I92I. No. 8. ON THE ECLOGITES OF NORWAY. 27 



(iimnacs S ot" Kristianssund. Nordmon- (3, 8; Th. KJitliIIL 



Hegerskjaeret in Hustadviken and Trekrem near Tingvold, Norilmorc (IIi. Kjerultl. 



Saksnaesodden in Halsefjord, Nordmore ( Th. Kjerulf ?l. 



Rofjeldets Hammere near Rovand, Hevne, Nordmore (Hauanl. 



Brandsaeter near Kornstadfjord, Nordmore Ij. H. L. V'ogtI. 



Halsnaes, Tusteren, Nordmore iHauan). 



Quantitative Investigations on the Eclogites. 



Within the areas of granitic gneiss in Nordtjord and Moi^e eclogite 

 occurs in two manners: i) as lenticular masses in the gneiss and 2) as 

 bands or lenses in the olivine-rock. 



The eclogites occurring in the masses of olivine-rock are quantitatively 

 very inconspicuous and rather present the appearance of aggregations of 

 the garnet and pyroxenes, found as accessories in the main rock. When 

 going to investigate the chemical composition of the minerals one finds, 

 however, that they are more independent than could be supposed from 

 the appearance : the garnets are not chemically the same as those in the 

 country-rock, but are richer in iron. On the other hand, they show chem- 

 ical characters clearly pointing to a close genetic connection with the 

 oli\"ine-rock : thev are poor in alkalies and rich in chromic oxide. Mineral- 

 ogically these segregations in the olivine-rock show a great variation, al- 

 most all the possible combinations of the four minerals oli\-ine, enstatite, 

 diopside and garnet being represented, though the combination diopside — 

 garnet (eclogite) is most common. 



The eclogites enclosed directly in gneiss are gread\' variable in their 

 chemical and mineralogicai composition as well as in structure. From the 

 segregations in the olivine-rock they differ in being almost free from 

 chromic oxide and containing considerable quantities of alkalies. 



The ccloi^itr from Rodliaiigcii, Alinklovdalvu , Soiidinoir. 



As an example of an eclogite in oli\ine-rock I examined quantitatively 

 a specimen marked "Almklovdalen". A comparison with specimens later 

 collected by myself made it certain that it had been taken fi-oni the hill 

 called Rodhaugen. 



The minerals being unaltered and free from inclusions, samples could 

 be prepared for anah'sis simply by picking out clean grains. The sample 

 of garnet thus obtained proved at once to be pure, and the same was the 

 case with the pyroxene, which, howexer, was also treated with the heavy 

 solution. 



The analysis of the garnet, made by the writer, gave the following 

 results : 



