Jökull - 01.12.1986, Page 44

Fig. 1. The location of Ketilsstadir
and other sites examined in southern
Iceland — Mynd 1. Rannsóknarstað-
ir á Suðurlandi.
Fig. 2. The bog at Ketilsstadir looking north-west-
wards towards the icecap Eyjafjallajökull from Geita-
fjall (1980). — Mynd 2. Mýrin við Ketilsstaði í Mýrdal.
Horft frá Geitafjalli til norðvesturs. Eyjafjallajökull í
baksýn. Myndin er tekin 1980.
Along the edge of the icecap, the Pleistocene pala-
gonite formation (móberg) is clothed in discontinuous
heath vegetation and is dissected by several deep
gorges, occupied by rivers draining from Mýrdalsjök-
ull onto the sandur. The heath now provides summer
pastures for the farms in the lower, more gently con-
toured land to the south. The sandur is poorly vege-
tated and has been much influenced by frequent ‘jök-
ulhlaup’, caused by eruption of the sub-glacial vol-
cano Katla, most recently in 1918 (Jónsson, 1980).
Much of Sólheimasandur is thought to have been ex-
tensively modified in a ‘hlaup’ during the fourteenth
century (Einarsson et al., 1980), which destroyed
much of the vegetation and grazing pressure has
further exacerbated the problem (Runólfsson, 1978).
Recently, parts of the sandur have been reclaimed by
seeding and are now available for hay crops.
The sampling locality selected (fig. 3) is now a com-
pletely drained bog of about 25 hectares lying south of
the main Reykjavík to Vík road towards the western
edge of Mýrdalur, 7km west of Vík. The modern farm
of Ketilsstadir, the school and other farms of the area
lie on land gently sloping up towards the heath and
the small lake, Oddnýjartjörn, north of the road. The
bog occupies a virtually enclosed basin, bounded to
the east by the 154m a.s.l. ridge of Geitafjall and to
the west by a low arcuate ridge, reaching 91m a.s.l.
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