摘要
普通透射光镜观察结果表明，珠三坳陷早第三纪文昌组和恩平组的湖相暗色泥岩中都含有丰富的无定形有机质，文昌组的无定形有机质中含有盘星藻碎屑，属淡水浮游植物质的无定形有机质，透射电镜揭示，恩平组泥岩中被透射光镜确定为无定形有机质的微屑实为煤质体（陆源植屑），因此，文昌组和恩平组的有机质类型反映了完全不同的古湖泊学特征，文昌组的无定形有机质反映了古湖泊表层水的高生产力和湖底水体的盆氧环境，恩平组的陆源植屑堆积与保存是古湖泊退缩消亡期的产物。
It is determined by transmited light microscopy that the abundant amorphous organic matter (AOM) is contained in the lacustrine dark mudstones of the Palaeogene Wengchang and Enping Formations. The AOM of the Wenchang Formation, mixed with the debis of Pediastrum, is considered to be produced from phytoplankton of fresh lake. The tiny debris of the Enping Formation , determined as AOM under transmitted light, can be recognized as subcoaly matter (terrestrial phytoclast) under TEM. The above results show that the palaeolimnologic characteristics of the Wenchang Formation are different from the Enping Formation. The abundant AOM of the Wenchang Formation reflects the high productivity in the surface water and reducing dysoxic conditions in the bottom water of the Palaeogene lake. The accumulation and preservation of the terrestrial phytoclasts in lacustrine sediments of the Enping Formation mainly resulted from the regression of Palaeogene lakes.
出处
《中国海上油气（地质）》
CAS
1996年第6期371-376,共6页
China Offshore Oil and Gas(Geology)
