Experimental neutron pole figures of minerals composing the bivalve mollusc shells

Abstract

Recently, several studies have focused on the crystallographic texture of bivalve mollusc shells. Unfortunately, these investigations have been limited to the local level. We demonstrate the similarities and differences between the texture measured over the whole shell and that measured over a small part of a shell. An analysis of the global crystallographic texture of bivalve mollusc shells of different genera was carried out using time-of-flight neutron diffraction. The reason for this analysis was to determine whether the crystallographic texture character was similar within the class Bivalvia. It was observed that the shells of mollusc species of the genus Mytilus consist of two phases, calcite and aragonite. Ostrea edulis shells consist of almost pure calcite, whereas Mya arenaria shells consist of almost pure aragonite. It was concluded that the character of the global textures of the different phases in the same shells is different. The advantages of characterisation of the global crystallographic texture are also discussed.

Effect of the Elemental Content of Shells of the Bivalve Mollusks (Mytilus galloprovincialis) from Saldanha Bay (South Africa) on Their Crystallographic Texture

“…We analyzed the aragonite pole figures for two reflexes jointly because they are overlapped in the diffraction pattern. A similar crystallographic texture for calcite and aragonite phases for Mytilus galloprovincialis shells from Black and Azov seas was observed in previous investigations [24].…”

“…The fact that such a trend is not observed for the second calcite pole figure (10)(11)(12)(13)(14) and both aragonite pole figures can be explained by measurement errors, that, at the pole density maximum, are approximately 0.2 MRD. Furthermore, the changes between the maximums of the same pole figures of the three samples are in the range of variability identified for the genus Mytilus [24]. It should be mentioned that in quantitative texture analysis, the RP value is commonly used to characterize the similarities of the pole figures [40],…”

“…The pole figures presented in this work were measured at the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research (Dubna, Russia). For that, the SKAT spectrometer (Spectrometer for Quantitative Texture Analysis) located on channel 7A-2 of the IBR-2 pulsed nuclear reactor was used [ 24 ]. Time-of-flight neutron diffraction was used to obtain diffraction reflections corresponding to the minerals that make up the shells.…”

Texture of the Freshwater Shells from the Unionidae Family Collected in the Czech Republic Investigated by X-ray and Neutron Diffraction

“…There are very few neutronographic studies in this field-see [10,11]. In addition, regarding some details, the obtained textural results are rather inconsistent-for instance, there is some discrepancy in the preferred orientation of the b-and c-axes of aragonite [12,13].…”

The structure of scleractinian coral skeleton analyzed by neutron diffraction and neutron computed tomography

“…the stereographic projections of the crystalline plane normals n of considered mineral, in our case, aragonite. PFs should be regarded as a graphical representation of a 3D distribution function of normals n to crystalline planes of sample 16 . This makes ND an useful tool for investigating the internal architecture of scleractinian skeleton.…”