Jökull - 01.12.1993, Blaðsíða 44

present coastline with relative sea-level close to 45 m
a.s.l. in this glacio-isostatically more depressed area.
The marine limit on the western Melrakkaslétta penin-
sula has, on the other hand, been 14C-dated to about
10,200 BP (Pétursson, 1991). Based on the above,
we suggest that a glacial advance and formation of the
regional 30 m marine limit and ice-marginal deposits
in the Þistilfjörður and Bakkaflói areas occurred in the
period between 10,200 and 9700 BP, i.e. at the ter-
mination of the Weichselian glaciation. The 50-40 m
level was, therefore, most likely formed during the
Younger Dryas.
The discovery of the rhyolitic Miðfjörður Tephra
is of considerable interest as it offers the possibil-
ity of tephrochronological correlation with other ar-
eas. Geochemical analyses show that the Miðfjörður
Tephra is chemically equivalent to the S-Tephra (Ta-
ble I), found in the lowermost part of several soil sec-
tions around and north of the Krafla volcano (Fig-
ure 1), some 80 km south-west of Miðfjörður. K.
Sæmundsson (1991) suggested that the deposition of
the S-Tephra occurred shortly after the early Holocene
deglaciation of the inland Krafla area. The stratigraph-
ical position and the tentative age of the Miðfjörður
Tephra clearly postdates the formation of the 30 m
regional marine limit there.
ACKNOWLEDGMENTS
We are indebted to Halldór G. Pétursson, The
Akureyri Museum of Natural History, for critically
reading earlier drafts of the manuscript and mak-
ing valuable comments, Dr. Karl Grönvold, Nordic
Volcanological Institute in Reykjavík, for doing the
Microprobe analyses, and Dr. Kristinn J. Alberts-
son for critically reading the manuscript, making
constructive comments and improving the English.
Dr. Leó Kristjánsson and two anonymous reviewers
are acknowledged for constructive criticism of the
manuscript. Thorsteinn Sæmundsson, Lund Univer-
sity, assisted in the field. Financial support (to Hregg-
viður Norðdahl) from the Icelandic Council of Sci-
ence, Division of Natural Sciences is acknowledged.
The study is a contribution to the IGCP Project 253:
Termination of the Pleistocene.
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