Jökull - 01.12.1956, Blaðsíða 14

Fig. 11. Hólárjökull
1891 or 1892. Photo
Fr. W. W. Howell.
THE AGE OF THE MORAINE AMPFII-
THEATRE OF KVÍÁRJÖKULL.
In order to find out the age of the moraine
amphitheatre of Kvíárjökull I visited that glacier
on Sept. 16th 1955 together with Sigurdur Björns-
son in Kvísker and dug the profiles De 28 and
De 31 shown on fig. 3. In Oct. 1955 Sigurdur
Björnsson on my request dug three more pro-
files, De 27, 29 and 30 on fig. 3. The location
of these profiles is shown on the map fig. 7.
De 27 is dug on the E slope of Kambsmýrar-
kambur N of the outflow of Kvíá eystri, De 28
is on a gravel terrace which is a continuation
of the outer slope of Kambsmýrarkambur and
clearly of the same age. De 29 and 30 are dug
on the outer slope of Kvíármýrarkambur and
De 31 on the NW slope of the innermost of
two small moraine hillocks, Kvíárhólar, (fig.
13) that form a continuation of Kvíármýrar-
kambur towards S on the W side of Kvíá vestri.
These hillocks may formerly have been directly
connected with Kvíármýrarkambur and later
separated by water erosion.
The profiles measured show without doubt
that the lower parts of the outer slopes of Kvíár-
mýrarkambur and Kambsmýrarkambur are much
older than the 1362 eruption. From field studies
it was evident, however, that the crest of Kvíár-
mýrarkambur is very young, in all probability
from the 1870’s, and the contact between the
recent moraine and the underlying older one
is clearly visible on the aerial photos of 1954.
Thus the glacier tongue had in the 1870’s near-
ly exactly the same extension as it had at the
time when the moraine amphitheatre was ori-
ginally formed. As to the age of these moraines,
it is possible to fix it somewhat closer than
merely stating that they are prehistoric. Be-
tween the northern end of Kvíármýrarkambur
and the steep southern slope of Stadarfjall
there is a breach named Kambsskard. This
place name is found in an ecclesiastical deed
(máldagi) of the church of Hnappavellir from
1343 — per se a proof of Kviármýrarkambur
being still older. A small basaltic prehistoric
but definitely postglacial lava flow has spread
over the gravel plain SW of Kambsskard and
can be followed to the breach where it dis-
appeares under moraine. The source of this lava
is on the E side of Kvíárjökull and the lava has
flowed to southwest at a time when Kvíárjökull
did not reach the lowland and that must have
been sometime during the Postglacial Warm
Period. My impression from a short visit —
aclmittedly too short for a sufficiently thorough
study — was that the lava flow is older than
Kvíármýrarkambur. Consequently that moraine
ridge should be younger than the Postglacial
Warm Period, and as it certainly is prehistoric
it seems to me most reasonable to regard both
Kvíármýrarkambur and Kambsmýrarkambur as
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