Chap. 7] 



GRAVITATIONAL METHODS 



275 



previously in connection with his experiments on Lake Shuvalovo to ex- 

 press the above relation. The difference in density between salt beds 

 and overburden was assumed to be 0.35. 



From 1925 to 1928 extensive gravity measurements were made in the 

 Emba district on the northeast shore of the Caspian Sea.^'* Numerous 



h/ief/e 



u (li 



and Depth in Profile 



6eo/ofica/fy assumed 

 Outline 



\ Outlint of 5a// Dome 

 I from seismK ivork 





Fig. 7-105. Seismic refraction depths, seismic outline gravity gradients, and gravity 

 profile on Oldau-Hambuehren (Wietze) salt dome in northern Germany. 



salt domes have been discovered there by the application of geophysical 

 methods. It appears that the whole region between the Ural and the 

 Volga rivers is fairly studded with salt domes. The Soviets estimated 

 that by 1934 they had discovered more than 400 salt domes by geophysics. 



"* lUd., 268-270. 



