Jökull - 01.12.1990, Qupperneq 44

Geochronology (Mangerud et al. 1974) Distribution of 14 C dates and glacier advances in lceland
14 C years B.P. Chrons North Northeast South Southwest West
9,500 1 Preboreal | Langhóll - Ljósavatn Ijj Vopnafjörður |'l|j -<F- Búöi 1 | Mosfellsdalur
10,500 : Younger Dryas ? -<— Belgsá i -<— Fornhólar 1 ? <— Kópasker •t 1 1 ? <— Reykjavík 1 Skorholtsmelar J
11,500 = Allerod 1 1 -|l| Skipanes -
Older Dryas O
12,500 - Bolling S 3 CJ a> co 3 (0 ■g 1, Melrakkaslétta \ """'
</> p ’cf LL Háubakkavík
Figure 10. Distribution of 14C dates (thick lines) and glacier advances (arrows) dealt with in this paper. The
14C dates are shown with ± one standard deviation, and glacier advances of uncertain age are marked with ? —
Dreifing >4C aldursákvarðana (þykkar línur) ogframrásir jökla (örvar) íýmsum landshlutum. Aldursákvarðanir
eru sýndar með ± einu staðalfráviki og jökulframrásir af óvissum aldri eru auðkenndar með ?
Younger Dryas age has also been assigned to a glacier
readvance on western Melrakkaslétta in Northeast Ice-
land (Pétursson, 1986; 1991)andintheReykjavíkarea
in Southwest Iceland (Fig. 10) (Hjartarson, 1989).
The Skipanes event in West Iceland is as yet the
only glacier readvance that has been directly dated to
the Older Dryas (Fig. 10). According to the 14C dates
this advance culminated at about 11,800 B.R (Ingólfs-
son, 1988). A 14Cdatedmarinetransgressiononwest-
ern Melrakkaslétta in Northeast Iceland was seem-
ingly accompanied by a glacier advance in Bplling
time (12,655 B.P.) (Fig. 10), and the Háubakkavík
profile displays a number of glacial events that are
older than the assumed Bplling advance (Pétursson,
1986; 1991). In North Iceland the Fnjóskadalur Se-
quence displays a number of glacier readvances prior
to the Younger Dryas Fornhólar readvance (Fig. 10)
(Norðdahl, 1990).
On basis of the data presented above it may be con-
cluded that changes in the extent of the Icelandic in-
land ice sheet and in its major outlet glaciers occurred
simultaneously on at least two separate occasions, i.e.
around 10,600 and 9,700 B.P. (Fig. 10). Compara-
ble Younger Dryas and Preboreal readvances are rel-
atively well documented in Scandinavia (Berglund,
1979; Sprensen 1979; Andersen 1980; Corner 1980)
and in East Greenland (Hjort, 1979). These concurrent
changes in the extent of the Icelandic inland ice sheet
42 JÖKULL, No. 40, 1990