Jökull - 01.12.1978, Page 3

JOKULL
28. Ár 1978 No. 28
JÖKLARANNSÓKNAFÉLAG ISLANDS JARÐFRÆÐAFÉLAG ÍSLANDS
The Deglaciation of the Southern Part of the Skagafjördur
District, Northern Iceland
SKÚLI VÍKINGSSON
National Energy Authority, Reykjavík, Iceland
ABSTRACT
The regional ice flow pattern in Skagafjördur-area
is discussed, particularly the confluence of glaciers
from the Central Iceland ice sheet on one hand and
from the mountainous area between Skagafjördur and
Eyjafjördur on the other. In the early stages the ice
recession was accelerated by calving. The deglaciation
seems to have proceeded without regional interrup-
tions. End moraines and other signs of stillstands or
readvances of the ice front are few and locally re-
stricted. No datings of Lateglacial sediments in the area
are available, but with comparison with other parts of
the country, a Saurbœr-interstadial (Alleröd) age is
most likely. Ice wedge casts formed during plurannual
permafrost indicate a coldperiod after the deglaciation
of the area. This cold period is assumed to be of the
Búdi-stage (Younger Dryas) age.
INTRODUCTION
Skagafjördur is the common name for the
fjord and the adjoining valley to the south
(Fig. 1). To the south this rather broad valley
divides into three valleys which from west to
east are called Svartárdalur, Vesturdalur and
Austurdalur. To the south of the valleys there
is a highland plateau of 700—800 m altitude,
a part of the Central Iceland Highlands. To
the west Skagafjördur is separated from the
Húnavatnssýsla district by mountains of
700—1000 m altitude. To the east a higher
and broader mountain massif (900—1500
m) separates Skagafjördur from the Eyja-
fjördur district. This mountain massive is the
highest range in the country.
DIRECTION OF GLACIER MOVEMENT
The general trend of glacier movement was
along the main valleys, Skagafjördur, Vestur-
dalur and Austurdalur. (Fig. 1). Glaciers from
tributary valleys, such as Nórdurárdalur and
Djúpidalur, did not affect the dominant flow
direction.
At the mouth of Djúpidalur some drumlins
run parallel to the Skagafjördur valley. This
indicates that the ice flow from the tributary
valley did not influence the north-
northwesterly ice flow in the Skagafjördur
valley. Lateral channels on Skálar in Austur-
dalur (Fig. 2) further illustrate the dominance
of the glacier from the main ice sheet over the
valley glaciers from the eastern mountains.
The channels run from Austurdalur,
approximately parallel to it into Ábæjardalur.
JÖKULL 28. ÁR 1