Sediment-rich meltwater plumes and ice-proximal fans at the margins of modern and ancient tidewater glaciers: Observations and modeling
<jats:title>Abstract</jats:title><jats:p>Turbid meltwater plumes and ice‐proximal fans occur where subglacial streams reach the grounded marine margins of modern and ancient tidewater glaciers. However, the spacing and temporal stability of these subglacial channels is poorly under...
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ftunivcam:oai:www.repository.cam.ac.uk:1810/247486 2024-02-04T09:59:01+01:00 Sediment-rich meltwater plumes and ice-proximal fans at the margins of modern and ancient tidewater glaciers: Observations and modeling Dowdeswell, JA Hogan, KA Arnold, NS Mugford, RI Wells, M Hirst, JPP Decalf, C 2015 application/pdf https://www.repository.cam.ac.uk/handle/1810/247486 English eng eng Wiley http://dx.doi.org/10.1111/sed.12198 Sedimentology https://www.repository.cam.ac.uk/handle/1810/247486 Ice-proximal fans Late Ordovician sediments schematic fan-development models subglacial drainage Svalbard ice cap tidewater glaciers turbid meltwater plumes Article 2015 ftunivcam 2024-01-11T23:32:10Z <jats:title>Abstract</jats:title><jats:p>Turbid meltwater plumes and ice‐proximal fans occur where subglacial streams reach the grounded marine margins of modern and ancient tidewater glaciers. However, the spacing and temporal stability of these subglacial channels is poorly understood. This has significant implications for understanding the geometry and distribution of Quaternary and ancient ice‐proximal fans that can form important aquifers and hydrocarbon reservoirs. Remote‐sensing and numerical‐modelling techniques are applied to the 200 km long marine margin of a Svalbard ice cap, Austfonna, to quantify turbid meltwater‐plume distribution and predict its temporal stability. Results are combined with observations from geophysical data close to the modern ice front to refine existing depositional models for ice‐proximal fans. Plumes are spaced <jats:italic>ca</jats:italic> 3 km apart and their distribution along the ice front is stable over decades. Numerical modelling also predicts the drainage pattern and meltwater discharge beneath the ice cap; modelled water‐routing patterns are in reasonable agreement with satellite‐mapped plume locations. However, glacial retreat of several kilometres over the past 40 years has limited build‐up of significant ice‐proximal fans. A single fan and moraine ridge is noted from marine‐geophysical surveys. Closer to the ice front there are smaller recessional moraines and polygonal sediment lobes but no identifiable fans. Schematic models of ice‐proximal deposits represent varying glacier‐terminus stability: (i) stable terminus where meltwater sedimentation produces an ice‐proximal fan; (ii) quasi‐stable terminus, where glacier readvance pushes or thrusts up ice‐proximal deposits into a morainal bank; and (iii) retreating terminus, with short still‐stands, allowing only small sediment lobes to build up at melt‐stream portals. These modern investigations are complemented with outcrop and subsurface observations and numerical modelling of an ... Article in Journal/Newspaper Austfonna glacier Ice cap Svalbard Tidewater Apollo - University of Cambridge Repository Svalbard Austfonna ENVELOPE(24.559,24.559,79.835,79.835) Moraine Ridge ENVELOPE(168.050,168.050,-72.300,-72.300) |
institution |
Open Polar |
collection |
Apollo - University of Cambridge Repository |
op_collection_id |
ftunivcam |
language |
English |
topic |
Ice-proximal fans Late Ordovician sediments schematic fan-development models subglacial drainage Svalbard ice cap tidewater glaciers turbid meltwater plumes |
spellingShingle |
Ice-proximal fans Late Ordovician sediments schematic fan-development models subglacial drainage Svalbard ice cap tidewater glaciers turbid meltwater plumes Dowdeswell, JA Hogan, KA Arnold, NS Mugford, RI Wells, M Hirst, JPP Decalf, C Sediment-rich meltwater plumes and ice-proximal fans at the margins of modern and ancient tidewater glaciers: Observations and modeling |
topic_facet |
Ice-proximal fans Late Ordovician sediments schematic fan-development models subglacial drainage Svalbard ice cap tidewater glaciers turbid meltwater plumes |
description |
<jats:title>Abstract</jats:title><jats:p>Turbid meltwater plumes and ice‐proximal fans occur where subglacial streams reach the grounded marine margins of modern and ancient tidewater glaciers. However, the spacing and temporal stability of these subglacial channels is poorly understood. This has significant implications for understanding the geometry and distribution of Quaternary and ancient ice‐proximal fans that can form important aquifers and hydrocarbon reservoirs. Remote‐sensing and numerical‐modelling techniques are applied to the 200 km long marine margin of a Svalbard ice cap, Austfonna, to quantify turbid meltwater‐plume distribution and predict its temporal stability. Results are combined with observations from geophysical data close to the modern ice front to refine existing depositional models for ice‐proximal fans. Plumes are spaced <jats:italic>ca</jats:italic> 3 km apart and their distribution along the ice front is stable over decades. Numerical modelling also predicts the drainage pattern and meltwater discharge beneath the ice cap; modelled water‐routing patterns are in reasonable agreement with satellite‐mapped plume locations. However, glacial retreat of several kilometres over the past 40 years has limited build‐up of significant ice‐proximal fans. A single fan and moraine ridge is noted from marine‐geophysical surveys. Closer to the ice front there are smaller recessional moraines and polygonal sediment lobes but no identifiable fans. Schematic models of ice‐proximal deposits represent varying glacier‐terminus stability: (i) stable terminus where meltwater sedimentation produces an ice‐proximal fan; (ii) quasi‐stable terminus, where glacier readvance pushes or thrusts up ice‐proximal deposits into a morainal bank; and (iii) retreating terminus, with short still‐stands, allowing only small sediment lobes to build up at melt‐stream portals. These modern investigations are complemented with outcrop and subsurface observations and numerical modelling of an ... |
format |
Article in Journal/Newspaper |
author |
Dowdeswell, JA Hogan, KA Arnold, NS Mugford, RI Wells, M Hirst, JPP Decalf, C |
author_facet |
Dowdeswell, JA Hogan, KA Arnold, NS Mugford, RI Wells, M Hirst, JPP Decalf, C |
author_sort |
Dowdeswell, JA |
title |
Sediment-rich meltwater plumes and ice-proximal fans at the margins of modern and ancient tidewater glaciers: Observations and modeling |
title_short |
Sediment-rich meltwater plumes and ice-proximal fans at the margins of modern and ancient tidewater glaciers: Observations and modeling |
title_full |
Sediment-rich meltwater plumes and ice-proximal fans at the margins of modern and ancient tidewater glaciers: Observations and modeling |
title_fullStr |
Sediment-rich meltwater plumes and ice-proximal fans at the margins of modern and ancient tidewater glaciers: Observations and modeling |
title_full_unstemmed |
Sediment-rich meltwater plumes and ice-proximal fans at the margins of modern and ancient tidewater glaciers: Observations and modeling |
title_sort |
sediment-rich meltwater plumes and ice-proximal fans at the margins of modern and ancient tidewater glaciers: observations and modeling |
publisher |
Wiley |
publishDate |
2015 |
url |
https://www.repository.cam.ac.uk/handle/1810/247486 |
long_lat |
ENVELOPE(24.559,24.559,79.835,79.835) ENVELOPE(168.050,168.050,-72.300,-72.300) |
geographic |
Svalbard Austfonna Moraine Ridge |
geographic_facet |
Svalbard Austfonna Moraine Ridge |
genre |
Austfonna glacier Ice cap Svalbard Tidewater |
genre_facet |
Austfonna glacier Ice cap Svalbard Tidewater |
op_relation |
https://www.repository.cam.ac.uk/handle/1810/247486 |
_version_ |
1789963647624151040 |