet coupling and potential habitability. For geodynamicists the challenge will be to infer the exoplanet’s interior dynamics from a limited amount of data only.

References:
Foley, B. J. and Driscoll, P. E.: Whole planet coupling between climate, mantle, and core: Implications for the evolution of rocky planets, Geochemistry, Geophysics, Geosystems, Vol. 17, 2016.
Lammer, H., et al.: What makes a planet habitable?, The Astronomy and Astrophysics Review, Vol. 17, 2009.
Seager, S.: Exoplanet Habitability. Science, Vol. 340, 2013.
Shahar, A., Driscoll, P., Weinberger, A. and Cody, G.: What makes a planet habitable?, Science, Vol. 364, 2019.
Way, M. J., et al.: Was Venus the first habitable world of our solar system?, Geophysical Research Letters, Vol. 43, 2016.

GD Guide to EGU19

GD Guide to EGU19

With this year’s EGU General Assembly (GA; #EGU19) looming in less than a week, it’s time for all attendees to finish (or start) their own scientific contributions, create their own personal programs as well as plan other activities during the conference. In this blog Nico Schliffke (GD ECS Rep) would like to share some useful advice how to successfully navigate through the conference and highlight relevant activities, both scientific and social, for Geodynamics Early Career Scientists (ECS).

The huge variety of scientific contributions (~18,000 at EGU18) might seem intimidating to begin with and makes it impossible for any individual to keep track of everything. To be well prepared for the conference, allow for a bit of time to create your own personal programme by logging in with your account details and search for relevant sessions, keywords, authors, friends or any other fields of interest. If you have found anything interesting, add it to your personal programme by ticking the ‘star’. After completing your personal programme you can print your own timetable or open it in the EGU 2019 app.

Besides all the (specific) scientific content of the GA, EGU19 offers a wide spread of exciting workshops and short courses to boost your personal and career skills, as well great debates, union wide events and division social events. Below you will find a list of highlight events, special ECS targeted events, social events and other things to keep in mind and to make the best of EGU19:

For first time attendees:

How to navigate the EGU: tips and tricks (Mon, 08:30 – 10:15, Room -2.16) – This workshop is led by several EGU ECS representatives and will give an overview of procedures during EGU as well as useful tips and tricks how to successfully navigate the GA.

GD workshops and short courses:

Geodynamics 101A: Numerical methods (Thur, 14:00-15:45, Room -2.62) Building on last year’s short course, we are happy to announce two short courses this year as a part of the ’Solid Earth 101’ series together with Seismology 101 and Geology 101. The first course deals with the basic concepts of numerical modelling, including discretisation of governing equations, building models, benchmarking (among others).

Geodynamics 101B: Large-scale dynamical processes (Fri, 14:00-15:45, Room -2.62)  The second short course will discuss the applications of geodynamical modelling. It will cover a state-of-art overview of main large-scale dynamics on Earth (mantle convection, continental breakup, subduction dynamics, crustal deformation..) but also discuss constraints coming from seismology (tomography) or the geological record.

Geology 101: The (hi)story of rocks (Tue, 14:00 – 15:45, Room -2.62)The complementary workshop in the 101 series: Find more about structural and petrological processes on Earth. It’s definitely worth knowing, otherwise why should we be doing many of these Geodynamical models?

Seismology 101 (Wed, 14:00 – 15:45, Room -2.62)The second complementary workshop in the 101 series. Many geodynamical models are based on observations using seismological methods. Find out more about earthquakes, beachballs and what semiologists are actually measuring – this is essential for any numerical or analogue geodynamical model!

GD related award ceremonies and lectures:

Arne Richter Award for Outstanding ECS Lecture by Mathew Domeier (Tue, 12:00-12:30 Room -2.21) – The Arne Richter award is an union-wide award for young scientists. We are happy to see that Mathew as a Geodynamicist has won the medal this year! Come along and listen to his current research.

Augustus Love Medal Lecture by Anne Davaille (Thur, 14:45-15:45, Room D1) – Listen to the exciting work of the first female winner of the Augustus Love Medal (the GD division award), Anne Davaille! She is specialised on experimental and analytical fluid dynamics which has given Geodynamics many new insights.

 Arthur Holmes Medal Lecture by Jean Braun  (Tue, 12:45-13:45, Room E1) – This one of the most prestigious EGU award for solid Earth geosciences. Jean is a geodynamicist from Potsdam and works on integrating surface and lithospheric dynamics into numerical models.

 

 

GD division social activities:

ECS GD informal lunch  (Mon, 12:30-14:00) – Come and meet the ECS team behind these GD activities! Meet in front of the conference center (look for “GD” stickers), to head to the food court in Kagran (2 subway stops away from the conference center, opposite direction to city centre).

ECS GD dinner (Wed, 19:30-22:00) – Join us for a friendly dinner at a traditional Viennese ‘Heurigen’ with fellow ECS Geodynamicists at Gigerl – Rauhensteingasse 3, Wien 1. Bezirk!  If you would like to attend the ECS GD dinner on Wednesday, please fill out this form to keep track on the number of people: https://docs.google.com/forms/d/e/1FAIpQLScpi8gvDDMOOOjLbtq4BrElsoBtTv86Mud7qNQ5yl7qWP5cUA/viewform  Remember to bring some cash to pay for your own food and drinks!

GD/TS/SM drinks (Wed, after ECS GD dinner) – Don’t worry if you cannot make for the ECS GD dinner! After dinner we’ll have a 5 min walk to Bermuda Bräu – Rabensteig 6, 1010 Wien for some drinks together with ECS from Seismology (SM) and Tectonics/Structural (TS), so you can meet us there too!  

GD Division meeting (Fri, 12:45-13:45 Room D2) – Elections and reports from the division president, ECS representative and other planning in GD related matters. Lunch provided!

Meet the division president of Geodynamics (Paul Tackley) and the ECS representative (Nico Schliffke) (Wed, 11:45-12:30, EGU Booth) – Come and discuss with the president and ECS rep about any GD related issues, suggestions or remarks.

Geodynamicists eating lunch at Kagran – it’s tradition by now.

EGU wide social activities:

Networking and ECS Zone (all week – red area)This area is dedicated to early career scientist all week and provides space to chillout, get your well deserved coffee or find out more about ECS related announcements.

Opening reception (Sun, 18:30 – 21:00, Foyer F) – Don’t miss out on many new faces and friends, as well as free food and drinks and the opening (ice-breaker) reception! There will also be a ECS corner to meet fellow young scientists, especially if it’s your first EGU.

EGU Award Ceremony (Wed, 17:30 – 20:00, Room E1) – All EGU medallists will receive their award at this ceremony.

ECS Forum (Wed, 12:45 – 13:45, Room L2)An open discussion on any ECS topic

ECS Networking and Careers Reception (by invitation only) (Tue, 19:00-20:30, Room F2)

Conveners’ reception (by invitation only) (Fri 19:30 – 0:00, Foyer F) 

Credit: Kai Boggild (distributed via imaggeo.egu.eu)

Great debates

Science in policymaking: Who is responsible?  (Mon, 10:45 – 12:30, Room E1) – Actively take part in one of the presently most important and hot topic!

How can Early Career Scientists prioritise their mental wellbeing? (Tue, 19:00 – 20:30, Room E1) – Many ECS find it challenging to prioritise their mental wellbeing. Discuss with many other young scientist how to tackle this really important issue and maybe learn helpful tips how to improve your own wellbeing! 

Other useful skills to polish your career/CV:

Help! I’m presenting at a scientific conference (Mon, 14:00 –15:45, Room -2.62) – Your first conference talk might be daunting. Find out best practices and tips how to create a concise and clear conference talk.

How to share your research with citizens and why it’s so important (Mon, 14:00-15:45, Room -2.16) – Do you share your research with the public? Can you explain in simple matters? An important topic for researchers currently!

How to make the most of your PhD or postdoc experience for getting your next job in academia (Tue, 16:15 – 18:00, Room -2.85) – It’s never too early to plan your next career step.

How to convene and chair a session at the General Assembly (Tue, 08:30-10:15, Room -2.85) – Find out what it needs to convene a session of short course at EGU. You may be surprised, but you could to it next year if you liked,

How to peer-review? (Mon, 16:15 -18:00, Room -2.85) – After the end of a PhD (or sometimes even earlier!) you may be asked to peer-review journal contributions, but hardly anyone knows the process beforehand.

How to find funding and write a research grant (Tue, 10:45-12:30, Room -2.16) – One of the major tasks when you finish your PhDs. It might even be useful when writing applications for travel support etc.

Funding opportunities: ERC grants (Tue, 12:45-13:45, Room 0.14) – Find out more about these generous grants and how to successfully apply for them

How to apply for the Marie Sklodowska-Curie grants (Wed, 12:45-13:45, Room 0.14)

Balancing work and personal life as a scientist (Wed, 16:15 – 18:00, Room -2.85) – Find out how not to lose sight of your hobbies and personal life in a increasingly competitive academic environment. 

Other interesting events:

Academia is not the only route (Thu, 10:45-12:30, Room -2.16) – Are you finishing your degree and not overly excited by an academic future? Try this short course on exploring career alternatives both inside and outside academia

Games for Geoscience (Wed, 16:15-18:00 (Talks) in Room L8 and 14:00-15:45 (Posters), Hall X4) – Games are more fun than work! Learn more on how to use games for communication, outreach and much more. 

Unconscious bias (Wed, 12:45-13:45, Room -2.32) – Become aware of the obstacles that some of your colleagues face every day, and that might prevent them from doing the best science

Promoting and supporting equality of opportunities in geosciences (Thu, 14:00-18:00, Room E1) – Any of us should promote an open, equal opportunity working environment and this session promises some very interesting talk on common issues, solutions and initiatives.

What I’ve learned from teaching geosciences in prisons – (Thu, 14:00-15:45, Hall X4 – Poster) by GD ECS Phil Heron.

Rhyme Your Research (Tue, 14:00 – 15:45, Room -2.16) – Reveal the poet in you and explain your research in an interesting and unusual way!

This is just a small list of possible activities during EGU19, and I’m sure to have missed out many more. So keep your eyes and ears open for additional events and spread the word if you know anything of particular interest. Also make sure you follow the GD Blog, our social media (EGU GD Facebook page) and EGU Twitter, to keep updated with any more information during the week! The official hashtag is #EGU19. All the best for EGU and I am looking forward to meeting many of you there!