This study focuses on the sedimentary characteristics and the chronostratigraphy of Holocene massflow deposits recognized in a lake-fill sedimentary succession. These deposits in lake Ulvådalsvatnet, western Norway, are discrete, sharp-bounded units of sand-sized sediment, running from gravelly and graded to silt-rich, and characterized by low total carbon and water contents. They are rich in terrestrial macrogflora detritus, dark brown in colour, and interpreted as high-density turbidity current deposits attributed to subaerial debris flows that plunged into the lake. Thirty-three 14C AMS dates were derived from three cores, and though the ages are somewhat inconsistent (macroflora invariably younger than bulk sediment samples), they indicate a marked increase in debris-flow processes after c. 2200 cal. yr BP, considered to reflect increased occurrence of heavy rainstorms.
Anda, E. , Blikra, L.H. and Braathen, A.2002: The Berill Fault – first evidence of neotectonic faulting in southern Norway . Norwegian Journal of Geology82, 175–182 .
2.
Ballantyne, C.K. and Benn, D.I.1994: Paraglacial slope adjustment and resedimentation following recent glacier retreat, Fåbergstølsdalen, Norway . Arctic and Alpine Research26, 255–269 .
3.
Barnekow, L. , Possnert, G. and Sandgren, P.1998: AMS 14C chronologies of Holocene lake sediments in the Abisko area, northern Sweden – a comparison between dated bulk sediment and macrofossil samples . GFF20, 59–67 .
4.
Blikra, L.H. 1986: Glasialgeologi og skråningsprosessar i Skjerdingsdalen og Grasdalen, Stryn, indre Nordfjord. Unpublished Cand. Scient. thesis, University of Bergen.
5.
Blikra, L.H. and Nemec, W.1993a: Postglacial avalanche activity in western Norway: depositional facies sequences, chronostratigraphy and palaeoclimatic implications. In Frenzel, B. , Matthews, J.A. and Gläser, B. , editors, Solifluction and climate variation in the Holocene, Paläoklimaforschung 11, Stuttgart: Gustav Fischer Verlag , 143–162.
6.
Blikra, L.H. and Nemec, W.1993b: Postglacial fan deltas in western Norway: a case study of snow avalanche-dominated, colluvial fans prograding into deep fjords. In Korean Sedimentology Research Group (organizers), Abstracts 3rd International Workshop on Fan Deltas, University of Seoul , 1–4.
7.
Blikra, L.H. and Nemec, W.1998: Postglacial colluvium in western Norway: depositional processes, facies and palaeoclimatic record . Sedimentology45, 909–959 .
8.
Blikra, L.H. and Nemec, W.2000: Postglacial colluvium in western Norway: depositional processes, facies and palaeoclimatic record – reply . Sedimentology47, 1058–1068 .
9.
Blikra, L.H. and Sæmundsson, T.1998: The potential of sedimentology and stratigraphy in avalanche-hazard research . Norwegian Geotechnical Institute Publication203, 60–64 .
10.
Brooks, S.M. , Anderson, M.G. and Collinson, A.J.C.1995: Modelling the role of climate, vegetation and pedogenesis in shallow translational hillslope failure . Earth Surface Processes and Landforms20, 231–242 .
11.
Church, M. and Miles, M.J.1987: Meteorological antecedents to debris flow in southwestern British Columbia; some case studies . Geological Society of America; Reviews in Engineering Geology7, 63–79 .
12.
Dahl, S.O. and Nesje, A.1994: Holocene glacier fluctuations at Hardangerjøkulen, central southern Norway: a high-resolution composite chronology from lacustrine and terrestrial deposits . The Holocene4, 269–277 .
13.
Dahl, S.O. and Nesje, A.1996: A new approach to calculating Holocene winter precipitation by combining glacier equilibrium-line altitude and pine-tree limits: a case study from Hardangerjøkulen, central southern Norway . The Holocene6, 381–398 .
14.
Eyles, N. , Eyles, C.H. and Miall, A.D.1983: Lithofacies types and vertical models; an alternative approach to the description and environmental interpretation of glacial diamict and diamictite sequences . Sedimentology30, 393–410 .
15.
Govi, M. and Sorzana, P.F.1980: Landslide susceptibility as a function of critical rainfall amount in Piedmont Basin (North-western Italy) . Studia Geomorphologica Carpatho-Balcanica14, 43–61 .
16.
Helle, S.K. , Anundsen, K. , Aasheim, S. and Haflidason, H.1997: Indications of a Younger Dryas marine transgression in inner Hardanger, west Norway . Norsk Geologisk Tidsskrift77, 101–117 .
17.
Houghton, J.T. , Ding, Y. , Griggs, D.J. , Noguer, M. , van der Linden, P.J. and Xiaosu, D. (editors) 2001: Climate change 2001: the scientific basis. Contribution of working group I to the third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). Cambridge: Cambridge University Press .
18.
Johnson, K.A. and Sitar, N.1990: Hydrological conditions leading to debris-flow initiation . Canadian Geotechnical Journal27, 789–801 .
19.
Jonasson, C. 1991: Holocene slope processes of periglacial mountain areas in Scandinavia and Poland. Doctoral thesis, Uppsala University Department of Physical Geography Rapport 79.
20.
Jonasson, C.1993: Holocene debris-flow activity in northern Sweden. In Frenzel, B. , Matthews, J.A. and Gläser, B. , editors, Solifluction and climate variation in the Holocene, Paläoklimaforschung 11, Stuttgart: Gustav Fischer Verlag , 179–195.
21.
Karlén, W. and Matthews, J.A.1992: Reconstructing Holocene glacier variations from glacier lake sediments: studies from Nordvestlandet and Jostedalsbreen – Jotunheimen, southern Norway . Geografiska Annaler74A, 327–348 .
22.
Lowe, D.R.1982: Sediment gravity flows: II. Depositional models with special reference to the deposits of high-density turbidity currents . Journal of Sedimentary Petrology52, 279–297 .
23.
MacDonald, G.M. , Beukens, R.P. , Kieser, W.E. and Vitt, D.H.1987: Comparative radiocarbon dating of terrestrial plant macrofossils and aquatic moss from the ‘ice-free corridor’ of western Canada . Geology15, 837–840 .
24.
Matthews, J.A. and Karlén, W.1992: Asynchronous neoglaciation and Holocene climatic change reconstructed from Norwegian glaciolacustrine sedimentary sequences . Geology20, 991–994 .
25.
Matthews, J.A. , Dahl, S.O. , Berrisford, M.S. , Nesje, A. , Dresser, P.Q. and Dumayne-Peaty, L.1997: A preliminary history of Holocene colluvial (debris-flow) activity, Leirdalen, Jotunheimen, Norway . Journal of Quaternary Science12, 117–129 .
26.
Matthews, J.A. , Dahl, S.O. , Nesje, A. , Berrisford, M.S. and Andersson, C.2000: Holocene glacier variations in central Jotunheimen, southern Norway based on distal glaciolacustrine sediment cores . Quaternary Science Reviews19, 1625–1647 .
27.
Matthews, J.A. , Harris, C. and Ballantyne, C.K.1986: Studies on a gelifluction lobe, Jotunheimen, Norway: 14C chronology, stratigraphy, sedimentology and palaeoenvironment . Geografiska Annaler68A, 345–360 .
28.
Moser, M. and Hohensinn, F.1983: Geotechnical aspects of soil slips in alpine regions . Engineering Geology19, 185–211 .
29.
Nesje, A.1992: A piston corer for lacustrine and marine sediments . Arctic and Alpine Research24, 257–259 .
30.
Nesje, A. , Dahl, S.O. , Andersson, C. and Matthews, J.A.2000: The lacustrine sedimentary sequence in Sygneskardvatnet, western Norway: a continuous, high-resolution record of the Jostedalsbreen ice cap during the Holocene . Quaternary Science Reviews19, 1047–1065 .
31.
Nesje, A. , Dahl, S.O. and Løvlie, R.1995: Late Holocene glaciers and avalanche activity in the Ålfotbreen area, western Norway: evidence from a lacustrine sedimentary record . Norsk Geologisk Tidsskrift75, 120–126 .
32.
Nesje, A. , Dahl, S.O. , Løvlie, R. and Sulebak, J.R.1994: Holocene glacier activity at the southwestern part of Hardangerjøkulen, central southern Norway: evidence from lacustrine sediments . The Holocene4, 377–382 .
33.
Nesje, A. , Kvamme, M. , Rye, N. and Løvlie, R.1991: Holocene glacial and climatic history of the Jostedalsbreen region, western Norway; evidence from lake sediments and terrestrial deposits . Quaternary Science Reviews10, 87–114 .
34.
Nesje, A. , Matthews, J.A. , Dahl, S.O. , Berrisford, M.S. and Andersson, C.2001: Holocene glacier fluctuations of Flatebreen and winter-precipitation changes in the Jostedalsbreen region, western Norway, based on glaciolacustrine sediment records . The Holocene11, 267–280 .
35.
Nyberg, R. and Lindh, L.1990: Geomorphic features as indicators of climatic fluctuations in a periglacial environment, northern Sweden . Geografiska Annaler72A, 203–210 .
36.
Oldfield, F. , Crooks, P.R.J. , Harkness, D.D. and Petterson, G.1997: AMS radiocarbon dating of organic fractions from varved lake sediments: an empirical test of reliability . Journal of Paleolimnology18, 87–91 .
37.
Palmer, T.N. and Räisänen, J.2002: Quantifying the risk of extreme seasonal precipitation events in a changing climate . Nature415, 512–514 .
38.
Prior, D.B. , Stephens, N. and Douglas, G.R.1970: Some examples of modern debris flows in north-east Ireland . Zeitschrift für Geomorphologie. N.F.14, 275–288 .
39.
Rapp, A.1963: The debris slides at Ulvådal, western Norway, an example of catastrophic slope processes in Scandinavia . Nachrichten der Akademie der Wissenschaften in Göttingen II. Mathematisch-Physikalische klasse13, 195–210 .
40.
RegClim 2000: RegClim General Technical Report No.5. Presentations from Workshop20–21 November 2000 at Geilo, Norway. Norwegian Meteorological Institute Report.
41.
RegClim 2002: Report: Mer variabelt vr om 50 år, Mer viten om usikkerheter. www.nilu.no/regclim (last accessed 12 June 2003).
42.
Sandersen, F.1997: The influence of meteorological factors on the initiation of debris flows in Norway. In Matthews, J.A. , Brunsden, D. , Frenzel, B. , Gläser, B. and Weiβ, M. , editors, Rapid mass movement as a source of climatic evidence for the Holocene, Paläoklimaforschung 19, Stuttgart: Gustav Fischer Verlag , 321–332.
43.
Sletten, K. and Blikra, L.H. 2002: Holocene debris-flow and waterflow processes in Gudbrandsdalen, eastern Norway; sediment characteristics, dating challenges and palaeoclimatic implications. In Sletten, K. and Blikra, L.H., Holocene mass-movement processes in Norway, and the development of a moraine complex on Svalbard, Geomorphology, sedimentology, chronostratigraphy and paleaoclimate, unpublished doctoral thesis, University of Bergen.
44.
Sollid, J.L. and Sørbel, L.1979: Deglaciation of the western central Norway . Norsk Geologisk Tidsskrift60, 72–81 .
45.
Strunk, H.1997: A 3300 years history of debris-flow activity in the southern Alps: vegetation cover, soil depth, forest fire and overgrazing as controlling factors. In Matthews, J.A. , Brunsden, D. , Frenzel, B. , Gläser, B. and Weiβ, M. , editors, Rapid mass movement as a source of climatic evidence for the Holocene, Paläoklimaforschung 19, Stuttgart: Gustav Fischer Verlag , 223–232.
46.
Stuiver, M. and Reimer, P.J.1993: Extended 14C database and revised CALIB 3.0 14C age calibration program . Radiocarbon35, 215–230 .
47.
Svendsen, J.I. and Mangerud, J.1987: Late Weichselian and Holocene sea-level history for a cross-section of western Norway . Journal of Quaternary Science2, 113–132 .
48.
Turney, C.S.M. , Coope, G.R. , Harkness, D.D. , Lowe, J.J. and Walker, M.J.C.2000: Implications for the dating of Wisconsinan (Weichselian) late-glacial events of systematic radiocarbon age differences between terrestrial plant macrofossils from a site in SW Ireland . Quaternary Research53, 114–121 .
49.
Törnqvist, T.E. , De Jong, A.F.M. , Oosterbaan, W.A. and Van der Borg, K.1992: Accurate dating of organic deposits by AMS 14C measurement of macrofossils . Radiocarbon34, 566–577 .
50.
Van Asch, T.W.J.1997: The temporal activity of landslides and its climatological signals. In Matthews, J.A. , Brunsden, D. , Frenzel, B. , Gläser, B. and Weiβ, M. , editors, Rapid mass movement as a source of climatic evidence for the Holocene, Paläoklimaforschung 19, Stuttgart: Gustav Fischer Verlag , 7–16.
51.
Weirich, F.H.1989: The generation of turbidity currents by subaerial debris flows, California . Geological Society of America Bulletin101, 278–291 .
