54 



I'FNTTI KSKOLA. 



M.-X. Kl. 



A nodule of ])iire eh r o m c - d i o ps i d e, about 30 cm thick, was 

 found near Ilcl^clioinsxanfl. It is coarsely-crystalline and deep green 

 in coloiii-. I'loiii the siuroimdini^ f)li\ine-rock it is isolated by a seam 

 of enstatitr. 



Inclusions of pure garnet were found as very small nodules. 



Most of the occurrences of eclogite in the olivine-rock are band-formed 



masses (fig. 5). Many of them could be taken for .small intrusive sills or 



pegmatite-like primary veins of later crystallization than the main rock. 



At closer investigation it may be found that the bands are lenticular in 



shape though mostly very thin. 

 Thick lenses and nodules or lumps, 

 liowever, were also found. More- 

 over, though they have mostly 

 sharp boundaries, they are sur- 

 rounded by zones of olivine-rock 

 in which the same minerals that 

 form the bands occur as enclosed 

 crystals. 



Thus the mode of occurrence 



of this eclogite proves it to be 



genetically \-ery closely connected 



with the dunite, but it does not, 



in itself, give any evidence as to 



which of the rocks has been formed 



earlier. Considering the mono- 



mineralic character of the dunite 



and the fact 'that at least diopside. 



the other chief constituent of the 



bimineralic eclogite, is a low-melting 



mineral as compared with olivine, it seems most probable that the 



bands, lenses and nodules of eclogite have crvstallized after the dunite 



had separated. 



g. 5. Bands of eclogite Plotted) in olivine- 

 rock (black I. Rodhaugen, Almklovdalen. 



Eclogite ill oliviiic-i'ocks in other countries. 



Eclogite as bands or nodules in olivine-rock.s or in serpentines derived 

 from the latter is of fairly common occurrence. A few examples may be 

 abstracted from the literature dealing with this subject. 



According to H. H. Müller' eclogite occurs as nodules in the serpen- 

 tine near Greifendorf in Saxony, from fist up to head size, in places very 

 profusely'. The eclogite passes over into serpentine. The same and some 



' H. H. Rli'iUer, Geognostische Skizze der Greifendorter Serpentin-Partie. N. Jahrb. Min. 

 1846, p. 266. 



