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The recognition of quartz grown from a melt during static and dynamic conditions

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thesis
posted on 28.03.2022, 23:41 by Joyjit Dey
Quartz microstructures are routinely used to establish the nature of solid-state deformation mechanisms. However, it is unclear which microstructures are typically developed in a melt present environment compared to a solid state, and how to distinguish between these two. The microstructural features of quartz crystallising from a silicate melt are investigated in a) slowly cooled granite, b-c) statically heated and cooled, and actively deforming migmatites, and d) in a melt-fluxed high strain zone. This study takes a holistic approach integrating microscopic observation along with electron back scatter diffraction (EBSD) and weighted burgers vector (WBV) analysis. Results show quartz pseudomorphing melts pockets forms sub-grain boundaries and shows crystal bending, and change in orientation very similar to a solid-state deformaion. EBSD and WBV analyses identify dislocations on both basal plane and non-basal plane, and identify slip and [c] slip, and sometimes a combination of both. Existence of slip-systems, though without a crystallographic preferred orientation (CPO), suggests the features are dependent on local stresses rather than regional differential stress, and are interpreted to be a result of mineral growth in pore spaces when the melt crystallises. Differences to solid-state deformation microstructures include well connected grains in 3D, lack of CPO, lack of grain shape preferred orientation, and high dauphine twin frequency at grain boundaries.

History

Table of Contents

Chapter 1. Introduction -- Chapter 2. Methods -- Chapter 3. Sample location and description -- Chapter 4. Results -- Chapter 5. Discussion -- Chapter 6. Conclusions -- References.

Notes

Bibliography: pages 53-64 Empirical thesis.

Awarding Institution

Macquarie University

Degree Type

Thesis MRes

Degree

MRes, Macquarie University, Faculty of Science and Engineering, Department of Earth and Planetary Sciences

Department, Centre or School

Department of Earth and Planetary Sciences

Year of Award

2018

Principal Supervisor

Nathan Daczko

Rights

Copyright Joyjit Dey 2018. Copyright disclaimer: http://mq.edu.au/library/copyright

Language

English

Extent

1 online resource (vi, 64 pages) colour illustrations

Former Identifiers

mq:71180 http://hdl.handle.net/1959.14/1271698