Chap. 7] 



GRAVITATIONAI- METHODS 



287 



not known whether he actually investigated any ore deposits. His asso- 

 ciate, Stephen Rybar, surveyed the contact-metamorphic iron ore deposits 

 of Banat in Rumania around 1917. In 1919 R. Schumann mapped the 

 area near Zilhngdorf north of Vienna to determine the structure of the 

 coal deposits there. In Russia the torsion balance was used by P. Niki- 

 forov, Lasareff, and Gamburzeff in connection with the magnetic survey 

 of the Kursk anomaly. Several torsion balance profiles across this 

 deposit are illustrated in Chapter 8 (Fig. 8-59). The gradients reach a 

 maximum amplitude of 80 and the curvature values an amplitude of 130 



=,-,>4 



tee 460 6o a -w* cas. 

 - Outline of mofnefltt depos/f 



— 20 — 



Mofnetic anoma/i/ in 1000^ 



Fig. 7-119. Torsion balance results on Caribou magnetite deposit, Colorado. 

 (Scale same as in Fig. 7-76) 



E.U. and can be explained on the assumption of a density difference of 

 0.8 between the iron quartzite and the surrounding metamorphic rocks. 

 The Swedish investigators, H. Lundberg, K. Sundberg, and E. Eklund/" 

 have lised the torsion balance in conjunction with electrical and magnetic 

 surveys and published the results of a reconnaissance survey on Mens- 

 trask Lake. 



In Germany the torsion balance was tried at about the same time on 

 some siderite veins of the Siegerland district. ^^^ Matuyama investigated 



"0 P. Lasareff and G. A. Gamburzeff, Gerlands Beitr., 15(1), 71-89 (1926), 19(2/3), 

 210-230 (1928). 



1" Sveriges Geol. Unders. Arsbok, 17(8), 86 (1925). 

 "2 H. Quiring, Glueckauf, 69, 405-410 (1923). 



