APPLICATIONS OF GEOTHERMICS TO GEOLOGY 33 
of heat that can be obtained by the oxidation of petroleum in its na- 
tural state. Let us assume that the heat-generating disk is 100 feet in 
thickness and that 1/3 of the entire volume is crude oil. Then a column 
of rock, 1 square centimeter in cross section and 100 feet in length, 
contains about goo grams of oil, and as the heat of combustion of crude 
oil is about 11,094 calories per gram, it follows from our preceding 
value of g that all of the oil would be oxidized in (11,094 X 900) /3.16 
=3.2X10° years. As this result is not in agreement with geological 
facts, we conclude that the oxidation of oil may be a contributing 
factor, but it is not sufficient in itself to maintain the constant tem- 
perature differences which exist at Haverhill. Werner (36) regards 
petroleum deposits as special sources of heat. He believes that the 
Cc 

source 
Annual Mean 
ow ” 
emperature 
9 Temperature 

Heat 
th 
Depths 

Fic. 13.—Sketch of depth-temperature curves. Heat source at h. 
presence of carbonic acid in the gases is evidence of oxidation brought 
about probably by the presence of free oxygen in salt water. 
In Figure 13, the line ad represents a depth-temperature curve on 
the basis of normal cooling. The excess of soil temperature over air 
temperature, e, is represented by aa. The line abc represents a depth- 
temperature curve when there is a source of heat at 6. Curves of this 
type have been found at El] Dorado, Kansas; Coalinga, California; Big 
Lake, Texas, and in some other fields. Ordinarily, however, the curva- 
ture is in the opposite direction. 
It remains to consider the possibility that radium is a source of heat 
beneath anticlines. Three factors are involved, namely, transmission 
of heat along the strata, an excess of radium in granite as compared 
with the sediments, and the presence beneath the oil-bearing strata of 
a granitic mass that stands above the general level of the basement 
rocks. The problem is illustrated in Figure 14 in which the height of 
the granite ridge is represented by ad. Inspection of the figure shows 
that transmission of heat along the strata may result in a considerable 
excess of heat beneath the anticline. Two sources of heat are available. 
First, excess of radioactivity in the granite and, second, an increased 
Sys}s) 
