Crystallographic Texture of the Mineral Matter in the Bivalve Shells of Gryphaea dilatata Sowerby, 1816

Abstract

It is assumed that the crystallographic texture of minerals in the shells of recent and fossil mollusks is very stable. To check this, it is necessary to examine the shells of animals that had lain in sediments for millions of years and lived in different conditions. It is revealed that the crystallographic texture of calcite in the shells of Gryphaea dilatata from deposits from the Middle Callovian–Lower Oxfordian (Jurassic), which lived in different water areas, is not affected by habitat conditions and the fossilization process. The crystallographic texture was studied using pole figures measured by neutron diffraction. The neutron diffraction method makes it possible to study the crystallographic texture in large samples—up to 100 cm3 in volume without destroying them. The recrystallization features of the G. dilatata valve, which affect the crystallographic texture, were discovered for the first time. This is determined from the isolines appearance of pole figures. The crystallographic texture of the G. dilatata mollusks’ different valves vary depending on their shape. The pole figures of calcite in the thick-walled valves of G. dilatata, Pycnodonte mirabilis, and Ostrea edulis are close to axial and display weak crystallographic texture.

Local Crystallographic Texture of a Nummulite (Foraminifera) Test from the Eocene Deposits of the Crimea Peninsula

“…The pole figure measurements have been developed for metals and alloys [22,23]. At present, there is a great interest in the crystallographic texture study of biological samples [24][25][26][27][28][29][30][31][32][33][34][35].…”

“…It was previously shown that the crystallographic texture of calcite and aragonite in the shells of bivalve mollusks is very stable over time [30,32], in different parts of the habitat under different climatic conditions [34], and under the influence of trace elements [35]. Some objects showed unusually high sharpness of crystallographic texture [30,33].…”

Paleontology in the 21st Century

“…Phylogenetically and physiologically informative tissues were probed by synchrotron [ 34 ] to support the previous identification of reproductive tissues in dinosaurs [ 35 , 36 ]. Technologies continue to broaden not only the type of questions to be asked, but the type of fossils we can analyze, from coprolites [ 33 ], teeth [ 37 ], and invertebrates [ 22 , 38 , 39 ] to dinosaurs [ 25 , 34 , 40 , 41 , 42 , 43 , 44 ], mammals [ 45 ], and our own lineage [ 29 , 32 , 46 ].…”