Carbonate, organic carbon, pyrolysis and composition of the extracts at DSDP Holes 76-534A and 44-391

The geochemical studies of Sites 534 and 391 and their comparison allow us to improve the chemical characterization of different geological formations dating from the early Callovian to the Maestrichtian along the continental margin of eastern North America. Three of the formations are favorable for the preservation of organic matter: (1) the unnamed formation (middle Callovian to Oxfordian), (2) the Blake-Bahama Formation (Berriasian to Barremian), and (3) the Hatteras Formation (Aptian to Cenomanian). The organic matter is mainly detrital, except for a few organic-rich layers where a contribution of aquatic material occurs. In these organic-rich layers, the petroleum potential is medium to good. Maturation has not quite reached the beginning of the oil window even for the deepest organic material.对534、391两个站位开展的地球化学研究及其对比分析，有助于完善北美东部大陆边缘早卡洛夫期至马斯特里赫特期不同地质地层的地球化学特征表征。 共有三套地层具备有机质保存潜力：（1）未命名地层（中卡洛夫期至牛津期）；（2）布莱克-巴哈马地层（贝里阿斯期至巴列姆期）；（3）哈特拉斯地层（阿普第期至森诺曼期）。区内有机质以陆源碎屑型为主，仅在少量富有机质层段中存在水生来源有机质的贡献。 在这些富有机质层段内，油气生成潜力中等至良好。即便针对埋藏最深的有机质样品，其成熟度也尚未达到生油窗的起始阶段。