Project: Deformation and metamorphism in the WOMB, part one

Here is another honours project recently completed, and another example of the projects we may offer.

Can you introduce yourself?

My name is Bradley Williams and I completed a B.Sc. (Hons) at UoN in July 2015. I am 31 years old and live in the Hunter region of NSW, Australia.

Can you tell us about your research project at UoN?

I undertook an Honours research project in structural and metamorphic geology, which focused on an area in southern NSW. I investigated the timing of peak metamorphism relative to deformation in rocks of the study area (southern part of WOMB, Wagga Omeo Metamorphic Belt). I also wanted to resolve the age of metamorphism to determine if granite emplacement was driving metamorphism in the country rock. Achieving this would allow some important geodynamic models for eastern Australia to be tested. The project involved one month in the field to: (i) map metamorphic zonation and structure, and (ii) collect samples for later detailed petrography and monazite geochronology.

What did you find?

My findings indicate metamorphism occurred much earlier in the structural record than what was previously thought, and that large granite bodies in the area were not the source of metamorphic heat. The findings supported one of two competing geodynamic models for eastern Australia, however differed from several geodynamic models previously proposed for rocks specific to the study area. Therefore, a revised geodynamic model was proposed.

What did you particularly enjoy about this project?

I really enjoyed this particular style of research; examining rocks in situ, collecting samples, analyzing thin sections, and dating minerals in colllected samples. Using these data to make interpretations on the geodynamics of eastern Australia was challenging but equally rewarding.

What are your plans for the future?

I am currently trying to secure an earth science career!

 

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Sample showing key metamorphic mineral (retrogressed crd) and 3 deformation fabrics

 

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Project: Elastoplasticity in large strain shear zones

With the year ending, we are looking at prospective honours students. Who’s best to answer questions about honours than current honours students and visitors.

So here we start with Maxime, who came to work with us last winter.

Max

Can you introduce yourself?

My name is Maxime Henriquet. I am 22 years old student From France and I am currently studying in Lyon. During the winter season (2015) I made an internship at UoN to complete my first year for the French Master degree in geosciences.

Can you tell us about your research project at UoN?

The research project I conducted at UoN focused on the elastic energy balance and the strain localization in shear zones with an analogue modeling approach. I realized simple shear experiments using visco-elasto-plastic materials in a 3-D thermomechanical apparatus. I analyzed the influence of the rheological parameters by varying the temperature of the experiments. The quantitative analysis is realized thanks to image correlations of high resolution pictures of the surface model (PIV system). I computed the evolution of velocity and shear strain in the experiments using matlab. Then I could investigate the shear localization and estimate the stored and dissipated elastic energy under different configurations.

lab1

What did you find?

The first results have shown that the deformation localization as well as the amount of stored and dissipated elastic energy are extremely sensitive to the rheology. At high temperature with less strain softening, the plastic strain becomes predominant and the elastic effects are less visible. After rupture of the model an important quantity of stored elastic energy is still conserved in the material. So far, the results are consistent with a new theory which focuses on large strain deformation (Karrech et al., 2011). The acquisition of experimental data could then be used to constrain the numerical model based on this theory.

What did you particularly enjoy about this project?

This project was an opportunity to manipulate thermomechanical apparatus and improved the numerical methods employed to analyze the data. In addition, it was really interesting to interact with the members of the team project as well as the researchers and students of the lab. I also thank David Boutelier for the liberty and the independence he gave to me on that project. I could think by myself about the issues and it was always possible to interact with David for analysis interpretations and to pursue the development of new experiments.

What are your plans for the future?

I am currently preparing a competitive exam to be qualified for teaching geological and biological sciences with an academic level. Next year I would like to finish my Master degree in geology and then pursue with a PhD.

 

After his internship, but before returning to France, Maxime visited Australia and send me these photos

 

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