Jökull - 01.12.1990, Blaðsíða 39

advanced and was probably divided by Akrafjall as the
glacier reached out into the mouth of the fjord. The
marine limit at 80-90 m a.s.l. was probably reached
during this readvance of the glaciers, which is referred
t0 as the Skipanes event (Fig. 5). Close to 11,700
B.P., the Borgarfjörðurglacier and the glacier in Hval-
fjörður both retreated to an unknown position (Ingólfs-
son, 1988). Simultaneously with the recession of the
glaciers relative sea-level was lowered, although not
falling below the 35 m level. This episode of glacier
retreat and regression of relative sea-level is referred
to as the Látrar event and has been 14C dated be-
tween 11,715 ± 120 B.P. (Lu-2372) and 10,965 ± 80
B-P (Lu-2056) (Ingólfsson, 1988). Some time around
11,000 B .P. the glacier in Borgarfjörður advanced and
reached a position similar to the one reached during
the Skipanes event, and formed the conspicuous Skor-
holtsmelar moraine (Fig. 5). This episode of glacier
advance has been named the Skorholtsmelar event and
it was terminated close to 10,155 ± 150 B.P. (Lu-
2378). About 10,300 B.P. the glacier retreated from
the Skorholtsmelar moraine when relative sea-level
was 60-70 m a.s.l. (Fig. 5). Subsequently relative
sea-level fell towards present sea-level. This event
has been named the Melabakkar event (Ingólfsson,
1988). Additionally, Ingólfsson (1988) assumed that
an intermittent 40-50 m raised shorelevel could be of
Preboreal age and possibly have been formed concur-
rently with a glacial episode in the upper Borgarfjörður
tributary valleys.
The most important result from these studies in
the lower Borgarfjörður region is the occurrence of
two Late Weichselian glacier advances and retreats
(stadials and interstadials). The stadials, the Skipanes
and Skorholtsmelar events culminated about 11,800
and 10,600 B.P. respectively, closely correspond to
the Older Dryas and the Younger Dryas stadials, and
the Asbakkar and Látrar events consequently corre-
spond to the Bplling and the Aileröd interstadials in
Northwest Europe. The Melabakkar event covers the
latest part of the Younger Dryas Chronozone and the
heginning of the Holocene (Ingólfsson, 1988). An-
°ther and equally interesting conclusion is that the
Icelandic inland ice sheet and its outlet glaciers were
ntuch more extensive in Younger Dryas time than
Figure 6. Late Weichselian and early Holocene
end-moraines and marine-limit features in Northeast
Iceland. Legend: 1) 14C dates. 2) Raised beaches. 3)
End-moraines. —Jökulgarðar og sjávarborðsmenjar
frá síðjökultíma og upphafi nútíma á Norðausturlandi.
Tákn: 1) Geislakolsaldursákvarðanir. 2) Fornfjöru-
mörk. 3) Jökulgarðar.
the previous DAD-model had suggested, and that the
glaciers attained approximately the same extent dur-
ing the Younger Dryas as they did in Older Dryas time
(Ingólfsson, 1988).
NORTHEAST ICELAND
In his studies of Weichselian sediments in the west-
ern part of the Melrakkaslétta peninsula in Northeast
Iceland (Fig. 6), Pétursson (1986; 1991) reached a
conclusion, which in important aspects differs from
the DAD-model conceming the chronological posi-
tion of the glacier readvance that overrode the Röndin
sediments at Kópasker and the deglaciation history of
the area. The sediments in westem Melrakkaslétta
were overridden by a glacier that flowed towards the
west away from a north-south orientated ice-divide
above the central parts of the peninsula and across
the present coastline (Fig. 6) (Pétursson, 1986). The
JÖKULL,No. 40, 1990 37