Project

Discipline

Polyphase rock, Rheology, HPT Experiments

Lead
Physics and chemistry of large strained, partially molten poly-phase rocks
Lay summary
We intend to deform fine grain quartz+muscovite and quartz+muscovite+albite aggregates. The experimental deformation of these two systems at partial melting conditions will be conducted for variable finite strains and laboratory scale strain rates. In addition, we propose to conduct experiments in different conditions by varying experimental parameters such as open and close systems, wet and dry systems etc. Apart from extraction of the mechanical data during the deformation experiments and looking at deformation induced microstructures, the project aims to provide a set of quantitative analytical methods directly relevant to the dynamics of crustal deformation. Field data from relevant migmatite outcrops will be collected to integrate experimental results into natural, partially molten rocks of continental, crustal composition.

Direct link to Lay Summary

Last update: 03.12.2012

We request three years (01.10.2011-30.09.2014) funding for one Post Doctoral researcher and one Ph.D. student. The proposal also requests funding for evolution and enhancements to the current experimental setup, required consumables, and limited fieldwork studies to place the experimental results into a geological perspective. The idea and science of this project is developed on the results obtained from Swiss National Fond project 200021-116153 and its one year extension project 200020-132772 ‘Burg, Jean-Pierre: Rheology and evolution of physical properties with increasing temperature and strain in illite+quartz and muscovite+quartz systems’ both in terms of aims and of technical challenges. The extension had been granted for one year, although it was requested for three years, in order to allow a successor to the former laboratory director, Luigi Burlini, to be appointed. In January 2011 the new laboratory director, Philip Benson, arrived at ETH and therefore this proposal aims to integrate both the original research aims as well as the new research avenues that this new appointment offers in a clear and crucial “re-launch” of scientific activity in the rock deformation laboratory at ETH-Z.The primary aim of the project, which will be mostly focused on high pressure, high temperature and large strain (? > 20) deformation experiments complemented with analyses of physical and chemical properties, is to establish the relation between deformation and metamorphism. The scientific outcomes of the SNF project 200021-116153 have opened several challenging windows of study, particularly for an interacting and / or deforming binary (solid- fluid) system, which has wide applications for the physical and chemical behaviour of the deep crust. As one of the starting materials, we wish to continue with fine grain quartz+muscovite aggregate because the laboratory has previous experience in handling and working with the system. In addition, we propose to investigate a more complex three phase system of fine grains of quartz+muscovite+albite. The experimental deformation of these two systems at partial melting conditions will be conducted for variable finite strains and laboratory scale strain rates. In addition, we propose to conduct experiments in different conditions by varying experimental parameters such as open and close system, wet and dry system etc. Apart from extraction of the mechanical data during the deformation experiments and looking at deformation induced microstructures, the proposal provides a set of quantitative analytical methods directly relevant to the dynamics of crustal deformation. Direct measurement of acoustic wave emission will be taken into account to hit the onset of dehydration reactions, partial melting and phase transition. We will also analyse the chemistry of the deformed samples to look into the mobility and chemical segregation of major and trace elements and establish its influence upon the bulk rheology and diffusion length scale. Field data from relevant migmatite outcrops will be collected to integrate experimental results into natural, partially molten rocks of continental, crustal composition.The Ph.D. student will specifically focus on developing the acoustic emission (AE) technique and the evolution of rock physical properties during large strain torsion experiments, followed by post-test data analysis. In addition to maintaining the laboratory and developing the new instrumentations, the Post-Doctoral researcher will conduct the more challenging experiments and perform detailed analyses of physical and chemical properties involving dry and wet (open and close system) conditions in order to simulate geological conditions in the presence of fluids as closely as possible. It is imperative that a Post-Doctoral fellow is hired as the experience of a senior scientist is critical to the re-launch of the laboratory and to permit its restoration into a fully operational mode. In particular the proposed fellow, Santanu Misra, is easily the most knowledgeable person concerning all current details of our laboratory; passing on his knowledge and experience to others is therefore a key goal of the laboratory in the medium term.