Greinar (Vísindafélag Íslendinga) - 01.01.1977, Blaðsíða 14

12
tain chain on the Reykjanes peninsula, Fig. 4, and could be term-
ed the Bláf jöll glacier, called after the highest part of the chain.
The space from Langjökull, southwest along the Median Active
Zone, but east of the Bláfjöll range, seems actually to have
been ice-free during Older Dryas, and the main shieldvolcano,
Skjaldbreiður could have been and was most probably formed
during Older Dryas time, cf. Chapter 3.
Þorl. Einarsson considers the Alleröd Stage to correspond
to a layer of thermophile shells between layers of glacier origin,
as discovered and described by G. G. Bárðarson early in this
century (5). The identification of the Alleröd Stage here is
supported by C-14 dating of the shells (4). The locality is in
the Saurbær district at the head of the Breiðif jörður bay, and
the regional name of the stage is Saurbær Stage.
The Younger Dryas rand moraines have been traced con-
fidently across the mid-southern lowlands in a WNW-ESE
direction, crossing the river Þjórsá at the waterfall Búði —
whence the regional name the Búði Stage. These randmoraines,
as well as the striae, show that the Younger Dryas glacier
had a divide along a line from Vatnajökull to Mýrdalsjökull,
and a glacier flowed westward to the mountain Bláfell near
Langjökull, so as to create a barrier for the main runoff from
the surrounding glaciers, the ,,Hvítá“ of that time, and from
a lake with a temporary outlet to the north, across the Kjölur
area between Langjökull and Hofsjökull.1)
Most of these apparently most surprising results concerning
the end of the last glaciation were the fruits of the patient
work of the late Guðmundur Kjartansson (6, 7). In addition,
he found that the medium-size shieldvolcano Leggjabrjótur
had formed at about this time, cf. Chapter 3.
The Younger Dryas age of the Búði stage rests on C-14 dat-
ings, and there is in general an undoubted correspondence
between the late-glacial and postglacial main climatic phases
of Iceland to those of Northern Europe, and Scandinavia in
particular.
1) See a reconsideration in Chapter 3, of the age of the lake stages and
that of I.eggjarbrjótur.