kidwell: analysis of a brine 



387 



times as highly mineraHzed as ocean water. It is remarkable 

 in its content of iodide in the absence of bromide, and to a lesser 

 extent in its content of barium, manganese, and strontium. 



According to Dr. Charles Butts, ^ Geologist, U. S. Geological 

 Survey, the brine probably issued from shales representing the 

 top or middle of the Hamilton formation of the Middle Devonian. 



TABLE 2 

 Reacting Values in Milligram Equivalents per Liter" 



° The reacting value of an element or radicle is obtained by dividing its valence 

 by its molecular weight and multiplying the resultant quotient by the number of 

 milligrams of the element or radicle obtained analytically. It may be defined as its 

 equivalence in capacity for chemical reaction to 1.008 milligrams of hydrogen or 

 8.000 milligrams of oxygen. 



* Fe and A' are considered to be present as Fe203 and AI2O3 and therefore do 

 not enter into the sum of reacting values. 



Many hypotheses have been proposed to explain the origin of 

 deep-seated brines. Several investigators have assumed that 

 they represent entrapped ancient sea waters the composition 

 of which has been altered by such agencies as precipitation, 

 reactions from contact with basic magmas, evaporation, and 

 leaching of sedimentary beds by percolating ground waters. 



Such hypotheses are inadequate for the explanation of differ- 

 ences in the chemical character of deep-well brines and the ocean 

 as it exists at the present time or as it existed in the past. The 

 chemical composition of the Devonian sea is conjectural. It 

 may have contained either more or less calcium and magnesium 

 than the present ocean and the predominance of magnesium over 

 calcium that now obtains in the ocean may have been reversed 



^ Personal communication. 



