The Textural Motif of Foliated Calcite in Ostreoidea (Mollusca)

The microstructure of bivalve foliated calcite is extraordinary. It consists of units formed of stacks of folia with individual folia consisting of arrowhead-ended crystal laths. We investigated the texture of the foliated microstructure, the texture of individual and arrays of folia and the texture...

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Main Authors: Erika Griesshaber, Anna Sancho Vaquer, Antonio G. Checa, Carmen Salas, Elizabeth M. Harper, Wolfgang W. Schmahl
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Crystals
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Online Access:https://www.mdpi.com/2073-4352/15/3/244
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author Erika Griesshaber
Anna Sancho Vaquer
Antonio G. Checa
Carmen Salas
Elizabeth M. Harper
Wolfgang W. Schmahl
author_facet Erika Griesshaber
Anna Sancho Vaquer
Antonio G. Checa
Carmen Salas
Elizabeth M. Harper
Wolfgang W. Schmahl
author_sort Erika Griesshaber
collection DOAJ
description The microstructure of bivalve foliated calcite is extraordinary. It consists of units formed of stacks of folia with individual folia consisting of arrowhead-ended crystal laths. We investigated the texture of the foliated microstructure, the texture of individual and arrays of folia and the texture of assemblies of foliated units of the gryphaeid oyster <i>Hyotissa hyotis</i> with low kV, high-resolution, electron backscatter diffraction (EBSD). We base our understanding of the foliated texture on the combined interpretation of crystallographic aspects of individual and stacks of folia with the nature of crystal organization in a folium, a foliated unit and in foliated unit aggregations. Calcite c- and a*-axes arrangement in a folium is single-crystal-like. Due to the parallel organization of adjacent laths in a folium and the stacked arrangement of folia in a foliated unit, the assembly of calcite c- and a*-axes in foliated units is graded. The result is a ring-like distribution of c- and a*-axes orientations in the pole figures; nonetheless, the orientation rings are substructured by c- and a*-axes orientation clusters. The direction of the arrowhead endings of the laths is coincident with the growth direction of the shell. The morphology of arrowheaded laths initiates the formation of planes with {105}, {106} directions and a parallel orientation to the inner shell surface. <i>H. hyotis</i>’s foliated microstructure has a specific texture that is not fully understood. We discuss axial, spherulitic, turbostratic-like textures the foliated microstructure and suggest that the foliated texture of <i>H. hyotis</i> can, to some degree, be described with a turbostratic pattern.
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spelling doaj-art-3f0f28b201a947e0a1e93d93a19a686c2025-08-20T02:11:09ZengMDPI AGCrystals2073-43522025-03-0115324410.3390/cryst15030244The Textural Motif of Foliated Calcite in Ostreoidea (Mollusca)Erika Griesshaber0Anna Sancho Vaquer1Antonio G. Checa2Carmen Salas3Elizabeth M. Harper4Wolfgang W. Schmahl5Department of Geo- and Environmental Sciences, Ludwig-Maximilians-Universität München, 80333 Munich, GermanyDepartment of Geo- and Environmental Sciences, Ludwig-Maximilians-Universität München, 80333 Munich, GermanyDepartamento de Estratigrafía y Paleontología, Universidad de Granada, 18071 Granada, SpainDepartamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, SpainDepartment of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UKDepartment of Geo- and Environmental Sciences, Ludwig-Maximilians-Universität München, 80333 Munich, GermanyThe microstructure of bivalve foliated calcite is extraordinary. It consists of units formed of stacks of folia with individual folia consisting of arrowhead-ended crystal laths. We investigated the texture of the foliated microstructure, the texture of individual and arrays of folia and the texture of assemblies of foliated units of the gryphaeid oyster <i>Hyotissa hyotis</i> with low kV, high-resolution, electron backscatter diffraction (EBSD). We base our understanding of the foliated texture on the combined interpretation of crystallographic aspects of individual and stacks of folia with the nature of crystal organization in a folium, a foliated unit and in foliated unit aggregations. Calcite c- and a*-axes arrangement in a folium is single-crystal-like. Due to the parallel organization of adjacent laths in a folium and the stacked arrangement of folia in a foliated unit, the assembly of calcite c- and a*-axes in foliated units is graded. The result is a ring-like distribution of c- and a*-axes orientations in the pole figures; nonetheless, the orientation rings are substructured by c- and a*-axes orientation clusters. The direction of the arrowhead endings of the laths is coincident with the growth direction of the shell. The morphology of arrowheaded laths initiates the formation of planes with {105}, {106} directions and a parallel orientation to the inner shell surface. <i>H. hyotis</i>’s foliated microstructure has a specific texture that is not fully understood. We discuss axial, spherulitic, turbostratic-like textures the foliated microstructure and suggest that the foliated texture of <i>H. hyotis</i> can, to some degree, be described with a turbostratic pattern.https://www.mdpi.com/2073-4352/15/3/244turbostratic texturehigh-resolution EBSDassembly of folia and foliated unitsgraded c- and a*-axes orientations of biocalcitespherulitic texture of biocalciteaxial texture of biocalcite
spellingShingle Erika Griesshaber
Anna Sancho Vaquer
Antonio G. Checa
Carmen Salas
Elizabeth M. Harper
Wolfgang W. Schmahl
The Textural Motif of Foliated Calcite in Ostreoidea (Mollusca)
Crystals
turbostratic texture
high-resolution EBSD
assembly of folia and foliated units
graded c- and a*-axes orientations of biocalcite
spherulitic texture of biocalcite
axial texture of biocalcite
title The Textural Motif of Foliated Calcite in Ostreoidea (Mollusca)
title_full The Textural Motif of Foliated Calcite in Ostreoidea (Mollusca)
title_fullStr The Textural Motif of Foliated Calcite in Ostreoidea (Mollusca)
title_full_unstemmed The Textural Motif of Foliated Calcite in Ostreoidea (Mollusca)
title_short The Textural Motif of Foliated Calcite in Ostreoidea (Mollusca)
title_sort textural motif of foliated calcite in ostreoidea mollusca
topic turbostratic texture
high-resolution EBSD
assembly of folia and foliated units
graded c- and a*-axes orientations of biocalcite
spherulitic texture of biocalcite
axial texture of biocalcite
url https://www.mdpi.com/2073-4352/15/3/244
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