158 



GRAVITATIONAL METHODS 



[Chap. 7 



direct determinations of gravity, however, by the torsion balance are e3{- 

 cluded from this section and discussed on pages 270-292 of this chapter. 

 Reference is made in this connection to Fig. 7-104, showing the gravity 

 anomalies on salt anticlines in the Maros Valley in Hungary; to Fig. 7-108, 

 in which the gravity results in the Solikamsk area (northern Urals) are 

 given; to Fig. 7-109, illustrating the gravity anomalies in a portion of the 

 Emba district in Russia; to Fig. 7-115, representing one of the earliest 

 gravity surveys in oil exploration (Egbell anticline) ; and to Fig, 10-67, in 

 which a gravity profile across the Grozny anticline is illustrated. 



Fig. 7-49. Gravimeter survey of Pierce Junction field (after Skeeters). 



Most gravimeter and pendulum work has probably been done in salt- 

 dome exploration. Fig. 7-49 represents an example of a comparatively 

 shallow dome, the gravity anomaly being about 1.0 to 1.4 milligals. The 

 dome shown in Fig. 7-50a was reached at the indicated well location at a 

 depth of 7200 feet, the anomaly along the apparent axis of the salt anti- 

 cline being about 2 milligals, rising to the east and west to several milligals. 

 One of the earliest pendulum surveys across a salt dome (Wietze, northern 

 Germany) is illustrated in Fig. 7-105. Seismic and torsion balance data 

 for the same dome are also shown. The possibilities of the gravimeter on 

 nonsalt dome type of structures are demonstrated by the survey of the 

 Ramsey field in Oklahoma,^^ shown in Fig. 7-506, which indicates an un- 



«<• J. F. Evans, Oil and Gas J., 38(26), 37 (Nov. 9, 1939). Contour interval: 

 0.2 milligal. 



