Thecosomata in late Quternary deposits of ODP Holes 134-830A and 134-831A

We undertook a quantitative study of Thecosomata shells (pelagic gastropods) and their remains in Quaternary foraminiferal oozes deposited on the tilted calcareous platform of the Bougainville Guyot (Hole 831 A), and in the late Quaternary volcanic siltstones, claystones and sandy interbeds on the upper forearc slope of the central New Hebrides Island Arc (Hole 830A). The distribution of the species is based on the identification of adult shells, juvenile stages, protoconchs, and characteristic shell fragments. By studying thecosomatous shells using a scanning electron microscope (SEM), we were able to specify the fine microstructure of the coiled Limacina inflata and compare it with the rod-type crossed-lamellar structure of some other Limacina species, as well as with the helical structure of the Cavoliniidae.

本研究针对布干维尔海山（Bougainville Guyot）倾斜碳酸盐台地上沉积的第四纪有孔虫软泥（831A钻孔），以及新赫布里底群岛弧中部上前弧坡区域的晚第四纪火山粉砂岩、黏土岩与砂质夹层（830A钻孔）中的被壳目（Thecosomata，浮游腹足类）壳体及其残骸开展了定量研究。
本研究中物种的分布依据成体壳体、幼体阶段、原壳及特征性壳体碎片的鉴定结果确定。
通过扫描电子显微镜（scanning electron microscope, SEM）对被壳目壳体的分析，我们明确了卷曲型膨胀翼螺（Limacina inflata）的精细微观结构，并将其与部分其他翼螺属（Limacina）物种的杆状交叉层状结构，以及驼蝶螺科（Cavoliniidae）的螺旋结构进行了对比。