MODERN SEDIMENTARY PROCESSES AND DEPOSITS AT THE KRONEBREEN-KONGSVEGEN TIDEWATER GLACIER FRONT, KONGSFJORDEN, SVALBARD, NORWAY
FERRY, Nicholas, Department of Geology, University of Kansas, Lawrence, KS 66045; Department of Geology & Environmental Geosciences, Northern Illinois University, De Kalb, IL 60115, POWELL, Ross D., Department of Geology & Environmental Geosciences, Northern Illinois University, De Kalb, IL 60115 and BRIGHAM-GRETTE, Julie, Department of Geosciences, University of Massachusetts, Amherst, MA 01003
Part of the Svalbard Research Experience for Undergraduates (REU) project, was designed to quantify modern sedimentary processes in the environment proximal to the Kronebreen-Kongsvegen subpolar tidewater glaciers that end in Kongsfjord, Svalbard, and relate those processes to sedimentary deposits. The purpose of this study is to first define the important processes that can contribute to the stability of these glaciers relative to global warming. A second goal is to provide a geological template for interpreting sedimentary records of these polythermal glacimarine environments in order to assess responses of these glaciers to past global temperature changes. To achieve this goal a series of sediment gravity- and boxcores were collected from Kongsfjorden during the summer of 2014. Sedimentary facies were identified within these cores by describing color, particle size, primary and penecontemporaneous sedimentary structures, and contact types following standard sedimentological procedures. The lithofacies delineated using these data were related to the observed and quantitatively measured processes occurring in the fjord.
The dominant depositional mechanisms in the fjord, included (i) turbidity currents and debris flows on the fjord floor as rapidly deposited sediment fails, (ii) settling of particles from suspension in sediment plumes flowing away from meltwater streams discharging from the glacier termini, and (iii) iceberg rafting of coarse-grained sediment released from icebergs as they melt while floating away from the terminus after calving. We found that the processes and deposits are unique to these glacial systems and can be used to characterize them in older deposits to infer past glacier behavior. Furthermore, these sediments could potentially accumulate fast enough to help slow glacial retreat; however, they do not appear to be accomplishing that at present and the ice continues to be lost to global warming and contributes to rising sea levels.