Jökull - 01.07.2003, Blaðsíða 37

Morphoclimates and morphodynamics of the northern Swedish Lapland and east Iceland
THE STUDY AREAS
The morphoclimate of an area is largely dependent
on the regional climate and existing landforms (Ah-
nert 1982). The mountains of northernmost Swedish
Lapland are situated close to the North Atlantic in
a prevailing westerly wind regime which gives rise
to a pronounced orographic effect and strong west-
east gradient in cloudiness and precipitation. Pre-
cipitation is mainly connected with cyclonic activity.
The northerly position of the area is partly counter-
acted by the influence of the Gulf Stream. The moun-
tains belong to the northern part of the Scandinavian
mountain chain (the Scandinavian Caledonides) with
individual peaks reaching 1440 m a.s.l. Typical are
flat plateaux at 1300 m a.s.l., intersected by glacially
sculptured valleys with floors at 1000 m a.s.l. (Kling
1996; 2003).
Iceland is located in the polar front area. The
proximity of passing low-pressure areas implies a
high cyclonic activity. Moreover, the climate in the
coastal areas of East Iceland is modified by the cold
East Iceland Stream, which may from time to time
carry drift-ice (Schunke 1979; Liebricht 1983; Einars-
son 1991). The mountains of the Icelandic Eastern
Fjords (Austfirðir) rise steeply out of the North At-
lantic, reaching maximum elevations of more than
1000 m a.s.l.
The Austdalur drainage basin is located at
65Æ16’N, 13Æ48’W in the subarctic-oceanic moun-
tain area of Seyðisfjörður whereas the Latnjavagge
drainage basin is situated at 68Æ20’N, 18Æ30‘E in the
arctic-oceanic mountains of northernmost Swedish
Lapland. Both exhibit principal geomorphologic and
geological characteristics and were thus chosen as
representative test areas for the field work (Figure 1).
Direct anthropogenic impact on the natural systems is
presently small.
Latnjavagge
The Latnjavagge drainage basin drains to the south
into the larger Kårsavagge basin. It has an area of ap-
prox. 9 km
, a length of 4600 m, and elevation rang-
ing from 950 m a.s.l. to 1440 m a.s.l. The bedrock of
Latnjavagge is mainly composed of Cambro-Silurian
mica-garnet shists and inclusions of marble (Kulling
1964; Kling 2003). Latnjavagge is dominated by
flat plateaux at approx. 1300 m a.s.l., steep slopes
which bound the glacially sculptured valley, and the
flat valley floor situated between 950 and 1200 m
a.s.l. Regional deglaciation occurred about 8000–
10000 yr ago (André 1995). The plateaux largely
consist of bare bedrock and boulder fields. The tran-
sition to steep slopes is generally abrupt and, on the
east-facing side, covered by perennial snow and ice
patches. The lower part of the valley floor is dom-
inated by a lake, Latnjajaure (0.73 km
), and a se-
ries of moraine ridges. The regolith thicknesses are
generally small (Beylich et al. 2003). The area be-
longs to the mid-alpine zone with a continuous vege-
tation cover comprising dwarf shrub heaths and alpine
meadows and bogs (Molau 2001; 2003). The distribu-
tion of permafrost is still not thoroughly investigated
but drilling outside the drainage basin at 1200 m a.s.l.
suggested permafrost down to 80 m below the surface
(Kling 1996; 2003; Beylich et al. 2003). Active de-
nudative slope processes are frost weathering, rock-
falls, boulder falls, ploughing boulders, avalanches,
slush flows, debris flows and slides, solifluction (lobes
and sheets), creep processes, chemical weathering and
denudation, aquatic slope denudation, and deflation.
In the main channels dissolved solids, suspended sed-
iments and debris are transported. The largest part
of the fluvially transported sediments is trapped in
the lake. The hydrological regime is nival (Beylich
2001a; 2003; Beylich et al. 2003).
Austdalur
The 23 km
Austdalur basin drains to the north into
the Seyðisfjörður fjord. It has a length of 6850 m,
and elevation ranging from sea level up to 1028 m
a.s.l. The Austfirðir Mountains are mainly composed
of Upper-Miocene plateau basalt layers with interca-
lated sedimentary rock layers slightly dipping to the
west (Schunke 1975; Einarsson 1994). Pleistocene
glaciations produced steep, alpine relief with trough
valleys, corries, ridges, and rock walls (Schunke
1979; Sigbjarnarson 1983). Regional deglaciation oc-
curred about 10000–12000 yr ago (Ingólfsson 1991).
The drainage basins of the Austfirðir Mountains are
mainly characterized by their steepness and high
drainage density. In addition to the talus cones de-
JÖKULL No. 52, 2003 35