t 
PERMIAN ROCKS AND STRUCTURES 
OF THE OSLO REGION 
Introduction. 
1 he German geologist Leopold v. Buch first described parts of 
what is now known as the Oslo region as an especially interesting 
district, in 1810. A first map and regional description of “Das Christi- 
ania Obergangsterritorium’* was published by B. M. Keilhau in 1838. 
The correct relationship between the volcanics and the underlying 
Cambro-Silurian rocks was established by Fh. Kjerulf. From his work 
in the years 1855 — 1880 may be mentioned several maps and the cor- 
rect interpretation of the faulting of the region, the cross-cutting nature 
of the plutonic rocks, the contact metamorphism, etc. But the Oslo 
region is first of all known from the works of W. C. Broker thrombi 
oo w 
more than 50 years. Most famous is his monograph of 1890 on the 
geology and mineralogy of the Langesundsfjord pegmatites, a voluni 
of 900 pages. It also contains the first general account of volcanic, 
plutonic and dike rocks of the region, described as families of 
dec r e a s i n g b a sicity. 
Soon afterwards Brogger (1894 a) was one of the first to point 
out that magmatic differentiation is governed by the laws of crystal- 
lization. I hen followed Brogger’s series: “Die Eruptivgesteine des 
Kristiania- (Oslo-) gebietes" in 7 volumes The first one appeared in 
1894, the last one in 1933. In this last volume he published 331 rock 
analyses ol igneous rocks, accompanied by general geological com- 
ments. Complete references to the publications of Brogger is found in 
Barth ( 1945a ) and to the older literature in Holtedald (1934). 
The age of the Oslo rocks was finally determined in 1931 when 
O. Moltedahl tound Permian fossils in sediments just below the lav 
After the death of Brogger in 1940 a new series of monograph 
(in English) was started by O. Moltedahl and T. F. W. Barth. Thi 
series has now lb volumes ( 1960). Short general surveys on the Osl 
v o J 
region are published by Moltedahl (1934. p. 340 — 356 and 1943. 
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1 V. 
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