Subsurface Methods as Applied in Geophysics 



1077 



nounced with depth. The gravity expression of the Hawkins field is 

 characteristic of many of the fields in the East Texas Basin. 



Tinsley Field, Mississippi — The structure of the Tinsley field in 

 Yazoo County, Mississippi, is also related to the movement of the deep- 

 seated salt mass. (See fig. 567.) The Tinsley anticline is an elongated 

 structure with several major faults across the crest of the structure and is 

 expressed by a marked gravity minimum. From the areal extent of the 

 anomaly it is apparent that a great volume of salt is involved in the move- 

 ment and that the salt mass does not approach the surface. It is interest- 

 ing to observe that the Jackson dome, lying about forty miles to the 



Contour Interval = 0.5 rag. 

 12 3 



Jim Wells Co. 



Brooks Co. 



Figure 568, Observed gravity contours over La Gloria field, Jim Wells and Brooks 

 Counties, Texas. Producing area is outlined. (After Wooley. Reproduced per- 

 mission Geophysics.) 



southeast, gives rise to large gravity maximum. Such gravity data give 

 valuable information as to the cause of structural deformation, the maxi- 

 mum of course being due to the intrusion of a large mass of igneous rock. 

 La Gloria Field, Texas — The La Gloria field in Jim Wells and Brooks 

 counties, Texas, was first indicated by torsion-balance work in the area.'**' 

 The gravity-meter map (see fig. 568) indicates a northeast-southwest 

 minimum axis extending along the west edge of the area. The structural 

 uplift is indicated by a change in the gradient of gravity on the east side 

 of the regional axis. This map shows the masking effect of strong regional 

 gradients, the anomalous area being indicated by only a very slight change 

 in gradient. Although a producing sand at — 5,650 feet has a closure of 

 about 400 feet, the gravity anomaly has a magnitude of only 0.4 milligals. 



^^ Wooley, W. C, Geophysical History of La Gloria Field, Jin 

 Geophysics, vol. 11, no. 3, pp. 292-302, July 1946. 



Wells and Brooks Counties, Texas : 



