Jökull - 01.12.1982, Blaðsíða 80

Miyashiro, A. 1978: Nature of alkalic volcanic rock
series. Contrib. Mineral. Petrol. 66: 91-104.
Oskarsson, N., G.E. Sigvaldason and S. Steinthorsson
1982: A dynamic model of rift zone petrogenesis
and the regional petrology of Iceland. J. Petrol.
23: 28-74.
Prestvik, T. 1979: Geology of the Öræfi district,
southwestern Iceland. Nordic Volcanological
Institute 7901, University of Iceland. 28 pp.
Prestvik, T. 1980: Petrology of hybrid intermediate
and silicic rocks from Öræfajökull, southeast
Iceland, Geol.Fören.Stockholm Förh. 101: 299-
307.
Stewart, D.C. and C.P. Thomton 1975: Andesite in
oceanic regions. Geology 3: 565-568.
Taylor, S.R. 1969: Trace element chemistry of an-
desites and associated calc-alkaline rocks. In:
A.R. McBimey (ed.): Proceedings of the Andesite
Conference, 43-63. State of Oregon Dept. of
Geology and Mineral Industries, Bull. no. 65.
Thorarinsson, S. 1958: The Öræfajökull eruption of
1362. Acta Naturalia Islandica 2: 1-99.
Thomton, C.P. and O.F. Tuttle 1960: Chemistry of
igneous rocks: Pt. I. Differentiation index. Am.J.
Sci.258: 664-684.
Manuscript accepted 20 May 1982
ÁGRIP
BREGFRÆÐILEG EINKENNI
GOSBERGS ÚR ÖRÆFAJÖKLI
Tore Prestvik, Þrándheimsháskóla
Lýst er bergfræðilegum rannsóknum á bergi frá
Öræíajökli, þar sem vera munu rofnar leifar tveggja
fornra megineldstöðva auk þeirrar sem nú er virk.
Berggerðir eru fjölbreyttar, en höfundur telur að
athuguðu máli, að bergið í Öræfajökli sé þóleiit-
iskrar ættar. Ræðir hann síðan þessa niðurstöðu í
víðara samhengi.
76 JÖKULL 32. ÁR