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

Seismic Stratigraphy records the deglacial history of Jakobshavn Isbrae, West Greenland
Seismic Stratigraphy records the deglacial history of Jakobshavn Isbrae, West Greenland
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 a detailed insight into the glacimarine sedimentary history of the Jakobshavn ice stream during the Holocene for the first time. We observe acoustically stratified and homogeneous sediments that drape an irregular substratum and were deposited between ~10 and c. 7.6 k 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 characterised by glacimarine and hemipelagic rainout with an increased ice-rafted detritus (IRD) fraction that record sedimentation following ice stream retreat into Jakobshavn Isfjord sometime after c. 7.8 k cal a BP
acoustic facies, deglaciation, Disko Bugt, glacimarine sedimentation, Jakobshavn Isbræ
0267-8179
757-766
Hogan, Kelly
a9604862-d9fc-4944-aca2-074492ae58cd
Dix, Justin
efbb0b6e-7dfd-47e1-ae96-92412bd45628
Lloyd, Jerry
5f6cf5a0-d402-470f-a1a7-214f1196bca2
Long, Antony
d1526009-4964-41ac-b148-fc902310fb90
Cotterill, Carol
cc09513b-fd65-4fa3-a95e-90fafb1aa37c
Hogan, Kelly
a9604862-d9fc-4944-aca2-074492ae58cd
Dix, Justin
efbb0b6e-7dfd-47e1-ae96-92412bd45628
Lloyd, Jerry
5f6cf5a0-d402-470f-a1a7-214f1196bca2
Long, Antony
d1526009-4964-41ac-b148-fc902310fb90
Cotterill, Carol
cc09513b-fd65-4fa3-a95e-90fafb1aa37c

Hogan, Kelly, Dix, Justin, Lloyd, Jerry, Long, Antony and Cotterill, Carol (2011) Seismic Stratigraphy records the deglacial history of Jakobshavn Isbrae, West Greenland. Journal of Quaternary Science, 26 (7), 757-766. (doi:10.1002/jqs.1500).

Record type: Article

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 a detailed insight into the glacimarine sedimentary history of the Jakobshavn ice stream during the Holocene for the first time. We observe acoustically stratified and homogeneous sediments that drape an irregular substratum and were deposited between ~10 and c. 7.6 k 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 characterised by glacimarine and hemipelagic rainout with an increased ice-rafted detritus (IRD) fraction that record sedimentation following ice stream retreat into Jakobshavn Isfjord sometime after c. 7.8 k cal a BP

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More information

Published date: October 2011
Keywords: acoustic facies, deglaciation, Disko Bugt, glacimarine sedimentation, Jakobshavn Isbræ
Organisations: Ocean and Earth Science, Coastal & Shelf Research

Identifiers

Local EPrints ID: 186575
URI: http://eprints.soton.ac.uk/id/eprint/186575
ISSN: 0267-8179
PURE UUID: 12e43819-d163-408f-aa21-c711998bcdca

Catalogue record

Date deposited: 13 May 2011 13:05
Last modified: 16 Jul 2019 23:37

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