Monitoring Termination II at high latitude: anomalies in the planktic foraminiferal record

• Published in: Marine Geology
• Main Author: Bauch, Henning A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 1996
• Subjects: Greenland; Greenland Sea
• Online Access: https://oceanrep.geomar.de/id/eprint/27860/; https://oceanrep.geomar.de/id/eprint/27860/1/1996_Bauch-Monitoring_MarGeol-131.pdf; https://doi.org/10.1016/0025-3227(95)00147-6

Microfaunal studies of planktic foraminifera carried out on 21 sediment cores from the Norwegian-Greenland Sea (NGS) reveal the spatial and lateral distribution as well as meltwater implication of today's non-polar/subpolar species Beella megastoma (Earland). Previous findings are verified in that this foraminifera is characteristic only of the deglaciation phases of Termination II, III, and VI and not the ensuing interglacial optima, thus, rendering this species a ‘meltwater’ indicator. Its distribution is restricted to cores from the central, i.e., more ‘pelagic’, part of the NGS covering an area as far north as 77 ° latitude. A detailed investigation of Termination II indicates that B. megastoma first appeared in the southwest of the NGS at ~131 ka and then about 6 kyr later in the eastern and northern parts of the NGS. For the entire duration B. megastoma always coincided with the deposition of distinct ice-rafted detritus (IRD) suggesting the presence of drifting icebergs during this period. Two different oceanographic models, each with a two-stepped evolution of the post-Saalian surface water circulation, are proposed to account for this time transgressive character. The mechanism of brine formation as possible oceanic phenomenon forcing Atlantic water northwards is suggested for being responsible for the occurrence of B. megastoma in the NGS during early Termination II. The presence of B. megastoma always ceased with the culmination of the interglacial optimum, oxygen isotopic Substage 5.51 (Eemian), when the subpolar foraminiferal fauna reached highest abundances and a general lack of IRD is observed.