Chap. 7] 



GRAVITATIONAL METHODS 



161 



to which is probably added the influence of the old Ordovician land surface. 

 The main features of the map are a series of maxima corresponding to the 

 Arbuckle Mountains, the continuation of the Wichita Mountains (Walters 

 Arch) and the Miinster Arch. A pronounced minimum is found between 

 the Arbuckle Mountains on one side and the Wichita Mountains and their 

 south-eastward continuation on the other, lending strong support to the 

 theory first advanced on the basis of geologic evidence that the Arbuckle 





>'> 



Fig. 7-51?). Gravimetric map of Wichita and Arbuckle mountains and of structural 

 trends along the Oklahoma-Texas border (after Van Weelden). 



and Wichita Mountains are separate systems separated by the Anadarko 

 and Ardmore basins.^^ A comparison of the gravity data with the results 

 of magnetic surveys made in the same area is of interest (see page 431). 

 Where overburden is shallow and veins comparatively wide, gravimeter 

 observations will give good results in ore prospecting. Accuracy require- 

 ments are high and corrections for adjacent formations often necessary. 



A. Van Weelden, World Petrol. Congr. Proc, Sec. B. I., 174-176 (1934). 



