Jökull - 01.12.1985, Side 21

Stadarvatn. There, with a sea level around 15 m higher
than today, it remained for a while, depositing the
Stadarvatn moraine ridges and the upper till bed.
(2) A simpler interpretation of the data includes
downwasting of one body of ice from the higher to the
lower lateral terraces and only one retreat of the glacier
to behind the present coastline. This was then followed
by a short oscillation of the ice front. Sea level would
then seem to have transgressed to the 15 m level rather
synchronously with this glacial readvance as the ridges
composed of the upper till are abraded to that level.
The very approximate position of the glacier front
during formation of the lower set of lateral terraces at
Hvarfnúpur is indicated as zone C in Fig. 6. The Stadar-
vatn moraine zone (Fig. 11) and a probable contempor-
aneous moraine in lower Thverdalur are indicated as
zone D.
Látrar and Rekavík: A lateral terrace can be traced
along the mountainside west and north of Látrar in
northern Adalvík. Its surface lies around 25 m above
present sea level at Látrar, where the terrace is about
200 m wide, and it rises to 40 m near the junction with
the Rekavík valley (gradient 10 m/km), there being
Fig. 11. Air-photo showing southeast-
ern Adalvík with lake Stadarvatn (S),
the Thverdalur valley (T) and Mount
Flvarfnúpur (H) indicated. The late-
ral terraces at 70—50 m and 50—35 m
altitude on the slopes of Hvarfnúpur
are indicated by black arrows. Within
the conspicuous terminal moraine
zone northwest of Stadarvatn, the
section shown in Fig. 8 is indicated by
an arrowhead. Note also how the
moraines from cirque X (floor alti-
tude ca. 150 m) northeast of the lake
cross the lateral moraines deposited
by the valley glacier, thus postdating
them and indicating a low ELA dur-
ing som late part of the Late Weichse-
lian. Cirque X was not glaciated dur-
ing the Little Ice Age. Photo pub-
lished with permission of the Geode-
tic Survey oflceland. 11. mynd. Loft-
mynd af suðausturhluta Aðalvíkur.
Staðarvatn: (S), Pverdalur: (T) og
Hvarfnúpur: (H). Svartar örvar
benda á jarðarhjalla í 70—50 m og
50—35 m hœð í hlíðum Hvarfnúps.
Staðsetning jarðlagasniðs á 8. mynd
sýnd með svörtum oddi. Takið eftir
hvernig jökulruðningur frá hvilft X
sker jaðargarða daljökulsins. Petta
bendir til að seint á síðjökultíma hafi
jöklunarmörk legið mjög lágt, en botn
hvilftarinnar er í um 150 m yfir sjó.
Hvilftin var jökullaus á Litlu Isöld.
about 50 m wide. At Látrar the terrace has an at least 10
m thick lower bed of sandy, silty till, with many rounded
stones and boulders, and an upper 15 m thick unit of
glaciofluvial sediments, mostly horizontally bedded
gravelly sand with beds of well rounded stones and
boulders. The glaciofluvial sediments were deposited
close to or above sea level, which at the onset of
deposition probably stood around or below the present
10 m level. The thickness of these sediments indicate
that the base level, i.e. sea level, gradually rose to about
25 m above the present sea level.
A branch of the glacier covering the lowlands behind
Látrar drained northwestwards through the Rekavík
valley (Figs. 2 and 5), and was reinforced there by two
local cirque glaciers. The altitude (17-19 m) of the
JÖKULL 35. ÁR 19