Greinar (Vísindafélag Íslendinga) - 01.01.1977, Page 13

Chapter 1
EARLY AND LATE STAGES OF THE LAST
GLACIATION OF ICELAND
CONTENTS
The aim of this chapter is twofold: 1) to show the importance of a
combination of observations and theoretical inference, and 2) to show the
ice-free areas where the so-called postglacial lavas could have flowed
and/or originated. The result of the present analysis is that the extension
of the Older and Younger Dryas glaciations of Iceland was quite different
from what has been postulated hitherto by Icelandic Quaternary geologists.
The present author has recently written a paper in Icelandic
(1), in which stages of retreat of the last glaciation in north-
ern Iceland play a role. He then noticed that the boundary of
the Younger Dryas stage of glaciation in this area, as given
by some Icelandic Quaternary geologists (2,3) needs a revision.
In the same way the ideas of the Older Dryas Stage and the
intervening Alleröd, should also be revised (4). Some points
of my analysis of the Younger Dryas (1) are repeated below,
before moving farther afield.1)
In southwestern Iceland, the rand moraines of the Older
Dryas have been recognized on the small peninsula Álftanes,
close to Reykjavík. The stage has therefore been given the
regional name of the Álftanes Stage (3). Þorleifur Einarsson (4)
takes this to mean the rand of a general, common glacier for
most of Iceland, Fig. 1. In reality, this moraine on Álftanes shows
the rand of a local Older Dryas glacier extending from the moun-
1) In the following introductory remarks, it is hardly necessary for the
reader to have at hand a good topographic map of the country, but later,
when we consider the Older Dryas Stage, the maps in the scales 1:100,000
and even 1:50,000 are most desirable, although the maps in 1:250,000 may
suffice for following the description and argumentation. The maps are
obtainable in Bókaverzlun Eymundsson, Austurstræti 18, and from Land-
mælingar Islands, Laugavegi 178, Reykjavík.