Greinar (Vísindafélag Íslendinga) - 01.01.1976, Page 147

146
Fig. 11: Abrasion bench (1) of Sandfell, covered with consolidated sediments (2),
volcanic rocks of normal (3) and reverse (4) magnetization. 1) Primary feldspar-
porphyritic tuff-breccia of an abrasion bench at the west side of southern Sandfell
(which is to the left of the picture). 2) Consolidated sediments of sand and well
worn gravel, with foreset bedding; formed exclusively of the feldspar-porphyritic
material. 1) and 2) are here seen in the wall of a gully running N to NW be-
tween Sandfell and the shown hill. On 2) rests a largely scree-covered hill reach-
ing 250 m height, consisting of two different rock types. An exposure of 1) and 2)
can also been seen on the west side of the hill. 3) Exposure of unporphyritic,
normally megnetized basaltic breccia, being a part of the extensive Stangarháls-
Lómatjarnarháls layer of tuff-breccia. The nearest main exposure is 300 m away,
at Mælifell. 4) Three separate exposures of olivine-porphyritic block- jointed
basalt. Clear reverse magnetizalion in all exposures. The outcrop indicated to the
left of 3, and a little higher consists of large reversely magnetized pillows in
situ. As dicussed in the main text, that is taken to mean an age of at least 0.69
million years. 5) Remnant of a hard cover made of debris from 4). 6) Loose scree
cover of the hill, largely formed of blocks from 4), but material from 3) also
occurs. See note at end of the paper.
where the west-directed run-off from the pass between Sandfell and
Mælifell has eroded it further, the bench was covered with sedi-
ments from the pass, which in turn were covered by an unpor-
phyritic sub-aquatic volcanic breccia of normal magnetization, and
a topmost pillow- and blocky olivine-porphyritic volcanic breccia of
reverse magnetization.
These rocks, cf. Fig. 11, are now left in a 250 m high hill be-
10