Náttúrufræðingurinn - 1955, Blaðsíða 24

132
NÁTTÚRUFRÆÐINGURINN
hana sönnum atburði um eldsuppkomuna í Borgarhrauni, sem á dögum
sögumannsins hefur enn geymzt með Islendingum. Þjóðsagan um hinn
mikla og illilega mann, sem gróf í stöpulhliðið í Hripi, jók við það gildi
sitt, henni var gefinn kjarni, sem ekki var hægt að véfengja.
SUMMARY
The following results may be mentioned:
The crater Eldborg in SW. Iceland, is not, as formerly believed, an isolated crater
(ein einzelner Krater) (4, 10). It stands on a fissure which has fed four other
craters now visible in the lava field Eldborgarhraun. The fissure runs in an ESE. —
WNW. direction. Two eruptions have taken place in the fissure and accordingly
there are two lava streams of very different ages. The older lava, of which the
main stream is made, was poured out during an eruption of a mainly effusive
character, and no pyroclasts were produced. This eruption occurred after the end
of the marine transgression which followed the end of the Glacial Period, on the
other hand it happened long before the settlement of Iceland.
The younger lava spread from the same fissure. The eruption was partly ex-
plosive and the crater row now seen in Eldborgarhraun (Fig. 1) was built up
simultaneously.
The age difference of the lavas may i. a. be judged from different luxuriance of
the vegetation which covers the surface of the lavas, from geomorphological features
and last but not least from different directions of magnetization of the lava
rocks.
The results of the geological investigation does not contradict the verity of ihe
story of Landnámabók which tells about an eruption in Borgarhraun in historical
times.
TILVITNANIR
1. Eggert Ólafsson og Bjarni Pálsson: Rejse igjennem Island, I, bls. 363. Sorö 1772.
2. Guðmundur G. Bárðarson: Fornar sjávarminjar. Rit vísindafélags Islendinga I.
Akureyri 1923.
3. Helgi Jónsson: Vegetionen paa Snæfellsnes. Vidensk. Medd. fra Dansk Nathurh.
Foren. Köbenhavn, 1900.
4. Henderson, E.: Iceland. Journal of Recidence in that island. Bls. 22. Edin-
burgh, 1818.
5. íslendingasögur, I. bd. Bls. 61. Islendingasagnaútgáfan. Reykjavík 1946.
6. Ólafur Lárusson: Snæfellsnes I. Bls. 61—63, Reykjavik 1946.
7. Þorvaldur Thoroddsen: Ferðabók III. Bls. 87. Kaupmannahöfn 1914.
8- — Lýsing Islands I. Bls. 115. Kaupmannahöfn 1911.
9- — Lýsing Islands II. Bls. 115. Kaupmannahöfn 1911.
10. — Island. Grundriss der Geographie und Geologie. Bls. 151. Petermanns Mit-
teilungen: Erganzungsheft Nr. 152. Gotha 1905.
11- — Geologiske Iagttagelser paa Snæfellsnes. Bls. 47—48. Svenska Vet. Akad.)
Handl., Bd. 17. Afd. II. No. 2. Stockholm. \