Advertisement

The Origin and Evolution of Holocene Sandur Deposits in Areas of Jökulhlaup Drainage, Iceland

  • Judith Maizels
Chapter
Part of the Glaciology and Quaternary Geology book series (GQGE, volume 7)

Abstract

The impact of jökulhlaup (flood) history on the origin and evolution of the coastal sandar of southern Iceland is explored in this paper through analysis of the morphology, sedimentology and stratigraphy of six different sandur environments. The results indicate that three distinct models of sandur evolution can be identified from the landform and lithofacies assemblages of the deposits. Type I sandur deposits are characterized by repeated, thin, upward-fining cycles of gravels, sands and silts, and are found in areas of seasonal meltwater activity associated with braided river systems. Type II sandur deposits are characterized by thick (>10m), coarsening-upward, clast-supported cobble gravels, overlain by a fining-upward sequence of fine gravels, sands and silts, which are found in areas of prolonged (days and weeks), high magnitude drainage events associated with subglacial geothermal activity or ice-dammed lake drainage. Finally Type in sandur deposits are typified by thick sequences (8m+) of structureless pumice granules, underlain by a crudely bedded basal unit, and capped by several metres of trough cross-bedded and horizontally bedded granules. These deposits are associated with catastrophic drainage events generated by subglacial volcanic eruptions. These floods are characterized by extremely high peak flows (>105 m3 s-1) and sediment concentrations (>35%), and shortlived hydrographs (peak flows reached in hours). Type I sandur plains form an extensive low relief surface marked by abandoned, braided palaeochannel networks, while Type II is normally associated with deep incision of meltwater channels into a pitted sandur surface; Type HI sandur plains are characterised by the most complex and varied proglacial morphology and surface landforms. Types II and HI appear to dominate the stratigraphy of the major Icelandic sandar of Sölheimasandur and Mýrdalssandur, and Skeiðararsandur, respectively, such that the braided sandur Type I occurs only locally or as a relatively thin surface veneer overlying Type II deposits. The paper concludes that the sandar forming the south coast of Iceland largely owe their origin to the dominating impact of infrequent but catastrophic, jökulhlaup events.

Keywords

Debris Flow Flood Event Sandur Deposit Sandur Surface Sedimentary Petrology 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Bagnold, R.A. (1954) ‘Experiments on a gravity-free dispersion of large solid spheres in a Newtonian fluid under shear,’ Proceedings of the Royal Society of London Series A 225, 49–63.CrossRefGoogle Scholar
  2. Björnsson, H. (1975) ‘Subglacial water reservoirs, jökulhlaups and volcanic eruptions’, Jökull 25, 1–14.Google Scholar
  3. Björnsson, H. (1976) ‘Marginal and supraglacial lakes in Iceland’, Jökull 26, 40–50.Google Scholar
  4. Björnsson, H. (1980) ‘Glaciers in Iceland’, in Geology of the European Countries, I.G.C., 203–209.Google Scholar
  5. Björnsson, H. (1988) ‘Hydrology of Ice Caps in Volcanic Regions’, Visindafélag Ídslendinga, Societas Scientarium Islandica Rit. XLV, 139pp.Google Scholar
  6. Bluck, B. (1974) ‘Structure and directional properties of some valley sandur deposits in southern Iceland’, Sedimentology 21, 533–554.CrossRefGoogle Scholar
  7. Bluck, B. (1979) ‘Structure of coarse — grained braided alluvium’, Transactions of the Royal Society of Edinburgh 70, 181–221.CrossRefGoogle Scholar
  8. Bluck, B. (1982) ‘Texture of gravel bars in braided stream’, in R.D. Hey, J.C. Bathurst and C.R. Thorne (eds.) Gravel-bed Rivers, Wiley & Sons Ltd, Chichester, 339–355.Google Scholar
  9. Bluck, B. (1987) ‘Bed forms and clast size changes in gravel-bed rivers’, in K.S. Richards (ed.) River Channels, Environment and Process, Blackwell, Oxford, 159–178.Google Scholar
  10. Boothroyd, J.C. and Nummedal, D. (1978) ’Proglacial braided outwash: A model for humid alluvial-fan deposits’, in A. Miall (ed.) Fluvial Sedimentology, Canadian Society of Petroleum Geologists Memoir 5, 641–668.Google Scholar
  11. Carswell, D.A. (1983) ‘The volcanic rocks of the Sólheimajökull area, southern Iceland’, Jökull 33, 61–71.Google Scholar
  12. Carter, R.M. (1975) ‘A discussion and classification of subaqueous mass-transport with particular attention to grain-flow, slurry-flow and fluxoturbidites’, Earth Science Reviews 11, 145–177.CrossRefGoogle Scholar
  13. Church, M. (1988) ‘Floods in cold climates’, in V.R. Baker, R.C. Kochel and P. C. Patton (eds.) Flood Geomorphology, Wiley, Chichester, 205–229.Google Scholar
  14. Clague, J. (1973) ‘Sedimentology andpaleohydrology of Late Wisconsin outwash, Rocky Mountain Trench, South-eastern British Columbia’, in A.V. Jopling and B.C. McDonald (eds.) Society of Economic Paleontologists and Mineralogists Special Publication No. 23, Tulsa, 223–237.Google Scholar
  15. Cossey, S.P.J. and Ehrlich, R. (1979) ‘A conglomerate, carbonate flow deposit, northern Tunisia: a link in the genesis of pebbly mud-stones’, Journal of Sedimentary Petrology 49, 11–22.Google Scholar
  16. Costa, J.E. (1984) ‘Physical geomorphology of debris flows’, in J.E. Costa and P.J. Fleisher (eds.) Developments and Applications of Geomorphology, Springer-Verlag, New York, 268–317.CrossRefGoogle Scholar
  17. Costa, J.E. (1988) ‘Rheologic, geomorphic, and sedimentologic differentiation of water flood, hyperconcentrated flows, and debris flows’, in V.R. Baker, R.C. Kochel & P.C. Patton (eds.) Flood Geomorphology, Wiley, Chichester, 113–122.Google Scholar
  18. Dugmore, A.J. (1989) ‘Tephrochronological studies of Holocene glacier fluctuations in south Iceland’, in J. Oerlemans (ed.) Glacier Fluctuations and Climatic Change, Kluwer Academic Publishers, Dordrecht, 37–55.Google Scholar
  19. Einarsson, E.H., Larsen, G., and Thórarinsson, S. (1980) ‘The Sólheimartephra layer and the Katla eruption of 1357’, Acta Naturalia Islandica 28, 24pp.Google Scholar
  20. Enos, P. (1977) ‘Flow regime in debris flow’, Sedimentology 24, 133–142.Google Scholar
  21. Fisher, R.V. (1971) ‘Features of coarse-grained, high-concentration fluids and their deposits’, Journal of Sedimentary Petrology 41, 916–927.Google Scholar
  22. Fraser, G.S. and Bleuer, N.K (1988) ‘Sedimentological consequences of two floods of extreme magnitude in the late Wisconsonian Wabash Valley’, in H.E. Clifton (ed.) Sedimentologic Consequences of Convulsive Geologic Events, Geological Society of America Special Paper 229, 111–125.CrossRefGoogle Scholar
  23. Galon, R.(1973) ‘Geomorphological and geological analysis of the proglacial area of Skeiðarárjökull, central section’, Geographica Polonica 26, 15–56.Google Scholar
  24. Haraldsson, H. (1981) ‘The Markarfljót sandur area, S. Iceland: Sedimentological, petrographical and stratigraphic studies’, Striae 15, 1–65.Google Scholar
  25. Hine, A.C. and Boothroyd, J.C. (1978) ‘Morphology, processes and recent sedimentary history of a glacial-outwash plain shoreline, southern Iceland’, Journal of Sedimentary Petrology 48, 901–920.Google Scholar
  26. Hjulström, F. (1952) ‘The geomorphology of the alluvial outwash plains (sandurs) of Iceland and the mechanics of braided rivers’, Proceedings of the 17th International Geographical Congress, Washington, 337–342,Google Scholar
  27. Jónsson, J. (1982) ‘Notes on the Katla volcanoglacial debris flows’, Jökull 32, 61–68.Google Scholar
  28. Kjartansson, G. (1967) ‘The Steinholtshlaup, central-south Iceland on January 15th, 1967’, Jökull 17, 249–262.Google Scholar
  29. Klimek, K. (1973) ‘Geomorphological and geological analysis of the proglacial area of Skeiðarárjökull. Extreme eastern and extreme western sections’, Geographica Polonica 26, 89–113.Google Scholar
  30. Krigström, A. (1962) ‘Geomorphological studies of sandur plains and their braided rivers in Iceland’, Geografiska Annaler 44, 328–346.CrossRefGoogle Scholar
  31. Larsen, V. and Steel, R.J. (1978) ‘The sedimentary history of a debris-flow dominated, Devonian alluvial fan — a study of textural inversion’, Sedimentology 25, 37–59.CrossRefGoogle Scholar
  32. Lowe, D.R. (1976) ‘Grain flow and grain flow deposits’, Journal of Sedimentary Petrology 46, 188–199.Google Scholar
  33. Maizels, J.K. (1983) ‘Lichenometry and paleohydrology of terraced sandur deposits, Sólheimajökuir’, in Geomorphological and Environmental Studies in Southern Iceland, Report of Aberdeen University Iceland Expedition 1983, Department of Geography, University of Aberdeen, 40–50.Google Scholar
  34. Maizels, J.K. (1987a) ‘Modeling of paleohydrological change during deglaciation’, Geographie Physique et Quaternaire 40, 263–277.Google Scholar
  35. Maizels, J.K. (1987b) ‘Large-scale flood deposits associated with the formation of coarsegrained, braided terrace sequences’, in F.G. Ethridge, A.M. Flores and M.D. Harvey (eds.), Recent Developments in Fluvial Sedimentology, Society of Economic Paleontologists and Mineralogists, Tulsa, 135–148.CrossRefGoogle Scholar
  36. Maizels, J.K. (1989a) ‘Sedimentology, paleoflow dynamics and flood history of jökulhlaup deposits: palaeohydrology of Holocene sediment sequences in southern Iceland sandur deposits’, Journal of Sedimentary Petrology 59, 204–223.Google Scholar
  37. Maizels, J.K. (1989b) ‘Sedimentology and palaeohydrology of Holocene flood deposits in front of a jökulhlaup glacier, south Iceland’, in K. Bevan and P. Carling (eds.) Floods: Hydrological, Sedimentological and Geomorphological Implications, Wiley and Sons, Chichester, 239–251.Google Scholar
  38. Maizels, J.K. (in press) ‘A radiocarbon date from Holocene sandur deposits in areas of jökulhlaup drainage, southern Iceland’, Radiocarbon.Google Scholar
  39. Maizels, J.K. and Dugmore, A.J. (1985) ‘Lichenometric dating and tephrochronology of sandur deposits, Sólheimajökull, southern Iceland’, Jökull 35, 69–78.Google Scholar
  40. Maizels, J.K., Fyfe, G. and Dugmore, A.J. (1987) ‘Geomorphic criteria for distinguishing jökulhlaup and non-jökulhlaup sandur deposits, south Iceland’, Unpublished field report, Aberdeen University, Department of Geography, 25pp.Google Scholar
  41. Miall, A. (1977) ‘A review of the braided river environment’, Earth-Science Reviews 13, 1–62.CrossRefGoogle Scholar
  42. Miall, A. (1978) ‘Lithofacies types and vertical profile models in braided river deposits: a summary’, in A.D. Miall (ed.) Fluvial Sedimentology, Canadian Society of Petroleum Geologists Memoir 5, Calgary, 597–604.Google Scholar
  43. Nemec, W., and Steel, R.J. (1984) ‘Alluvial and coastal conglomerates: their significant features and some comments on gravelly mass-flow deposits’, in E.H. Koster and R.J. Steel (eds.) Sedimentology of gravels and conglomerates, Canadian Society of Petroleum Geologists Memoir 10, 1–31.Google Scholar
  44. Pierson, T.C. (1980) ‘Erosion and deposition by debris flows at Mt. Thomas, north Canterbury, New Zealand’, Earth Surface Processes 5, 227–247.CrossRefGoogle Scholar
  45. Pierson, T.C. (1981) ‘Dominant particle support mechanisms in debris flows at Mt. Thomas, New Zealand, and implications for flow mobility’, Sedimentology 28, 49–60.CrossRefGoogle Scholar
  46. Pierson, T.C. (1985) ‘Initiation and flow behaviour of the 1980 Pine Creek and Muddy River lahars, Mount St. Helens, Washington’, Bulletin of the Geological Society of America 96, 1056–1096CrossRefGoogle Scholar
  47. Postma, G. (1986) ‘Classification for sediment gravity-flow deposits based on flow conditions during sedimentation’, Geology 14, 291–294.CrossRefGoogle Scholar
  48. Rist, S. (1983) ‘Floods and flood danger in Iceland’, Jökull 33, 119–132.Google Scholar
  49. Rust, B. (1978) ‘Depositional models for braided alluvium’, in A.D. Miall (ed.) Fluvial Sedimentology, Canadian Society of Petroleum Geologists Memoir 5, Calgary, 605–625.Google Scholar
  50. Scott, K.M. (1988) ‘Origin, behaviour and sedimentology of prehistoric catastrophic lahars at Mount St. Helens, Washington’, in H.E. Clifton (ed.) Sedimentologic consequences of convulsive geologic events, Geological Society of America Special Paper 229, 23–35.CrossRefGoogle Scholar
  51. Smith, G.A. (1987) ‘The influence of explosive volcanism on fluvial sedimentation: the Deschutes Formation (Neogene) in Central Oregon’, Journal of Sedimentary Petrology 57, 613–629.CrossRefGoogle Scholar
  52. Smith, N.D. (1985) ‘Proglacial fluvial environments’, in G.M. Ashley, J. Shaw and N.D. Smith (eds.) Society of Economic and Petrological Mineralogists, Short Course Lecture Notes No. 16, 85–134.Google Scholar
  53. Thompson, A. and Jones, A. (1986) ‘Rates and causes of proglacial river terrace formation in southeast Iceland: an application of lichenometric dating techniques’, Boreas 15, 231–246.CrossRefGoogle Scholar
  54. Thórarinsson, S. (1957) ‘The jökulhlaup from the Katla area in 1955 compared with other jökulhlaups in Iceland’, Jökull 7, 21–25.Google Scholar
  55. Thórarinsson, S. and Guðmundsson, H. (1979) ‘Mýrdalssandur. A geophysical survey’, Jarðefnaiðnaður h/f, OS79022JKD06, Reykjavík, 34pp.Google Scholar
  56. Tómasson, H. (1974) ‘Grimsvatnahlaup 1972, mechanism and sediment discharge’, Jökull 24, 27–39.Google Scholar
  57. Tómasson, H., Palsson, S. and Ingólfsson, P. (1980) ‘Comparison of sediment load transport in the Skeiðará jökulhlaups in 1972 and 1976’, Jökull 30, 21–33.Google Scholar
  58. Ward, L.G., Stephen, M.F., and Nummedal, D. (1976) ‘Hydraulics and morphology of glacial outwash distributaries, Skeiðararsandur, Iceland’, Jökull 46, 770–777.Google Scholar
  59. Pórarinsson, S. (1975) ‘Katla og annall Kötlugosa’, Árbok Ferðafélags Íslands, 1975, 124–149.Google Scholar

Copyright information

© Springer Science+Business Media Dordrecht 1991

Authors and Affiliations

  • Judith Maizels
    • 1
  1. 1.Department of GeographyUniversity of AberdeenAberdeenUK

Personalised recommendations