【摘要】 渤海海域黄河口南斜坡新生代火山岩规模大,喷发期次多,非均质性强,地震反射杂乱,地层划分对比难度大。为了厘定渤海海域黄河口南斜坡火山岩系地层层位,对研究区火山岩的岩石学特征及火山岩系夹层中的化石展开系统研究。薄片分析结果表明,渤海海域黄河口南斜坡火山岩主要分为火山熔岩和火山碎屑岩两大类,其中火山熔岩主要有杏仁状玄武岩、气孔玄武岩、致密玄武岩、辉绿岩以及角砾熔岩四种,火山碎屑岩以凝灰岩为主。结合渤海海域黄河口南斜坡火山岩中常见铁方解石、沸石、绿泥石等热水沉积矿物、部分玄武岩保存有淬碎结构、氧化系数（Fe₂O₃/FeO）低以及火山岩与黑色泥岩互层等四方面,证据证实研究区部分火山岩具有水下喷发特征。渤海海域黄河口南斜坡火山岩系夹层中发现了丰富的介形虫、藻类和孢粉化石,指示火山岩系上段为东营组二段沉积,火山岩系下段主体为东营组三段。根据化石的层位指示意义,明确黄河口南斜坡东营组三段沉积时期物源主要来自莱北低凸起的中生界和沙河街组一段地层。通过化石的古环境指示意义,对这套地层的形成过程进行恢复。这套地层层位的落实对明确黄河口南斜坡新生代油气成藏规律具有重要意义。更多还原

【Abstract】 The Cenozoic volcanic stratigraphic sequence on the south slope of Huanghekou sag, Bohai Sea is characterized by the large scale, multi-eruption, strong heterogeneity and desultory seismic reflection. Lithologic characteristics and the microfossils in the sequence are analyzed. According to the thin sections, the volcanic rocks can be classified into volcanic lava and pyroclastic rock. The volcanic lava includes amygdaloidal basalt, vesicular basalt, tight basalts, diabase and breccia lava, whereas the pyroclastic rock is mainly composed of the tuffs. Four lines of evidence confirm that part of the volcanic rocks in the south slope of Huanghekou sag are subaqueous volcanic rocks. The evidence are as follows:（1） hydrothermal sedimentary minerals are widespread, such as iron calcite, zeolite, chlorite;（2） quench textures occurs in some basalts;（3） oxidation index（Fe₂O₃/FeO） is low; and（4） volcanic rocks are interbedded with the black mudstone. Abundant microfossils including ostracods, sporopollens and algae in the interbedded mudstone indicate that the upper of volcanic rock sequence belongs to the second member of the Dongying Formation and the lower part is the third member of the Dongying Formation. The microfossils also suggest that the sediments of the south slope of Huanghekou sag were from the Mesozoic rocks and the first member of Shahejie Formation in Laibei low uplift during the depositional period of the third member of the Dongying Formation. In addition, the palaeoenvironment significance of the microfossils was discussed. The present study provides important data for evaluating the Cenozoic hydrocarbon resources in the southern slope of Huanghekou sag.更多还原