Investigations on two sediment cores from the Arctic Ocean, supplement to: Knies, Jochen (1994): Spätquartäre Sedimentation am Kontinentalhang nordwestlich Spitzbergens. Der letzte Glazial/Interglazial-Zyklus. Diploma Thesis, Fachbereich Geowissenschaften und Geographie der Justus-Liebig-Universität Giessen & Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, 95 pp

• Main Author: Knies, Jochen
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 1994
• Subjects: Giant box corer; Gravity corer Kiel type; ARK-VIII/2; Polarstern; Paleoenvironmental Reconstructions from Marine Sediments @ AWI AWI_Paleo; Quaternary Environment of the Eurasian North QUEEN; Arctic; Arctic Ocean; Svalbard; Whalers Bay; Alfred Wegener Institute; Foraminifera*; Fram Strait; glacier; Ice Sheet; Planktonic foraminifera; Spitsbergen
• Online Access: https://dx.doi.org/10.1594/pangaea.727527; https://doi.pangaea.de/10.1594/PANGAEA.727527

During the "RV Polarstem"-Expedition ARK VIII/2 sediment samples were obtained at the continental slope of NW-Spitsbergen. Detailed sedimentological and geochemical analysis were carried out at two undisturbed box cores (PS2122-1GKG, PS2123-2GKG) as well as two gravity cores (PS2122-1SL, PS2123-2SL). The following parameters were deterrnined: Organic carbon, nitrogen and carbonate contents, hydrogen index, stable isotopes, ice rafted debris, grain-size distribution and biogenic opal. The main objective of this study was the reconstruction of paleoenvironmental changes off the northwest coast of Spitsbergen during the last glacial/interglacial-cycle, i.e., during the last about 128.000 years.The results of the investigations can be summarized as follows:- During isotope stage 1 (Holocene) and 5.5 (Eemian Interglacial), light stable isotopes (d180: 3.4-2 %o; d13C: 0.26-0.5 %o), increased bioturbation, high content of planktonic foraminifera and biogenic opal and low quantity of ice-rafted material, indicate seasonally ice-free conditions along the northwest coast due to the intfluence of the Westspitsbergen Current.- Additionally, the sediment characteristics of the middle of isotope stage 2 (Last Glacial Maximum) and at the end of stage 3 confirms an inflow of warmer Atlantic water. The highest production of planktonic and benthic foraminifera (N. pachyderma sin., Cassidulina teretis) (CaC03: 10 %) may reflect the expansion of the 'Whalers Bay'-Polynya as a result of the influence of the Westspitsbergen Current. Presumably, occasionally open-ice conditions provide sufficient precipitation to buildup the Svalbard/Barents Ice Sheet.- The time intervals for the glacier advances on Svalbard given by Mangerud et al. (1992), can be correlated with increased accumulation of ice-rafted material in the sediments at the northwest coast of Spitsbergen. Especially during isotope stage 4 and at the beginning of the Last Glacial Maximum (isotope stage 2), a drastically increased supply of coarse terrigenous material occurs. The high accumulation rate (0.18-0.21 g/cm**2/ka) of terrigenous organic carbon is indicated by high C/N ratios (until 16) and low hydrogen index (50 mg HC/gC). In constrast to deep sea sediments in the Fram-Strait (Hebbeln 1992), the glacier advance between 118.000 and 108.000 years B.P. ist documented in the continental slope sediments.- At the end of the Weichselian ice age, the deglaciation at the northwest coast starts with a typical melt-water signal in the stables isotope record (d18O: 3.5 %o; d13C: -0.16 %o) and high contents of gravel (6-13 %). The signal can be assigned to an event at the westcoast of Spitsbergen (core NP90-39), dated to 14.500 years B.P. (Andersen et al. 1993).