Pakhnevich Alexey, Nikolayev Dmitry, Lychagina Tatiana
Borissiak Paleontological Institute, Russian Academy of Sciences, 117647 Moscow, Russia.
Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna, Russia.
Biology (Basel). 2022 Aug 31;11(9):1300. doi: 10.3390/biology11091300.
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 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 cm in volume without destroying them. The recrystallization features of the 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 mollusks' different valves vary depending on their shape. The pole figures of calcite in the thick-walled valves of , , and are close to axial and display weak crystallographic texture.
假定近期和化石软体动物外壳中矿物的晶体结构非常稳定。为了验证这一点，有必要检查那些在沉积物中埋藏了数百万年且生活在不同条件下的动物的外壳。研究发现，来自中卡洛维阶 - 下牛津阶（侏罗纪）不同水域沉积物中的贝类外壳中方解石的晶体结构不受栖息地条件和石化过程的影响。利用中子衍射测量的极图研究了晶体结构。中子衍射方法能够在不破坏大样本（体积达100立方厘米）的情况下研究其晶体结构。首次发现了影响晶体结构的瓣鳃的再结晶特征。这是根据极图的等值线外观确定的。不同瓣鳃的软体动物的晶体结构因其形状而异。、和厚壁瓣鳃中方解石的极图接近轴向且显示出较弱的晶体结构。
