Jökull - 01.12.1978, Page 52

gravel bodies, but is nearer to a N—S orien-
tation. An inspection of the sonographs shows
that in most cases the sharp sand/gravel
boundary is on the eastern and northeastern
sides of the gravel outcrops. The fact that
there exist two non-perpendicular orientation
trends may indicate that there are two main
directions of transport, i.e. an easterly and a
southeasterly one.
The transverse patches running N—S
across the slope to the east of the patches dis-
cussed above resemble in many ways features
described by Kenyon (1970, right-hand side of
Pl. 1) although less curved. The boundaries
are quite sharp, but where a distinction can
be made, the sharpness is greater on the
eastern side. Easterly transport of sand is
therefore indicated.
On the southeastern side, the border bet-
ween units 2 and 3 describes numerous
cresentic shapes. Similar shapes are seen
within unit 3 and in the border zone between
units 3 and 4. These shapes are regarded as
being transverse and patches of a barchan-like
appearance in plan. Again, where a distinc-
tion can be made, the boundaries suggest
eastwards transport. Crescentic sand patches
occur in the Celtic Sea (Kenyon, op. cit.), but
their inferred sense of movement is opposite to
the present ones.
The criss-cross sand patches observed in unit
4 are similar to patches found in the Celtic
Sea. and to the west of Ireland (Belderson,
Kenyon, Stride and Stubbs, 1972, Figs. 67, 69, 70),
and although their boundaries give no infor-
mation on transport direction, it seems very
likely that their orientation indicates that in-
stead of the easterly transport in unit 3 the
direction here is more southeasterly.
The direction of sediment transport, as
evidenced by bedforms in the area is sum-
marised in Fig. 9.
CONCLUSIONS
The rock floor of southern Faxaflói is made
up of indurated sediments. The coarse grain-
size of these suggests that they are of glacial or
inferred from the orientation and shape of
sand patches.
Mynd 9. Flutningsstefna sets á svœðinu. Byggt á
l'ógun sandflekkja.
fluvio-glacial origin. After cementation of
these sediments took place, the rocks were
scoured by ice.
The second oldest deposit in the area is
thought to be the gravel of unit 4. The worn
and discoloured appearance of shells from this
area lends support to the suggestion that the
gravels are relict.
Recent sediments are represented by the
shell gravels and sands of units 2 and 3. In the
virtual absence of terrigenous sedimentation
these sediments are made up dominantly of
biogenic carbonates. Although their grain-size
appears to decrease with depth, the orien-
tation of sand patches indicates transpor-
tation towards the east rather than downslope.
Considerable accumulation of sediments is
indicated in the eastern and northeastern
parts of the area.
ACKNOWLEDGEMENTS
The author wishes to express his gratitude to the
director and staff of the Icelandic Hydrographic Ser-
vice for their considerable contribution to this study.
50 JÖKULL 28. ÁR