Jökull - 01.12.1978, Page 44

The Sea-bed of the Southern Part of Faxaflói, Iceland
KJARTAN THORS
Marine Research Institute, Reykjavík, Iceland
ABSTRACT
Some 500 km2 of sea-bed in the bay of Faxaflói,
SW-Iceland have been surveyed with side-scan sonar.
A map of the area, based on complete sonar coverage,
shows the sea-bed to be made up of solid rock, gravel
and sand. Dredge samples of the solid rock show it to
be of sedimentary origin. Grab samples of the gravel
and sand are very carbonate rich and a pattern of
decreasing carbonate content with depth is observed.
The orientation of sand patches and ripples in the
gravels indicate sediment transport from west to east,
i.e. into the bay. Boomer profiles indicate sediment
buildup in the eastern part of the area.
INTRODUCTION
The southern part of the bay of Faxaflói is
incised by a channel entering the bay from the
northwest. Inside the bay the channel makes
an elbow bend to the southwest, thus separat-
ing extensive shallows to the west from the
shallows of the eastern shores of the bay (Fig.
1). The 40 m isobath traces the outlines of the
channel, which has maximum depths of 50—
60 m inside the bay. The shallower ground to
the west of the channel rises gently from about
40 m depth towards the two topographic highs
of Sydra Hraun and Vestra Hraun. These two
Fig. 1. Map of the
southern part of the bay
of Faxaflói showing out-
lines of study area. Iso-
baths in metres.
Mynd I. Mælingasvœðið í
Faxaflóa. Dýpi í metrum.
42 JÖKULL 28. ÁR