Dear all,
Please inform possibly interested students of the following PhD-position available at Basel Univerisity, Switzerland. Contact Renee Heilbronner or Holger Stuenitz for further information:
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PhD position in Rock Deformation - Structure Analysis
The Rock Deformation Group (Geological Institute, Departement of
Geosciences, Basel University, Switzerland) has a grant for a PhD position for
one of the following projects:
- Single and bicrystal deformation of quartz
- Deformation of quartz in polymineralic rocks
One of these projects will be funded by the Swiss National Science
Foundation; the choice of project will depend on the strength of the applicants.
Duration:
April 2006 to April 2009, with a possible extension of 1 year.
Principal investigators: Prof. Dr. Renée Heilbronner, Basel University
Co-Investigators: PD Dr. Holger Stünitz, Basel University, and PD Dr.
Karsten Kunze, ETH Zürich.
Collaboration: Prof. Jan Tullis of Brown University, U.S.A. and Dr. John
FitzGerald, ANU, Australia.
Additional information:
Applications (including CV, research statement, references):
Prof. Dr. Renée Heilbronner
Geological Institute
Bernoullistr.32
CH-4056 Basel
Switzerland
(We do not accept e-mail applications)
Description:
Single and bicrystal deformation of quartz
This PhD project is in the field of experimental rock deformation and involves
two different types of experiments: (a) Single crystal experiments on natural
quartz - to study the temperature effect on the activation of different slip
systems in quartz. (b) Bi-crystal experiments using two different crystal
orientations - to study aspects of recovery and recrystallization and the CPO
development. All experiments will be carried out in our Griggs-type solid
medium apparatus.
The microstructures and the texture of the deformed samples will be studied
in detail. The misorientation analysis of recovery and recrystallization of all
samples will be performed by computer-integrated-polarization (CIP)
microscopy. The method allows for a fast data acquisition of orientation
imagining and shape- and grain- (crystallographic domain) size analysis.
Additional to the CIP-analysis, other crystallographic directions than the <c>-
axis and their misorientation due to deformation will be determined by electron
backscattered diffraction (EBSD) in the SEM.
The aim of the study is to better understand the fundamental processes active
in quartz deformation and the importance of these processes for dislocation
glide and recovery and recrystallization. The knowledge of these processes is
the prerequisite for accurate physical models of deformation, such as those
existing for olivine. We also want to obtain quantitative data on quartz slip
system activation and recrystallization and their dependence on temperature
and/or H2O content.
We are looking for a student with a keen interest in the physical processes
that operate during mineral and rock deformation. Applicants should have a
talent for experimental work and a good background in structural geology.
Deformation of quartz in polymineralic rocks
This PhD project is addressed to naturally deformed granitic rocks in
comparison with synthetically produced and experimentally deformed quartzcontaining
polyphase rocks.
The project includes mapping and sampling of naturally deformed tonalites
and granitoids in the Bergell and Adamello intrusions along different
temperature and strain profiles. The quartz content of these rocks is only on
the order of 20%, however, its rheological behaviour is important and its
microstructure very varied. Using a combination of SEM backscatter imaging
(to separate the phases) and CIP analysis (masking out all of the non-quartz
phases) and EBSD, the microstructure and texture of the quartz occurring in
polyphase rocks will be characterized and compared to the microstructure and
texture of pure quartzites.
The natural samples are then to be compared with exerimentally deformed
samples of polyphase material (collaboration with Jan Tullis, Brown
University) using the same analytical methods on the experimental material as
on the natural one. Depending on the range of microstructures found,
additional field areas will be investigated.
The aim of this study is to enhance our ability to interprete the deformation
conditions of naturally deformed granitic rocks. We hope that the deformed
quartz in granitoids may serve as a key mineral, as it has done in the case of
quartz veins and fibres in previous studies. We therefore expect that through
detailed analysis of deformed quartz in polyphase materials we may derive
the physical conditions of the rock at the time of deformation.
Also, we expect that we may contribute to our understanding of changing
(inverted) viscosity contrasts of minerals in polymineralic rocks as a function
of increasing temperature, decreasing strain rate or flow stress. This would be
important for the extrapolation of the rheology of polyphase materials from
experiments to nature.
We are looking for a student who is interested in working both in the field and
in front of the computer screen. Successful applicants should have good
mapping skills, a strong background in structural geology, and a talent for
digital image processing.