Late Quaternary benthic foraminiferal assemblages from the central Arctic Ocean
(English)Article in journal (Refereed) Submitted
Sediment cores retrieved from the Morris Jesup Rise and the southern Lomonosov Ridge north off Greenland reveal an extended microfossil record compared to most other cores recovered from the central Arctic Ocean. The identified benthic foraminifera can be divided into six assemblages, all of which are dominated by the most common species Cassidulina neoteretis. This species is observed in surface sediments throughout the central Arctic Ocean at water depth under the influence of the Arctic Intermediate Water suggesting that this condition prevailed for a long time and also show that is an important factor for assemblage composition. The important accessory species in the top two assemblages, Oridorsalis tener, suggests oligotroph conditions and probable high sea ice cover during the Marine Isotope Stages (MIS) 1 to 5.1. The occurrence of the phytodetrital exploiting species Epistominella exigua characterizes the assemblages 3 to 6 (MIS 5.5 and older). This species is not present in recent central Arctic Ocean sediments and has been used as biostratigraphic marker for MIS 5.5 as a unique event. This study shows that E. exigua rather has its last occurrence in this time interval and is continuously found in older sediments. For the environmental conditions during this time period the presence of E. exigua implies higher primary production in the surface waters and with that lesser summer sea ice compared to present day conditions. While the abundance of agglutinated specimens increases downcore a complete switch as described from most other central Arctic Ocean cores during MIS 7 to 9 cannot be confirmed.
Research subject Geology
IdentifiersURN: urn:nbn:se:su:diva-56910OAI: oai:DiVA.org:su-56910DiVA: diva2:413820