Fjord sediments in Greenland:A climate archive at the intersection between the ocean and the ice sheet
In recent years, the Greenland Ice Sheet has experienced persistent mass loss, contributing significantly to global sea level rise. About a third of this mass loss is attributed to dynamical discharge via marine terminating glaciers. In order to understand the current processes better and to put the...
Main Author: | |
---|---|
Format: | Book |
Language: | English |
Published: |
Natural History Museum of Denmark, Faculty of Science, University of Copenhagen
2019
|
Subjects: | |
Online Access: | https://curis.ku.dk/portal/da/publications/fjord-sediments-in-greenland(512a73b9-171b-407a-9dc9-7f5c77ec207f).html https://soeg.kb.dk/permalink/45KBDK_KGL/1pioq0f/alma99123532513105763 |
id |
ftcopenhagenunip:oai:pure.atira.dk:publications/512a73b9-171b-407a-9dc9-7f5c77ec207f |
---|---|
record_format |
openpolar |
spelling |
ftcopenhagenunip:oai:pure.atira.dk:publications/512a73b9-171b-407a-9dc9-7f5c77ec207f 2023-05-15T16:01:06+02:00 Fjord sediments in Greenland:A climate archive at the intersection between the ocean and the ice sheet Wangner, David Johannes 2019 https://curis.ku.dk/portal/da/publications/fjord-sediments-in-greenland(512a73b9-171b-407a-9dc9-7f5c77ec207f).html https://soeg.kb.dk/permalink/45KBDK_KGL/1pioq0f/alma99123532513105763 eng eng Natural History Museum of Denmark, Faculty of Science, University of Copenhagen info:eu-repo/semantics/closedAccess Wangner , D J 2019 , Fjord sediments in Greenland : A climate archive at the intersection between the ocean and the ice sheet . Natural History Museum of Denmark, Faculty of Science, University of Copenhagen . < https://soeg.kb.dk/permalink/45KBDK_KGL/1pioq0f/alma99123532513105763 > book 2019 ftcopenhagenunip 2021-11-10T23:56:37Z In recent years, the Greenland Ice Sheet has experienced persistent mass loss, contributing significantly to global sea level rise. About a third of this mass loss is attributed to dynamical discharge via marine terminating glaciers. In order to understand the current processes better and to put these changes into a longer-term perspective it is important to study past environmental conditions and the glacier response to them. In this thesis, marine sediment cores from five different fjords in West- and South-East Greenland were investigated to determine the dynamics of marine terminating glaciers in response to ocean temperature variability. The annual deposition of iceberg rafted debris was used to gain understanding of glaciological change, such as iceberg productivity, margin changes and margin type (calving or floating glacier). Ocean temperature was reconstructed using either benthic foraminifera assemblages or alkenone based paleo-thermometry. In West Greenland, the studies reconstructing ocean and glacier change of the last 2000 years in Disko Bugt, and the last 100 years in Upernavik Isfjord, reveal a link between bottom water temperature within the West Greenland Current and glacier stability of Jakobshavn Isbræ and Upernavik Glacier, respectively. Moreover, a lack of IRD sedimentation in Disko Bugt between 1500 to 1850 CE indicates the development of a floating glacier tongue at Jakobshavn Isbræ during the Little Ice Age. In South-East Greenland, the study reconstructing the last 2000 years of ocean and glacier change in Sermilik Fjord shows relatively minor changes in IRD sedimentation from Helheim Glacier, although SSTs warmed significantly during the Little Ice Age. Besides persistent sea-ice, this was again linked to the existence of a floating glacier tongue. At the onset of the 20th century SSTs raised and Helheim and Kangerlugssuaq glaciers responded with ice tongue collapses. In contrast to that, the study of Thrym Glacier by Nørre Skjoldungesund shows limited response to similar changes in SSTs, which was mostly linked to its glacier configuration limiting ice-ocean interaction. Furthermore, this thesis also discusses the applicability of established proxies, such as alkenone paleothermometry, foraminifera assemblage and IRD, in complex fjord systems of Greenland. A focus on observations of the processes behind of these proxies in the present day environment may help to reduce uncertainties in the interpretation of the longer-term data set. Book Disko bugt East Greenland glacier Greenland Ice Sheet Jakobshavn Jakobshavn isbræ Sea ice Sermilik Upernavik University of Copenhagen: Research Greenland Isfjord ENVELOPE(-26.917,-26.917,73.333,73.333) Jakobshavn Isbræ ENVELOPE(-49.917,-49.917,69.167,69.167) Upernavik Isfjord ENVELOPE(-55.417,-55.417,72.917,72.917) |
institution |
Open Polar |
collection |
University of Copenhagen: Research |
op_collection_id |
ftcopenhagenunip |
language |
English |
description |
In recent years, the Greenland Ice Sheet has experienced persistent mass loss, contributing significantly to global sea level rise. About a third of this mass loss is attributed to dynamical discharge via marine terminating glaciers. In order to understand the current processes better and to put these changes into a longer-term perspective it is important to study past environmental conditions and the glacier response to them. In this thesis, marine sediment cores from five different fjords in West- and South-East Greenland were investigated to determine the dynamics of marine terminating glaciers in response to ocean temperature variability. The annual deposition of iceberg rafted debris was used to gain understanding of glaciological change, such as iceberg productivity, margin changes and margin type (calving or floating glacier). Ocean temperature was reconstructed using either benthic foraminifera assemblages or alkenone based paleo-thermometry. In West Greenland, the studies reconstructing ocean and glacier change of the last 2000 years in Disko Bugt, and the last 100 years in Upernavik Isfjord, reveal a link between bottom water temperature within the West Greenland Current and glacier stability of Jakobshavn Isbræ and Upernavik Glacier, respectively. Moreover, a lack of IRD sedimentation in Disko Bugt between 1500 to 1850 CE indicates the development of a floating glacier tongue at Jakobshavn Isbræ during the Little Ice Age. In South-East Greenland, the study reconstructing the last 2000 years of ocean and glacier change in Sermilik Fjord shows relatively minor changes in IRD sedimentation from Helheim Glacier, although SSTs warmed significantly during the Little Ice Age. Besides persistent sea-ice, this was again linked to the existence of a floating glacier tongue. At the onset of the 20th century SSTs raised and Helheim and Kangerlugssuaq glaciers responded with ice tongue collapses. In contrast to that, the study of Thrym Glacier by Nørre Skjoldungesund shows limited response to similar changes in SSTs, which was mostly linked to its glacier configuration limiting ice-ocean interaction. Furthermore, this thesis also discusses the applicability of established proxies, such as alkenone paleothermometry, foraminifera assemblage and IRD, in complex fjord systems of Greenland. A focus on observations of the processes behind of these proxies in the present day environment may help to reduce uncertainties in the interpretation of the longer-term data set. |
format |
Book |
author |
Wangner, David Johannes |
spellingShingle |
Wangner, David Johannes Fjord sediments in Greenland:A climate archive at the intersection between the ocean and the ice sheet |
author_facet |
Wangner, David Johannes |
author_sort |
Wangner, David Johannes |
title |
Fjord sediments in Greenland:A climate archive at the intersection between the ocean and the ice sheet |
title_short |
Fjord sediments in Greenland:A climate archive at the intersection between the ocean and the ice sheet |
title_full |
Fjord sediments in Greenland:A climate archive at the intersection between the ocean and the ice sheet |
title_fullStr |
Fjord sediments in Greenland:A climate archive at the intersection between the ocean and the ice sheet |
title_full_unstemmed |
Fjord sediments in Greenland:A climate archive at the intersection between the ocean and the ice sheet |
title_sort |
fjord sediments in greenland:a climate archive at the intersection between the ocean and the ice sheet |
publisher |
Natural History Museum of Denmark, Faculty of Science, University of Copenhagen |
publishDate |
2019 |
url |
https://curis.ku.dk/portal/da/publications/fjord-sediments-in-greenland(512a73b9-171b-407a-9dc9-7f5c77ec207f).html https://soeg.kb.dk/permalink/45KBDK_KGL/1pioq0f/alma99123532513105763 |
long_lat |
ENVELOPE(-26.917,-26.917,73.333,73.333) ENVELOPE(-49.917,-49.917,69.167,69.167) ENVELOPE(-55.417,-55.417,72.917,72.917) |
geographic |
Greenland Isfjord Jakobshavn Isbræ Upernavik Isfjord |
geographic_facet |
Greenland Isfjord Jakobshavn Isbræ Upernavik Isfjord |
genre |
Disko bugt East Greenland glacier Greenland Ice Sheet Jakobshavn Jakobshavn isbræ Sea ice Sermilik Upernavik |
genre_facet |
Disko bugt East Greenland glacier Greenland Ice Sheet Jakobshavn Jakobshavn isbræ Sea ice Sermilik Upernavik |
op_source |
Wangner , D J 2019 , Fjord sediments in Greenland : A climate archive at the intersection between the ocean and the ice sheet . Natural History Museum of Denmark, Faculty of Science, University of Copenhagen . < https://soeg.kb.dk/permalink/45KBDK_KGL/1pioq0f/alma99123532513105763 > |
op_rights |
info:eu-repo/semantics/closedAccess |
_version_ |
1766397096822308864 |