94 



PENTTI F.SKOI.A. M.-N. Kl. 



100.31 



Kolderup remarks that this analysis differs from those of most other 

 eclogites in btnng low in Al^O^ and rich in CaO and Na^O. It is, however, 

 a truly gabbroid composition. Placing analyses of a normal labradorite- 

 rock, a pyroxene- and garnet-bearing labradorite-rock and this eclogite along 

 side they appear to form a continuous series, in which the percentages 

 of SiO.2, ALO3, Fe.,03 and Na.,0 sink while those of FeO, MgO and 

 CaO rise. 



Several occurrences of serpentine are then described in great 

 detail (p. 74 — 85). Only a few features, highly interesting for us, will be 

 quoted here. 



"Die Serpentine treten in- verschiedenartiger Weise auf. So findet 

 man den Serpentin als selbständige Bildung mitten im Labradorfelsgebiete, 

 von dem er sich durch scharfe Grenzen unterscheidet; er tritt auch als 

 Grenzfaciesbildung des Labradorfelses und des Saussuritgabbros auf und 

 bildet Intrusivmassen sowohl in den Gneissgesteinen als auch in den sicher 

 silurischen Bergensschiefern." 



An analysis of serpentine from Rodholmen in Lindaas shows 38.21 

 SiO.„ 3.25 A1,,0., 3.56 Fe.303, 4.66 FeO, 37.60 MgO, 0.00 CaO, 1.40 

 Na.iO, 11.75 H.,0, sum 100.43. 



Some serpentines contain remains of p3Toxenes and are thought to 

 have been derived from pyroxenites, while others contain some unaltered 

 olivine, being changed peridotites. 



Interesting for us is also the fact that many occurrences of serpentine, 

 are situated near those of eclogites, e. g. near Landsvik on Holsene and 

 Arnevaagen near Bergen. 



Still many other kinds of igneous rocks belong to the same diflfe- 

 rentiation series, such as norites, olivine-gabbros, mangerites, acid syenites 

 and granites. The eclogite is considered bv Kolderup as a member ot the 

 series between labradorite-rock and pyroxenites. 



