288 



GRAVITATIONAL METHODS 



[Chap. 7 



fnonzonHe 



I III nil #^t^ 



M^ryjl ^"^^l/l Ijji 1/1/ 'Ij 



\ 



/ 



^eO CotrH 



Fig. 7-120. Gravimetric, magnetic, and electrical indications on Caribou magnetite 

 deposit. G, gradients; K, curvature values; AV, magnetic vertical intensity; C, rei. 

 conductivity. 



the vicinity of the Fushun 

 Colliery and located a fault 

 separating gneiss from sedi- 

 mentary rocks.^^' Whether 

 the coal seams were indi- 

 cated remained doubtful on 

 account of terrain interfer- 

 ence. Shaw and Lancaster- 

 Jones conducted a recon- 

 naissance survey across a 

 barite deposit about 50 feet 

 in depth, which was known 

 from underground work 

 ings 



(akMtd 



^^ Mason observed a 



v>-' 



Fig. 7-121. Torsion balance and magnetic 

 anomaly (AZ) on Swynnerton dike (after McLin- 

 tock and Phemister). 



1" Op. cit., 2(2), 91-106 (1924). 



"^ H. Shaw and E. Lancaster- 

 Jones, Mining Mag., Jan. <fe 

 Feb., 1925. 



