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Esker formation during deglaciation of the Scandinavian Ice Sheet, northeast Skåne and Blekinge, Sweden

Langkjaer, Henrik LU (2026) In Dissertations in Geology at Lund University GEOR02 20252
Department of Geology
Abstract
Eskers are a key component when it comes to understanding glacier dynamics, in particular during deglaciation. Eskers contain a lot of information regarding ice sheets and glaciers, and may serve as indicators of ice-front positions, meltwater discharge rates, and glacial drainage systems of the downwasting ice masses. Eskers deposited by the Scandinavian Ice Sheet (SIS) in northeast Skåne and west to central Blekinge in Sweden have been investigated in the past to determine the genesis and accumulation of glacial and associated sediments. However, no recent efforts have been made to follow up on these studies. At the same time, a lot of progress has been made within the field of Quaternary geology since their publication. The aim of the... (More)
Eskers are a key component when it comes to understanding glacier dynamics, in particular during deglaciation. Eskers contain a lot of information regarding ice sheets and glaciers, and may serve as indicators of ice-front positions, meltwater discharge rates, and glacial drainage systems of the downwasting ice masses. Eskers deposited by the Scandinavian Ice Sheet (SIS) in northeast Skåne and west to central Blekinge in Sweden have been investigated in the past to determine the genesis and accumulation of glacial and associated sediments. However, no recent efforts have been made to follow up on these studies. At the same time, a lot of progress has been made within the field of Quaternary geology since their publication. The aim of the study has therefore been to reinvestigate the understanding of the sequencing, distribution, and spatial arrangement of the esker elements and the accretion of associated sediments in northeast Skåne and west to central Blekinge. Two sites with readily available exposures were selected for further studies. The study site Johannishus is located in central Blekinge, in between the towns of Ronneby and Listerby, while the study site Olofström-Näsum is located in the northeastern region of Skåne, between the towns of Olofström and Näsum. The morphology of the investigated esker systems, in which the study sites are located, were mapped and analysed through DEMs and geological data (supplied by the governmental institutions Lantmäteriet and Svergies geologiska undersökning), while the sedimentology of the exposures were analysed through field logging and sampling for both grainsize and clast shape analyses. Both the Johannishus and the Olofström-Näsum esker systems were interpreted to be simple esker complexes and deposited as type II eskers within a glaciolacustrine environment as a series of subaqueous fans derived from the downwasting or retreating ice margin of the SIS most probably around 16 to 15 ka BP. The sediments which make up the esker beads at the study sites were most likely derived from the subglacial regime and got transported through pressurised drainage channels. Drainage fluctuated heavily, either due to seasonal or diurnal effects, and was probably temporarily enforced by supraglacial meltwater. Deformation structures located within some strata hint towards the possibility of an oscillating ice margin and potentially an active ice sheet, but the evidence is scarce and further investigations are needed to determine whether the SIS was actively retreating or had stagnated and was downwasting. (Less)
Abstract (Swedish)
Rullstensåsar är en nyckelkomponent när det gäller att förstå glacial dynamik, speciellt under deglaciationsstadier. Rullstensåsar innehåller mycket information gällande inlandsisar och glaciärer, och kan potentiellt förmedla information om isutbredning, nedsmältning, dränering av ismassor och smältvattensystem. Deponerade rullstensåsar i nordöstra Skåne och västra till centrala Blekinge av den skandinaviska inlandsisen har tidigare undersökts sedimentologiskt för att klargöra deras tillkomst och ackumulation. Uppföljningen av dessa studier har varit bristande och sedan deras publicering har det skett framsteg inom fältet kvartärgeologi. Målet med studien var därför att utöka förståelsen av rullstensåsar i nordöstra Skåne och västra till... (More)
Rullstensåsar är en nyckelkomponent när det gäller att förstå glacial dynamik, speciellt under deglaciationsstadier. Rullstensåsar innehåller mycket information gällande inlandsisar och glaciärer, och kan potentiellt förmedla information om isutbredning, nedsmältning, dränering av ismassor och smältvattensystem. Deponerade rullstensåsar i nordöstra Skåne och västra till centrala Blekinge av den skandinaviska inlandsisen har tidigare undersökts sedimentologiskt för att klargöra deras tillkomst och ackumulation. Uppföljningen av dessa studier har varit bristande och sedan deras publicering har det skett framsteg inom fältet kvartärgeologi. Målet med studien var därför att utöka förståelsen av rullstensåsar i nordöstra Skåne och västra till centrala Blekinge gällande deras uppbyggnad, bildning och utbredning. Två studielokaler med tillgängliga exponeringar valdes för utförandet av den sedimentologiska undersökningen. Studielokalen Johannishus är belägen i centrala Blekinge, mellan staden Ronneby och byn Listerby, medan studielokalen Olofström-Näsum är belägen i nordöstra Skåne, mellan städerna Olofström och Näsum. Morfologin av rullstensåsarnas utbredning som studielokalerna befann sig i karterades och analyserades med hjälp av DEMs och geologisk data (hämtad från de svenska myndigheterna Lantmäteriet och Sveriges geologiska undersökning), medan sedimentologin av exponeringarna analyserades genom loggning och provtagning av kornstorleksanalyser och partikelform. Rullstensåssystemen i Johannishus och Olofström-Näsum tolkades som enkla rullstensåskomplex och deponerades troligen som typ II rullstensåsar inom en glacilakustrin miljö som en serie av undervattensisälvsavlagringar från den skandinaviska inlandsisens nedsmältande eller retirerande iskant troligtvis omkring 16 till 15 ka BP. Sedimenten som rullstensåsarna är uppbyggda av kom troligtvis från den subglaciala regimen och transporterades genom trycksatta dräneringskanaler. Dräneringen av smältvatten fluktuerade kraftigt, antingen på grund av säsongsbundna eller dagliga processer, och var förmodligen tidvis förstärkt av supraglacialt vatten. Deformationsstrukturer inom ett fåtal sektioner av exponeringarna indikerar på en potentiellt oscillerande iskant och en aktiv inlandsis, men i brist på bevis krävs ytterligare undersökningar om den skandinaviska inlandsisen aktivt retirerande eller hade stagnerat vid deponeringen av rullstensåsarna. (Less)
Please use this url to cite or link to this publication:
author
Langkjaer, Henrik LU
supervisor
organization
course
GEOR02 20252
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Esker, Esker morphology, Esker deposition, Glaciofluvial sediments, Meltwater drainage, Deglaciation, Scandinavian Ice Sheet, Skåne, Blekinge
publication/series
Dissertations in Geology at Lund University
report number
725
language
English
id
9221314
date added to LUP
2026-01-28 15:31:15
date last changed
2026-01-28 15:31:15
@misc{9221314,
  abstract     = {{Eskers are a key component when it comes to understanding glacier dynamics, in particular during deglaciation. Eskers contain a lot of information regarding ice sheets and glaciers, and may serve as indicators of ice-front positions, meltwater discharge rates, and glacial drainage systems of the downwasting ice masses. Eskers deposited by the Scandinavian Ice Sheet (SIS) in northeast Skåne and west to central Blekinge in Sweden have been investigated in the past to determine the genesis and accumulation of glacial and associated sediments. However, no recent efforts have been made to follow up on these studies. At the same time, a lot of progress has been made within the field of Quaternary geology since their publication. The aim of the study has therefore been to reinvestigate the understanding of the sequencing, distribution, and spatial arrangement of the esker elements and the accretion of associated sediments in northeast Skåne and west to central Blekinge. Two sites with readily available exposures were selected for further studies. The study site Johannishus is located in central Blekinge, in between the towns of Ronneby and Listerby, while the study site Olofström-Näsum is located in the northeastern region of Skåne, between the towns of Olofström and Näsum. The morphology of the investigated esker systems, in which the study sites are located, were mapped and analysed through DEMs and geological data (supplied by the governmental institutions Lantmäteriet and Svergies geologiska undersökning), while the sedimentology of the exposures were analysed through field logging and sampling for both grainsize and clast shape analyses. Both the Johannishus and the Olofström-Näsum esker systems were interpreted to be simple esker complexes and deposited as type II eskers within a glaciolacustrine environment as a series of subaqueous fans derived from the downwasting or retreating ice margin of the SIS most probably around 16 to 15 ka BP. The sediments which make up the esker beads at the study sites were most likely derived from the subglacial regime and got transported through pressurised drainage channels. Drainage fluctuated heavily, either due to seasonal or diurnal effects, and was probably temporarily enforced by supraglacial meltwater. Deformation structures located within some strata hint towards the possibility of an oscillating ice margin and potentially an active ice sheet, but the evidence is scarce and further investigations are needed to determine whether the SIS was actively retreating or had stagnated and was downwasting.}},
  author       = {{Langkjaer, Henrik}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{Dissertations in Geology at Lund University}},
  title        = {{Esker formation during deglaciation of the Scandinavian Ice Sheet, northeast Skåne and Blekinge, Sweden}},
  year         = {{2026}},
}