01whole.pdf (25.63 MB)
Download file

Fluid-rock interaction: from simple single crystals to complex natural systems

Download (25.63 MB)
thesis
posted on 28.03.2022, 22:08 by Liene Spruzeniece
Fluid is present in many tectonic settings in the Earth's crust and plays a fundamental role in controlling chemical, physical and kinetic properties of rocks in both static and dynamic environments. This PhD project aims to provide a deeper understanding of the interaction between fluid, rock microstructure and chemical reactions by combining experimental and field approaches. In the experimental studies, a variety of aspects of fluid-mediated mineral replacement are explored in controlled static conditions. This study demonstrates that in simple salt systems fluid-mediated replacement reactions can create deformationresembling microstructures. Similar microstructures in natural samples may be misinterpreted as resulting from crystal-plastic deformation. The experiments on polycrystalline materials reveal that the microstructures of reaction products as well as the reaction pathways can vary dramatically depending on the rate-limiting step in the replacement process (either dissolution, component transport or precipitation) and can be modified by varying fluid composition. Even slight changes in the chemistry of the reactive fluid determine if the reaction is controlled by grain boundary geometry, crystallographic orientation or reaction-generated porosity. Furthermore, this study demonstrates that in systems, where fluid undergoes continuous compositional evolution during interaction with the parent material, rapid dissolution-precipitation processes can create mineralogically and structurally complex, symplectite microstructures. The thesis is concluded with a field study, comparing samples deformed in fluid-limited versus fluid-abundant conditions. The two cases display significant differences in the activated deformation mechanisms and chemical processes, indicating dramatically different rheologies and paths of microstructural evolution. Results of this thesis show that the presence of a reactive fluid in geologic systems is more than just a kinetic factor. Fluid can control the mechanisms that govern deformation and mineral reactions on a fundamental level. In-depth understanding of these controls can lead to more accurate models for predicting the consequences of fluid-rock interaction in a variety of physio-chemical systems.

History

Table of Contents

1. Introduction -- 2. Deformation-resembling microstructure created by fluid-mediated replacement reactions -- 3. The role of fluid chemistry, grain boundaries, phase boundaries and deformation in fluid-mediated mineral replacement reactions -- 4. Symplectic formation in the presence of a reactive fluid: insights from hydrothermal experiments -- 5. Strain localization in brittle-ductile shear zones: fluid abundant vs. fluid-limited conditions (and example from Wyangala area, Australia -- 6. Discussion -- 7. Conclusions -- Appendices.

Notes

Theoretical thesis. Includes bibliographical references

Awarding Institution

Macquarie University

Degree Type

Thesis PhD

Degree

PhD, 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

2016

Principal Supervisor

Sandra Piazolo

Rights

Copyright Liene Spruzeniece 2016. Copyright disclaimer: http://mq.edu.au/library/copyright

Language

English

Extent

1 online resource (167 pages : illustrations, maps)

Former Identifiers

mq:71611 http://hdl.handle.net/1959.14/1276221