摘要
介绍渐新世/中新世分界面(即古近纪/新近纪分界面)附近的浮游有孔虫和钙质超微化石事件及其新年龄。2004年国际地层年代表确定该分界面位于第58长偏心率周期弱振幅处,古地磁事件C6Cn.2n底面,经天文调谐后的年龄为23.03 Ma。发生在该界面附近的生物地层学事件主要是浮游有孔虫Paragloborotalia kugleri的始现面(22.96 Ma)和钙质超微化石Sphenolithus delphix的末现面(23.11 Ma)。在南海北部东沙群岛附近的大洋钻探ODP1148站,渐新世/中新世界面以崩塌沉积物为特征,有明显沉积间断,标志南海当时有较大范围的构造运动。
New ages of planktonic foraminiferal and nannofossil events across the Oligocene/Miocene boundary （also the Paleogene/Neogene boundary）are introduced. The 2004 international geologic time scale placed the boundary at the base of magnetic subchron C6Cn. 2n, close to a period of weak eccentricity amplitude referable to the long eccentricity cycle 58, with an astronomically-tuned age of 23.03 Ma. The most important bio-events occurring close to the boundary are the first occurrence of planktonic foraminifer Paragloborotalia kugleri at 22.96 Ma and the last occurrence of nannofossil Sphenolithus delphix at 23. 11 Ma. At ODP Site 1148 from near the Dongsha Islands, the Oligocene/Miocene boundary is characterized by a slumped deposit with several sedimentation breaks, indicating a series of wide scale tectonic activities in the then South China Sea.
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
2007年第5期57-64,共8页
Marine Geology & Quaternary Geology
基金
国家自然科学基金项目(405760314047603040631007)
关键词
渐新世/中新世分界
新近纪
浮游有孔虫
钙质超微化石
氧同位素
南海
Oligocene/Miocene boundary
planktonic foraminifera
calcareous nannofossil
oxygen isotopes
Neogene
South China Sea
