南海珠江口盆地LH-19-4-1井新近纪有孔虫生物地层研究

THE NEOGENE FORAMINIFERAL STRATIGRAPHY OF THE LH-19-4-1 BORE HOLE, PEARL RIVER MOUTH BASIN, SOUTH CHINA SEA

标准化石的末现面(LAD)被广泛用于全球性地层划分和对比,但是,只有像白垩纪与第三纪之间的撞击事件所引起的全球性生物集群绝灭(LAD)才具有全球等时间的性质。标准浮游有孔虫化石带的LAD,可能与白垩纪与第三纪之间的撞击事件所引起的LAD一样、具有全球等时面的性质,所以它可以用于全球地层的划分和对比。依据标准浮游有孔虫带的研究,南海珠江口盆地LH-19-1-1井的岩屑地层(430m-2 630m)一共识别出20个带(N_(22)-N_3)。更新世:N_(22)带(430m-620m);晚上新世:N_(21)-N_(20)带(620m-680m);早上新世:N_(19)-N_(18)带(680m-790m);晚中新世:N_(17)-N_(16)带(790m-1 139m);中中新世:N_(15)-N_8带(1 139m-1 898m);早中新世:N_7-N_4带(1 898m-2 588m);晚渐新世:N_3带(2 588m-2 630m)。它们可以和世界其他地区的地层作准确的对比。

The Last Appearance Datum(LAD)of index fossil is widely applied to the division and correla- tion in the global stratigraphy,but only the LAD,such as the mass extinction(LAD)between the Creta- ceous and Tertiary(K/T)boundary caused by the impact event,is of global isochronic datum character. The LAD of the gulde planktonic foraminiferal zones may be same as be the LAD caused by the impact event at the K/T boundary,it is of the global isochronic datum character also.It may be employed in the division and correlation of global stratigraphy. Based on the study of the index planktonic foraminiferal zones,twenty zones(N_(22)-N_3)have been re cognized from the drilling cuttings stratigraphy(430m—2 630m)of the LH-19-4-1 bore hole,Pearl River Mouth Basion,South China Sea.They are the Pleistocene:N_(22) zone(430m—620m);the late Pliocene: N_(21)—N_(20)zone(620m-680m);the early Pliocene:N_(19)-N_(18) zone(680m-790m),the late Miocene N_(17)- N_(16)zone(790m-1139m),the middle Miocene N_(15)-N_(18)zone(1139m-1898m),the early Miocene N_7- N_4 zone(1898m—2 588m),and the late Oligocene N_3 zone(2 588m—2 630m).They may be compared with the stratigraphy of the other areas in the world accurately.