洋中脊硫化物热液区的贻贝类生物壳体是热液喷口周围生态环境信息的潜在记录者。 然而目前对组成其壳体的矿物分布特征、 超微结构和成因还缺乏深入的研究。 中国科考人员2017年利用载人深潜器首次在西北印度洋卧蚕1号热液区获得了贻贝等生物样品, 是研究这一科学问题的理想样本。 利用扫描电子显微镜、 激光拉曼光谱和傅里叶转换红外光谱分析了该热液区印度洋深海偏顶蛤(Bathymodiolus marisindicus)的壳体天然断面形貌与矿物组成。 结果表明, 印度洋深海偏顶蛤壳体的纵向生长从外到内依次为角质层、 方解石棱柱层、 过渡层、 文石板片层和肌棱柱层。 在棱柱层中, 呈纤维状的棱柱体c轴截面出现不规则状, 方解石棱柱体垂直a轴截面的宽度约为818~960 nm, 与文石层呈近45°斜交, 且方解石棱柱体出现交错现象; 过渡层形状极不规则, 延续了棱柱层的生长取向, 但整体显示从棱柱状到文石板片状过渡的趋势; 文石层总厚度约为205~1 260 nm, 具有片状结构。 在卧蚕-1热液喷口深海偏顶蛤壳体的文石层中, 同一区域的文石板片厚度相同, 不同区域的板片厚度存在差异。 肌棱柱层具有简单的棱柱状超微结构, 棱柱层和珍珠层(文石板片层)均覆盖在肌棱柱层上。 光谱学分析显示深海偏顶蛤壳体珍珠层和棱柱层矿物分别为结晶度相对略高的无机成因文石和生物成因方解石。 该研究分析的深海偏顶蛤壳体形貌、 矿物成分及成因, 可为研究热液区软体动物壳体形成机制与生物诱导成矿过程提供一定的参考依据。

The Mussel organisms from the sulfide hydrothermal field of the mid-ocean ridge can virtually record the ecological environment information around the region. However, the distribution characteristics, ultrastructure and genesis of the minerals of the shells are not well studied. A mount of mussels were first collected from the Wocan-1 hydrothermal field in the Northwest Indian Ocean, by the Manned deep-sea submersible (JIAOLONG) in 2017, which were ideal samples for investigating this scientific issue. The mussel, deep-sea Bathymodiolus of the Indian Ocean (Bathymodiolus marisindicus), is analysed by the Scanning electron microscope, Laser Raman spectroscopy, and Fourier transform infrared spectrum for their natural cross-section morphology, and mineral component. The results show that the longitudinal growth of the Bathymodiolus shell includes periostracum, prism layer,transition layer, aragonite slate layer and myostracum from the outer to the inner. In the fibrous prismatic prism layer of the shell, the c-axis cross-section of the prism is irregular, and the width of the calcite prism perpendicular to a-axis is about 818~960 nm, and it is nearly 45° oblique with the aragonite layer, and there are interlaced calcite prisms. The shape of the transition layer of the shell is extremely irregular, and it continues the growth orientation of the prismatic layer showing a trend of transition from the prismatic to the slate of aragonite. The aragonite layer has a lamellar structure, and its about 205~1 260 nm in thickness. In the aragonite layer of the Bathymodiolus shell of the Wocan-1 hydrothermal vent, the thickness of the aragonite tablets of the same region is the same, but the thickness of the tablet of different regions is different. The myostracum has a simple prismatic ultrastructure, which is overlaid by both prismatic and nacre layers (aragonite lamellar layer). Spectral analysis shows that the minerals of the nacre and prism layers of the Bathymodiolus shell are inorganic aragonite with relatively high crystallinity and biogenic calcite,respectively. The morphology characteristics, mineral components, and genesis of the Bathymodiolus shell analyzed in the study can provide a potential example for studying the hydrothermal fields mollusk shell formation mechanism and bioinduced mineralization process.