Jökull - 01.12.1984, Blaðsíða 121

area and to point out the most important aspects
of future research. It is hoped that the literature
survey will also give some insight into the present
position of Late Weichselian studies in Iceland in
general.
In this paper the term Weichselian substitutes
the term Last Glaciation, and Late Weichselian is
used for Late Glacial. This is in agreement with
the proposal of Mangerud et al. (1974) for the
terminology and classification of the Quaternary
stratigraphy of Norden. The lower boundary of
the Late Weichselian is taken to be 25.000 years
BP as proposed by Mangerud and Berglund
(1978). This terminology has previously been
applied in Iceland by Th. Einarsson (1967),
Norddahl (1979, 1981, 1983) and Andersen
(1981).
RESEARCH HISTORY
Earliest research
During the years 1753—57 the Icelandic
naturalist Eggert Ólafsson visited the Borgarfjör-
dur region. Ólafsson (1772) made the first stra-
tigraphical observation in the area when he dis-
tinguished three clay units in the lowlands of
Leirársveit, one of which he considered to be of
marine origin. He also discovered localities at the
Leirá- and Laxá rivers where subfossil marine
molluscs are preserved in the sediments. Ólafs-
son concluded that the oceans were diminishing,
resulting in the emergence of land from the sea.
Ólafsson’s localities at Leirá and Laxá became
somewhat classic in the 19th century geological
literature on Iceland, and were frequently refer-
red to (Paijkull 1867, Mörch 1871, Keilhack 1884,
1886, Thoroddsen 1892, Hallgrímsson 1934).
The Icelandic geologist and poet Jónas
Hallgrímsson and the Danish zoologist Japetus
Steenstrup visited the Borgarfjördur region in
1840. Hallgrímsson (1934) briefly described a
bluish marine clay he observed at a few localities
on the lowland south of the Hafnarf-
jall-Skardsheidi massif. He suggested fluviogla-
cial origin for laminated deposits he observed in
the vicinity of the River Hvítá. Hallgrímsson was
the first investigator to visit the Melabakkar
cliffs, where a roughly five km long coastal sec-
tion of sediments is exposed. He was convinced
that the marine sediments had emerged from the
sea because of land upheaval, which he consi-
dered still to be active. Although Steenstrup
never published any of the results from his
research in Iceland, he contributed considerable
data to later workers (Thoroddsen 1902, 1911,
1913). Bárdarson (1923) published and discussed
a list of mollusc species collected in the Borgarf-
jördur region by Jónas Hallgrímsson and identi-
fied by Japetus Steenstrup.
The first geological maps of Iceland were pub-
lished by Paijkull (1867) and Keilhack (1886).
They both remarked on the fossiliferous sedi-
ments in Leirársveit. Paijkull was one of the first
geologists to point out the importance of glacial
erosion in the sculpturing of the Icelandic land-
scape. Helland (1882) referred to Paijkull on
glacial erosion in Iceland, and added that Lake
Skorradalsvatn occupies an ice-scoured hollow.
The contributions of Keilhack and Thoroddsen
Keilhack (1884) wrote an important paper on
the postglacial marine deposits of Iceland. He
published a compiled map of Iceland showing
areas formerly submerged, which included the
Borgarfjörður region. This map is more accurate
than the corresponding map published by Thor-
oddsen (1892), and it was not matched in details
until Th. Einarsson (1961, 1963) presented a
similar map with isobases. Keilhack determined
the upper limit of marine clay in western Iceland
to be at about 40 m above present sea level. He
concluded that the clay had been deposited by
glacial rivers at the end of the glaciation, and
pointed out that similar clay is still being depo-
sited off the coasts of Iceland. Keilhack (1884)
discussed a list of mollusc species which he col-
lected from clay deposits at many localities in
Iceland, and suggested that arctic conditions
were prevalent during the deposition of the clay.
Pjetursson (1905) pointed out that Keilhack had
not distinguished between Late Weichselian and
Interglacial sediments found in the vicinity of
Reykjavík. However, Keilhack’s general conclu-
sions on the arctic character of the fossil fauna
were later confirmed by Bárdarson (1923),
Áskelsson (1934) and Kjartansson (1943).
Keilhack (1884, p. 160) correlated the clay
deposits with the “upper drift deposits of Scot-
land, the Yoldia clay of Scandinavia and the
Champlain-Formation of North America”.
Keilhack (1886) mapped the Melasveit and
Leirársveit sediments as fluvioglacial deposits,
thereby suggesting the existence of glaciers in the
near vicinity at the time of their deposition.
JÖKULL 34. ÁR 119