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Seismic stratigraphy records the deglacial history of Jakobshavn Isbrae, West Greenland

Hogan, K.A.; Dix, J.K.; Lloyd, J.M.; Long, A.J.; Cotterill, C.J.

Authors

K.A. Hogan

J.K. Dix

C.J. Cotterill



Abstract

Jakobshavn Isbræ is one of the largest ice streams in the Greenland Ice Sheet, presently draining c. 6.5% of the Inland Ice. Here we present high-resolution Chirp and Sparker sub-bottom profiles from a seismic survey conducted just outside of the Jakobshavn Isfjord, which provides detailed insight into the glacimarine sedimentary history of the Jakobshavn ice stream during the Holocene. We observe acoustically stratified and homogeneous sediments that drape an irregular substratum and were deposited between ∼10 and c. 7.6k cal a BP. The stratified lower units are interpreted as the product of ice-proximal glacimarine sedimentation deposited rapidly when the grounded ice margin was located close to depositional basins on topographic highs. The upper acoustically homogenous units reflect suspension settling of fine-grained material and gravitational flows that were extruded from an increasingly unstable ice margin as the ice retreated into the fjord. Proximity to the ice margin and bedrock topography were the dominant controls on sediment accumulation during deglaciation although the 8.2-ka cooling event probably influenced the position of the ice margin at the fjord mouth. The post-glacial sedimentary record is characterized by glacimarine and hemipelagic rainout with an increased ice-rafted detritus fraction that records sedimentation following ice stream retreat into Jakobshavn Isfjord sometime after c. 7.8k cal a BP.

Citation

Hogan, K., Dix, J., Lloyd, J., Long, A., & Cotterill, C. (2011). Seismic stratigraphy records the deglacial history of Jakobshavn Isbrae, West Greenland. Journal of Quaternary Science, 26(7), 757-766. https://doi.org/10.1002/jqs.1500

Journal Article Type Article
Publication Date Oct 1, 2011
Deposit Date Sep 5, 2011
Journal Journal of Quaternary Science
Print ISSN 0267-8179
Electronic ISSN 1099-1417
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 26
Issue 7
Pages 757-766
DOI https://doi.org/10.1002/jqs.1500
Keywords Acoustic facies, Deglaciation, Disko Bugt, Glacimarine sedimentation, Jakobshavn Isbræ.
Public URL https://durham-repository.worktribe.com/output/1505587