The Cenomanian-Turonian boundary at Eastbourne (Sussex, UK): a proposed European reference section
The Cenomanian-Turonian boundary at Eastbourne (Sussex, UK): a proposed European reference section
复制标题
DOI：
10.1016/s0031-0182(99)00009-7
复制
发表时间：
1999-06
期刊：
影响因子：
--
通讯作者：
C. Paul;M. Lamolda;S. Mitchell;M. Vaziri;A. Gorostidi;J. Marshall
中科院分区：
文献类型：
--
作者：
C. Paul;M. Lamolda;S. Mitchell;M. Vaziri;A. Gorostidi;J. Marshall
位于英格兰苏塞克斯郡伊斯特本的Cenomanian-Turonian界线剖面是盎格鲁-巴黎盆地中露头最厚的剖面，剖面整体韵律性好，富含宏、微、超微化石，与欧洲西北部其他剖面相比，成岩蚀变较少。地球化学和生物地层学数据都与详细的（韵律）岩石地层学有关，可以与全球边界层型剖面进行20，000年内的对比，并准确估计变化率。非常详细的氧和碳的稳定同位素曲线，并显示建立阶段的CTB碳偏移有两个部分分开的低谷。粗粒级底栖有孔虫（> 250 μ m）的出现模式显示出两个灭绝高峰，对应于碳漂移的两个积累阶段。底栖和南极有孔虫，介形虫和钙质超微化石都显示在整个CTB的多样性和丰度下降。有孔虫的大小也显著下降。CTB的关键生物标志物事件包括：菊石Fagesia catinus和Mammites nodosoides，双壳类Mytiloides，浮游有孔虫Helvetoglobotruncana praehelvetica和Marginotruncana renzi的首次出现，以及钙质超微化石Quadrum intermedium，Q. gartneri和Eprolithus octopetalus;以及最后出现的菊石Sciponoceras、南极有孔虫Rotalipora greenhornensis和R. cushmani、Corolithion kennedyi、Axopodorhabdus albianus、Lithraphidites acutus、Rhagodiscus asper和Microelithus chiastius。旋回地层学允许非常精确的同位素和生物事件与欧洲和北美的其他部分的相关性。伊斯特本被推荐为西北欧洲标准段。
The Cenomanian–Turonian boundary (CTB) section at Eastbourne, Sussex, England is the thickest at outcrop in the Anglo–Paris Basin, is rhythmic throughout, rich in macro-, micro- and nanno-fossils, and shows less diagenetic alteration than other sections in NW Europe. Geochemical and biostratigraphic data are all related to detailed (rhythmic) lithostratigraphy, allowing correlation with the global boundary stratotype section to within 20,000 years and accurate estimates of rates of changes. Very detailed stable isotope curves for oxygen and carbon are presented and show that the build-up phase of the CTB carbon excursion had two portions separated by a trough. Patterns of occurrence of coarse-fraction benthic foraminifera (>250 μm) show two peaks of extinction corresponding to the two build-up phases of the carbon excursion. Benthic and planktic foraminifera, ostracods and calcareous nannofossils all show declines in diversity and abundance across the CTB. Foraminifera also decline significantly in size. Key biomarker events for the CTB include: first occurrences of the ammonites Fagesia catinus and Mammites nodosoides, the bivalve Mytiloides, the planktic foraminifera Helvetoglobotruncana praehelvetica and Marginotruncana renzi, and the calcareous nannofossils Quadrum intermedium, Q. gartneri and Eprolithus octopetalus; and last occurrences of the ammonite Sciponoceras, the planktic foraminifera Rotalipora greenhornensis and R. cushmani, the calcareous nannofossils Corolithion kennedyi, Axopodorhabdus albianus, Lithraphidites acutus, Rhagodiscus asper and Microstaurus chiastius. Cyclostratigraphy allows very precise correlation of isotopic and bioevents with other sections in Europe and North America. Eastbourne is recommended as a NW European standard section.