Náttúrufræðingurinn - 1964, Blaðsíða 49

NÁTTÚRUFRÆÐINGURINN
143
Peat beneath the tephra layer Hj in Hratnkelsdalur, E.-Iceland (9)
770 ± 90 years (T-394)
The sample was collected for dating in order to clear up some doubt as to
whether this rhyolitic layer, found in E Iceland, was produced by Hekla’s first
eruption in Historical Time (1104 A. D.) or possibly of prehistoric age. At
tlie farntruin Thorisstadir in Hrafnkelsdalur a heap of sheep bones was found
beneath this layer (cf. Fig. 11). The C14 dating as well as field studies of the
extension of this layer leave no douixt that this layer is the 1104-layer. The
first settlement in Hrafnkelsdalur is considerably older, and may well be from
the Settlement Time (870—930 A. D.).
Charcoal in brown tephra layer short NW of Hckla (15)
2660 ± 80 ycai-s (St. 814)
This tephra layer (Fig. 9, Cd 50), produced by Hekla, has spread towards NW.
It may prove useful for a more exact dating of the beginning of the Sub-
atlantic climatic deterioration in Iceland.
Bottom layer of a submarine peat in Seltjörn, SW Iceland (3)
9030 ± 280 years (Y-247)
8780 ± 150 yeai-s (H 404/370)
This dating is of a great importance for our knowledge of the postglacial
shore line development in Iceland as it proves that 9000 years ago the sea
level was at least about 2 m below the present one.
The isostatic uplift during the first millenium after the end of the Younger
Dryas Period lias been very rapid.
Radiocarbon dating of subfossil shells
by Thorleifur Einarsson
University llesearch Institute, Reykjavík, Iceland,
Brúará at Spóastaðir in Biskupstungur (18)
55 m above sea level.
(Mytilus edulis, Zirphaea crispata, Saxicava arctica var. rugosa)
9930 ± 190 years (T-362, 1963)
Hellisholtalækur in Hrunamannahreppur (17)
75 m above sea level.
(Mytilus edulis)
9580 ± 140 years (U-416, 1964)
9800 ± 150 years (U-417, 1964)
Iteykjavíkurflugvöllur (airport) (2)
13 m above sea level.
fPecten islandicus)
9940 ± 260 years (U-413, 1964) 10230 ± 190 years (U-415, 1964)
10450 ± 160 years (U-414, 1964) 10310 ± 260 years (U-412, 1964)