Rates of Holocene chemical weathering,`Little Ice Age' glacial erosion and implications for Schmidt-hammer dating at a glacier—foreland boundary,Fåbergstølsbreen,southern Norway
Restricted accessResearch articleFirst published online September, 2007
Rates of Holocene chemical weathering,`Little Ice Age' glacial erosion and implications for Schmidt-hammer dating at a glacier—foreland boundary,Fåbergstølsbreen,southern Norway
Average rates of Holocene chemical weathering and `Little Ice Age' glacial erosion of bedrock are estimated across the glacier—foreland boundary of an outlet glacier of the Jostedalsbreen ice-cap, southern Norway. Estimates are derived from two types of evidence: (1) the heights of quartz veins above adjacent surfaces of granitic or granodioritic gneiss; and (2) Schmidt-hammer R-values of rock hardness. Average and maximum rates of surface lowering of gneiss surfaces by chemical weathering are 1.63 and 3.61 mm/ka, respectively, whereas many quartz veins exhibit negligible weathering after c. 9700 years. `Little Ice Age' glacial erosion rates are at least two orders of magnitude greater than the chemical weathering rates, except in a narrow marginal zone inside, but close to, the `Little Ice Age' limit, where patches of weathered surface survive. Bedrock surfaces outside and well inside the `Little Ice Age' glacier—foreland boundary are shown to have potential for improved calibrated-age dating using R-values, compared with moraine surfaces.
André.M-F.1996: Rock weathering rates in arctic and subarctic environments (Abisko Mts., Swedish Lappland). Zeitschrift für Geomorphologie40, 499—517.
2.
——— 2002: Rates of postglacial rock weathering on glacially scoured outcrops (Abisko-Riksgränsen area, 68° N). Geografiska Annaler64A, 139—50.
3.
Aune, B.1993: Temperatur normaler, normalperiode 1961—90. Rapport 02/93. Den norske meteorologiske institutt.
4.
Benn, D.I. and Evans, D.J.A.1998: Glaciers and glaciation. Arnold.
5.
Bickerton, R.W. and Matthews, J.A.1993: `Little Ice Age' variations of outlet glaciers from the Jostedalsbreen ice cap, southern Norway: a regional lichenometric-dating study of ice-marginal moraine sequences and their climatic significance. Journal ofQuaternary Science8, 45—66.
6.
Boulton, G.S.1979: Processes of glacial erosion on different substrates. Journal of Glaciology23, 15—38.
7.
Caine, N.2004: Mechanical and chemical denudation in mountain systems . In Owens, P.N. and Slaymaker, O., editors, Mountain geomorphology . Arnold, 132—52.
8.
Dahl, R.1967: Postglacial micro-weathering of bedrock surfaces in the Narvik District of Norway. Geografiska Annaler49A, 155—66.
9.
Dahl, S.O., Nesje, A., Lie, , Fjordheim, K. and Matthews, J.A.2002: Timing, equilibrium-line altitudes and climatic implications of two early-Holocene glacier readvances during the Erdalen Event at Jostedalsbreen, western Norway. The Holocene12, 17—25.
10.
Dixon, J.C., Thorn, C.E., Darmody, R.G. and Campbell, S.W.2002: Post-glacial rock weathering processes on a roche moutonnée in the Riksgränsen area (68°N), northern Norway. Norsk Geografisk Tidsskrift56, 257—64.
11.
Førland, E.J.1993: Nedbør normaler, normalperiode 1961—90. Rapport 39/93. Den norske meteorologiske institutt.
12.
Goudie, A.2006: The Schmidt hammer in geomorphological research. Progress in Physical Geography30, 703—18.
13.
Grove, J.M.2004: Little ice ages: ancient and modern. Routledge. Gurnell, A.M. and Clark, M.J., editors 1987: Glacio-fluvial sediment transfer: an alpine perspective. Wiley.
14.
Hall, A.M. and Phillips, W.M.2006: Weathering pits as indicators of relative age of granite surfaces in the Cairngorm Mountains, Scotland. Geografiska Annaler88A, 135—50.
15.
Hall, K., Thorn, C.E., Matsuoka, N. and Prick, A.2002: Weathering in cold regions: some thoughts and perspectives . Progress in Physical Geography26, 577—603.
16.
Hallet, B., Hunter, L. and Bogen, J.1996: Rates of erosion and sediment evacuation by glaciers: a review of field data and their implicatons. Global and Planetary Change12, 213—35.
17.
Harbor, J. and Warburton, J.1993: Relative rates of glacial and nonglacial erosion in alpine environments. Arctic and Alpine Research25, 1—7.
18.
Lutro, O. and Tveten, E.1996: Geologisk kart over Norge, berggrunskart Årdal (1:125,000) . Norges Geologiske Undersøkelse.
19.
Matthews, J.A. and Shakesby, R.A.1984: The status of the `Little Ice Age' in southern Norway: relative-age dating of neoglacial moraines with Schmidt hammer and lichenometry. Boreas13, 333—46.
20.
McCarroll, D.1987: The Schmidt hammer in geomorphology: five sources of instrument error. British Geomorphological Research Group, Technical Bulletin36, 16—27.
21.
——— 1991: The age and origin of neoglacial moraines, Jotunheimen, southern Norway: new evidence from weathering-based data. Boreas20, 283—95.
22.
——— 1994: The Schmidt hammer as a measure of the degree of rock surface weathering and terrain age. In Beck, C., editor, Dating in exposed surface contexts. University of New Mexico Press, 29—46.
23.
Nesje, A. and Whillans, I.M.1994: Erosion of Sognefjord, Norway. Geomorphology9, 33—45.
24.
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—65.
25.
strem, G., Liestøl, O. and Wold, B.1977: Glaciological investigations at Nigardsbreen. Norsk Geografisk Tidsskrift30, 187—209.
26.
Owen, G., Matthews, J.A. and Shakesby, R.A.2006: Rapid Holocene chemical weathering on a calcitic lake shoreline in an alpine periglacial environment: Attgløyma, Sognefjell, southern Norway. Permafrost and Periglacial Processes17, 3—12.
27.
Shakesby, R.A., Matthews, J.A. and Owen, G.2006: The Schmidt hammer as a relative-age dating tool and its potential for calibrated-age dating in Holocene glaciated environments. Quaternary Science Reviews25, 2846—67.
28.
Sigmond, E.M.O., Gustavson, M. and Roberts, D.1984: Berggrunnkart over Norge (1:1 million). Norges Geologiske Undersøkelse.
29.
Thorn, C.E., Darmody, R.G., Dixon, J.C. and Schlyter, P.2001: The chemical weathering regime of Kärkevagge, arctic-alpine Sweden. Geomorphology41, 37—52.
