Elastic stresses can form metamorphic fabrics

Geology

Abstract

Detailing the relationship between stress and reactions in metamorphic rocks has been controversial, and much of the debate has centered on theory. Here, we add to this discussion and make a major advance by showing in time-resolved synchrotron microtomography experiments that a reacting and deforming sample experiencing an elastic differential stress produces a fabric orthogonal to the largest principal stress. This fabric forms very early in the reaction and can be shown to be unrelated to strain. The consequences of this are significant because a non-hydrostatic stress state is a very common geological occurrence. Our data provide the basis for new interpretations of the classical, and enigmatic, serpentine fabrics of Val Malenco, Italy, and Cerro del Almirez, Spain, where we relate the reported fabrics to transient, and cyclical, differential stresses from magma intrusion and the earthquake cycle.

Authors 14

1. James Gilgannon

   University of Edinburgh

   Affiliation as printed

   1School of Geosciences, The University of Edinburgh, The King’s Buildings, Edinburgh EH9 3FE, UK

2. Damien Freitas

   University of Edinburgh

   Affiliation as printed

   1School of Geosciences, The University of Edinburgh, The King’s Buildings, Edinburgh EH9 3FE, UK

3. Roberto Emanuele Rizzo

   University of Florence · University of Edinburgh

   Affiliation as printed

   1School of Geosciences, The University of Edinburgh, The King’s Buildings, Edinburgh EH9 3FE, UK

   2Department of Earth Sciences, University of Florence, Via La Pira 4, 50121 Florence, Italy

4. JOHN ARCHIBALD WHEELER

   University of Liverpool

   Affiliation as printed

   3Department of Earth, Ocean and Ecological Sciences, University of Liverpool, 4 Brownlow Street, Liverpool L69 3GP, UK

5. Ian B. Butler

   University of Edinburgh

   Affiliation as printed

   1School of Geosciences, The University of Edinburgh, The King’s Buildings, Edinburgh EH9 3FE, UK

6. Sohan Seth

   University of Edinburgh

   Affiliation as printed

   1School of Geosciences, The University of Edinburgh, The King’s Buildings, Edinburgh EH9 3FE, UK

7. Federica Marone

   Paul Scherrer Institute · Swiss Light Source

   Affiliation as printed

   4Swiss Light Source, Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland

8. Christian Matthias Schlepütz

   Paul Scherrer Institute · Swiss Light Source

   Affiliation as printed

   4Swiss Light Source, Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland

9. Gina McGill

   University of Edinburgh

   Affiliation as printed

   1School of Geosciences, The University of Edinburgh, The King’s Buildings, Edinburgh EH9 3FE, UK

10. Oliver Plümper

    Utrecht University

    Affiliation as printed

    5Department of Earth Sciences, Utrecht University, Budapestlaan 4, 3584CD Utrecht, Netherlands

11. Lisa Eberhard

    Utrecht University

    Affiliation as printed

    5Department of Earth Sciences, Utrecht University, Budapestlaan 4, 3584CD Utrecht, Netherlands

12. Hamed Amiri

    Utrecht University

    Affiliation as printed

    5Department of Earth Sciences, Utrecht University, Budapestlaan 4, 3584CD Utrecht, Netherlands

13. Alireza Chogani

    Utrecht University

    Affiliation as printed

    5Department of Earth Sciences, Utrecht University, Budapestlaan 4, 3584CD Utrecht, Netherlands

14. Florian Fußeis Aachen 6Applied Structural Geology

    RWTH Aachen University · University of Edinburgh

    Affiliation as printed

    1School of Geosciences, The University of Edinburgh, The King’s Buildings, Edinburgh EH9 3FE, UK

    6Applied Structural Geology, RWTH-Aachen University, Lochnerstrasse 4-20, 52064 Aachen, Germany