Tectonics and Structural Geology

Tectonics and Structural Geology

Solid Earth journal: the possibilities of open access publishing

Solid Earth journal: the possibilities of open access publishing

Fabrizio Storti

The third blog for TS is an invited guest blog by Fabrizio Storti, the chief executive editor of the EGU journal Solid Earth. Solid Earth publishes open access manuscripts on the composition, structure, and dynamics of the Earth from the surface to the deep interior. It is the journal for our community and we encourage everyone to see if they can contribute a manuscript and/or participate in the open review process. This blog is also posted by other divisions working on solid earth themes.


Open access publishing in Solid Earth


The importance of publishing open access is increasing every year in Scientific Institutions worldwide and is becoming mandatory in several research funding
programmes. Many funding institutions, including ERC, are financially supporting publishing in open access journals. EGU and Copernicus launched open access publishing in 2001, well before other publishers, and this means that we have accumulated a lot of experience with making articles available open access. But not only our journals are open access, we also have a fully open, interactive review system.

Without entering into details, which are available in the EGU portal (http://www.egu.eu/publications/open-access-journals/), the major diagnostic features are the following:

–       As soon as a manuscript is submitted, it undergoes a preliminary assessment by the relevant Executive Editor and, if found suitable for possible publication, a Topical Editor is assigned to immediately start the review process. At this stage the manuscript receives a DOI and can be cited as published in the Discussion version of the journal (the non-peer review journal).

–       The review process is open, so reviewers upload their reports in the public domain, as well as authors do with their rebuttal letters. Everybody can download manuscripts under review and upload comments, which will help authors improve their manuscripts.

Solid Earth (SE: http://www.solid-earth.net/) is the EGU open access journal in the broad area of Earth system sciences: http://www.solid-earth.net/about/aims_and_scope.html. The journal is organized into six topical clusters (http://www.solid-earth.net/), each one handled by an Executive Editor. Different types of manuscripts can be submitted: http://www.solid-earth.net/about/manuscript_types.html, including special issues, pending approval of proposals by Executive Editors.

EGU is a bottom-up union that relies on the fundamental contributions by members to organize events, first of all the Annual General Assembly.

The same approach has allowed several EGU journals to become leaders in their fields. Solid Earth is still young and, as such, it has a great potential of growing up to get established as one of the best journals in Earth system sciences. With your contribution, the journal impact factor, higher than 2.0, can significantly increase and start a virtuous loop to attract more and more good papers.

Please take few minutes of your time to browse the journal homepage (http://www.solid-earth.net/), sign in to get alerts and enjoy published papers, and think about submitting a manuscript. We are all volunteers in EGU and by supporting the self-managed, non-profit Solid Earth journal, all together we can make it one of the reference journals in Earth system sciences.

Looking forward to handle your manuscripts!

Best regards,

SE Editorial Team.

Minds over Methods: Numerical modelling

Minds over Methods: Numerical modelling

Minds over Methods is the second category of our T&S blog and is created to give you some more insights in the various research methods used in tectonics and structural geology. As a numerical modeller you might wonder sometimes how analogue modellers scale their models to nature, or maybe you would like to know more about how people use the Earth’s magnetic field to study tectonic processes. For each blog we invite an early career scientist to share the advantages and challenges of their method with us. In this way we are able to learn about methods we are not familiar with, which topics you can study using these various methods and maybe even get inspired to use a multi-disciplinary approach! This first edition of Minds over Methods deals with Numerical Modelling and is written by Anouk Beniest, PhD-student at IFP Energies Nouvelles (Paris).


Approaching the non-measurable

Anouk Beniest, PhD-student at IFP Energies Nouvelles, Paris

‘So, what is it that you’re investigating?’ It’s a question every scientist receives from time to time. In geosciences, the art of answering this question is to explain the rather abstract projects in normal words to the interested layman. Try this for example: “A long time ago, the South American and African Plate were stuck together, forming a massive continent, called Pangea, for many millions of years. Due to all sorts of forces, the two plates started to break apart and became separated. During this separation hot material from deep down in the earth rose to the surface increasing the temperature of the margins of the two continents. How exactly did this temperature change over time, since the separation until present-day? How did this change affect the basins along continental margins?”

These are legitimate questions and not easy to answer, since we cannot measure temperature at great depth or back in time. In this first post on numerical methods, we will be balancing between geology and geophysics, highlighting the possibilities and limits of numerical modelling.

The migration of ‘temperature’ through the lithosphere is a process that takes time and depends heavily on the scale you look at. Surface processes that affect the surface temperature can be measured and monitored, yielding interesting results on the present-day state and variations of the temperature. The influence of mantle convection cycles and radiogenic heat production are already more difficult to identify, take much more time to evolve and might not even affect the surface processes that much. Going back in time to identify a past thermal state of the earth seems almost impossible. This is where numerical models can be of use, to improve, for example, our understanding on the long-term behaviour of ‘temperature’.

Temperature is a parameter that affects and is affected by a variety of processes. When enough physical principles are combined in a numerical model, we can simulate how the temperature has evolved over time. All kinds of different parameters need to be identified and, most importantly, they need to make sense and apply to the observation or process you try to reproduce. Some of these parameters can be identified in the lab, like the density or conductivity of different rock types. Others need to be extracted from physical or geological observations or even estimated.

Once the parameters have been set, the model will calculate the thermal evolution. It is not an easy task to decide if a simulation approaches the ‘real’ history and if we can answer the questions posed above. We should always realise that thermal model results at best approach the real world. We can learn about the different ways temperature changes over time, but we should always be on the hunt to find measurements and observations that confirm what we have learned from the simulations.



Features from the field: Slickenside Lineations

Features from the field: Slickenside Lineations

In this Tectonics and Structural Geology blog we will use different categories for our blog-posts. The first category we present to you is all about field geology: “Features from the field”. One of our bloggers, Mehmet Köküm, spends a lot of time in the field for his PhD and will share some of the features used in structural geology with us. This edition of ‘Features of the Field’ will be all about Slickenside lineations!

Paleostress Studies Reveals Deformation Mechanism 

It is assumed that faults are formed as pure strike slip or dip-slip faults. However, we widely come across oblique faults. If they are formed as pure strike-slip or dip-slip faults, then something should have affected its behavior. This can be done by many things, such as a change in tectonic regime or a block rotation. Many areas in the world have experienced several different tectonic regimes in the past. Faults should have been affected by these tectonic regime changes. A normal fault could have worked as a reverse fault in the past or vice versa. In other words, if we may figure out a faults’ past behavior, we could figure out the evolution of tectonic regimes in the related area.

Within this blog I will explain how structural geologists determine the behavior of a fault in the past and present. The principle purpose of my PhD project is to determine the deformation mechanism and the relation between past and present behavior of the East Anatolian Fault (EAF) by using paleostress analysis. The EAFZ is one of the most active intracontinental transform faults in Turkey.

During a field trip as part of my PhD project, one of the goals was to find slickenside lineation on a slip surface along the East Anatolian Fault in Turkey. Slicken-lines are series of parallel lines on a fault plane and represent the direction of relative displacement between the two blocks separated by the fault. Hence, direction and sense of slip can be obtained from slickenside lineation on a fault plane. Knowing this for numerous faults helps us to understand previous and present behavior of faults.

The aim of using slickenside lineation is to calculate the paleostress tensor. Paleostress tensors provide a dynamic interpretation (in terms of stress orientation) to the kinematic (movement) analysis of brittle features. Paleostress tensor analysis enables identification of the stress history of a studied area.

There are two principal types of slicken-lines: those that form by mechanical abrasion (striations) and those formed by mineral fibrous growth (mineral fiber lineations). The former can occur either in relief or groove on a fault surface. It can be a small quartz grain or larger grain causing striations on a fault surface. The latter developed due to crystal growth fibres or other grains being crystallized during fault slip. Most are made of calcite, quartz, gypsum etc. These two types of lineations are reliable criteria for calculating the paleostress tensor and common in low-grade metamorphic rocks and sedimentary rocks.

In this work, the key issue is to find and collect as much fault slip data sets as possible. In that sense, it is important to know what kind of rocks may include slicken-lines. Striations or slicken-lines are particularly found on limestone, sandstone and claystone. Moreover, mineral fiber lineations are seen most in limestone. Therefore, limestone should be investigated in more detail to collect fault slip data.

Paleostress studies require great care, effort, and attention in the field, but its outcomes for the behavior of the faults are important, since they reveal the tectonic evolution of the area. For this reason, many structural geologist touch on palestress studies in their work in order to relate observed structures to the causative tectonic forces.

New blog!

New blog!

We are very happy to announce that from now on, also the Tectonics and Structural Geology division will have its own EGU blog! With this blog we would like to provide a platform for exchanging thoughts and ideas within the global tectonics and structural geology community.

Here, we will write, on a monthly or fortnightly basis, about topics or techniques addressed by the many research groups that are working in fields like rheology, rock mechanics, geophysics, metamorphism, sedimentology, tectonics and neotectonics. With this we would like to provide a better link between the various different approaches and provide a more powerful understanding of deformation processes and systems. We will also share news, events, activities and job opportunities useful for the TS community.

Enjoy reading our blog posts here, and feel free to contact us any time if you want to join the team or contribute with a guest blog!

Best wishes,

The Tectonics and Structural Geology Team