Geological Survey of Finland Bulletin 289 - arkisto.gsf.fi

Geologieal Survey of Finland, Bulletin 289 29
sinee the origin of the magma presumably lies several kilometres below the erosion
level today. The direetion of maximum pressure was probably in the direetion
NE-SW while minimum pressure was at right angles to this, approximately in
a horizontal direetion. This NW-SE direetion is also at right angles to the direetion
of the rapakivi massifs in SW Finland. A doser study of diabases eneapsuled
in the rapakivi massif and more eareful petrographie studies of the trapp diabases,
the different rapakivi types and olivine diabases and a eollation of existing material
might east more light on this eomplex intrusion system of basaltie and granitie
magmas.
ACKNOWLEDGEMENTS
The authors wish to thank professor il; Edelman for valuable diseussions while the manuseript
was prepared and for eritieally reading it.
Information about diabases was given by Professor Hans Hausen, Mr. Leif Bergman, FiUie.
(Brändö), Mr. Leif Björk, M.Se. (SW Kumlinge), Mr. Kurt Karlsson, M.Se. (Sottunga ) and
Mr. Veli Suominen, Fil.lie. (Föglö, S. Kumlinge, Kökar and Sottunga).
The authors also wish to express their gratitude to Professor Herman Stigzelius for letting
the manuseript be published in the Bulletin series of the Geologieal Survey of Finland.
Mr. Christopher Grapes, B.A. translated the manuseript into English.
Manuscript received 8 October 1976
Revised manuscript received 18 November 1976