【摘要】 钙质超微化石的生物地层学是对钴结壳定年的可靠方法。由于沉积环境、结壳形成的古气候等因素的影响,使保存于结壳中的钙质超微化石数量不丰富,增加了化石发现的难度。本次工作对采自西北太平洋中部海山区的CHA56富钴锰结核进行了细致的钙质超微化石分析,发现了大量化石,共鉴别出20属41种,并对主要的化石属种进行了描述,进一步划分出了古新世至更新世的6个化石组合带,由下至上为Neocrepidolithus fossus-Discoaster megastypus;Zygodiscus sigmoides-Cyclicargolithus luminis;Reticulofenestra umbilica-Cyclicargolithus marismontium;Discoaster calculosus-Helicosphaera ampliaperta;Sphenolithus moriformis-S.neoabies;Sphenoli-thus neoabies-Umbellosphaera tenuis组合带。化石组合时代显示,CHA56结壳是属于古新世至更新世的沉积。更多还原

【Abstract】 Calcareous nannofossil biostratigraphy is an effective method to date Co-rich ferromanganese crust. The sample CHA56 of the Co-rich crust was collected from the Northwestern Pacific seamount, and yields abundant nannofossils. In this work, 41 species of 20 genera have been identified and illustrated. Six calcareous nannofossil zones have been divided, including the Neocrepidolithus fossus-Discoaster megastypus; Zygodiscus sigmoides-Cyclicargolithus luminis; Reticulofenestra umbilica-Cyclicargolithus marismontium; Discoaster calculosus-Helicosphaera ampliaperta; Sphenolithus moriformis-S. neoabies; Sphenolithus neoabies-Umbellosphaera tenuis assemblages. The ages of these fossil assemblages indicate that the Co-rich crust’ accumulation is from Paleocene to Pleistocene.更多还原