Holocene RSL variation on southwestern Disko Island (Greenland):an interpretation based on GPR data, topography and luminescence dating
We investigate RSL variations during the Holocene in Lakse Bugt by assessing topography, internal structure, and luminescence ages of fossil beach ridges and the modern beach. Lakse Bugt (Bay) lies on the southwestern coast of Disko Island in a mesotidal regime and a mild wave climate. Beach ridges...
Main Authors: | , , , , , |
---|---|
Format: | Conference Object |
Language: | English |
Published: |
2016
|
Subjects: | |
Online Access: | https://curis.ku.dk/portal/da/publications/holocene-rsl-variation-on-southwestern-disko-island-greenland(5e92e2a1-550b-4367-8975-13a814d474c3).html http://adsabs.harvard.edu/abs/2016AGUFMEP13C1048E |
id |
ftcopenhagenunip:oai:pure.atira.dk:publications/5e92e2a1-550b-4367-8975-13a814d474c3 |
---|---|
record_format |
openpolar |
spelling |
ftcopenhagenunip:oai:pure.atira.dk:publications/5e92e2a1-550b-4367-8975-13a814d474c3 2023-05-15T16:30:33+02:00 Holocene RSL variation on southwestern Disko Island (Greenland):an interpretation based on GPR data, topography and luminescence dating Emerich Souza, Priscila Nielsen, Lars Kroon, Aart Murray, Andrew Sean Sohbati, Reza Clemmensen, Lars B 2016 https://curis.ku.dk/portal/da/publications/holocene-rsl-variation-on-southwestern-disko-island-greenland(5e92e2a1-550b-4367-8975-13a814d474c3).html http://adsabs.harvard.edu/abs/2016AGUFMEP13C1048E eng eng info:eu-repo/semantics/openAccess Emerich Souza , P , Nielsen , L , Kroon , A , Murray , A S , Sohbati , R & Clemmensen , L B 2016 , ' Holocene RSL variation on southwestern Disko Island (Greenland) : an interpretation based on GPR data, topography and luminescence dating ' , AGU Fall meeting 2016 , San Francisco , United States , 12/12/2016 - 16/12/2016 . < http://adsabs.harvard.edu/abs/2016AGUFMEP13C1048E > conferenceObject 2016 ftcopenhagenunip 2021-09-23T18:10:24Z We investigate RSL variations during the Holocene in Lakse Bugt by assessing topography, internal structure, and luminescence ages of fossil beach ridges and the modern beach. Lakse Bugt (Bay) lies on the southwestern coast of Disko Island in a mesotidal regime and a mild wave climate. Beach ridges are widespread over the marine terrace, extending from ~40 above sea level (m asl). The most recent ridges terminate either at the beach or at the coastal sandy cliffs ~8 m asl immediately behind the modern beach. These ridges are covered mainly by rounded boulders; the terrain surfaces of the swales have clearly been deformed by freezing and thawing processes, in contrast to those of the ridge crests, which are relatively smooth. High-resolution reflection GPR data and high resolution topographical data were collected along cross-shore transects using a shielded 250 MHz antennae system and a DGPS system, respectively. Sediment samples were collected along these transects from holes ~0.5 m deep using lightproof plastic tubes, and dated using standard optically stimulated luminescence (OSL) techniques on sand-sized quartz grains. Beach profiles show that current berms lie much above the high tide range, and therefore they must have been formed under conditions more energetic than usual. Additionally, the low-tide level is well-marked by a sharp transition of sediment grain size: cobbles occur on the upper shoreface, whereas the foreshore is sandy. Seaward down-lap reflection points were identified in the internal structure of all beach ridges. Radar reflections are strongly scattered at or just below the down-lap points, indicating the transition to a deeper layer with coarser material. Therefore, we suggest that in this location the radar down-lap points correspond to low-tide level at the time of deposition. Preliminary luminescence dating for samples collected ~9 m asl indicates that they were deposited in the late Holocene (4 to 2 ka ago); based on ridge separation, this suggests an accretion rate for these beach-ridges of ~8m/ka. Conference Object Greenland University of Copenhagen: Research Greenland |
institution |
Open Polar |
collection |
University of Copenhagen: Research |
op_collection_id |
ftcopenhagenunip |
language |
English |
description |
We investigate RSL variations during the Holocene in Lakse Bugt by assessing topography, internal structure, and luminescence ages of fossil beach ridges and the modern beach. Lakse Bugt (Bay) lies on the southwestern coast of Disko Island in a mesotidal regime and a mild wave climate. Beach ridges are widespread over the marine terrace, extending from ~40 above sea level (m asl). The most recent ridges terminate either at the beach or at the coastal sandy cliffs ~8 m asl immediately behind the modern beach. These ridges are covered mainly by rounded boulders; the terrain surfaces of the swales have clearly been deformed by freezing and thawing processes, in contrast to those of the ridge crests, which are relatively smooth. High-resolution reflection GPR data and high resolution topographical data were collected along cross-shore transects using a shielded 250 MHz antennae system and a DGPS system, respectively. Sediment samples were collected along these transects from holes ~0.5 m deep using lightproof plastic tubes, and dated using standard optically stimulated luminescence (OSL) techniques on sand-sized quartz grains. Beach profiles show that current berms lie much above the high tide range, and therefore they must have been formed under conditions more energetic than usual. Additionally, the low-tide level is well-marked by a sharp transition of sediment grain size: cobbles occur on the upper shoreface, whereas the foreshore is sandy. Seaward down-lap reflection points were identified in the internal structure of all beach ridges. Radar reflections are strongly scattered at or just below the down-lap points, indicating the transition to a deeper layer with coarser material. Therefore, we suggest that in this location the radar down-lap points correspond to low-tide level at the time of deposition. Preliminary luminescence dating for samples collected ~9 m asl indicates that they were deposited in the late Holocene (4 to 2 ka ago); based on ridge separation, this suggests an accretion rate for these beach-ridges of ~8m/ka. |
format |
Conference Object |
author |
Emerich Souza, Priscila Nielsen, Lars Kroon, Aart Murray, Andrew Sean Sohbati, Reza Clemmensen, Lars B |
spellingShingle |
Emerich Souza, Priscila Nielsen, Lars Kroon, Aart Murray, Andrew Sean Sohbati, Reza Clemmensen, Lars B Holocene RSL variation on southwestern Disko Island (Greenland):an interpretation based on GPR data, topography and luminescence dating |
author_facet |
Emerich Souza, Priscila Nielsen, Lars Kroon, Aart Murray, Andrew Sean Sohbati, Reza Clemmensen, Lars B |
author_sort |
Emerich Souza, Priscila |
title |
Holocene RSL variation on southwestern Disko Island (Greenland):an interpretation based on GPR data, topography and luminescence dating |
title_short |
Holocene RSL variation on southwestern Disko Island (Greenland):an interpretation based on GPR data, topography and luminescence dating |
title_full |
Holocene RSL variation on southwestern Disko Island (Greenland):an interpretation based on GPR data, topography and luminescence dating |
title_fullStr |
Holocene RSL variation on southwestern Disko Island (Greenland):an interpretation based on GPR data, topography and luminescence dating |
title_full_unstemmed |
Holocene RSL variation on southwestern Disko Island (Greenland):an interpretation based on GPR data, topography and luminescence dating |
title_sort |
holocene rsl variation on southwestern disko island (greenland):an interpretation based on gpr data, topography and luminescence dating |
publishDate |
2016 |
url |
https://curis.ku.dk/portal/da/publications/holocene-rsl-variation-on-southwestern-disko-island-greenland(5e92e2a1-550b-4367-8975-13a814d474c3).html http://adsabs.harvard.edu/abs/2016AGUFMEP13C1048E |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland |
genre_facet |
Greenland |
op_source |
Emerich Souza , P , Nielsen , L , Kroon , A , Murray , A S , Sohbati , R & Clemmensen , L B 2016 , ' Holocene RSL variation on southwestern Disko Island (Greenland) : an interpretation based on GPR data, topography and luminescence dating ' , AGU Fall meeting 2016 , San Francisco , United States , 12/12/2016 - 16/12/2016 . < http://adsabs.harvard.edu/abs/2016AGUFMEP13C1048E > |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766020280301387776 |