638 J Ht) VOGE 
resorption phenomena at the stage I to K we refer to the explanation 
in a later paragraph. 
With regard to the structure of the deposits of pyrrhotite- 
hy persthenites, -olivinites, -norites, etc., formed by magmatic differen- 
tiation, I refer to my earlier publication “‘Die Sulfid-Silikat- 
schmelzlésungen”’ (in Norsk geologisk tidsskrift, 1917). I shall here 
only give a short summary. 
We shall commence with the per se very rare pyrrhotite-olivinites, 
and as an example choose the deposit at Bruvand (Ballangen, 
100FeS§ : ofes 
OFeS, 100f eS, 
Fic. 36.—The binary system FeS:FeS, at high pressure. (The melting-points 
for FeS and pyrrhotite refer to low pressure.) 
Ofoten in Norway) where the olivinite carries about 8 per cent 
sulphides, which we for brevity’s sake shall term ‘“nickel- 
pyrrhotite” (pyrrhotite with some pentlandite, chalcopyrite, and 
pyrite, in the present case with about 6-7 per cent nickel). 
The rock consists, with deduction of the sulphides, of 
about 85-90 per cent olivine (according to chemical analysis 
0.12 Fe,SiO,:0.88 Mg,SiO,, and accordingly. quite poor in iron 
and not the least serpentinized), and in addition a little bronzite, 
primary hornblende, etc. The sulphides are not quite evenly 
distributed over the whole rock, but accumulated in small patches, 
especially on the boundary between the olivine grains (see Fig. 37). 
