Distribution of calcareous nannofossils in the Miocene interval of DSDP Hole 94-608 in the north Atlantic (Fig. 1)

• Main Author: Gartner, Stefan
• Format: Dataset
• Language: English
• Published: PANGAEA 1992
• Subjects: 94-608; Amaurolithus delicatus; Amaurolithus ninae; Amaurolithus primus; Calcidiscus leptoporus; Calcidiscus macintyrei; Calcidiscus premacintyrei; Calcidiscus tropicus; Catinaster calyculus; Catinaster sp.; Coccolithus miopelagicus; Coccolithus pelagicus; Coccolithus pliopelagicus; Coccolithus streckeri; Coronocyclus nitescens; Cribrocentrum latipons; Cryptococcolithus takayamae; Cyclicargolithus floridanus; Cyclolithella cricota; Cyclolithella protoannula; Cyclolithella rotula; Deep Sea Drilling Project; Dictyococcites abisectus; Dictyococcites bisectus; Discoaster asymmetricus; Discoaster bellus; Discoaster berggrenii; Discoaster bollii; Discoaster braarudii; Discoaster brouweri; Discoaster calculosus; Discoaster deflandrei; Discoaster druggii; Discoaster exilis; Discoaster hamatus; Discoaster kugleri; Discoaster loeblichii; Discoaster neohamatus; Discoaster neorectus; Discoaster obtusus; Discoaster pentaradiatus; Discoaster prepentaradiatus; Discoaster quinqueramus; Discoaster surculus; Discoaster variabilis; Discolithina sp.; DRILL; Drilling/drill rig; DSDP; DSDP/ODP/IODP sample designation; Recta; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.687629; https://doi.org/10.1594/PANGAEA.687629

DSDP North Atlantic Site 608 yielded an excellent Miocene pelagic section which affords a further opportunity for elucidating the chronology of the calcareous nannofossil succession in the framework of magnetostratigraphic control. Most of the conventional (zonal) markers have been documented for this site and some of the earlier results are confirmed and refined. In addition several unconventional and less known markers have been added. The first two are the highest (last) occurrence of Sphenolithus delphix and Sphenolithus capricornutus at 23.6 Ma, which is immediately above the Oligocene-Miocene boundary as identified by the last occurrence of Reticulofenestra bisecta at 23.7 Ma. The next unconventional datum is the highest (last) occurrence of Ilselithina fusa at 22.8 Ma, which is also the highest (last) occurrence of Helicosphaera recta. Calcidiscus tropicus' lowest (first) occurrence is at 19.5 Ma, which is also the lowest occurrence of Sphenolithus belemnos, and Calcidiscus leptoporus' lowest (first) occurrence coincides with that of Sphenolithus heteromorphus at 18.5 Ma. Sphenolithus dissimilis' highest (last) occurrence is at 18.2 Ma and the Calcidiscus premacintyrei lowest (first) and highest (last) occurrences are, respectively, at 17.7 and 11.7 Ma. Discoaster braarudii occurs from 11.6 to 11.3 Ma and its highest (last) occurrence corresponds to that of Cyclicargolithus floridanus. Minylitha convallis occurs from 9.0 to 6.9 Ma. Within the range of Minylitha, at 8.0 Ma, a major shift occurs in reticulofenestrid placoliths from dominantly large (Reticulofenestra pseudoumbilicus) and medium size (Reticulofenestra minutula) species below to significant numbers of very small species (Dictyococcites productus and Gephyrocapsa) above. This is interpreted to be a major, though perhaps seasonal, change of productivity of the North Atlantic at Site 608. A new genus and species Cryptococcolithus takayamae, is described and a variety, Reticulofenestra pseudoumbilicus var. amplus is identified.