CORRELATION OF ISOGEOTHERMAL SURFACES 49 
clusively that the temperature distribution in this field is highly abnormal. 
The only exception appears to be the possible agreement of the observed and 
computed gradients at depths of about 2000 feet. 
At Salt Creek, the evidence of variation of temperature with structure 
is conclusive. At Long Beach, the evidence is confused on account of the fact 
that in some of the wells the temperatures at the higher levels were increased 
by pumping operations while in a few of the remaining wells, the tempera- 
tures may have been lowered as a result of the wells being on a vacuum. 
However, proceeding on the assumption that we have a normal distribution of 
temperatures, and taking into account the fact that the abnormal tempera- 
tures in some of the wells have tended to increase the values of (1/8), it 
follows that the observed variation in the values of (1/6) as we pass from the 
plain to the summit of-the hill, should have exceeded slightly the theoretical 
variation; but, just the converse is true—the observed variation is only a 
small fraction of the theoretical variation. Hence we are driven to the con- 
clusion that abnormal temperature conditions in this field have tended to 
neutralize the effects of surface topography. 
2 
CG 
x 


5 Sig ae 

Fig. 10. Long Beach Dome. The numbers opposite well locations 
represent feet per degree Fahrenheit, 100-2000 feet. 
CAUSES OF TEMPERATURE VARIATIONS 
Depth to the crystalline rocks and flow of heat along the strata appear to 
be possible explanations of the close relationship that apparently exists be- 
tween the isotherms and the general trend of the strata in central Oklahoma 
(See Fig. 2). 
A similar explanation may apply at Salt Creek, which is an exceptionally 
well defined local uplift. Steep dips occur on the western side of the field 
(See Figs. 3 and 5) and very hard granite was found by The Midwest Re- 
fining Company at a depth of 5420 feet near the top of the dome in the S.W. 
1/4 N.W. 1/4, sec. 35, T. 40 N., R. 79 W. This evidence suggests the pos- 
sibility that the depth to the granite is least on top of the dome, and that the 
direct contact of the granite with the hot crystalline rocks at great depths 
serves to maintain lines of flow from an almost inexhaustible heat source to 
the top of the dome. Additional evidence in substantiation of this conclusion 
is to be found in the fact that the values of 1/b vary from 1°F in about 29 
feet on top of the dome to 1°F in about 56 feet in Sec. 15, T. 40 N., R. 79 
193 
