Dinoflagellate cysts of the Early Cretaceous North Atlantic Ocean

Early Cretaceous dinoflagellate cysts were reinvestigated from nine deep-sea sites of the North and Central Atlantic. In general the zonation scheme developed for the western Central Atlantic (Habib, 1977; Habib and Drugg, 1983 ) can also be applied to the eastern Central Atlantic. Comparison with the probabilistic zonation of Gradstein et al. (1992) show, however, that the first occurrences of the important marker species Druggidium apicopaucicure, Druggidium deflandrei, Druggidium rhabdoreticulatum and Odontochitina operculata appear to occur slightly later in the eastern Central Atlantic in respect to nannofossils and benthic foraminifers. Muderongia neocomica has a shorter stratigraphic range in the eastern Central Atlantic than in the western Central Atlantic.本研究对北大西洋及中大西洋9个深海站位的早白垩世沟鞭藻囊孢（dinoflagellate cysts）开展了重新分析。总体而言，针对中大西洋西部建立的沟鞭藻囊孢生物地层分带方案（Habib, 1977; Habib & Drugg, 1983）同样适用于中大西洋东部海域。不过，与Gradstein等人（1992）提出的概率型生物地层分带方案对比后发现，相较于以钙质超微化石（nannofossils）和底栖有孔虫（benthic foraminifers）为地层对比基准的序列，重要标志种Druggidium apicopaucicure、Druggidium deflandrei、Druggidium rhabdoreticulatum以及Odontochitina operculata的首现层位在中大西洋东部海域均略晚。Muderongia neocomica在中大西洋东部海域的地层延限要短于其在中大西洋西部的地层延限。