I92I. No. 8. ON THE FXLOGITES OF NORWAY. 47 



rocks near Bryggen in Nordtjord closel}- associated with the other types 

 of eclogite. 



This is the protoclastic structural modification of eclogite, while the 

 non-foliated porphyritic Duen type represents that form of igneous eclogite 

 which solidified under the most quiet conditions. 



4. TJic Sildcii fvpc. Distinctly foliated, almost even-grained, medium- 

 grained, the pyroxene present as short prisms, the garnet as lenticular 

 aggregates. Often banded. This type is transitional between i and 2. 



To this type belong some very beautiful occurrences on the islands 

 Silden and Barmen and near Listo in Selje and near Bryggen in Nordtjord. 



5. T/ic Saltkjael type. Aphanitic. I have found mylonitized eclogite 

 resembling the aphanitic rock from Saltkjael in Selje, and it is not quite 

 certain whether it is a posterior mylonitic or a primary protoclastic struc- 

 ture. The rock occurs as a narrow band in the gneiss. Other similar 

 examples have not been met with. 



6. The Ro/iiS(fa/s/ioni type. Non-foliated, even-grained and medium- 

 grained. Characterized by a double set of minerals : those of a hornblende- 

 gabbro besides the eclogite-constituents. Represented, besides in the type- 

 locality, in several occurrences near Romsdalsfjord, as Gryten and Rune- 

 berget. 



The evidence of this peculiar structure will be again discussed in the 

 chapter on the change of the facies. 



Besides these types, examples of which were studied quantitatively, 

 we may add short descriptions of the following primary types. 



7. Avipliibok-eclogite of the Gangeskar type. Mainly composed of 

 garnet with coarse long-prismatic amphibole. 



A specimen from the "cape west of G ange s kar" in Selje is com- 

 posed of clin oamp hibole, colourless clinopyroxene and red garnet 

 with brown rutile and colourless zircon as minor constituents 



The amphibole is megascopically dark green, in thin sections almost 

 colourless, and optically negative with large axial angle; c : y = 27 . It 

 is present as anhedral crystals of an average size of about 0.5 -< 1x2 cm. 

 This light-coloured amphibole probably belongs to the tremolite-actinolite 

 series. It is what, in the eclogite-literature, has been formerly called 

 smaragdite. 



All the other minerals are enclosed in this amphibole, the garnet and 

 pyroxene as irregular grains of resorbed appearance, but the rutile and 

 zircon mostly as microlitic euhedral crystals. The pyroxene has the common 

 omphacite characters and 2Vy about 60'. The Gangeskar specimens are 

 almost non-foliated, while most other occurrences consist of foliated varieties. 



This is a common rock type, though often still much coarser in grain. 

 I have observed it near Aaland in Br3-ggen, in a banded occurrence of 

 eclogite whose other bands consist of the Lyngenes and Duen types and 

 in part of garnet- and pyroxene-rock. 



