Insights into drumlin development from ground-penetrating radar at Múlajökull, Iceland, a surge-type glacier
Drumlins form at the ice/bed interface through subglacial processes that are not directly observable. The internal stratigraphy of drumlins provides insight into how they developed and associated subglacial processes, but traditional stratigraphic logging techniques are limited to natural exposures...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2020-10-01
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| Series: | Journal of Glaciology |
| Subjects: | |
| Online Access: | https://www.cambridge.org/core/product/identifier/S0022143020000507/type/journal_article |
| _version_ | 1827994454809640960 |
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| author | Jacob B. Woodard Lucas K. Zoet Ívar Ö. Benediktsson Neal R. Iverson Andrew Finlayson |
| author_facet | Jacob B. Woodard Lucas K. Zoet Ívar Ö. Benediktsson Neal R. Iverson Andrew Finlayson |
| author_sort | Jacob B. Woodard |
| collection | DOAJ |
| description | Drumlins form at the ice/bed interface through subglacial processes that are not directly observable. The internal stratigraphy of drumlins provides insight into how they developed and associated subglacial processes, but traditional stratigraphic logging techniques are limited to natural exposures and excavations. Using ground-penetrating radar, we imaged the internal stratigraphy of seven drumlins from a recently exposed drumlin field in the forefield of Múlajökull, Iceland. Data were collected with 100 and 200 MHz antennas with maximum resolvable depths of 8 and 4 m, respectively. Longitudinal echograms contained coherent down-ice dipping reflectors over the lengths of the drumlins. Near the drumlin heads (i.e., stoss sides), down-glacier dipping beds lie at high angles to the surface, whereas on the lee sides, the down-glacier dipping beds lie at low angles, or conform, to drumlin surfaces. Transverse echograms exhibited unconformities along the flanks of drumlin heads and conformable bedding across the lee side widths of the drumlins. These observations were ground-truthed with stratigraphic logs from a subset of drumlins and good agreement was found. The stratigraphic patterns support previous conclusions that drumlins at Múlajökull formed on a deformable bed through both depositional and erosional processes which may alternate between its surge and quiescent phases. |
| first_indexed | 2024-04-10T04:41:10Z |
| format | Article |
| id | doaj.art-cf3a80013b604c5ca9fd025f2d09a761 |
| institution | Directory Open Access Journal |
| issn | 0022-1430 1727-5652 |
| language | English |
| last_indexed | 2024-04-10T04:41:10Z |
| publishDate | 2020-10-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Journal of Glaciology |
| spelling | doaj.art-cf3a80013b604c5ca9fd025f2d09a7612023-03-09T12:40:59ZengCambridge University PressJournal of Glaciology0022-14301727-56522020-10-016682283010.1017/jog.2020.50Insights into drumlin development from ground-penetrating radar at Múlajökull, Iceland, a surge-type glacierJacob B. Woodard0https://orcid.org/0000-0002-3095-0774Lucas K. Zoet1Ívar Ö. Benediktsson2Neal R. Iverson3Andrew Finlayson4Department of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin, USADepartment of Geoscience, University of Wisconsin-Madison, Madison, Wisconsin, USAInstitute of Earth Sciences, University of Iceland, Askja, Sturlugata 7, Reykjavík, IS-101, IcelandDepartment of Geological and Atmospheric Sciences, Iowa State University, Ames, Iowa, USABritish Geological Survey, The Lyell Centre, Research Avenue South, EdinburghEH14 4AP, UKDrumlins form at the ice/bed interface through subglacial processes that are not directly observable. The internal stratigraphy of drumlins provides insight into how they developed and associated subglacial processes, but traditional stratigraphic logging techniques are limited to natural exposures and excavations. Using ground-penetrating radar, we imaged the internal stratigraphy of seven drumlins from a recently exposed drumlin field in the forefield of Múlajökull, Iceland. Data were collected with 100 and 200 MHz antennas with maximum resolvable depths of 8 and 4 m, respectively. Longitudinal echograms contained coherent down-ice dipping reflectors over the lengths of the drumlins. Near the drumlin heads (i.e., stoss sides), down-glacier dipping beds lie at high angles to the surface, whereas on the lee sides, the down-glacier dipping beds lie at low angles, or conform, to drumlin surfaces. Transverse echograms exhibited unconformities along the flanks of drumlin heads and conformable bedding across the lee side widths of the drumlins. These observations were ground-truthed with stratigraphic logs from a subset of drumlins and good agreement was found. The stratigraphic patterns support previous conclusions that drumlins at Múlajökull formed on a deformable bed through both depositional and erosional processes which may alternate between its surge and quiescent phases.https://www.cambridge.org/core/product/identifier/S0022143020000507/type/journal_articleDrumlinsGround-penetrating radarSubglacial processes |
| spellingShingle | Jacob B. Woodard Lucas K. Zoet Ívar Ö. Benediktsson Neal R. Iverson Andrew Finlayson Insights into drumlin development from ground-penetrating radar at Múlajökull, Iceland, a surge-type glacier Journal of Glaciology Drumlins Ground-penetrating radar Subglacial processes |
| title | Insights into drumlin development from ground-penetrating radar at Múlajökull, Iceland, a surge-type glacier |
| title_full | Insights into drumlin development from ground-penetrating radar at Múlajökull, Iceland, a surge-type glacier |
| title_fullStr | Insights into drumlin development from ground-penetrating radar at Múlajökull, Iceland, a surge-type glacier |
| title_full_unstemmed | Insights into drumlin development from ground-penetrating radar at Múlajökull, Iceland, a surge-type glacier |
| title_short | Insights into drumlin development from ground-penetrating radar at Múlajökull, Iceland, a surge-type glacier |
| title_sort | insights into drumlin development from ground penetrating radar at mulajokull iceland a surge type glacier |
| topic | Drumlins Ground-penetrating radar Subglacial processes |
| url | https://www.cambridge.org/core/product/identifier/S0022143020000507/type/journal_article |
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