摘要
珠江口盆地下第三系始新统至渐新统恩平组分布广泛。孢粉组合为Dicolpopollis kockelii-Gothanipollis bassensis组合。主要特征是以属、种繁多的被子类花粉占优势,其中以Quercokhtes、Cupuliferoipollenites、Alnipollenietes为主,并掺入较多喜热分子Dicolpopollis kockelii Liquidambarpollenites等,Gothanipollis bassensis在中上部较连续集中出现;裸子类Bisaccatepollen发育;少见古老类型分子。这一孢粉组合及其与上覆珠海组和下伏文昌组比较,特征更接近珠海组而与文昌组区别较大。并可与邻区北部湾盆地涠洲组对比,时代归属渐新世。白云7-1-1井恩平组发现浮游有孔虫N_3带和钙质超微化石NP24/23带,均说明恩平组归属渐新世。但恩平组下部孢粉化石数量少,未发现有孔虫化石和钙质超微化石,所以不能排除恩平组下部归属始新世的可能性。
The continental deposits of Enping formation aged from Oligocene to Eocene of Palaeocene are well-developed and widespreaded in the Pearl River Mouth Basin. Pollen and spore Fossils are very abundant within the formation. The assemblage of pol-len and spores are characterized by Dicolpopollis kockelii-Gothanipollis bassensis zones. This assemblage is dominated by rich type of Angiospermae woody, like QuercoiditesCupuliferoipollenites. And the assemblage also contains some warm plant Dicolpopollis kockelii and Liguidambarpollenites etc., and Gothanipollis hassensis is consistent in the Enping formation. The assemblage is relatively rich of bisaccate pollen. but the older pollen and spores are very rare or absent. The upper boundary of this assemblage(Miocene/Oligocene)is marked by the consis-tent present of Gothanipollis bassensis. The lower boundary(Oligocene/Eocene)of this as-semblage is marked by the consistent present of Pentapollenites. The characteristics of this as-semblage are very similar to the assemblage in the overlain Zhuhai formation, but they are different from the assemblage in the underlain Wenchang formation, and can be correleted with Wezhou formation of Baibuwan basin. It is also mentioned in this article that some Planktonic N_3 zone and Calcareous nannofossils NP_(24/23) zones are found in the Baiyu 7-1-1 well, The absolute age of Enping formation is 35.5ma. All of these indicate that the age of Enping formation is Oligocene. In some of the wells, pollen and spores fossils are very rare in the lower part of Enpingformation and also no microforaminifera and nannofossils are discovered, so there is a possi-bility that the age of lower part of Enping formation is Eocene.
出处
《石油学报》
EI
CAS
CSCD
北大核心
1992年第2期258-267,共10页
Acta Petrolei Sinica
