Project AMS vs. shear zone

DomůProject AMS vs. shear zone

AMS vs. shear zone (GJ16-25486Y) 

Acquire new knowledge about evolution of anisotropy of magnetic susceptibility with progressive deformation. Understanding of microstructural processes controlling acquisition of magnetic fabrics. Role of inherited magnetic fabric for the formation of the AMS generated by the superpose deformation.
Background and motivation
Relationship between anisotropy of magnetic susceptibility (AMS) and microstructure will be studied in natural and analogue shear zones and compared with numerical modelling. Shear zones in monomineralic rocks (calcite, quartzite) are great natural laboratories for studying magnetic fabric,
texture and microstructure in order to unravel the micro-scale processes controlling the AMS acquisition. Analogue models will be performed at variable tectonic settings with rheologically strain-rate dependent material. Numerical models will calculate the AMS based on real microstructure and correlate with
observed fabrics and fabric overprints. Combined field, laboratory and numerical study should provide powerful insight in the problems of the time and space relationships between finite strain and AMS fabric. Through the assessment of the rheological behavior of matrix and embedded magnetic minerals understanding of magnetic fabric in shear zones will be enhanced, with strong applicability to general understanding of all petrofabrics.

Vladimír Kusbach, principal investigator

Geodynamics

Zuzana Roxerová, team member

Geodynamics

Martin Staněk, team member

Geodynamics

Outputs

  • 16.-21.4. – EGU 2016 preliminary results were presented as a poster: Small scale shear zone in calcite: AMS and microstructure; Zuzana Roxerová, Matej Machek, Vladimír Kusbach, Martin Racek, Pedro F. Silva.

  • 24.-29.4. – EGU 2017 results from analysis of AMS and magnetic properties of volcanic rocks were presented as poster: Flow dynamics of dacite lava flow – AMS, microstructure and porosity case study; Prokop Závada, Vladimír Kusbach, Matěj Machek, Martin Staněk, and Aleš Špičák.

  • 30.4.-4.5. – DRT 2017 progress in study of natural shear zone was presented as poster: Shear zone in calcite: AMS and microstructure; V. Kusbach, Z. Roxerová, M. Machek, M. Racek and P. F. Silva.

  • 8.4.–13.4. 2018 – EGU 2018 progress in study of natural shear zone was presented as talk: Localization effect on inverse AMS fabric in marble – microstructural evidence across small-scale shear zone; Kusbach, V., Roxerová, Z., Machek, M., Racek M., Silva, P.F.
  • 8.4.–13.4. 2018 – EGU 2018 – progress in study of analogue shear zone was presented as poster: Analogue modelling of magnetic fabric in ductile shear zones; Machek, M., Roxerová, Z., Kusbach, V.

Publications

  • Kusbach, V.K., Machek, M., Roxerová, Z. et al. Localization effect on AMS fabric revealed by microstructural evidence across small-scale shear zone in marble. Sci Rep 9, 17483 (2019) doi: 10.1038/s41598-019-53794-y
  • Machek, M., Závada, P., Roxerová, Z., Petrovský, E., Špičák, A., & Kusbach, V. (2019). Crystal mush flow in small concentrically expanded pluton (Castle Crags pluton; Klamath Mountains, CA, USA). Geochemistry, Geophysics, Geosystems, 20, 1954– 1974. DOI: 10.1029/2018GC008018
  • Machek, M., Kalvoda, L., Hladil, J., Roxerová, Z., Vratislav, S., Drahokoupil, J., Ryukhtin, V., (2018). Petrophysical record of evolution of weakly deformed low-porosity limestone revealed by small-angle neutron scattering, neutron diffraction and AMS study. Geophysical Journal International 215, 895-908. doi:10.1093/gji/ggy309
  • Anisotropy of remanent and induced magnetization in hematite ore deformed in torsion; Matěj Machek, Eduard Petrovský, Zuzana Roxerová, Vladimír Kusbach, Ramon Egli, Heinrich Siemes. Geochem. Geophys. Geosyst. (in prep.)

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