Jökull


Jökull - 01.12.1990, Side 35

Jökull - 01.12.1990, Side 35
Figure 2. An index map with the individual research veas (1-7) indicated: 1) North Iceland. 2) Northwest Iceland. 3) West Iceland. 4) Northeast Iceland. 5) East Iceland. 6) South Iceland and 7) Southwest Iceland. —Lega þeirra landsvœða (1-7), sem þessi 8rein fjallar um: 1) Norðurland. 2) Norðvesturland. 3) Vesturland. 4) Norðausturland. 5) Austurland. 6) Suðurland og 7) Suðvesturland. Alftanes advance in Southwest Iceland. The Kópa- sker and Ekruhom localities were later proposed as type sites“ for the Kópasker stage and the Saurbær stage in an Icelandic chronostratigraphical arrange- ment, which comprised two stadials; the Álftanes and Búði stages corresponding to the Older and Younger Dryas stadials in Northwest Europe, and two intersta- dials; the Kópasker and Saurbær stages corresponding to the Bplling and Allerpd interstadials in Northwest Europe (Th. Einarsson, 1979). RECENT STUDIES OF THE DE- glaciation During the last 10-15 years several geologists have been studying different aspects of Late Weich- selian deglaciation and sea-level changes in different Parts of Iceland. This account reviews the main re- sults and conclusions from studies in North, Northeast, East, South, Southwest, West and Northwest Iceland (Fig. 2). Although the aims and methods of these stud- les are somewhat different, their results throw some new light upon and enable conclusions to be drawn conceming the deglaciation history of Iceland at the end of the Weichselian glaciation and the beginning of the Holocene. NORTH ICELAND In his study of Late Weichselian deglaciation his- tory of the Skagafjörður district in the westem part of North Iceland, Víkingsson (1976, 1980) concluded that the deglaciation of the area was accelerated by calving and that it proceeded without any regional interruptions. Furthermore, he inferred that end- moraines found within the study area only reflected lo- cal readvance or standstill of the glacier margin. Vík- ingsson (1980) described three major deltas in Skaga- fjörður; at Sauðárkrókur, Reynistaður and Vindheima- melar, which were all formed when relative sea-level stood about 45 m a.s.l. (Fig. 3). The deltas are not synchronous formations and they indicate that glacial isostatic recovery of the land kept pace with eustatic rise of sea-level along with a southward recession of an ice margin in Skagafjörður. Absolute dates are as yet not available conceming the deglaciation history of Skagafjörður, but Víkingsson (1980) proposed an Allerpd age for the deglaciation of the area and for the formation of the marine limit at about 45 m a.s.l. Morivaki (1990) determined the height of the marine limit on the Skagi peninsula west of Skagafjörður and in the Húnaflói area west thereof to 50-60 m a.s.l. and suggested that the marine limit was reached concur- rently with a glacier advance in Younger Dryas time (Fig. 3). Comprehensive geomorphological, sedimentolog- ical and lithostratigraphical studies of sediments within the Fnjóskadalur drainage basin in central North Iceland (Fig. 3) have elucidated the Weichselian glacial history of the area (Norðdahl 1981,1983). The main features of the stratigraphical arrangement in Fnjóskadalur are several different and repeated depo- sitional environmental phases that have been assigned to nine stages of glacier readvance (stadials) and seven stages of glacier retreat (interstadials), which together comprise the Fnjóskadalur Sequence. The Fnjóska- dalur Sequence and thus the glacial history have been divided into three main phases (Norðdahl 1983). The maximum phase includes the culmination of JÖKULL, No. 40, 1990 33
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