Benthic foraminifera groups of ODP Site 162-982

• Main Authors: Kawagata, Shungo, Hayward, Bruce William, Grenfell, Hugh R, Sabaa, Ashwaq T
• Format: Dataset
• Language: English
• Published: PANGAEA 2005
• Subjects: 162-982; Accumulation rate; benthic foraminifera by number; benthic foraminifera extinction group by number; benthic foraminifera low oxygen group by number; benthic foraminifera opportunistic group by number; COMPCORE; Composite Core; Counting >63 µm fraction; Density; grain; Depth; composite; sediment/rock; DSDP/ODP/IODP sample designation; Foraminifera; benthic; benthic extinction group; benthic low oxygen group; benthic opportunistic group; Fragmentation index; Ice rafted debris; Intercore correlation; Joides Resolution; Leg162; North Atlantic Ocean; Number of species; Ocean Drilling Program; ODP; Sample code/label; Sample mass; Sand; mass netto; North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.774885; https://doi.org/10.1594/PANGAEA.774885

The pulsed decline and eventual extinction of 51 species of elongate, cylindrical deep-sea benthic foraminifera (Stilostomellidae, Pleurostomellidae, and some Nodosariidae) occurred at intermediate water depths (1145–2168 m, Sites 980 and 982) in the northern North Atlantic during the mid-Pleistocene transition (MPT, 1.2–0.6 Ma). In the early Pleistocene, prior to their disappearance, these species comprised up to 20% of the total abundance of the benthic foraminiferal assemblage at 2168 m, but up to only 2% at 1145 m. The MPT extinction of 51 species represents ?20% of the total benthic foraminiferal diversity at bathyal depths in the North Atlantic (excluding the myriad of small unilocular forms). The extinction rate during the MPT was approximately 10 species per 0.1 myr, being one or two orders of magnitude greater than normal background turnover rates of deep-sea benthic foraminifera. Comparison of the precise timings of declines and disappearances (= highest occurrences) of each species shows that they were often diachronous between the two depths. The last of these species to disappear in the North Atlantic was Pleurostomella alternans at ~0.679 and ~0.694 Ma in Sites 980 and 982, respectively, which is in good agreement with the previously documented global “Stilostomella extinction” datum within the period 0.7-0.58 Ma. Comparison with similar studies in intermediate depth waters in the Southwest Pacific Gateway indicates that ~61% of the extinct species were common to both regions, and that although the pattern of pulsed decline was similar, the precise order and timing of the extinction of individual species were mostly different on opposite sides of the world. Previous studies have indicated that this extinct group of elongate, cylindrical foraminifera lived infaunally and had their greatest abundances in poorly ventilated, lower oxygen environments. This is supported by our study where there is a strong positive correlation (r = ~+ 0.8) between the flux of the extinction group and low-oxygen/high ...