THE BARITE DEPOSITS OF MISSOURI 77 



metals from the surrounding rocks. Since barite is a very com- 

 mon gangue mineral, they would presumably advocate a similar 

 origin for the barite, altho they make no such specific statement. 



W. S. T. Smith^ in his paper on the lead, zinc, and fluor- 

 spar deposits of Kentucky mentions barite as an important gan- 

 gue mineral. He decides that all the substances in the veins were 

 derived from the adjacent rocks. 



Dickson,^ after a series of careful analyses of the associated 

 rocks, concluded that the barium in a vein in a quarry near 

 Kingston, Ontario, did not come from the adjacent limestone, 

 which showed only a trace of BaO, but that it came from the 

 weathering of some igneous rocks on the surface that had a high 

 percentage of barium. 



This short summary of the conclusions of the various geol- 

 ogists who have studied barite deposits indicates that the preva- 

 lent beliefs are that the barite has been derived from the sur- 

 rounding rocks. In order to examine this critically, and determine 

 if possible, how adequate meteoric waters are to cencentrate 

 barite, it will be necessary to go into considerable detail as to the 

 source of barium and the means of transporting and precipitat- 

 ing it from solution. 



Source of the barium 



Clarke® gives the following figures for the amount of barium 

 in the various sorts of rocks in the lithosphere. The average of 

 793 determinations of BaO in igneous rocks was ,102% ; in ele- 

 mental form .092%. Seventy-eight shales had an average of 

 .05% of BaO; 253 sandstones .05%; and 345 limestones showed 

 none. Also a composite analysis of 498 building limestones 

 showed no barium. Clarke gives the figure .09% as the weight- 

 ed average for the lithosphere. The absence of barium in the 

 composite analysis of the limestones should be noted. 



The various geologists who have worked with the barite de- 

 posits have usually analyzed the adjacent rocks in an endeavor 

 to find the source of the barium. Following are some of the re- 



"Smith, W. S. T., P. P. 36, U. S. G. S., pp. 150-154. 1905. 

 'Dickson, C. W., School of Mines Quart., vol. 23, pp. 266-270, 1001- 

 i002. 



'Clarke, F. W., Bull. 616, U. S. G. S., pp. 27-34. 



