Middleton, C;
(2012)
Investigation of the rheological properties of planetary ice-rock analogues using triaxial deformation and neutron diffraction experiments.
Doctoral thesis , UCL (University College London).
Abstract
In this thesis I present work on the rheological properties of ice-rock mixtures, with particular application to the flow of materials in icy planetary bodies. Details of manufacture of analogue samples, triaxial deformation experiments, and combined deformation and neutron diffraction experiments are presented. These experimental results are used to consider the effect of an ice rock rheology on planetary processes through computer modelling of the evolution of the dwarf planet Ceres. Water ice is present in large quantities in the outer solar system, and this prevalence makes it an important planetary forming material. Within outer solar system bodies ice is often combined with other materials, such as rock or salt hydrates. Therefore, to understand the evolution of these bodies, it is important to understand the properties of water ice and how these properties are affected by the presence of other phases. Deformation experiments have been carried out on polycrystalline samples of pure H₂O ice, H₂O–ice fluorite (CaF₂), and D₂O–ice fluorite mixtures. Constitutive flow law equations are determined from the experimental data, where the effects on the flow law of the presence of particulates, and deuteration of the ice are considered. Combined deformation and neutron diffraction experiments allow the grain scale interaction between ice and fluorite to be studied; investigating strain partitioning between the phases, and also the possibility of localised melting of the ice brought about by indentation of the fluorite into the surrounding ice grains. The flow laws found from these experiments have been used in simple computer models of the differentiation of Ceres. This modelling shows a difference in predicted differentiation, dependent on an input rheology of ice or ice rock. These results demonstrate the importance of including the effects of impurities when considering the flow of planetary ices, and the necessity for increased knowledge of material properties through continued experimental studies.
| Type: | Thesis (Doctoral) |
|---|---|
| Title: | Investigation of the rheological properties of planetary ice-rock analogues using triaxial deformation and neutron diffraction experiments. |
| Language: | English |
| UCL classification: | UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1357941 |
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