Jökull - 01.12.1979, Page 65

Fig. 5. Map of the Setberg area, Snaefellsnes, showing the distribution of rock types. From Sig-
urdsson, 1970.
mugearites. Noteworthy is the occurrence of
anorthoclase as a phenocryst phase in a
benmoreite. It should be noted here, that no
trachyte was found associated with this series in the
Setberg area. Phlogopite and hornblende is
occasionally found interstitially in the groundmass
in this rock series. In the alkalic rock suite of Vest-
mannaeyjar (mainly Postglacial), where only alkali
basalts and hawaiites have developed so far, a
similar mineralogy is encountered. The mineralogy
of the transitional series is as yet imperfectly
known.
POSTGLACIAL PETROLOGICAL ZONES
The Postglacial volcanism is a direct
continuation of the Upper Pleistocene volcanism.
About 26—28 volcanic systems have been active in
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