湖相沉积浮游藻类及有机质类型与烃源研究

Research on Phytoplankton and Organic Matter in the Lacustrine Sediments and Hydrocarbon Source Conditions

中国含油盆地的湖相生油岩大多含有丰富的化石浮游藻类，主要包括非海相沟鞭藻囊孢和单细胞绿藻珠江口盆地西部早第三纪湖相生油岩的详细研究证实，化石浮游藻类相对丰度（占孢粉型总数）和无定形有机质含量（占干酪根总量）的高值指示古湖表层水高生产力和底部水体贫氧环境．表层水高生产力为湖泊沉积物提供大量的原地生藻质富氢有机质，贫氧的湖底有利于这类藻质无定形有机质堆积与保存．

It has been shown that the lacustrine source rocks of the Chinese hydrocarbon-bearing basins contain usually abundant fossil Phytoplankton including mainly nonmarine dinocysts and unicellular green algae.A detailed studyon the Palaeogene lacustrine sourcerocks in the west of the Pearl River Mouth Basin has demonstrated that there existhigh values of percentage of fossil Phytoplankton of total palynomorphs and that the amorphousorganic matter (AOM)of total kerogen indicates the high productivity in the surface water and the reducing anoxic condition in the bottom wa ter of the palaeo-lakes.The high productivity in the surface water contributes greatly autochthonous phytoplankton hy-drogen-rich roganic matter to the lacustrine sediments.The oxygen-depleted bottom water,as a result of the lakestratification,favoures the accumulation and perservation of the phytoplankton source AOM.