Small cycle sedimentation of organic matter from ODP Hole 128-798B in the Japan Sea (Table 1)

Sedimentological and organic geochemical investigations of sediments of Site 798 give important information about the paleoenvironmental and paleoceanographic conditions of the Japan Sea. Distinct dark/light cycles from the uppermost 37 m of the record (i.e. the last 200,000 years) were sampled in detail and analyzed for TOC content, C/N-ratios and hydrogen index values to characterize the organic material. A subdivision into three types of cycles was possible, representing different environmental conditions during formation of the dark/light rhythms. Additionally, the data were correlated with the global oxygen isotope curve and biogenic opal data to define the stratigraphic framework and stage boundaries. The results indicate that glacial intervals are generally dominated by a very distinctive cyclicity whereas interglacial sediments are more homogenous and cycles less pronounced. […]

对 Site 798 沉积物的沉积学及有机地球化学研究，为探讨日本海的古环境及古海洋学条件提供了重要信息。详细采样并分析了记录最上部 37 米（即过去 20 万年）中明显的暗/亮周期，包括总有机碳含量、碳氮比以及氢指数值，以表征有机物质。该记录可进一步划分为三种循环类型，分别代表了形成暗/亮节奏期间不同的环境条件。此外，这些数据与全球氧同位素曲线及生物成因蛋白石数据相关联，以界定地层框架和阶段界限。研究结果揭示，冰期间的沉积物普遍呈现出非常独特的周期性特征，而间冰期的沉积物则更为均质，周期性特征亦较为不明显。