Sediment descriptions, stage, calcium carbonate, organic carbon, delta 13C and geolipids at DSDP Hole 93-603B

Organic matter contents of black shales from the Cretaceous Hatteras and Blake-Bahama formations have been compared to those from surrounding organic-poor strata using C/N ratios, d13C values, and distributions of extractable and nonsolvent-extractable, long-chain hydrocarbons, acids, and alcohols. The proportion of marine and land-derived organic matter varies considerably among all samples, although terrigenous components generally dominate. Most black shales are hydrocarbon-poor relative to their organic-carbon concentrations. Deposition of the black shales in Hole 603B evidently occurred through turbiditic relocation from shallower landward sites and rapid reburial at this outer continental rise location under generally oxygenated bottom-water conditions.

本研究通过碳氮比（C/N）、δ¹³C值以及可萃取与非溶剂萃取长链烃类、酸类和醇类的分布特征，对白垩纪哈特拉斯组（Hatteras）与布雷克-巴哈马组（Blake-Bahama）黑色页岩的有机质含量，及其周边贫有机质地层的有机质含量开展对比分析。所有样品中海源与陆源有机质的占比差异显著，但整体仍以陆源组分为主导。相较于自身有机碳浓度，多数黑色页岩的烃类含量偏低。603B钻孔中的黑色页岩沉积过程，显然是通过浊流作用从较浅的向陆区域搬运而来，并在该大陆隆外缘位置的普遍富氧底水环境中得以快速埋藏。