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Diamagnetic fabrics in polymineralic mylonites

English title Diamagnetic fabrics in polymineralic mylonites
Applicant Hirt Ann M.
Number 115897
Funding scheme Project funding
Research institution Institut für Geophysik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Geophysics
Start/End 01.07.2007 - 31.07.2010
Approved amount 174'771.00
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All Disciplines (2)


Keywords (10)

anisotropy of magnetic susceptibility; diamagnetic susceptibility; paramagnetic susceptibility; seismic anisotropy; lattice preferred orientation; mineral fabric; diamagnetic anisotropy; mylonite zones; calcite; quartz

Lay Summary (English)

Lay summary
The primary focus of the this project is a practical, geological field application, using the methods that have been developed under a previous SNF project, which focused on the determination of the magnetic anisotropy of carbonate minerals and how these contribute to the magnetic anisotropy of a rock. A unique method was developed to isolate the anisotropy due to the diamagnetic carbonate minerals. The proposed work will be done in collaboration with PD Dr. M. Herwegh from the Geological Institute at the University of Berne, whose research group has made an extensive investigation of microfabrics in carbonate mylonites from the Morcles Nappe (cf., SNF Project 200020-103720). They have shown that secondary mineral phases in carbonate rocks do not behave as rigid, static particles but become incorporated into the deformation system, so that they interact with the calcite matrix. Our goal will be to investigate how the magnetic fabric of the primary calcite phase and secondary paramagnetic phases behave in this system. In addition elastic properties that define the seismic anisotropy in the rocks will also be examined. This work will aid in our understanding of 1) how physical anisotropies are controlled by microfabric evolution in large-scale shear zones; and 2) how physical anisotropies can be best interpreted and linked to existing geophysical models in mylonitic zones, which are important in the interpretation of geodynamic processes.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants


Associated projects

Number Title Start Funding scheme
107675 Magnetic and seismic anisotropy as related to mineral fabrics in carbonate rocks 01.07.2005 Project funding