Late Glacial/early Holocene benthic foraminifera assemblages, stable isotopes, IRD, magnetic susceptibility, Mn/Fe ratio and vivianite count from Storfjordrenna, western Barents Sea

• Main Authors: Łącka, Magdalena, Michalska, Danuta, Pawłowska, Joanna, Szymańska, Natalia, Szczuciński, Witold, Forwick, Matthias, Zajączkowski, Marek
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2020
• Subjects: Arctic; Barents Sea; Benthic foraminifera; Holocene; Stable isotopes; Storfjorden Trough; Svalbard; vivianite; XRF; Younger Dryas; Gravity corer; JM09702; Jan Mayen; Norway; Tromsø; Storfjordrenna; Climate change; Foraminifera*; Magnetic susceptibility; Storfjorden; Arctic University of Norway; University of Tromsø
• Online Access: https://dx.doi.org/10.1594/pangaea.917645; https://doi.pangaea.de/10.1594/PANGAEA.917645

Lateglacial/early Holocene interval from the sediment core JM09-020GC recovered in Storfjordrenna (western Barents Sea) has been studied for benthic foraminifera assemblages, stable isotopes, IRD, vivianite microconcretions, magnetic susceptibility, and elemental composition in order to identify the causes and mechanisms of abrupt climate change during the Younger Dryas.The core was retrieved with R/V Jan Mayen (University of Tromsø – The Arctic University of Norway, UiT) in November 2009 from the Storfjordrenna (76°31489' N, 19°69957' E) at a bottom depth of 253 m. Prior to sediment core opening, the magnetic susceptibility was measured using a loop sensor installed on a GEOTEK Multi Sensor Core Logger at the Department of Geology, UiT. Core sections were stored in the laboratory for one day prior to measurements, thus allowing the sediments to adjust to room temperature and avoiding measurement errors related to temperature changes (Weber et al., 1997). Qualitative element-geochemical measurements were performed with Avaatech X-ray fluorescence (XRF) core scanner using the following settings: 10 kV, 1000 µA, 10-s measuring time, and no filter. Sediment samples for foraminiferal and vivianite analyses were freeze-dried, weighed, and wet sieved using sieves with mesh sizes of 500 µm and 100 µm. The residues were dried, weighed again, and subsequently split on a dry micro-splitter. Where possible, at least 300 specimens of foraminifera were counted in every 1 cm of sediment. Species identification under a binocular microscope (Nikon SMZ1500) was supported using the classification of Loeblich and Tappan (1987), with few exceptions, and percentages of the eight indicator species were applied. The benthic foraminiferal abundance and ice-rafted debris (IRD; grains >500 µm) were counted under a stereo-microscope and expressed as flux values (number of specimens/grains cm-2 ka-1) using the bulk sediment density and sediment accumulation rate.