GeoLog

Laura Roberts-Artal

Laura Roberts Artal is the Communications Officer at the European Geosciences Union. She is responsible for the management of the Union's social media presence and the EGU blogs, where she writes regularly for the EGU's official blog, GeoLog. She is also the point of contact for early career scientists (ECS) at the EGU Office. Laura has a PhD in palaeomagnetism from the University of Liverpool. Laura tweets at @LauRob85.

The known unknowns – the outstanding 49 questions in Earth sciences (Part III)

We continue exploring the biggest conundrums in Earth sciences in this third post of the known unknowns. In the two previous instalments of the series we’ve discovered what the major questions still to be answered about the early days of planet Earth and its inner workings are. We now move onto the planet’s surface. The advent of plate tectonic theory, arguably one of the biggest advancements in the geosciences of the past century, has allowed us to far better understand how continents are built and the hazards associated with moving plates. Nevertheless, there is still much we do not comprehend, opening the door for hugely exciting and innovative research opportunities.

Tectonic-plate motion and deformation

A cross section illustrating the main types of plate boundaries  (Image Source; WikimediaCommons; Author: Jose F. Vigil. USGS, http://pubs.usgs.gov/gip/earthq1/plate.html)

A cross section illustrating the main types of plate boundaries (Image Source: WikimediaCommons; Author: Jose F. Vigil. USGS, http://pubs.usgs.gov/gip/earthq1/plate.html)

  1. What is the relative importance of the forces driving plate tectonics: slab pull, slab suction, mantle drag, and ridge push? (e.g., Conrad & Lithgow-Bertelloni,JGR, 2004; Negredo et al., GRL, 2004, vs. van Benthem & Govers, JGR, 2010). What is the force balance and the geochemical cycle in subduction zones? (Emry et al., JGR, 2014) How much water (and how deep) penetrates into the mantle? (Ranero et al., Nature 2003) How much subcontinental erosion takes place under subduction areas? (Ranero et al.,Nature, 2000)
  2. What happens after the collision of two continents? Does continental collision diminish the rate of plate subduction, as suggested by the slab-pull paradigm? (Alvarez, EPSL, 2010)  How frequent are the processes of mantle delamination and slab break-off? What determines their occurrence? (Magni et al., GRL, 2013; Durezt & Gerya, Tectonoph., 2013)
  3. Why are orogens curved when seen from space? (Weil & Sussman, 2004, GSASP 383)
  4. How well do different approaches to establish plate motion compare? How does the long-term deformation derived from paleomagnetism and structural geology link quantitatively to the present-day motions derived from GPS and from neotectonic patterns of crustal deformation? (Calais et al., EPSL, 2003) How do these last two relate to each other? (Wang et al., Nature, 2012) Can we learn from regional structure of the crust/lithosphere from that link (or viceversa)?
  5. Are plate interiors moving in steady-state linear motion? How rigid are these and why/when did they deform? (Davis et al., Nature, 2005, and Wernicke & Davis, Seismological Research Letters, 2010).
  6. How is relative motion between continents accommodated in diffuse plate boundaries? (eg., the Iberian/African plate boundary). What determines the (a)seismicity of a plate contact?
  7. How/when does deformation propagate from the plate boundaries into plate interiors? (e.g., Cloetingh et al.,QSR, 2005)
  8. What is the rheological stratification of the lithosphere: like a jelly sandwich? Or rather like a creme brulée? (Burov & Watts, GSA Today, 2006). Is the lower crust ductile? Is strength concentrated at the uppermost mantle? Or just the other way around? (e.g., McKenzie et al., 2000, JGR; Jackson, GSA Today, Handy & Brun, EPSL, 2004; and a nice blog post).
  9. Does the climate-controlled erosion and surface transport of sediment modify the patterns of tectonic deformation? Does vigorous erosion cause localized deformation in the core of mountain belts and prevent the propagation of tectonic shortening into the undeformed forelands? Does the deposition of sediment on the flank of mountains stop the frontal advance of the orogen? Is there field evidence for these effects predicted from computer models? (Philip Allen’s blog) (Willett, JGR,1999,Whipple, Nature, 2009Garcia-Castellanos, EPSL, 2007)

    Earthquake damage to the Alexandia Square building in Napa, California (Image Source: Wikimedia Commons, Author: Jim Heaphy; User: Cullen328).

    Earthquake damage to the Alexandia Square building in Napa, California (Image Source: Wikimedia Commons, Author: Jim Heaphy; User: Cullen328).

  10. Can earthquakes be predicted? (Heki, 2011, GRLFreed, 2012, Nat.Geosc.). How far away can they be mechanically triggered? (Tibi et al., Nature, 2003). Little is known about how faults form and when do they reactivate, and even worse, there seems to be no clear pathway as to solve this problem in the near future. Unexpected breakthroughs needed.
  11. How can the prediction of volcanic eruptions be improved? What determines the rates of magma accumulation in the chamber and what mechanisms make magmas eruptible? See for example this article on the Yellowstone Caldera  and this paper regarding volcanic uplift.
  12. How much of the Earth’s surface topography is dynamically sustained by the flow in the mantle? In many regions, the elevation of the continents does not match the predictions from the classical principle of isostasy for the Earth’s outer rigid layer (the lithosphere). This deviation is known as dynamic topography, by opposition to isostatic topography. But what are the mechanisms responsible? Can we learn about the mantle dynamics by estimating dynamic topography? (Braun, Nature Geoscience, 2010). Can the hidden loads needed to explain the accumulation of sediment next to orogens (foreland basins) be linked to these dynamic forces? (Busby & Azor, 2012).
  13. How do land-forming processes react to climate change at a variety of scales, ranging from the Milankovitch cycles to the late Cenozoic cooling of the Earth? Is there a feedback from erosion into climate at these time scales, through the Carbon cycle and the weathering of silicates, for example? What is the role of the surface uplift and erosion of Tibet on the drawdown of atmospheric CO2 over the Cenozoic? (Garzione, Geology, 2008)

 

Have you been enjoying the series so far? Let us know what you think in the comments section below, particularly if you think we’ve missed any fundamental questions!

In the second to last post in the series we will outline the top outstanding research questions with regards to the Earth’s surface: Earth’s landscape history and present environment.

By Laura Roberts Artal, EGU Communications Officer, based on the article previously posted on RetosTerricolas by Daniel Garcia-Castellanos, researcher at ICTJACSIC, Barcelona

Imaggeo on Mondays: Marble outcrops

This week’s Imaggeo on Mondays image was taken by Prof. Konstantinos Kourtidis, in Alykes, along the southern coast of Thassos island, where he photographed the beautifully white marbles that outcrop along the coastline. The Greek Island of Thassos is located in northeastern Greece, close to the coast of Thrace in the Aegean Sea, although geographically it belongs to the Macedonia region. There is geological evidence to suggest that at one time, the island was joined to the mainland.

Marble Outcrops. (Credit: Konstantinos Kourtidis via imaggeo.egu.eu)

Marble Outcrops. (Credit: Konstantinos Kourtidis via imaggeo.egu.eu)

“The island is formed of alternating marbles, gneisses and schists” explains Konstantinos, “in the southern Thassos area, where this image was taken, Palaeozoic (around 400 million years in age) and Mesozoic metamorphosed rocks of the Rhodopi Massif and more recent sedimentary Miocene formations (around 25 million years old) are exposed.” The sediments in this area are dominated by conglomerates, sandstones and argillaceous sands.

Banded iron formations, also known as BIFs, are repeated thin layers of iron-rich material which are alternated with shales and/or silica rich cherts. There are numerous occurrences of BIFs across Thassos island and this is interesting because BIFs are typical sediments of the Precambrian rock record and can indicate the presence of rocks which are in excess of 3 billion years old! It is unusual to find BIFs in the younger rocks record. On Thassos Island their formation is associated with changes in the depositional environment and climate.

During the formation of BIFs, volcano-sedimentary units become heavily mineralised and rich in iron and manganese oxides. In addition the island has dense accumulations of zinc and lead. As a result there is a long mining history on Thassos, dating back to 13,000 BC. The marbles seen in today’s Imaggeo on Mondays image belong to an ancient mine at sea level which was “exploited given the excellent quality of the marbles” states Konstantinos. The stone has been used in art projects, monuments and the building of numerous ancient temples.

Ancient Marble Quarry in Thassos, Eastern Macedonia, Greece. (Credit: Konstantinos Kourtidis via imaggeo.egu.eu)

Ancient marble quarry in Thassos, Eastern Macedonia, Greece. (Credit: Ioannis Daglis via imaggeo.egu.eu)

Given the islands rich archeological and geological heritage the Greek Institute of Geology and Mineral Exploration (IGME) has produced a geological guide for the southern part of the island, which also includes 4 geotrails and is available online.

GeoEd: Under review

In this month’s GeoEd column, Sam Illingworth tells us about how teaching undergraduate students about peer review can help eliminate bad practice.

To anybody other than a researcher, the words peer review might seem like a fancy new age management technique, but to scientists it is either the last bastion of defence against the dark arts or an unnecessary evil that purports to ruin our greatest and most significant works.

According to Wikipedia (itself a fine proponent), peer review is defined as “the evaluation of work by one or more people of similar competence to the producers of the work (peers). It constitutes a form of self-regulation by qualified members of a profession within the relevant field.”

Peer review itself is not a new concept; the first documented description of a peer-review process, being found in the ‘Ethics of the Physician’ by Ishap bin Ali Al Rahwi (854–931), states that the notes of physicians were examined by their contemporaries to assess if treatment had been performed according to the expected standards (you can read more on the history of the peer-review process in this article).

Even the great Carl Sagan found the critique of his work difficult to stomach (Photo credit: NASA JPL, via Wikimedia Commons).

Even the great Carl Sagan found the critique of his work difficult to stomach (Photo credit: NASA JPL, via Wikimedia Commons).

“Why do we put up with it? Do we like to be criticized? No, no scientist enjoys it.” So sayeth American cosmologist and author Carl Sagan about the ‘joys’ of peer review, in his book ‘The Demon-Haunted World: Science as a Candle in the Dark.’ He goes on to say that “Every scientist feels a proprietary affection for his or her ideas and findings. Even so… the hard but just rule is that if the ideas don’t work, you must throw them away.”

Just reading these words brings me out in the kind of cold sweat that I normally associate with seeing the bill from mechanic, after having your car serviced. You know that you are going to have to bite the bullet, but in your heart of hearts you just wish that it weren’t so.

Love it or loathe it the peer-review system is an integral part of being a researcher, and given its prevalence it is strange that for many scientists the whole notion of it is a completely alien concept until they first encounter the publication process during their postgraduate studies.

During the first year of my PhD I remember being aghast at the notion that two, or possibly three, strangers would be wholly responsible for deciding whether or not my research was deemed ‘suitable’ for publication, and despite my otherwise excellent undergraduate education I had nothing to prepare me for the whole ordeal. Thankfully I had a very experienced supervisor who was able to guide me through the whole process and teach me a few tricks of the trade (always respond politely, compliment the reviewer for their suggestions, avoid the urge to break down into tears and instead break the comments down into manageable chunks), but even now I still feel a sense of dread when an email notification appears in my inbox telling me that “the reviewer’s comments have been posted.”

Is this how reviewers are perceived? (Photo credit: deviantArt)

Is this how reviewers are perceived? (Photo credit: deviantArt)

By nature I am quite a defensive person, and have been known to take criticism (fair or otherwise) rather to heart, but my experiences of the peer review system have certainly helped me take a more level–headed and professional approach to the critique of my work. Crucially it has also helped me to become a better reviewer myself.

Constructive criticism is essential in order to help one develop as a researcher, and indeed as an individual, but some of the peer reviews that I have seen (and sadly been subjected to) are nothing more than mean-spirited attempts by the reviewer to assert their own supposed authority on a subject. This kind of analysis is beneficial to absolutely no one, and it should be the responsibility of the editors and administrative staff of the journals and e-zines to help eradicate it. There is always something positive to be said about any piece of research (unless it is utterly nonsensical, in which case again the editor should have stopped it from ever being submitted to a reviewer), and being totally negative in your comments will only serve as fuel for a vicious cycle in which young researchers believe that the purpose of peer review is to find fault in the work of others. Instead, good peer review should be a helpful critique of a fellow colleagues work, which politely points out any shortcomings, makes suggestions for improvements, and praises what is good.

I will now be teaching my own university students about the peer-review system, and will be asking them to mark one another’s work throughout the unit that I teach on Science Communication at Manchester Metropolitan University. I think that most undergraduate courses would benefit from a similar approach, not only to prepare future scientists, but also to help students learn how to respond to criticism and how to critique the work of others in a productive and conducive manner. By educating and encouraging young scientists in this way we can hope to potentially avoid these kinds of reactions in the future.

Teaching about peer review at university can help to eliminate bad practice (Photo credit: Gideon Burton).

Teaching about peer review at university can help to eliminate bad practice (Photo credit: Gideon Burton).

For those of you who are currently reviewing a paper, I set you the challenge of explicitly writing at least one compliment to the author. This could be in regards to the excellence or originality of their research, the structure or fluidity of the article, or indeed the clarity with which they express their ideas. To those of you who are not reviewing a paper, try and find at least one positive thing to say (the colour really brings out your eyes, it’s certainly an affordable mode of transport, these scones are delicious!) the next time that your opinion is required; I guarantee that it will leave everyone feeling just a little bit more capable of themselves and what they can achieve.

 By Sam Illingworth, Lecturer, Manchester Metropolitan University

Apply now to take part in the 2015 GIFT workshop!

The General Assembly is not only for researchers but for teachers and educators with an interest in the geosciences also. Every year the Geosciences Information For Teachers (GIFT) is organised by the EGU Committee on Education to bring first class science closer to primary and high school teachers. The topic of the 2015 edition of GIFT is mineral resources and will be taking place on April 13–15 at the EGU General Assembly in Vienna, Austria.

The workshop will explore one of the most important challenges faced by modern society: access to raw materials, including base and strategic minerals, in a rapidly developing and growing world.

Mineral resources, the theme for this years GIFT workshop at the General Assembly

Mineral resources, the theme for this year’s GIFT workshop at the General Assembly

Teachers from Europe and around the world can apply to participate in the 2015 edition of GIFT, and to receive a travel and accommodation stipend to attend the workshop, by November 28. Application information is available for download in PDF format, a document which also includes the preliminary programme of the workshop.

Not sure what to expect? More information about GIFT workshops can be found in the GIFT section of the EGU website. You can also take a look at the post about the 2014 workshop at the GA and at some videos of the workshop videos from 2013.