Skip to main content Accessibility help
×
Home

Ice-sheet scale distribution and morphometry of triangular-shaped hummocks (murtoos): a subglacial landform produced during rapid retreat of the Scandinavian Ice Sheet

  • Antti E. K. Ojala (a1), Gustaf Peterson (a2) (a3), Joni Mäkinen (a4), Mark D. Johnson (a3), Kari Kajuutti (a4), Jukka-Pekka Palmu (a1), Elina Ahokangas (a4) and Christian Öhrling (a2)...

Abstract

High-resolution digital elevation models of Finland and Sweden based on LiDAR (Light Detection and Ranging) reveal subglacial landforms in great detail. We describe the ice-sheet scale distribution and morphometric characteristics of a glacial landform that is distinctive in morphology and occurs commonly in the central parts of the former Scandinavian Ice Sheet, especially up-ice of the Younger Dryas end moraine zone. We refer to these triangular or V-shaped landforms as murtoos (singular, ‘murtoo’). Murtoos are typically 30–200 m in length and 30–200 m in width with a relief of commonly <5 m. Murtoos have straight and steep edges, a triangular tip oriented parallel to ice-flow direction, and an asymmetric longitudinal profile with a shorter, but steeper down-ice slope. The spatial distribution of murtoos and their geomorphic relation to other landforms indicate that they formed subglacially during times of climate warming and rapid retreat of the Scandinavian Ice Sheet when large amounts of meltwater were delivered to the bed. Murtoos are formed under warm-based ice and may be associated with a non-channelized subglacial hydraulic system that evacuated large discharges of subglacial water.

  • View HTML
    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Ice-sheet scale distribution and morphometry of triangular-shaped hummocks (murtoos): a subglacial landform produced during rapid retreat of the Scandinavian Ice Sheet
      Available formats
      ×

      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Ice-sheet scale distribution and morphometry of triangular-shaped hummocks (murtoos): a subglacial landform produced during rapid retreat of the Scandinavian Ice Sheet
      Available formats
      ×

      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Ice-sheet scale distribution and morphometry of triangular-shaped hummocks (murtoos): a subglacial landform produced during rapid retreat of the Scandinavian Ice Sheet
      Available formats
      ×

Copyright

This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

Corresponding author

Author for correspondence: Antti E. K. Ojala, E-mail: antti.ojala@gtk.fi

References

Hide All
Ahokangas, E and Mäkinen, J (2014) Sedimentology of an ice margin esker with implications for the deglacial dynamics of the Finnish Lake District lobe trunk. Boreas 43(1), 90116. doi: 10.1111/bor.12023.
Andrews, LC and 7 others (2014) Direct observations of evolving subglacial drainage beneath the Greenland Ice Sheet. Nature 514, 8083. doi: 10.1038/nature13796.
Banerjee, I and McDonald, BC (1975) Nature of esker sedimentation. In Jopling, AV and McDonald, BC (eds), Glaciofluvial and Glaciolacustrine Sedimentation, vol. 23. Tulsa, Oklahoma: Society of Economic Paleontologists and Mineralogists, Special Publication, pp. 133154.
Boulton, GS, Dongelmans, P, Punkari, M and Broadgate, M (2001) Palaeoglaciology of an ice sheet through a glacial cycle: the European ice sheet through the Weichselian. Quaternary Science Reviews 20(4), 591625. doi: 10.1016/S0277-3791(00)00160-8.
Clark, CD, Hughes, AL, Greenwood, SL, Spagnolo, M and Ng, FS (2009) Size and shape characteristics of drumlins, derived from a large sample, and associated scaling laws. Quaternary Science Reviews 28(7–8), 677692. doi: 10.1016/j.quascirev.2008.08.035.
Clayton, L and Moran, SR (1982) Chronology of Late Wisconsinan glaciations in middle North America. Quaternary Science Reviews 1, 5582.
Das, SB and 6 others (2008) Fracture propagation to the base of the Greenland ice sheet during supraglacial lake drainage. Science 320(5877), 778781. doi: 10.1126/science.1153360.
Deschamps, P and 8 others (2012) Ice-sheet collapse and sea-level rise at the Bølling warming 14,600 years ago. Nature 483, 559564. doi: 10.1038/nature10902.
Dow, CF and 10 others (2015) Modeling of subglacial hydrological development following rapid supraglacial lake drainage. Journal of Geophysical Research: Earth Surface 120(6), 11271147. doi: 10.1002/2014JF003333.
Dunlop, P and Clark, CD (2006) The morphological characteristics of ribbed moraine. Quaternary Science Reviews 25(13-14), 16681691. doi: 10.1016/j.quascirev.2006.01.002.
Flowers, GE (2015) Modelling water flow under glaciers and ice sheets. Proceedings of the Royal Society of London. Series A 471(2176), 20140907. doi: 10.1098/rspa.2014.0907.
Frödin, G (1954) De sista skedena av centraljämtlands glaciala historia. Geographica. 24, 1251.
Gravenor, CP and Kupsch, WO (1959) Ice-disintegration features in western Canada. Journal of Geology 67(1), 4864.
Greenwood, SL, Clason, CC, Helanow, C and Margold, M (2016) Theoretical, contemporary observational and palaeo-perspectives on ice sheet hydrology: processes and products. Earth-Science Reviews 155, 127. doi: 10.1016/j.earscirev.2016.01.010.
Hättestrand, C (1998) The glacial geomorphology of central and northern Sweden. Sveriges Geologiska Undersökning 85, 147.
Hughes, ALC, Gyllencreutz, R, ØS, Lohne, Mangerud, J and Svendsen, JI (2015) The last Eurasian ice sheets – a chronological database and time-slice reconstruction, DATED-1. Boreas 45(1), 145. doi: 10.1111/bor.12142.
Jasiewicz, J and Stepinski, TF (2013) Geomorphons – a pattern recognition approach to classification and mapping of landforms. Geomorphology 182, 147156. doi: 10.1016/j.geomorph.2012.11.005.
Jenness, J (2013) DEM surface tools. Jenness enterprises. Available at http://www.jennessent.com/arcgis/surface_area.htm.
Johansson, P, Lunkka, JP and Sarala, P (2011) The glaciation of Finland. Developments in Quaternary Sciences 15, 105116. doi: 10.1016/B978-0-444-53447-7.00009-X.
Johnson, MD and Clayton, L (2003) Supraglacial landsystems in lowland terrain. In Evans, D (ed.), Glacial Landsystems. London: Arnold, pp. 228258. doi: 10.4324/9780203784976.
Johnson, MD, Mickelson, DM, Clayton, L and Attig, JW (1995) Composition and genesis of glacial hummocks, western Wisconsin, USA. Boreas 24(2), 97116. doi: 10.1111/j.1502-3885.1995.tb00630.x.
Johnson, M and 7 others (2018) Geomorphology and distribution of subglacial triangular hummocs (murtoos) in Sweden and Finland. In Belmonte, L and 16 others (eds), Abstracts of the Nordic Geological Winter Meeting 2018, 10–12.1.2018, Copenhagen, Denmark: Geological Society of Denmark, p. 172.
Kajuutti, K, Mäkinen, J, Ahokangas, E, Ojala, A and Palmu, J-P (2018) New subglacial landforms detected from LiDAR data. In Belmonte, L and 16 others (eds), Abstracts of the Nordic Geological Winter Meeting 2018, 10–12.1.2018, Copenhagen, Copenhagen: Geological Society of Denmark, p. 175.
Kleman, J and Hättestrand, C (1999) Frozen-bed Fennoscandian and Laurentide ice sheets during the Last Glacial Maximum. Nature 402, 6366.
Kleman, J, Hättestrand, C, Borgström, I and Stroeven, A (1997) Fennoscandian palaeoglaciology reconstructed using a glacial geological inversion model. Journal of Glaciology 43, 283299.
Kleman, J, Stroeven, AP and Lundqvist, J (2008) Patterns of Quaternary ice sheet erosion and deposition in Fennoscandia and a theoretical framework for explanation. Geomorphology 97, 7390.
Koistinen, T and 5 others (2001) Geological Map of the Fennoscandian Shield, Scale 1:2 000 000. Trondheim: Geological Survey of Norway, Uppsala: Geological Survey of Sweden, Moscow: Ministry of Natural Resources of Russia, Espoo: Geological Survey of Finland.
Lagerbäck, R (1988) The Veiki moraines in northern Sweden-widespread evidence of an Early Weichselian deglaciation. Boreas 17, 469486. doi: 10.1111/j.1502-3885.1988.tb00562.x.
Lagerbäck, R and Robertsson, A (1998) Kettle holes-stratigraphical archives for Weichselian geology and palaeoenvironment in northernmost Sweden. Boreas 17(4), 439468. doi: 10.1111/j.1502-3885.1988.tb00561.x.
Lundqvist, J and Saarnisto, M (1995) Summary of project IGCP-253. Quaternary International 28, 918. doi: 10.1016/1040-6182(95)00046-L.
Lundqvist, J and Wohlfarth, B (2001) Timing and east–west correlation of south Swedish ice marginal lines during the Late Weichselian. Quaternary Science Reviews 20, 11271148. doi: 10.1016/S0277-3791(00)00142-6.
Mäkinen, J (2003) Development of depositional environments within the interlobate Säkylänharju-Virttaankangas glaciofluvial complex in SW Finland. Annales Academiae Scientiarum Fennicae. Series A3: Geologica Geographica 165, 1165.
Mäkinen, J, Kajuutti, K, Palmu, J-P, Ojala, A and Ahokangas, E (2017) Triangular-shaped landforms reveal subglacial drainage routes in SW Finland. Quaternary Science Reviews 164, 3753. doi: 10.1016/j.quascirev.2017.03.024.
Mäkinen, J, Kajuutti, K, Ahokangas, E, Ojala, AEK and Palmu, J-P (2018) Sedimentology of murtoos – new subglacial landforms detected from LiDAR data in SW Finland. In Belmonte, L and 16 others (eds), Abstracts of the Nordic Geological Winter Meeting 2018, 10–12.1.2018, Copenhagen, Denmark: Geological Society of Denmark, pp. 176177.
Malmberg Persson, K and Persson, M (2011) Jordartskartan 4F Lessebo NV, Geological Survey of Sweden map, K 359, scale 1:100 000.
Meierbachtol, T, Harper, J and Humphrey, N (2013) Basal drainage system response to increasing surface melt on the Greenland ice sheet. Science 341(6147), 777779. doi: 10.1126/science.1235905.
Mooers, HD (1989). Drumlin formation: a time transgressive model. Boreas 18(2), 99107. doi: 10.1111/j.1502-3885.1989.tb00379.x.
Munro, M and Shaw, J (1997) Erosional origin of hummocky terrain in south-central Alberta, Canada. Geology 25(11), 10271030. doi: 10.1130/0091-7613(1997)025<1027:EOOHTI>2.3.CO;2.
Nienow, PW, Sole, AJ, Slater, DA and Cowton, TR (2017) Recent advances in our understanding of the role of meltwater in the Greenland Ice Sheet System. Current Climate Change Reports 3(4), 330344. doi: 10.1007/s40641-017-0083-9.
Paul, MA (1983) The supraglacial landsystem. In Eyles, N (ed.), Glacial Geology. Oxford: Pergamon, pp. 7190.
Perttunen, M, Stén, C-G, Hyyppä, J and Grönlund, T (1984) Explanation to the map of superficial deposits, Sheet 2114 Toijala. Geological Survey of Finland, Espoo. p. 63.
Peterson, G, Johnson, M and Smith, C (2017) Glacial geomorphology of the south Swedish uplands – focus on the spatial distribution of hummock tracts. Journal of Maps 13(2), 534544. doi: 10.1080/17445647.2017.1336121.
Peterson, G, Johnson, M and Öhrling, C (2018). Sedimentological and morphological implications for the understanding of murtoo formation in Sweden. In Belmonte, L and 16 others (eds), Abstracts of the Nordic Geological Winter Meeting 2018, 10-12.1.2018, Copenhagen, Denmark, p. 177.
Putkinen, N and 13 others (2017) High-resolution LiDAR mapping of ice stream lobes in Finland. Bulletin of the Geological Society of Finland 89(2), 6481. doi: 10.17741/bgsf/89.2.001.
Rasmussen, SO and 23 others (2014) A stratigraphic framework for abrupt climatic changes during the Last Glacial period based on three synchronized Greenland ice-core records: refining and extending the INTIMATE event stratigraphy. Quaternary Science Reviews 106, 1428. doi: 10.1016/j.quascirev.2014.09.007.
Regnéll, C, Mangerud, J and Svendsen, JI (2019) Tracing the last remnants of the Scandinavian Ice Sheet: ice-dammed lakes and a catastrophic outburst flood in northern Sweden. Quaternary Science Reviews 221, 105862. doi: 10.1016/j.quascirev.2019.105862.
Ringberg, B (1979) Varve chronology of the glacial sediments in Blekinge and northeastern Skåne, southeastern Sweden. Boreas 8(2), 209215. doi: 10.1111/j.1502-3885.1979.tb00802.x.
Seppälä, MVJ (2016) Lidar-based detection and interpretation of glaciotectonic features of the morainic topography of Finland. Journal of Geology Research 2016, 4292806. doi: 10.1155/2016/4292806.
Sjogren, DB, Fisher, TG, Taylor, LD, Jol, HM and Munro-Stasiuk, MJ (2002) Incipient tunnel channels. Quaternary International 90(1), 4156. doi: 10.1016/S1040-6182(01)00091-X.
Storrar, RD, Stokes, CR and Evans, DJ (2013) A map of large Canadian eskers from Landsat satellite imagery. Journal of Maps 9(3), 456473. doi: 10.1080/17445647.2013.815591.
Stroeven, AP and 15 others (2016) Deglaciation of Fennoscandia. Quaternary Science Reviews 147, 91121. doi: 10.1016/j.quascirev.2015.09.016.
Utting, DJ, Ward, BC and Little, EC (2009) Genesis of hummocks in glaciofluvial corridors near the Keewatin Ice Divide, Canada. Boreas 38(3), 471481. doi: 10.1111/j.1502-3885.2008.00074.x.
Virkkala, K (1962) Explanation to the map of superficial deposits, Sheet 2123, Tampere. Geological Survey of Finland, Espoo. p. 70.

Keywords

Ice-sheet scale distribution and morphometry of triangular-shaped hummocks (murtoos): a subglacial landform produced during rapid retreat of the Scandinavian Ice Sheet

  • Antti E. K. Ojala (a1), Gustaf Peterson (a2) (a3), Joni Mäkinen (a4), Mark D. Johnson (a3), Kari Kajuutti (a4), Jukka-Pekka Palmu (a1), Elina Ahokangas (a4) and Christian Öhrling (a2)...

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed