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北冰洋首次大洋钻探(IODP302)在罗蒙诺索夫海岭获取了晚白垩世以来的沉积记录,为认识该区的沉积环境演变及烃原岩特征提供依据。该区晚白垩世以来有两次大的沉积间断:晚白垩世—晚古新世(80～56Ma)和中始新世—早中新世(44～17.5Ma)。有沉积纪录的晚古新世—中始新世(56～44Ma),平均沉积速率为12.8m/Ma;早中新世以来(0～17.5Ma),平均沉积速率11.4m/Ma。从沉积物特征及有机碳含量来看,该钻孔可以分成上下两部分:下部,古新世—中始新世,主要为灰黑色粉砂质泥岩,处于还原环境,TOC含量很高,为1.77%～6.30%;上部,中中新世以来,沉积物颜色呈条带状,主要为氧化环境,TOC含量很低,<0.4%。对全岩进行Rock-Eval指标测定,表明中始新世富有机碳沉积物大多有很好的生烃潜力,而晚白垩世、晚古新世生烃潜力较差。T_(max)与R_o值表明,钻孔的晚白垩世和古新世沉积物有机质尚处于未成熟状态,没有生烃;因此中始新统的中部较高的S1值,可能是由于烃类产生于其他更成熟的层位后运移至该处聚集的结果。
The first oceanic drilling in the Arctic Ocean (IODP 302) acquired sedimentary records from the Late Cretaceous in the Lomonosov Ridge, providing a basis for understanding the evolution of sedimentary environment and the characteristics of hydrocarbon source rocks in this area. There have been two major sedimentary discontinuities since the Late Cretaceous in this area: Late Cretaceous-Late Paleocene (80-56 Ma) and Middle Eocene-Early Miocene (44-17.5 Ma). Late Pleistocene-mid-Eocene (56-44 Ma) with sedimentary records and average deposition rate of 12.8 m / Ma. The average sedimentation rate was 11.4 m / Ma since Early Miocene (0-17.5 Ma). From the characteristics of sediments and organic carbon content, the borehole can be divided into upper and lower parts: the lower part, the Paleocene-middle Eocene, mainly gray-black silty mudstone, in a reducing environment with high TOC 1.77% ~ 6.30%. Since the upper and middle Miocene, the sediments are banded in color, mainly in an oxidizing environment with a low TOC content of <0.4%. Rock-Eval measurements of whole rock indicate that most of the Eocene organic carbon deposits have good hydrocarbon generation potential, while late Cretaceous, Late Paleocene hydrocarbon generation potential is poor. The T_ (max) and R_o values indicate that the Late Cretaceous and the Paragonian sediments in the boreholes are still in an immature state with no hydrocarbon generation. Therefore, the higher S1 value in the middle of the Middle Paleocene may be due to hydrocarbon Produced in other more mature horizons after migration to the Department of the results.