Late Holocene Sedimentation and Environmental Change Record in Billefjorden, Svalbard

• Main Author: Szczuciński, Witold
• Other Authors: Lorenc, Stanisław
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2004
• Subjects: Spitsbergen; Svalbard; Billefjorden; Petuniabukta; Adolfsbukta; Nordenskioldbreen; Fjord; Sediments; Marine sediments; Fjord sediments; Sediment geochemistry; Arctic; Pyramiden; Sedimentation; Glacimarine sedimentation; Meltwater river; Glacial bay; Glaciers; Glaciomarine; Sediment provenance; Sediment traps; Sedimentation rate; Sediment accumulation rate; Flocculation; Hydrography; Oceanography; particulate matter flux; seasonal changes; suspended sediment; suspended particulate matter; sediment cores; Holocene; dating; radiocarbon; 210Pb; 137Cs; accumulation rate; ice rafted debris; coal; anthropogenic impact; environmental changes; XRD; tidewater glacier; tidal flat; sedimentary record; mud; grain size; REE; lead-210; caesium-137; Adolfbukta; Mimerbukta; Central Basin; glacier; Iceberg*; Tidewater
• Online Access: https://hdl.handle.net/10593/27355; https://doi.org/10.13140/RG.2.2.18687.38564

The Late Holocene sedimentation in Billefjorden (Svalbard) was studied through investigations of modern sedimentation conditions and their effects recorded in sediments. Sedimentation in the fjord is dominated by settling from surface turbid water plumes originating from rivers and subglacial outflows of tidewater glacier. Sedimentation is confined to the summer season (July - August) and is largely influenced by flocculation. It results in high particulate matter fluxes (up to 100 g m-2 day-1), poorly sorted sediments, and trapping of most of the sediments in the proximal few hundred meters (in case of rivers ending on tidal flats – flocculation occurs on tidal flat) to a couple of km in the case of tidewater glacier (flocculation happens after reaching the fjord waters). In the fall season, sedimentation rates are much smaller – mainly due to a smaller sediment supply but also in the effect of a largely diminished flocculation process. The latter one was found to be controlled primarily by the mixing of fresh and saline waters (so by freshwater inflow) and not by SPM concentrations. Sediment accumulation rates decrease exponentially from the source with more than 4 cm per year in the proximal settings to about 0.1 cm y-1 in the central basin. Sedimentation from icebergs has at least one order of magnitude lower rates. Fjord bottom sediments are mostly muds with bimodal grain size distribution (due to at least two sedimentation processes: suspension settling and iceberg rafting). Differences in their chemical (major, trace elements, and REE) mineralogical and coarse grain fraction composition are small but distinct. The deposits can be divided into regions supplied by local sources (e.g. Adolfbukta, Petuniabukta, Mimerbukta, central basin, entrance sill), supporting the conclusion of sediment trapping in proximal settings. The influence of rafted sediments is visible – especially in central basin sediments because the bulk of them is supplied from catchments of different geology. In the studied cores, early ...