Next Article in Journal
Riverine Sediment Geochemistry as Provenance Fingerprints along the Eastern Coast of China: Constraint, Approach, and Application
Previous Article in Journal
REE Enrichment during Magmatic–Hydrothermal Processes in Carbonatite-Related REE Deposits: A Case Study of the Weishan REE Deposit, China
Previous Article in Special Issue
Texture Development and Stress–Strain Partitioning in Periclase + Halite Aggregates
Open AccessArticle

Crystallographic and Seismic Anisotropies of Calcite at Different Depths: A Study Using Quantitative Texture Analysis by Neutron Diffraction

1
Dipartimento di Scienze della Terra, Università degli Studi di Milano, 20133 Milano, Italy
2
Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX 77004, USA
3
Laboratoire de Cristallographie et Sciences des Matériaux (CRISMAT), Ecole Nationale Supérieure d’Ingénieurs de Caen University of Caen, 14050 Caen, France
4
Institut Laue-Langevin, 71 avenue des Martyrs CS 20156, 38042 Grenoble, France
*
Author to whom correspondence should be addressed.
Minerals 2020, 10(1), 26; https://doi.org/10.3390/min10010026
Received: 3 November 2019 / Revised: 22 December 2019 / Accepted: 23 December 2019 / Published: 27 December 2019
(This article belongs to the Special Issue Texture and Microstructural Analysis of Crystalline Solids)
Eight samples of limestones and marbles were studied by neutron diffraction to collect quantitative texture (i.e., crystallographic preferred orientations or CPO) of calcite deforming at different depths in the crust. We studied the different Texture patterns developed in shear zones at different depth and their influence on seismic anisotropies. Samples were collected in the French and Italian Alps, Apennines, and Paleozoic Sardinian basement. They are characterized by isotropic to highly anisotropic (e.g., mylonite shear zone) fabrics. Mylonite limestones occur as shear zone horizons within the Cenozoic Southern Domain in Alpine thrust-and-fold belts (Italy), the Briançonnais domain of the Western Alps (Italy-France border), the Sardinian Paleozoic back-thrusts, or in the Austroalpine intermediate units. The analyzed marbles were collected in the Carrara Marble, in the Austroalpine Units in the Central (Mortirolo) and Western Alps (Valpelline). The temperature and depth of development of fabrics vary from <100 C, to 800 C and depth from <10 km to about 30 km, corresponding from upper to lower crust conditions. Quantitative Texture Analysis shows different types of patterns for calcite: random to strongly textured. Textured types may be further separated in orthorhombic and monoclinic (Types A and B), based on the angle defined with the mesoscopic fabrics. Seismic anisotropies were calculated by homogenizing the single-crystal elastic tensor, using the Orientation Distribution Function calculated by Quantitative Texture Analysis. The resulting P- and S-wave anisotropies show a wide variability due to the textural types, temperature and pressure conditions, and dip of the shear planes. View Full-Text
Keywords: calcite; seismic anisotropy; texture; CPO; thrust; shear zone; neutron diffraction; crust calcite; seismic anisotropy; texture; CPO; thrust; shear zone; neutron diffraction; crust
Show Figures

Graphical abstract

MDPI and ACS Style

Zucali, M.; Chateigner, D.; Ouladdiaf, A.B. Crystallographic and Seismic Anisotropies of Calcite at Different Depths: A Study Using Quantitative Texture Analysis by Neutron Diffraction. Minerals 2020, 10, 26.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop