Jökull - 01.12.1982, Page 18

the submarine shelf which is 50 to 100 km wide out
to the 200 m isobath; it is not however likely to have
extended far westwards from the present limit.
THE 850 M EROSION SURFACE
The mountain summits rise to an elevation gen-
erally of800 to 900 m in a strip of country (stippled
on Fig. 3) averaging 10 km wide east of the area of
the 1100 m surface. The accordance of summits is
exemplified north of Breiðdalsvík where 12 peaks
distributed along a ridge lOkm long have elevations
(from west to east) of 868, 851, 843, 799, 851, 769,
844, 861, 808, and 782 m. Thissurface ofaccordant
levels is referred to as the 850 m erosion surface.
Within the area of the 1100 m surface there are also
numerous mountainside benches and flat-topped
ridges at around 900 m jutting out from the main
mountain masses. The plateau in the headwaters of
the Eyvindará at this level is perhaps the broad
valley of the ancestral Eyvindará, through which
the present rivers have cut deep trenches. An exten-
sive upland area mostly between 800 and 900 m
occurs also in the SW cornerof the study area, but it
is probably not related to the850 m surface found in
the Austfirðir.
Within the area of the 1100 m surface the total
downcutting to the 850 m surface averages 450 m
and varies from 700 or 850 m west and northeastof
Reyðarfjörður and west of Hamarsíjörður to 200 m
1 Origjnal |wötershed
■ PresentJ
a Wind cjaps
■Original | ri
’ Captured J
vers
Fig. 4. Distribution of the 650 m
erosion surface in the Austíirðir
and inland plateau west of it. The
solid black and cross-shaded
areas are remnants of the 650 m
surface. Figures give height above
sea level in hundreds of metres.
Bar-stipple — moberg mountains
rising above the 650 m surface.
'I'he map also shows features of
the river system explained by the
caption.
Mynd 4. Utbreiðsla 650 m rofflatar
á Austfj'órðum og svœðum vestur af
þeim. Móbergsjj'óll sem ná upp fyrir
fl'ótinn eru merkt meðgrófum smástrik-
um. Vatnaskil eru einnig sýnd.
16 JÖKULL 32. ÁR