Jökull - 01.12.1956, Blaðsíða 12

papers as the variations of Svínafellsjökull—
Skaf tafellsjökull):
1934-35 0 m
1935-36 - 10 „
1936-37 O co 1
1937-45 o GO CM 1
1945-47 no measurements
1947-48 + 50 m
1948-49 + 20 „
1949-50 - 45 „
1950-51 - 7 „
1951-52 - 4 „
1952-53 + 7.5 „
1953-54 - 23 „
1954-55 - 32 „
1955-56 O CM 1
ENTONNOIRS ON KVÍÁRJÖKULL.
At the end of his paper Björnsson describes
some peculiar features on the surface of Kvíár-
jökull. These are circular or somewhat ellipse-
shaped depressions, commonly 20—30 m broad
and 6—8 m cleep with rather steep slopes and
a flat bottom. In the bottom is a narrow water
furrow. These depressions are founcl in great
number on the relatively ílat southwestern part
of the glacier tongue, W of the median moraine.
I may here add that these depressions are
visible on an aerial photo taken by P. Elannes-
son May 28tli 1938 (published in Thorarinsson
1943, p. 31), which supports Björnsson’s state-
ment that these depressions have existed at
least two decades.
Depressions of this type have been described
from Gorner Glacier and some other glaciers in
the Alps. They are also known from Malaspina
Glacier (Alaska) ancl Tasman Glacier (New Zea-
land). They have been especially studied on
Gorner Glacier (Renaud 1936) where they are
termecl entonnoirs. However, their formation
seems not yet to be quite satisfactorily ex-
plained.
REDUCTION OF KVÍÁRJÖKULL
SINCE AB. 1870.'
The map fig. 7 is based on the Danish General
Staff map of 1904 (sheet 87 Öræfajökull SA),
the U. S. Army Service maps of 1950 (6018 I and
6018 IV), based on aerial photography 1945 and
Á. Bödvarssons aerial photos of Sept. 15, 1945.
The sections figs. 8 and 9 are based on the
same maps. Tlie dash lines marking the exten-
sion and thickness of the glacier ab. 1870 must
be regarded as approximate. The extension of
the glacier at that time must however have been
practically the same as its maximum one in
Postglacial Time.
The following figures are based on the 1904
and 1950 maps.
IvVÍÁRJ ÖKULL.
Area below the 1100 m con-
tour 1904 ............... 11.1 km2
Area below the 1100 m con-
tour 1945 ............... 9.5 „
Total areal loss 1904—1945 . . 1.6 „ (14,5%)
Frontal areal loss 1904—1945 . 1.0 „ (9.0%)
Max. frontal recession 1904—
1945 .................... 0.55 km
Average thinning along section
C—D 1904-1945 ........... 60 m
The average thinning below the present 200
m contour ab. 1870—1945 may be estimated 80—
10