Advances in the Petrography of Natural Fine-Grained Materials: A Microscale Answer to Their Genetic Pathways and Applications

Dear Colleagues,

Fine-grained materials are difficult to study petrographically due to the small size of their constituents, especially those consisting of clay-sized particles (<2–4 µm). Many papers include petrographic descriptions of fine-grained materials, especially in the silt and clay size range (<63 µm), as a complement to other procedures and techniques—either a facies analysis or compositional characterization. Commonly, these fine-grained materials correspond to sediments and rocks formed by inherited minerals and, more rarely, those formed by authigenic phases.

This Special Issue is focused on the petrography of fine-grained (mostly clay-sized) materials composed of minerals resulting from authigenesis, either from the transformation of previous crystalline or amorphous phases (precursors) or from direct precipitation (neoformation). The correct interpretation of their textural features is of great help in the genetic interpretation of their constituent minerals and thus of their formation environment. These genetic environments include both continental and marine settings in which syngenetic, diagenetic and edaphic processes are responsible for the textural variations presented by the materials. Fine-grained materials related to hydrothermal processes are also included in this.

In addition, many fine-grained materials of authigenic origin, especially claystones, exhibit physical and physico-chemical properties that lend them to important industrial and technological applications. These properties may vary in materials of the same mineral composition, even within the same deposit, with one of the causes being texture. For this reason, in addition to the determination of mineralogical and chemical composition, petrographic characterization and its correct interpretation is fundamental in order for these materials to provide an adequate response during specific applications. The use of polarized light microscopy supplemented with both scanning and transmission electron microscopy, and associated analytical procedures and techniques, are of particular relevance.

Prof. Dr. Manuel Pozo Rodríguez
Prof. Dr. Emilia García Romero
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Minerals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• clay and clay minerals
• petrography
• electron microscopy
• texture and microfabric
• properties
• genesis
• paleoenvironment
• applications

Title: Significant change in the optical properties of chlorites due to minor smectite mixed-layering

Authors: Zahra Ahmadi, Fernando Nieto, and et al