TS
Tectonics and Structural Geology

Tectonics and Structural Geology

Folding and Fracturing of Rocks – 50 years of research since the seminal textbook of JG. Ramsay

Folding and Fracturing of Rocks – 50 years of research since the seminal textbook of JG. Ramsay

John G. Ramsay1 wrote his seminal textbook on the folding and fracturing of rocks in 1957, almost 20 years before I was born (and I don’t count myself as young!). So why did I co-convene a session at EGU in 2017 to celebrate the book? Because the book, in many ways, expresses the legacy that John has given to structural geology. He followed it with a series of books of the same ilk – Ramsay and Huber ‘The Techniques of Modern Structural Geology’, published in two volumes (1984 and 1987), was a main stay for me as an undergraduate and postgraduate and well actually now; although, it is often not to be found on my bookshelf, but on the desk of one of my graduate students. The Techniques of Modern Structural Geology, like the Folding and Fracturing of Rocks, is beautifully illustrated and describes geometrically and mathematically many of the now commonly used techniques in structural geology. So to me Ramsay, although I did not know him personally, was the name behind this interesting subject structural geology.

John Ramsay opening the session on his book “Folding and Fracturing of Rocks”

It was as a postgraduate student that I met John at a Tectonic Studies Group (TSG) meeting and had the pleasure of dancing with him after the conference dinner! Many years on I am now the Chair of TSG, one of several specialist groups affiliated to the Geological Society of London. John was instrumental in founding TSG in 1970 @TSG_since1970 , when he was working at Imperial College London. As the Chair of TSG I was approached by several people enquiring about plans to celebrate 50 years since the publication of the Folding and Fracturing of Rocks. Given John’s European career and global impact EGU seemed the place to celebrate and I contacted some of John’s PhD students and collaborators to join me in convening a session to celebrate the book, John and structural geology.

Early on the morning of April 25th John gave the opening paper for the session to a large audience. He spoke not to a series of power point slides but to the audience about the book, his interests and his life as a structural geologist. I think one of the key messages for me is the one that he ended his paper with; that fieldwork is fundamental to structural geology and models need to be derived from and tested against field observations. John was followed by a series of speakers from Rod Graham, of Ramsay and Graham (1970)2 on shear zones from the field to seismic interpretation, to Richard Lisle (co-author with John on the third volume in the Techniques of Modern Structural Geology series)3. Richard gave an overview of the citations for the Folding and Fracturing of Rocks; it is the most cited structural geology textbook. Further papers were given in the afternoon poster session, celebrating and giving modern, and old, twists on aspects of the book.

Afterwards at the reception

John joined many well-wishers at a reception and dinner after the session. John has given a legacy to structural geology, through his focus on the geometry and mathematics of structures backed up with detailed field observations, work that very much forms part of modern structural geology today.

The Folding and Fracturing of Rocks is currently published by Blackburn press.

 

Click here to go to the webpage of EGU Session TS1.3.

 

 

Blog by Clare Bond,

University of Aberdeen

Thanks to TecTask and TSG for sponsorship

 

1.John was born in 1931 in London, he was educated at Imperial College, London gaining a first class degree in 1952 and a PhD, working on superposed folds at Loch Monar Scotland. After military service he returned to the staff at Imperial, before taking up Professorial positions at the University of Leeds and the ETH in Zurich. He has been recognized for his work in advancing structural geology with many awards: Bigsby (1973) and Wollaston (1986) medals of the Geological Society of London, the Société Géologique de France Prestwich Medal in 1989, Sir Arthur Holmes Medal of the European Union of Geosciences (EGU) in 1984, C. T. Clough medal (1962) of the Geological Society of Scotland, the University of Liège medal in 1988. In 1992 he was named a Commander of the Most Excellent Order of the British Empire in the Queen’s Honours list. He is a Fellow of the Royal Society(elected 1973), and holds Honorary Fellowships of the Geological Society of America, the Société Géologique de France, the Indian National Science Academy, the American Geophysical Union, the US National Academy of Sciences and the Geological Society of London.

2.Ramsay, J.G. and Graham, R.H., 1970. Strain variation in shear belts. Canadian Journal of Earth Sciences7(3), pp.786-813.

3.Ramsay, J.G. and Lisle, R.J., 2000. The techniques of modern structural geology. Volume 3: Applications of continuum mechanics in structural geology. Academic, San Diego, Calif.

 

You’re an early career scientist and you want to go somewhere… but where?

You’re an early career scientist and you want to go somewhere… but where?

Only a few more days and the General Assembly of the EGU 2017 will start! Five exciting days with science and the opportunity to meet your colleagues and collaborators, both the old and the new. Earlier this week the outgoing TS President Susanne Buiter and the incoming TS President Claudio Rosenberg posted a blog with TS highlights, but what are the must-see for the Early Career Scientists? This is where we, outgoing TS ECS reps, come in! So we provide here tips for the hottest TS ECS events the coming week.

 

Meetings/socials:

Don’t forget to come for dinner with the other TS ECS at Brandauers Bierbogen (Heiligenstädter Str. 31) on Monday, at 20h.

We welcome everyone to the ECS corner at the icebreaker on Sunday. Pick up your badge, meet old and new friends at Foyer E, from 18h30 to 21h.

http://meetingorganizer.copernicus.org/EGU2017/session/25204

The TS Division Meeting is on Wednesday, 12h15-13h15. Lunch will be provided. What happened within the TS Division last year? What are the plans for next year?

http://meetingorganizer.copernicus.org/EGU2017/session/25276

Come give feedback! Your new TS ECS representative Anouk Beniest organizes an informal get-together over lunch on Thursday. We meet at 12h15 at the EGU flags just outside the building, we’ll get a sandwich and find a nice spot to sit and chat on how to improve things for TS ECS. All are welcome!

Meet your reps! The EGU Division President Claudio Rosenberg and the outgoing ECS Representatives Anne Pluymakers and João Duarte plus the incoming ECS Representative Anouk Beniest! They will all be at the EGU booth on Thursday from 14h15 to 15h.

 

Short courses:

For those of you who have not been to Vienna before, start the week with a crash course on how to navigate EGU as a first-timer, on Monday from 8h30 to 10h in Room -2.31. http://meetingorganizer.copernicus.org/EGU2017/session/25606#

If you like fully open access and transparent publishing, you should consider the course on how to publish in EGU journals: Solid Earth and Earth Surface Dynamics. Meet the Editors on Monday, 13h30 – 15h in room -2.91.

http://meetingorganizer.copernicus.org/EGU2017/session/25617

Of course we would love to see more TS-related research, also by the youngsters! So come to ‘How to write a successful ERC Grant proposal’ on Tuesday, 13h30 – 15h, in room -2.91.

http://meetingorganizer.copernicus.org/EGU2017/session/25127

Publish more pretty pictures to show of those beautiful structures with ‘Virtual Polarizing Microscopy in Petrology and Microtectonics’ on Wednesday 10h30 – 12h00, in room -2.16. http://meetingorganizer.copernicus.org/EGU2017/session/25156

 

Debates:

After open access publishing, we seem to transition now towards open science: all data available for everyone. Is this really the way to go? Come to the panel debate on Thursday, 15h30-17h in Room E1.

http://meetingorganizer.copernicus.org/EGU2017/session/25038

With the decreased amounts of funding and less and less permanent jobs the pressure of ‘publish or perish’ is mounting. What is the best way of judging early career scientists? Come to the group debates on Wednesday 19h-20h30 in room G1.

http://meetingorganizer.copernicus.org/EGU2017/session/25040

If you have a disability or chronic condition and want to find out more about the Chronically Academic Network and the type of support it provides, this is the meeting to attend. This meeting will also gather some information that will be provided to EGU to make the GA and EGU in general more accessible – so your input is much appreciated. Come come! Thursday 12h15 – 13h15 to room Room 2.61

http://meetingorganizer.copernicus.org/EGU2017/session/25644

 

Sessions:

Every TS session is an ECS session! So browse the program, and look for something that captures your interest, either directly inside your field or just outside. Due to its size EGU is the perfect conference to look across the boundary into other fields. Create your program online and download it into the EGU2017 app for Apple and Android.

http://meetingorganizer.copernicus.org/EGU2017/sessionprogramme

http://meetingorganizer.copernicus.org/egu2017/app

If you have no other plans, come to the Arne Richter Award lecture by outgoing ECS rep João Duarte “The Future of Earth’s Oceans: consequences of subduction invasion in the Atlantic” on Wednesday 9h30–10h in Room D3.

http://meetingorganizer.copernicus.org/EGU2017/session/25355

Equal opportunities for all! On Friday there are talks from women in geosciences from 10h30 to 12h15 in Room L4/5  and on equal opportunities in general from 13h30–17h in Room L4/5.

http://meetingorganizer.copernicus.org/EGU2017/session/23685

http://meetingorganizer.copernicus.org/EGU2017/session/23686

 

These and other sessions for ECS across all program groups can be found at http://meetingorganizer.copernicus.org/EGU2017/sessions-of-special-interest/ECS

 

written by: Anne Pluymakers and João Duarte, outgoing TS ECS reps

photo credits: TS Twitter and Facebook pages and EGU blog

Highlights at EGU 2017 from the division for Tectonics and Structural Geology

Susanne Buiter (outgoing TS president, Geological Survey of Norway) and Claudio Rosenberg (incoming TS president, UPMC France)

It is with great pleasure that we write this blog welcoming everyone to EGU’s upcoming General Assembly in Vienna, and especially to the many events organised by our division for Tectonics and Structural Geology! We are highlighting some of the week’s many events below, though it is in fact really difficult to choose highlights as of course the contribution of every individual to the success of the meeting is a highlight!

The TS programme can be found directly at these two links:

http://meetingorganizer.copernicus.org/EGU2017/meetingprogramme/TS

http://egu2017.eu/EGU2017_schedule_TS.pdf

We would encourage you to download the meeting app (http://app.egu2017.eu) and/or make a personal programme (http://meetingorganizer.copernicus.org/egu2017/personal_programme) in addition to taking the above pdf schedule along to Vienna.

In the list below we emphasized award lectures, PICO sessions, poster-only sessions, short courses that TS co-organises, and of course the opportunities where you can give us feedback, such as the division meeting and Meet EGU. But please don’t forget that we are running several scientific sessions in parallel throughout the day!

At the General Assembly and throughout the year, you can follow the division via our webpage (http://www.egu.eu/ts/home/), Facebook (http://www.facebook.com/TSdivision), twitter (https://twitter.com/EGU_TS) and the division mailing list (http://lists.egu.eu/cgi-bin/mailman/listinfo/ts).

Don’t forget to tweet about the General Assembly using #EGU17TS and #EGU17!

We wish you a great conference!

Susanne and Claudio

 

Monday 24 April

  • Start of the TS scientific programme at 08:30 with three sessions in parallel: TS1.4 “New geochronological approaches for quantification of geological processes”, 3 “Structures and patterns in fractured and porous media: witnesses for paleostress and fluid flow”, and TS7.4 “Probing the subduction plate interface”
  • Short course SC48 “Publishing in EGU journals: Solid Earth and Earth Surface Dynamics – Meet the Editors”, 13:30-15:00, room -2.91
  • PICO TS8.1 “Digital mapping and 3D visualization approaches in the Earth Sciences”, 15;30-17:00, PICO spot 5a
  • TS division Early Career Scientists event at Brandauers Bierbögen (Heiligenstädter Str 31), starting at 20:00

 

 

Tuesday 25 April

  • TS1.3 “Folding and Fracturing of Rocks – 50 years of research since the seminal text book of JG. Ramsay”, 08:30 – 10:00/D3 and 17:30-19:00/Hall X2
  • PICO TS8.3 “Analogue and numerical modelling of tectonic processes”, 10:30-12:00, PICO spot 5a
  • The Stephan Mueller medal lecture by Cees Passchier, “Panta Rhei – the changing face of rocks “, 16:00-17:00, room D3
  • Poster-only session TS1.1 “Open Session on Tectonics and Structural Geology”, 17:30 – 19:00, Hall X2

 

 

Wednesday 26 April

  • PICO TS1.2 “Teaching Structural Geology and Tectonics in the 21st century”, 08:30-10:00, PICO spot 1
  • The Arne Richter Award lecture by João Duarte “The Future of Earth’s Oceans: consequences of subduction invasion in the Atlantic”, 09:30-10:00, room D3
  • Short course SC9/TS10.1 “Virtual Polarizing Microscopy in Petrology and Microtectonics”, 10:30-12:00 room -2.16
  • Division meeting of Tectonics and Structural Geology: Your chance to provide us with feedback on the division and our programme. A light lunch will be provided. 12:15 – 13:15, room G1
  • PICO TS3.3 “Microstructure and texture analysis: New methods and interpretations”, 13:30-15:00, PICO spot 5b
  • Poster-only sessions:
    • TS8.4 “Learning from failed models and negative results”
    • TS9.2 “Oceanic and continental transform plate boundaries: nucleation, evolution and tectonic significance”

 

 

Thursday 27 April

  • PICO TS8.2 “Unravelling the Earth subsurface structure from seismic imaging and interpretation, geological observations, and numerical Experiments” 10:30-12:00, PICO spot A
  • Arthur Holmes medal lecture by Jean-Pierre Brun, “The extending lithosphere”, 12:15-13:15, room E1
  • Meet the EGU Division Presidents of Tectonics and Structural Geology (us!), 13:30-14:15, EGU Booth
  • Meet the incoming EGU Division President (Claudio) and the ECS Representatives of Tectonics and Structural Geology (Anne Pluymakers and João Duarte (both outgoing), and Anouk Beniest (incoming)), 14:15-15:00, EGU Booth

 

Friday 28 April

  • 17:30 – 19:00 Friday evening poster sessions! All are in Hall X2:
    • TS5.1 “Bridging Earthquakes and Tectonics: give-and-take”
    • TS5.4 “Advances in understanding earthquake processes and hazards in regions of slow lithospheric deformation”
    • TS6.1 “The evolution and architecture of rifts, rifted passive margins, and mid oceanic ridges: from mantle dynamics to surface processes”
    • TS7.5 “The Caledonian orogen of the North Atlantic region: understanding tectonic processes in collisional belts”
    • TS7.6 “Lithospheric and crustal dynamics of the Wilson Cycle: The Iberia case study”

 

(photos by Susanne Buiter)

Strike Slip Faults Classification

Strike Slip Faults Classification

A strike slip faults is a fault on which most of the movement is parallel to the fault strike (Bates and Jackson, 1987). The term ‘wrench fault’ is also popularized in some researchers. Sylvester (1988) suggest not using wrench fault term for defining strike slip fault as general term because wrench fault was defined by Anderson (1905) as deep seated, regional and vertical faults. Many major strike slip faults; however, are not vertical and do not cut the lithosphere on the continental crust.

Strike slip faults are clas sify by two major groups by Sylvester (1988) with regard to where they occur: Transform faults are general term that cut the whole lithosphere and Transcurrent faults are general term do not cut the lithosphere.

Sylvester (1988) classification of the strike slip faults is the most used and convenient way to determine the type of the strike slip faults.

Table 1. Classification Strike Slip Faults by Sylvester (1988).

Figure 1. Plate tectonic setting of major classes of strike slip faults by Sylvester (1988).

Figure 2. Plate tectonic setting of major classes of strike slip faults by Sylvester (1988).

Minds over Methods: Reconstruction of salt tectonic features

Minds over Methods: Reconstruction of salt tectonic features

What is the influence of salt tectonics on the evolution of sedimentary basins and how can we reconstruct such salt features? Michael Warsitzka, PhD student at the Friedrich Schiller University of Jena, explains which complementary methods he uses to better understand salt structures and their relation to sedimentary basins. Enjoy!

 

Reconstruction of salt tectonic features from analogue models and geological cross-sections

Michael Warsitzka, PhD student, Institute of Geosciences, Friedrich Schiller University Jena

Salt tectonics, as a sub-discipline of structural geology, describe deformation structures developing due to the special deformation behaviour of salt (as synonym for a sequence of evaporitic rocks). Salt behaves like a viscous fluid over geological time scales and, therefore, it may flow due to lateral differences in thickness and density of the supra-salt layers. This influences the structural evolution of sedimentary basins, because salt flow can modify the amount of regional subsidence of the basin. Local sinks (“minibasins”) develop in regions from where salt is squeezed out and salt structure uplifts, e.g. diapirs or pillows evolve in regions of salt influx. Unfortunately, temporal changes of salt flow patterns are often difficult to reconstruct owing to enigmatic ductile deformation structures in salt layers. Understanding the evolution of salt-related structures requires either forward modelling techniques (e.g. physically scaled sandbox experiments) or restoration of sedimentary and tectonic structures of the supra-salt strata.

In my PhD thesis, I tried to integrate both, analogue modelling and restoration, to investigate salt structures and related minibasins developed in the realm of extensional basins. The sandbox model is a lab-scale, simplified representative of natural salt-bearing grabens, e.g. the Glückstadt Graben located in the North German Basin (Fig. 1). A viscous silicone putty and dry, granular sand were used to simulate ductile salt and brittle overburden sediments. Cross sections were cut through the model at the end of each experiment to conduct reconstruction of the final experimental structures. The material movements were monitored with a particle tracking velocimetry (PIV) technique at the sidewalls of the experimental box.

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Fig 1: 2D restoration of the supra-salt (post-Permian) strata in the Glückstadt Graben (Northern Germany)

Using experimental and geological cross sections, structures in the overburden of the ductile layer can be reconstructed, if present-day layer geometries and lithologies of the overburden strata can be identified. From natural clastic and carbonatic sediments we know that they compact with burial, reducing the layer thickness. Therefore, the reconstruction procedure sequentially removes the uppermost layer and layers beneath are decompacted and shifted upwards to a horizontal surface (Fig. 2). The sequence of decompaction and upward shifting is then repeated until the earliest, post-salt stage is reached (Fig. 1). It intends to restore the initial position, shape and thickness of each reconstructed layer.

In analogue experiments, no decompaction is necessary, because the compressibility of the granular material is insignificant for depths of a few centimetre. Restoration can be directly applied to coloured granular layers revealing detailed layer geometries for each experimental period (Fig. 2a). The PIV technique displays coeval material movement and strain patterns occurring during the subsidence of the experimental minibasins (Fig. 2b). Based on the observation that the experimental structures resemble those reconstructed from the natural example (Glückstadt Graben during the Early Triassic, Fig. 1), it can be inferred that strain patterns observed in the experiments took place in a similar manner during the early stage of extensional basins. This demonstrates the advantage of applying both methods. First, original geometries of basin structures can be determined from the restoration and then reproduced in the model. If the restored geometries are suitably validated by the models, the kinematics observed in the model can be translated back to nature and help to understand the effect of salt flow on the regional subsidence pattern.

Fig 2: Result of an analogue model showing (a) reconstructed sand layers restored from a central cross section, and (b) monitored displacement and strain patterns in the viscous layer above the left basal normal fault

Minds over Methods: Sensing Earth’s gravity from space

Minds over Methods: Sensing Earth’s gravity from space

How can we learn more about the Earth’s interior by going into space? This edition of Minds over Methods discusses using satellite data to study the Earth’s lithospere. Anita Thea Saraswati, PhD student at the University of Montpellier, explains how information on the gravity of the Earth is obtained by satellites and how she uses this information to get to know more about the lithosperic structure in subduction zones.

 

Sensing Earth’s gravity from space

Anita Thea Saraswati – PhD student, Géosciences Montpellier

From the basic physics we all know that the value of the gravity is a constant 9.81 meter per second squared. This assumption would be true if the Earth were a smooth nonrotating spherical symmetric body made of uniform element and material. However, because of the Earth’s rotation, internal lateral density variation, and the diversity of the topography (including mountains, valleys, oceans and glaciers), the gravity  varies all over the surface. These tiny changes in gravity due to the mass variations could be a crucial hint for understanding the structure of the Earth, both on the surface and at depth.

The determination of Earth’s gravity field has benefited from various gravity satellite missions that have been launched recently. Among them are the Challenging Minisatellite Payload (CHAMP) (2000-2010), the Gravity Recovery and Climate Experiment (GRACE) (2002-recent), and most recently the Gravity field and steady-state Ocean Circulation Explorer (GOCE) (2009-2013). From these missions, finally a global high quality coverage of Earth’s gravity field became available. (Yay!)

GRACE observation data are very useful for the temporal analysis of changes in gravity. For example to detect the gravity signal before and after a big earthquake, like the Sumatra Mw 9.1 (2004) and Tohoku Mw 9.1 (2011) ones. By analyzing the changes of gravity signal during a certain period of time, it could also be used to detect the drought over a large scale area, which is used in several areas in Africa and Australia.

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Design of GOCE satellite observation. A geoid’s shape is showed on the bottom left. On the top right, the GOCE gravity gradients in six components. (Source : ESA)

 

Meanwhile, GOCE is very suitable for the construction of a static model of Earth’s gravity field. Since this satellite has a very low orbit, ~250 km above mean sea level, it has a better spatial resolution. Its accuracy is also better than the previous missions, up to 1 mGal. GOCE is equipped with a gradiometer, which measures the gravity acceleration in three directions (x, y, and z). Afterwards this information is processed into a gravity-gradient dataset containing six components (XX, XY, XZ, YY, YZ, ZZ).

This gravity gradient is the first derivative of the gravity acceleration, which provides us better information about the geometry of the earth’s structure than the gravity acceleration itself. For my PhD, I use this gravity gradient dataset to analyze the lithospheric structure of subduction zones. Before treating the GOCE observation data, I am developing a computational code to calculate the gravity and gravity gradient due to the effect of topography, also called the topographic reduction. The observed gravity and gravity gradient values will be reduced by this topography effect in order to get the anomaly signal. This means that only the signal due to other geodynamic phenomena over the observed area (e.g. slab, isostasy, mantle plum, etc.) is left. By doing further processing, we can obtain the lateral variations of the lithospheric structure in the study areas and then investigate the correlation with the occurrence of mega-earthquakes in these subduction zones.

Since there is still some ambiguity about the information that is produced by gravity data only, it is better to combine the use of them with others geophysical or geological measurements, e.g. seismic tomography measurements and magnetic field observations.

 

Global coverage of GOCE gravity gradient (in milliEötvös) in radial direction (ZZ) (Panet, I. et al., 2014)

 

Reference:

Panet, I., Pajot-Métivier, G., Greff-Lefftz, M., Métivier, L., Diament, M. and Mandea, M., 2014. Mapping the mass distribution of Earth/’s mantle using satellite-derived gravity gradients. Nature Geoscience7(2), pp.131-135.

Features from the Field: Growth Faults

Features from the Field: Growth Faults

Growth faults are syndepositional or syn-sedimentary extensional faults. Growth faults develop when sediments are being deposited, are key elements in understanding deformation processes. Indeed, successively deposited sedimentary layers are involved in the different stages of the growth of the structure and produce a record of the deformation history. Their fault plane dips mostly toward the basin and has long-term continuous displacement.

As the fault grows upward, it cuts through the newly formed sedimentary layers at the top. Therefore, the overall displacement along the fault plane is not the same. Further, the lowermost layer has higher displacement than the uppermost layer while the intermediate layer displacement lies in between (See Figure). Because the fault plane flattens into décollement, the downthrown block moves basinward and the displaced sedimentary layer of the downthrown block bends close to the fault plane forming rollover anticline, synthetic and antithetic faults.

Minds over Methods: studying dike propagation in the lab

Minds over Methods: studying dike propagation in the lab

Have you ever thought of using gelatin in the lab to simulate the brittle-elastic properties of the Earth’s crust? Stefano Urbani, PhD student at the university Roma Tre (Italy), uses it for his analogue experiments, in which he studies the controlling factors on dike propagation in the Earth’s crust. Although we share this topic with our sister division ‘Geochemistry, Mineralogy, Petrology & Volcanology (GMPV)’, we invited Stefano to contribute this post to ‘Minds over Methods’, in order to show you one of the many possibilities of analogue modelling. Enjoy!

 

dscn0024Using analogue models and field observations to study the controlling factors for dike propagation

Stefano Urbani, PhD student at Roma Tre University

The most efficient mechanism of magma transport in the cold lithosphere is flow through fractures in the elastic-brittle host rock. These fractures, or dikes, are commonly addressed as “sheet-like” intrusions as their thickness-length aspect ratio is in the range of 10-2 and 10-4 (fig.3).

Understanding their propagation and emplacement mechanisms is crucial to define how magma is transferred and erupted. Recent rifting events in Dabbahu (Afar, 2005-2010) and Bardarbunga (Iceland, 2014, fig.1) involved lateral dike propagation for tens of kilometers. This is not uncommon: eruptive vents can form far away from the magma chamber and can affect densely populated areas. Lateral dike propagation has also been observed in central volcanoes, like during the Etna 2001 eruption. Despite the fact that eruptive activity was mostly fed by a vertical dike to the summit of the volcano, several dikes propagated laterally from the central conduit and fed secondary eruptive fissures on the southern flank of the volcanic edifice (fig.2). Lateral propagation can hence occur at both local (i.e. central volcanoes) and regional (i.e. rift systems) scale, suggesting a common mechanism behind it.

fig-3mario-cipollini

Fig. 2 Lava flow near a provincial road, a few meters from hotels and souvenir shops, during the 2001 lateral eruption at Etna. Credit: Mario Cipollini

Therefore, it is of primary importance to evaluate the conditions that control dike propagation and/or arrest to try to better evaluate, and eventually reduce, the dike-induced volcanic risk. Our knowledge of magmatic systems is usually limited to surface observations, thus models are useful tools to better understand geological processes that cannot be observed directly. In particular, analogue modelling allows simulating natural processes using scaled materials that reproduce the rheological behavior (i.e ductile or brittle) of crust and mantle. In structural geology and tectonics analogue modelling is often used to understand the nature and mechanism of geological processes in a reasonable spatial and temporal scale.

d_grad_dike57_080Field evidence and theoretical models indicate that the direction of dike propagation is controlled by many factors including magma buoyancy and topographic loads. The relative weight of these factors in affecting vertical and lateral propagation of dikes is still unclear and poorly understood. My PhD project focuses on investigating the controlling factors on dike propagation by establishing a hierarchy among them and discriminating the conditions favoring vertical or lateral propagation of magma through dikes. I am applying my results to selected natural cases, like Bardarbunga (Iceland) and Etna (Italy). To achieve this goal, I performed analogue experiments on dike intrusion by injecting dyed water in a plexiglass box filled with pig-skin gelatin. The dyed water and the gelatin act as analogues for the magma and the crust, respectively. Pig-skin gelatin has been commonly used in the past to simulate the brittle crust, since at the high strain rates due to dike emplacement it shows brittle-elastic properties representative of the Earth’s crust. We record all the experiments with several cameras positioned at different angles, taking pictures every 10 seconds. This allows us to make a 3D reconstruction of the dike propagation during the experiment.

In order to have a complete understanding of the dike intrusion process it is essential to compare the laboratory results with natural examples. Hence, we went to the field and studied dikes outcropping in extinct and eroded volcanic areas, with the aim of reconstructing the magma flow direction (Fig. 3). This allows validating and interpreting correctly the observations made during the laboratory simulations of the natural process that we are investigating.

fig-1

Fig. 3 Outcrop of dikes intruding lava flows. Berufjordur eastern Iceland.

 

Introducing the people behind the TS division

This week we present the many volunteers behind the activities of the Tectonics and Structural Geology (TS) division. We can also be found on http://www.egu.eu/ts, Facebook and twitter. We are always happy to hear new ideas and feedback! Just drop a message on ts@egu.eu and don’t forget to stop by the division meeting during the General Assembly in April next year.


Susanne Buiter
President

susanneI am a senior researcher and team leader for Geodynamics at the Geological Survey of Norway and am also for 20% at the Centre for Excellence CEED at the University of Oslo. I use a model-based approach to investigate deformation processes on the scale of the upper crust to the upper mantle. These include rifted margins, sedimentary basins, thrust wedges, subduction zones, continental collision, and the entire Wilson Cycle itself.

As president for the TS division since 2013 I have tried to serve our community through a broad and hopefully exciting TS session programme at our General Assembly in Vienna. It has been great fun working closely together with all of you! Apart from geo-spamming your inbox and GA scheduling, my work also involves short courses (e.g. ERC funding or Open Access publishing), the EGU Outreach Committee (e.g., the ECS-medallist networking reception), the TS division Outstanding Early Career Scientists Award committee, tweeting division news and maintaining close ties with our sister organisations, the GSA Structural Geology and Tectonics Division and AGU Tectonophysics section.

All of this is of course only possible with the expertise help of the TS team who have been absolutely wonderful to collaborate with! I will step down at the General Assembly in April 2017 when I will take over as EGU Programme Committee chair, looking forward to that!

Personal webpage: http://www.geodynamics.no/buiter

 

Magdalena Scheck-Wenderoth – Deputy President

leniCurrently I’m a professor for basin analysis at RWTH Aachen University in joint appointment with the German Research Centre for Geosciences GFZ in Potsdam, where I lead the section basin modelling. This includes studies on the structure and dynamics of sedimentary basins on one hand and the utilization of the subsurface on the other. Therefore I work on data-based 3D lithosphere-scale to reservoir-scale basin models of sediments, crust and lithospheric mantle, coupled transport of heat and fluids in the subsurface, regional 3D gravity modelling, structural and subsidence history and salt dynamics.

As deputy president of TS I try to assist the current president Susanne Buiter where needed. As my research is focused on Geoenergy and Geodynamics of sedimentary basins, I try to make links of TS with the ERE and GD divisions aiming at avoiding overlap and making the best possible programme.

Personal webpage:

http://www.gfz-potsdam.de/en/section/basin-modeling/staff/profil/magdalena-scheck/

 

Marcel FrehnerNews & Media Officer and Webmaster

mfrehnerI am a senior scientist and lecturer (so-called “Oberassistent”) at the ETH Zurich (Switzerland) in the Group for Structural Geology and Tectonics. My main scientific interest is the mechanical investigation of geological and geophysical processes. For this, I developed various numerical modelling codes, but I also integrate my theoretical and numerical work with field and laboratory data. My process-oriented research focuses on topics in structural geology (i.e., deformation of rock units, mostly folding) and rock physics (i.e., mostly seismic properties of porous and/or fractured rocks).

Within the EGU-TS team, I am the News & Media Officer. In fact, the TS Division does not have much direct contact with media representatives, as they would contact the scientists directly. So, my job mainly involves running and feeding the TS homepage, Facebook page, and Twitter account, as well as coordinating external communication among the TS board.

Personal webpage: http://www.marcelfrehner.ch/

 

Francesca CifelliOutstanding Student Poster and PICO award coordinator

picture_cif_cropI am associate professor in structural geology at the Department of Science (Roma TRE University) in Rome, Italy. My research activity mainly focuses on palaeomagnetic studies applied to the reconstruction of the rotational history and structural evolution of curved mountain chains. Among my study areas are the Calabrian Arc, Northern Apennines, Gibraltar Arc, Central Iran, and the Central Anatolian Plateau. In Italy, I am very active in science communication and high-school teachers training.

I am a member of the EGU Committee of Education (CoE) for the organization of the GIFT (Geophysical Informations for Teachers) workshop. Within the TS team, I coordinate together with the TS President the Outstanding Student Poster and PICO (OSPP) Awards.

 

Fabrizio StortiStephan Mueller Medal Committee Chair

storti%20foto%201I have been president of the TS Division from 2009 to 2013, after serving as vice-president since 2005. Over the last four years I chaired the TS Stephan Mueller Medal committee, a role always taken by the past president of the division. From 2013 to 2016 I also chaired the EGU Topical Events Committee. So I spend more than a decade in the EGU and it is now time for me to step down and leave space to new people, with new ideas and a renewed enthusiasm. My experience in EGU is very positive because of the bottom-up philosophy that allowed me to propose ideas, strategies and improvements that contributed in some way to help the Union to constantly grow and offer higher standards, assembly after assembly, and to start playing a role much broader than the organization of congresses. I believe that dedicating some time and energy to contribute improving “our environment” as scientists and mentors is somehow dutiful, very rewarding and instructive, and so I warmly encourage all you to think about volunteering for some kind of support to the activities of the TS Division. This support includes considering the journal Solid Earth for publishing your work, help it to grow and become a well reputed, reference journal for Earth Scientists. You can find more information on publishing in Solid Earth in these two TS blogs (blogs.egu.eu/divisions/ts): Solid Earth journal: the possibilities of open access publishing and Publishing in Solid Earth: interview with Anna Rogowitz

Personal webpage: http://www.next.unipr.it/index.php/en/

 

Anne PluymakersEarly Career Scientists Representative
João DuarteEarly Career Scientists Co-Representative

anne-225x300joao-225x300

 

 

 

 

 

 

 

Read more about Anne and João, and the TS Early Career Scientists team, in the TS blog “Introducing our Early Career Scientist Team”!

 

Andrea ArgnaniProgramme Committee member for Methods and Techniques

andrea_maccalube2_2016-cropI am a Senior Scientist at the Institute of Marine Sciences of the National Research Council in Bologna, Italy. In the last 20 years, I carried out research on the tectonic evolution, kinematic reconstructions and geodynamics of the Mediterranean, with special attention to the central Mediterranean palaeogeography, the flank instability of Mount Etna, and the active tectonics of the Messina Straits, Malta Escarpment and central-southern Adriatic Sea. I started with sandbox modelling of Inversion Tectonics in Ken McClay’s laboratory at Royal Holloway (UK), and have been (much later) in charge of the Analogue Modelling Lab at the University of Parma for a couple of years.

I joined the Tectonic Division panel only recently, last year, and am supervising the Methods and Techniques sessions, with much help from Susanne.

Personal webpage: http://www.ismar.cnr.it/people/argnani-andrea?set_language=en&cl=en

 

Rebecca BellProgramme Committee member for Extensional Tectonic Settings

photo_bellI am a Lecturer in Geology and Geophysics at Imperial College London (UK) and I study tectonic evolution in a variety of settings using next generation controlled-source seismic methods and drilling data. One of my primary research interests involves understanding what factors control the geometry and evolution of continental rifts.

I am a member of the programme committee for Extensional Tectonics, which involves developing an exciting programme of sessions on rift-related topics at the EGU General Assembly.

Personal webpage:

https://www.imperial.ac.uk/people/rebecca.bell

 

Stéphane BonnetProgramme Committee member for Interplay between Tectonics and Surface Processes

photosbonnetnb-1I am Professor of Earth Sciences at the University of Toulouse (France). My research activity focus on landscape evolution and on interactions and feedbacks between tectonic, climatic and surface processes, through a combination of original laboratory-scale modelling of landscape erosion and field studies, in France, Pyrénées, Argentina, Chile, Nepal and New Zealand.

In the TS programme committee I work together with the conveners on sessions related to the interaction of tectonics with surface processes.

Personal webpage: http://www.get.obs-mip.fr/profils/Bonnet_Stephane

 

Rüdiger KillianProgramme Committee member for Brittle Deformation and Fault-related Processes and Ductile Deformation, Metamorphism and Magmatism

ruediger-cropI am a post-doc doing research and teaching in the Department of Environmental Sciences, University Basel in Switzerland. One of my main interests is the study of deformed rocks. Trying to identify the involved processes as well as quantifying their contribution based on the analysis of microstructures isn’t only incredibly exciting but might also help to improve rheological models and laboratory to nature extrapolations.

I am in the TS programme committee since 2014 taking care of “Brittle deformation and Fault-related processes” and “Ductile Deformation, Metamorphism and magmatism” which is a very interesting and instructive task. Despite at the beginning, I have sometimes wished there’d be something between “brittle” and “ductile” or no separation at all, by now I’m pretty fine with this historically grown subdivision and I hope I’ll do my job to everyone’s satisfaction; to those who send in their session proposals and we try to find a suitable place for their ideas as well as to all those people who want to find the best session for their abstract within the “brittle” or “ductile” part of our programme.

 

Olivier LacombeProgramme Committee member for Convergent Tectonic Settings

img_blog-olI am professor of tectonics and structural geology in the Institut des Sciences de la Terre de Paris (ISTeP), Université Pierre et Marie Curie (UPMC), Paris, France. My fields of interest are various, including analysis of micro/meso structures in the field and under the microscope, paleostress reconstructions, fluid-rock-tectonics interactions and tectonic evolution and mechanics of fold-and-thrust belts.

Within the TS team, I am the officer of the programme committee in charge of ‘Convergent tectonic settings’, and I am trying through years to build a complete and attractive set of sessions on the topic, in close relation to the TS division president.

Personal webpage: http://merco220.free.fr

 

Hiroki SoneProgramme Committee member for Earthquake Tectonics and Crustal Deformation

hirokiI am an assistant professor in Geological Engineering at the University of Wisconsin-Madison, USA and a visiting researcher at the German Research Centre for Geosciences GFZ in Potsdam. I work on experimental rock mechanics looking at the long-term ductile deformation of rocks at crustal depths. I apply knowledges gained in the lab to understand stress states around faults, and how they influence earthquake mechanics, and other geomechanical problems related to petroleum/geothermal reservoirs and subsurface waste management.

I have been a programme committee member for the TS team since 2015 helping organize sessions for the subdivision “Earthquake Tectonics & Crustal Deformation”.

Personal webpage: http://gle.wisc.edu/hiroki-sone-ph-d/

Publishing in Solid Earth: interview with Anna Rogowitz

Publishing in Solid Earth: interview with Anna Rogowitz

Following our previous blog about the EGU journal Solid Earth, we now would like to share some experiences of open access publishing in this journal with you. Therefore, we interviewed Anna Rogowitz, who recently published in Solid Earth, about her experiences. 

 

annaAbout Anna:

Anna is an Assistant Professor in the Structural Processes Group at the Department of Geodynamics and Sedimentology (University of Vienna, Austria) since December 2015. She finished her MSc degree in geology in the beginning of 2011 at the Institute of Geology, Mineralogy and Geophysics (Ruhr-University Bochum, Germany). Anna then carried on to a PhD in the field of structural geology with focus on strain rate dependent calcite deformation (Department of Geodynamics and Sedimentology, University of Vienna); using field observations in combination with detailed microfabric analyses to study strain localization processes in the lithosphere, with special focus on the ductile regime. Anna is also presently part of our TS ECS team.

 

1. You recently published a very interesting paper in Solid Earth. In three or four sentences, what is it about?

Thanks! The study was part of my PhD thesis in which I analysed the isotopic and mechanical impact of strain localization in a calcite marble at varying strain rates. The manuscript is dealing with the simultaneous activation of grain boundary sliding (GBS) and dislocation motion as a powerful strain softening mechanism in calcite. We analysed a pretty highly strained calcite marble and observed grain size reduction by bulging recrystallization, resulting in an almost strain-free ultramylonite that got subsequently deformed by dislocation activity, with clear evidence for GBS. The combination of these two mechanisms has been recently discussed more often for experimentally deformed rocks (Wang et al., 2010; Hansen et al., 2011). For us it was a bit surprising, as the deformation occurred at high differential stresses, relatively low temperatures and strain rates of nearly 10-9 s-1. At these conditions, brittle deformation could be anticipated rather than ductile behaviour.

 

2. Why did you choose Solid Earth?

One of the Editors, Luca Menegon (Plymouth University) was a visiting professor at our department while I was working on the study. We discussed our findings and he suggested that I submit the work to Solid Earth, as they were working on a Special Issue on ‘Deformation mechanisms and ductile strain localization in the lithosphere’ at that point. The topic of the Special Issue fit perfect to our results, so it was pretty easy to decide for Solid Earth.

 

3. Did the fact that it is an open access journal contribute to your decision?

Definitely! I like the idea of research being accessible for everybody who is interested.
I know some colleagues that have access to only a very limited number of journals. Of course there is always the possibility to write an e-mail to the author and ask for a copy of a specific manuscript but I also know that especially young researchers might be too shy or afraid to do so. Another reason for choosing an open access journal was that part of my study was funded by the Austrian Science Fund (FWF) and open access publications are mandatory.

 

4. EGU journals have a very transparent peer-review process in which reviews and author replies are posted online. How did you experience this?

I think the idea of an open review process, where people interested in a specific topic can discuss a manuscript is great. Honestly, I would have liked more people to join the discussion on our publication. I think it helps to improve the quality of a manuscript and could also help to connect people. Maybe even result in more interdisciplinary studies.

 

5. As an early career researcher, what are the most important things you look for when choosing a journal to submit a paper to?

I always go with some suggestions to my co-authors and discuss with them what would be the best choice for our manuscript. One of the most important factors for me is if it is a journal that I read regularly and preferably has open access. As an early career researcher but not that young/early anymore I have to admit that the impact factor starts to play a more important role. And of course the publication costs. I prefer to spend my funding on research and analyses than the journal I publish in.

 

6. Do you have suggestions for improvements concerning the submission, review and publication process in Solid Earth?

I thought that it was a bit time consuming that the submitted manuscript got edited as a discussion paper before it went into the review process. Also the fact that we had to pay for the preparation of the discussion paper even though it might have possibly been rejected was something I disliked. But from what I understood, these two things have been changed already. Another thing is that I would like the entire review process to be public. Of course the discussion and review process has to stop at some point but I think it would be nice if this is not before the final decision by the editor has been made. I would like that further exchanges by editor and authors could also be followed and commented on by the community.

 

7. Do you have recommendations for authors who are considering publishing in Solid Earth?

Hah! Beside ‘Go for it’… No, I really think that Solid Earth is a great journal that covers a broad field of Earth sciences. The fact that it is open access and affordable (even for early career scientists that may not have a lot of funding) is a big plus. And different to some other journals, the review process is pretty fast, which nowadays is a very important factor. Personally, I would definitely consider to submit another publication to Solid Earth. Probably, I would try to motivate a few more people to comment on the manuscript during the peer-review process. Some people have started to announce their discussion papers in the Geo-Tectonics forum, which is a very smart idea.

 

Paper’s reference:

Rogowitz, A., White, J.C., and Grasemann, B., 2016. Strain localization in ultramylonitic marbles by simultaneous activation of dislocation motion and grain boundary sliding (Syros, Greece). Solid Earth 7, 355-366, Doi:10.5194/se-7-355-2016

 

This blog was established as a group effort of the T&S team.

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