Stable isotope record of planktonic foraminifera from sediment core MD96-2085

• Main Authors: Chen, Min-Te, Chang, Yuan-Pin, Chang, Cheng-Chieh, Wang, Liping, Wang, Chung-Ho, Yu, Ein-Fen
• Format: Dataset
• Language: English
• Published: PANGAEA 2002
• Subjects: CALYPSO; Calypso Corer; IMAGES; IMAGES II; International Marine Global Change Study; Marion Dufresne (1995); MD105; MD962085; MD96-2085; off Orange River; Antarctic; The Antarctic; Antarc*; Neogloboquadrina pachyderma; Planktonic foraminifera
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.736657; https://doi.org/10.1594/PANGAEA.736657

A high-resolution (~4-5cm/kyr) giant piston core record (MD962085) retrieved during an IMAGES II-NAUSICAA cruise from the continental slope of the southeast Atlantic Ocean reveals striking variations in planktonic foraminifer faunal abundances and sea-surface temperatures (SST) during the past 600 000 yr. The location and high-quality sedimentary record of the core provide a good opportunity to assess the variability of the Benguela Current system and associated important features of the ocean-climate system in the southeast Atlantic. The planktonic foraminifer faunal abundances of the core are dominated by three assemblages: (1) Neogloboquadrina pachyderma (right coiling) + Neogloboquadrina dutertrei, (2) Globigerina bulloides, and (3) Globorotalia inflata. The assemblage of N. pachyderma (right coiling) + N. dutertrei shows distinctive abundance changes which are nearly in-phase with glacial-interglacial variations. The high abundances of this assemblage are associated with major glacial conditions, possibly representing low SST/high nutrient level conditions in the southwestern Africa margin. In contrast, the G. bulloides and G. inflata assemblages show greater high-frequency abundance change patterns, which are not parallel to the glacial-interglacial changes. These patterns may indicate rapid oceanic frontal movements from the south, and a rapid change in the intensity of the Benguela upwelling system from the east. A single episode of maximum abundances of a polar water species N. pachyderma (left coiling) occurred in the beginning of stage 9 (~340-330 kyr). The event of the maximum occurrence of this species shown in this record may indicate instability in the Benguela coastal upwelling, or the Antarctic polar front zone position. A winter season SST estimate using transfer function techniques for this record shows primarily glacial-interglacial variations. The SST is maximal during the transitions from the major glacial to interglacial stages (Terminations I, II, IV, V), and is associated with the ...