珠江口盆地PY27—2—1井高分辨率钙质超微生物地层和层序地层研究

通过定量统计分析,对珠江口盆地PY27-2-1井进行了高分辨率钙质超微生物地层和层序地层研究,共识别出18个生物事件,划分出17个化石带(或联合带)和18个三级层序,在此基础上建立了该井钙质超微生物地层和层序地层框架.基于对珠江口盆地39口钻井钙质超微化石NN5和NN4带厚度分布特点的分析,认为“上薄下厚”是这两个化石带在盆地内分布的一般规律,PY27-2-1等井出现“上厚下薄”则是在非正常海相环境下形成的特殊现象,文中对“上簿下厚”和“上厚下薄”的成因进行了讨论.

HIGH RESOLUTION CALCAREOUS NANNOFOSSIL BIOSTRATIGRAPHY AND SEQUENCE STRATIGRAPHY OF WELL PY27-2-1,PEARL RIVER MOUTH BASIN

High-resolution calcareous nannofossil biostratigraphic and sequence stratigraphic study has been performed by means of quantitative analysis. According to the 18 bio-events recovered, 17 nannofossil zones (integrated zones)and 18 third-order sequences recognized,the calcareous nannofossil biostratigraphic and sequence stratigraphic frames were established. The study of 39 wells shows that thinner zone NN5 and thicker zone NN4 appear in most wells and may be the general pattern in depth distribution of the two zones in the Pearl River Mouth Basin. A few wells,including PY27-2-1,seems to be thicker zone NN5 and thinner zone NN4,which is interpreted as special cases due to abnormal marine conditions. The contributing mechanism is discussed too.