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通过渤海5口钻井的沉积有机质分析,以沉积有机质中浮游藻类丰度和类型、无定形有机质含量变化以及地层序列中富藻沉积层发育程度,作为指示湖相沉积环境发育的标志,确定渤海新近纪湖相沉积层的分布特征及渤海古坳陷湖的发育特征。分析表明,浮游藻类和无定形有机质含量高的层段在馆陶组和明下段都有分布,但发育最好的是在明下段下部。这是渤海新近纪湖相沉积地层存在的直接证据。从湖相沉积发育的差异看,馆陶组和明化镇组时期的古湖有着不同的特征,馆陶组早期渤海的湖泊可能很小,馆陶组中、晚期为湖泊扩张期,从含浮游藻类和无定形有机质沉积层纵向变化频繁出现可以看出浅湖沉积环境的不稳定性。新近纪古湖的盛期是在明下段下部沉积时段,当时渤海淡水湖泊普遍存在。
Based on the analysis of sedimentary organic matter in the five wells of Bohai Sea, the abundance and type of phytoplankton in the sedimentary organic matter, the content of amorphous organic matter and the development of algae sedimentary layer in the sequence of sediment are used as indicators to indicate the sedimentary environment of lacustrine sediments. Distribution Characteristics of Lacustrine Sediments and Development Characteristics of Paleogene Depression Lakes in. The analysis shows that the layers with high content of phytoplankton and amorphous organic matter are distributed in both Guantao Formation and Ming Dynasty, but the best development is in the lower part of Ming Dynasty. This is direct evidence of the existence of the lacustrine sedimentary strata in the Bohai Sea. According to the difference of deposition and deposition in the lacustrine facies, the ancient lakes in the Guantao Formation and the Minghuazhen Formation have different characteristics. The lakes in the early Guantao Formation may be small in the early Bohai Sea. For the late Guantao Formation, Longitudinal changes in sediment of algae and amorphous organic sediments show the instability of shallow lake sedimentary environment. The Neogene ancient lake peak is in the lower Ming Dynasty deposition period, when the prevalence of freshwater Bohai Sea.