﻿176 Canadian Record of Science. 



Segregation in Ores and Mattes. 



By David H. Browne, Sudbury, Ontario. 



[Reprinted from The Columbia School of Mines Qarterly, No. 4^ 

 Vol. XVI.] 



During the last few years, the origin of the Sudbury 

 nickel-ore deposits has been the subject of much discus- 

 sion. The igneous and the aqueous theories have been 

 both strongly championed, and at the present date, while 

 the balance of opinion leans to the igneous side, the lack of 

 any decisive testimony on which arguments ])ro and con 

 could be based, has tended to make a decision necessarily 

 difficult and unsatisfactory. 



Bell, in his report on the Sudbury ores,^ says : " The 

 general character of the deposits seems to indicate that 

 they have originated primarily from a state of fusion." 

 H. B. Yon Fullon- states that "Die Erze sind nicht 

 wasserigen, soudern feuer fliissigen Ursprunges," i.e., " not 

 of aqueous but of igneous origin." Yogt^ assigns these 

 and other similar sulphide ores to " segregation from 

 a molten basic magma," and Kemp^ gives it as his opinion 

 that the appearance of the ores " leaves no reasonable 

 alternative but to conclude that they are as much an 

 original crystallization from the igneous magma as any 

 other mineral in the rock." 



On the other hand, Posepny refers to the igneous theory 

 as something extraordinary ; Emmens^ thinks that nickel 

 is an essential constituent of the gangue, and ArgalP " sub- 

 mits that it is to the leaching of basic eruptives at or near 

 the surface our principal deposits of nickel are due." 



All these latter opinions, based as they are on 

 resemblance to other ore-deposits, may be considered as 



1 Report on the Sudbury Mining District, p. 49. 



2 Ueber Einige Nickelerzvorkoninieii, p. 281. 



3 Zeitschrift fur praktische Geologie, Nos. 1, 4, 7, IS93. 



4 Ore-I)e}>osits of the United States, p. 319. 



6 Ciiiiadian Mining and Meoh., Rev., August, 1893. 



6 Nickel, etc., Colorado Scientific Society, December, 1893. 



