Jökull - 01.07.2003, Síða 53

Morphoclimates and morphodynamics of the northern Swedish Lapland and east Iceland
tively low. In July, August and September they give
rise to low channel discharges, with smaller creeks
drying up completely (Beylich 1999a; 2000c).
MORPHOCLIMATE AND
PRESENT-DAY MORPHODYNAMICS IN
LATNJAVAGGE AND AUSTDALUR
A quantitative recording and labelling of present-day
morphodynamics of Austdalur is possible after cal-
culating the sediment budget of the drainage basin
(Beylich 1999a; 1999b; 2000a; 2000b; 2003). The
dominance of aquatic slope denudation over chemi-
cal denudation is due to the low intensity of chemical
weathering, to the relatively high share of vegetation-
bare slope surfaces, and to the mobility of channel
debris beds in the very steep drainage basin. The
very high wind speeds cause a further expansion of
the vegetation-bare surfaces. The process which is
third most important regarding annual mass transfer
[t m yr ] are ground avalanches, followed by rock-
falls/boulder falls, creep processes, debris slides and
flows and deflation. High amounts of runoff may oc-
cur all year long. Annual mass transfers in the main
channels clearly dominate over slope processes, with
the fluvial transport of solids being more important
than the transport of dissolved salts. The intensity
of the processes active in the present periglacial mor-
phoclimate is altogether low (Beylich 1999a; 1999b;
2000a; 2000b). The hydrological regime in Latn-
javagge is very different from Austdalur, with flu-
vial discharge and general forming activity being lim-
ited to the period from middle/end of May to Octo-
ber/November. Permafrost exists at least sporadically
in the area (Kling 1996; 2003; Beylich et al. 2003).
Slush flows, triggered by rapid snow melt in early
summer, are an important process. Because of the al-
most complete and very stable vegetation cover and
the stability of fluvial step-pool systems in the less
steep drainage basin slope wash processes are much
less important than in Austdalur. Although the in-
tensity of chemical weathering is low, chemical de-
nudation is more important than mechanical fluvial
denudation (Beylich 2001a; Beylich et al. 2003). The
intensities of the geomorphological processes active
in this periglacial environment are also low. In both
periglacial environments Holocene modification of
the glacial relief is negligible (Beylich 2001a; 2003;
Beylich et al. 2003).
CONCLUSIONS
The characteristics of the present-day morphoclimates
control the type and intensity of geomorphologic pro-
cesses in Latnjavagge and Austdalur. The comparison
of the different periglacial environments provides in-
formation on controlling factors of the processes and
sediment budgets in the areas. Similar studies to the
present one carried out in other periglacial environ-
ments having different morphoclimates seem to be
worthwhile in order to obtain a better understanding
of the importance of the prevailing wind, temperature
and precipitation regimes for the current geomorpho-
logic processes, sediment budgets and trends of relief
development. They would also provide a more re-
liable evaluation of possible geomorphologic effects
of predicted (morpho-)climate changes (Barsch 1993;
Schlyter et al. 1993; Rapp 1995; Beylich 2001b;
Beylich 2003).
Acknowledgements
Field work in East Iceland was carried out within
the framework of a Graduierten-Stipendium of Bun-
desland Sachsen-Anhalt, Germany, 1996–1998. The
four field campaigns in Iceland were financially
supported by Deutscher Akademischer Austauschdi-
enst (DAAD), Bonn. Research in Swedish Lapland
was carried out within the framework of a Post-
Doc-grant given by Deutscher Akademischer Aus-
tauschdienst (DAAD), Bonn: Post-Doc-Programm,
HSP III (Stipendium des DAAD im Rahmen des
Gemeinsamen Hochschulsonderprogramms III von
Bund und Ländern, 1999–2001, grant to Achim A.
Beylich). Since 2002 research has been funded
by the Deutsche Forschungsgemeinschaft (DFG,
Bonn, Emmy Noether-Programm, grant to Achim A.
Beylich). This paper was written in the Physical Geo-
graphy Programme of the Department of Earth Sci-
ences, Uppsala University. Meteorological data were
made available by Úrsúla E. Sonnenfeld and Trausti
Jónsson (Icelandic Meteorological Office, Veðurstofa
JÖKULL No. 52, 2003 51