Distribution of late Neogene age calcareous nannofossils in ODP Hole 111-677A (Table 2)

• Main Author: Houghton, Simon D
• Format: Dataset
• Language: English
• Published: PANGAEA 1989
• Subjects: 111-677A; Amaurolithus amplificus; Amaurolithus delicatus; Amaurolithus primus; Amaurolithus tricorniculatus; Angulolithina arca; Calcidiscus leptoporus; Calcidiscus macintyrei; Ceratolithus acutus; Ceratolithus cristatus; Ceratolithus rugosus; Ceratolithus telesmus; Coccolithus pelagicus; Coccolithus streckeri; Dictyococcites antarcticus; Dictyococcites productus; Discoaster asymmetricus; Discoaster berggrenii; Discoaster brouweri; Discoaster intercalaris; Discoaster pentaradiatus; Discoaster pseudovariabilis; Discoaster quinqueramus; Discoaster stellulus; Discoaster surculus; Discoaster tamalis; Discoaster triradiatus; Discoaster variabilis; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Emiliania huxleyi; Epoch; Gephyrocapsa oceanica; Gephyrocapsa spp.; Helicosphaera carteri; Helicosphaera neogranulata; Helicosphaera sellii; Joides Resolution; Leg111; Nannofossil abundance; Nannofossils preservation; Nannofossil zone; Martini; 1971; Neosphaera coccolithomorpha; North Pacific Ocean; Ocean Drilling Program; ODP; Antarc*; antarcticus
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.745483; https://doi.org/10.1594/PANGAEA.745483

The calcareous nannofossil assemblages recovered from Site 677A range in age from latest Miocene (NN11) to latest Pleistocene. The consistently high sediment-accumulation rate (mean of 48 m/m.y.) coupled with little dissolution of carbonate has ensured that generally rich, well-preserved coccolith assemblages occur at this site. Exceptions are the Pliocene/Pleistocene boundary sediments, which show evidence of dissolution, and upper Miocene basement sediments, which show evidence of diagenetic overgrowths. The apparent paradox of the occurrence of large numbers of the cool-water species Coccolithus pelagicus together with subtropical and tropical nannofossil species is thought to represent increased seasonality in the degree of upwelling in the Panama Basin. Seasonal upwelling was particularly intense during the late Miocene, when common C. pelagicus occurred with Thalassionema diatoms. Populations of C. pelagicus probably bloomed during a winter period of upwelling that was associated with a shallow thermocline and depressed surface-water temperatures.