Marine geophysical and geological investigations of past flow and stability of a major Greenland ice stream in the Late Quaternary
Lead Research Organisation:
Durham University
Department Name: Geography
Abstract
Recent observations from around the Greenland Ice Sheet have shown that the fast flowing glaciers - 'ice streams' - which drain the ice sheet into the sea are thinning, speeding up and in some cases their floating margins are disintegrating. It is unknown if this is part of a natural cycle or if it is a response to human-induced climate change. The ice streams are important because they are responsible for most of ice discharged from the Greenland Ice Sheet today and would have played a similar important role in the past. If ice-stream velocities increase, more ice will be delivered to the oceans around Greenland, and as a consequence global sea level will rise. Ice streams are the main mechanism by which icebergs and meltwater are delivered to the ocean. They therefore affect ocean circulation and climate. Computer simulations of the effects of melting of the Greenland Ice Sheet on the North Atlantic have shown that the freshwater runoff produced by this melting could seriously weaken or even stop the thermohaline circulation which is ultimately responsible for the relatively mild climate of much of western Europe. It is therefore important to understand if these changes to the Greenland Ice Sheet are unique to the present day or if similar changes have occurred to Greenland ice streams in the 'recent' geological past of the Late Quaternary (last 50,000 years or so) i.e., prior to any possible human-influence on climate. It is also important to understand what controls the fast flow of such ice streams and what might cause them to speed up or slow down. In this project we propose to address the question of the past behaviour of one of the major ice streams to drain the modern Greenland Ice Sheet: Jakobshavns Isbrae in central west Greenland. Jakobshavns Isbrae is the fastest ice stream in the Greenland Ice Sheet today. It flows at several kilometres per year and accounts for about 7% of the total ice drained from the ice sheet. It therefore exerts a major influence on the ice sheet today and would likely have had a similar influence in the past. Our overall scientific goal in this project is to reconstruct the behaviour of Jakobshavns Isbrae during the Late Quaternary period and particularly since about 20,000 years before present. We will collect marine geophysical data and cores of sea-bed sediments from offshore of Jakobshavns Isbrae in order to answer questions regarding how long this ice stream has been in existence; what were it's dimensions during past glaciations; when and how rapidly did it last retreat from the continental shelf of Greenland; what are the processes responsible for the high flow velocities of this ice stream and what are the major controls on it's location; what is the nature of sedimentation associated with Jakobshavns Isbrae; and has it undergone large-scale collapse prior to modern times. The results from this project will significantly advance scientific understanding in the following areas: (1) The behaviour of Jakobshavns Isbrae - a major ice stream of the Greenland Ice Sheet / in the recent geological past (last 50,000 years) and its role in the evolution of the ice sheet as a whole during this period. In particular if Jakobshavns Isbrae has experienced past episodes of large-scale disintegration analogous to those occurring around Greenland today; (2) The mechanisms by which ice streams flow fast; (3) The factors that cause ice streams to form and to stop; (4) The nature of sediments beneath ice streams and the relationship of these sediments to the high velocities of ice streams. These results will be highly relevant to workers in the related fields of glaciology, oceanography, and climate modelling.
People |
ORCID iD |
Colm O'Cofaigh (Principal Investigator) |
Publications
Ownsworth E
(2023)
Tracking sediment delivery to central Baffin Bay during the past 40 kyrs: Insights from a multiproxy approach and new age model
in Quaternary Science Reviews
Pope E
(2019)
Controls on the formation of turbidity current channels associated with marine-terminating glaciers and ice sheets
in Marine Geology
Jennings A
(2018)
Baffin Bay paleoenvironments in the LGM and HS1: Resolving the ice-shelf question
in Marine Geology
Batchelor C
(2018)
Submarine landforms reveal varying rates and styles of deglaciation in North-West Greenland fjords
in Marine Geology
Ó Cofaigh, C
(2018)
The role of meltwater in high-latitude trough-mouth fan development: the Disko Trough-Mouth Fan, West Greenland
in Marine Geology
Streuff K
(2017)
Seafloor geomorphology and glacimarine sedimentation associated with fast-flowing ice sheet outlet glaciers in Disko Bay, West Greenland
in Quaternary Science Reviews
Jennings A
(2017)
Ocean forcing of Ice Sheet retreat in central west Greenland from LGM to the early Holocene
in Earth and Planetary Science Letters
Sheldon C
(2016)
Ice stream retreat following the LGM and onset of the west Greenland current in Uummannaq Trough, west Greenland
in Quaternary Science Reviews
Rignot E
(2016)
Bathymetry data reveal glaciers vulnerable to ice-ocean interaction in Uummannaq and Vaigat glacial fjords, west Greenland
in Geophysical Research Letters
Hogan K
(2016)
Deglaciation of a major palaeo-ice stream in Disko Trough, West Greenland
in Quaternary Science Reviews
Dowdeswell J
(2014)
Late Quaternary ice flow in a West Greenland fjord and cross-shelf trough system: submarine landforms from Rink Isbrae to Uummannaq shelf and slope
in Quaternary Science Reviews
JENNINGS A
(2013)
Paleoenvironments during Younger Dryas- E arly Holocene retreat of the Greenland Ice Sheet from outer Disko Trough, central west Greenland
in Journal of Quaternary Science
Hogan K
(2012)
Glacimarine sedimentary processes and depositional environments in an embayment fed by West Greenland ice streams
in Marine Geology
Ó Cofaigh C
(2012)
Glacimarine lithofacies, provenance and depositional processes on a West Greenland trough-mouth fan
in Journal of Quaternary Science
O Cofaigh C
(2012)
An extensive and dynamic ice sheet on the West Greenland shelf during the last glacial cycle
in Geology
Kilfeather A
(2011)
Ice-stream retreat and ice-shelf history in Marguerite Trough, Antarctic Peninsula: Sedimentological and foraminiferal signatures
in Geological Society of America Bulletin
Andrews J
(2011)
Surface (sea floor) and near-surface (box cores) sediment mineralogy in Baffin Bay as a key to sediment provenance and ice sheet variations
in Canadian Journal of Earth Sciences
Kilfeather A
(2009)
Micromorphological characteristics of glacimarine sediments: implications for distinguishing genetic processes of massive diamicts
in Geo-Marine Letters
Title | Night Orders: Poems from Antarctica and the Arctic |
Description | A polar notebook in poetry form. Poetry, prose poetry, notebook entries, photographs and scientific images - graphs, screen grabs, ship tracks - documenting Antarctic and Arctic scientific research voyages, 2005-2009. By Jean McNeil. Artist in residence on board the RRS James Clark Ross during cruise JR175 in 2009 |
Type Of Art | Creative Writing |
Year Produced | 2011 |
Impact | A creative writers view of polar science and experiencing the Arctic including climate change and Greenland Ice Sheet change. |
URL | http://www.jeanmcneil.co.uk/book/night-orders-poems-antarctica-and-arctic |
Title | The Speed of Ice |
Description | The Speed of Ice'; feature, photographs and poetry; lead feature on paleo-climate research in Greenland for the launch of a new online literary magazine, the Writers' Hub (www.writershub.co.uk), January 2010. By Jean McNeil who was an artist in residence on the board cruise JC175 of the RRS James Clark Ross to West Greenland in 2009. |
Type Of Art | Creative Writing |
Year Produced | 2010 |
Impact | An artistic perspective on a geological research cruise and understanding ice sheet change on Greenland |
URL | http://www.writershub.co.uk/features-piece.php?pc=203 |
Description | The major findings of this project to date are the following: 1. The Greenland Ice Sheet (GIS) extended to the edge of the continental shelf bordering Baffin Bay during the last glacial maximum (ca. 20,000 years ago). 2. The ice sheet was characterised by a series of fast-flowing ice streams, including an ancestral Jakobshavn Isbrae, which occupied prominent cross-shelf bathymetric troughs on the continental shelf. Former ice stream presence is indicated by streamlined sublgacial landforms and glacial tills recording flow of a grounded ice sheet. 3. Retreat of the GIS from the shelf edge was underway by 14,9000 years ago but in Dikso Trough overall retreat was interrupted by a readvance of the ancestral Jakobshavn Isbrae onto the outer shelf during the Younger Dryas cold stadial (12.8-11.5 kyr BP). 4. A series of prominent submarine sediment fans located at the mouths of cross-shelf bathymetric troughs record glacigenic sediment delivery onto the continental slope when the GIS was positioned at the shelf edge. |
Exploitation Route | Hydrocarbon exploration on the west Greenland continental margin. |
Sectors | Energy Environment |
Description | In 2010 we exchanged multibeam swath bathymetric data with CAIRN Energy PLC (Edinburgh) who were carrying out hydrocarbon exploration along the central west Greenland margin. |
First Year Of Impact | 2010 |
Sector | Energy |
Impact Types | Economic |