58 



I'KXTTI KSKOI.A. 



M.-X. Kl. 



The Eclogite in the Gneiss. 



Mode of occurrence. 



In many |)art.s of the gneiss area in Nordfjord and Møre inclusions of 

 eclogite occur in great numbers. They are all small. I do not know any 

 continuous mass over loo meters in the longest diameter. In describing 

 their mode of occurrence we may first quote (in translation) what l)r. II. 

 Reusch, in his unpublished notes of 1883, writes in an account of the eclogite 

 on the island Silden in Selje, west of the island Barmen: 



"On the east side of the island there occur, in a moderately garnet- 

 iferous grey gneiss, a few lenses which, in their central part, consist of 



Fig. 6. Lenses of eclogite with boundary-zones of amphibolite. Silden, Selje. 

 After H. H. Reusch. 



eclogite, towards the boundaries pa.ssing over into a hornblende-rock. 

 The eclogite is banded owing to various proportions of the garnet and 

 pyroxene." (Fig. 6.) 



A specimen from the one meter long lens ser\"ed as material for my 

 quantitative investigation (p. 37). Reusch continues: 



"Somewhat towards the North, from the farm-house N. Silden another 

 larger mass of eclogite rises up from the sea" (Fig. 7). "The elongated prisms 

 of the pyroxene are arranged parallel, giving the rock a pronounced foliation 

 which dips 30 towards the East and is also apparent in the surrounding 

 gneiss. At right angles to the foliation the rock is cut b}- joints, in part 

 filled up with quartz. Beginning from these joints the rock has altered 

 into a hornblende-rock, some 25 or 30 cm at both sides. The eclogite 

 contains some quartz and mica; of these the former appears unchanged in 

 the altered zones, while the mica disappears. The eclogite passes gradually 

 over into the hornblende-rock, as is also the case along the boundaries 

 where a zone of the latter invariably occurs." 



