THE BARITE DEPOSITS OF MISSOURI 75 



any residual material once there has been removed by the Pleis- 

 tocene glaciation. 



Conclusion as to concentration by weathering 



The present workable deposits of barite are found in a deep 

 red clay, which was derived from the underlying dolomite thru 

 the normal process of chemical weathering, aided by mechancial 

 disintegration. 



That the barite and associated minerals were derived from 

 veins and replacements in the underlying dolomite is shown by 

 the close similarity of the features of the materials in the veins 

 to the features of the materials in the clay. 



ORIGIN OF THE BARITE 



CONCENTRATION FROM THE SURROUNDING ROCKS 



Chemical and mechancial weathering will account only for 

 the concentration of the material in the residual clay. The fun- 

 damental question is, what was the origin of the barite in the un- 

 derlying formations which in this case are carbonate rocks ? The 

 suggestions for the origin are reducible to two propositions : ( 1 ) 

 the barium was concentrated from the surrounding rocks and de- 

 posited in the veins, caves, etc. ; (2) the barite was deposited by 

 deep-seated solutions as veins, replacements, and cave deposits. 

 These suggestions will be discussed in the order mentioned. 



Ever since the study of ore deposits began, there has been 

 one school of geologists who have believed that the surrounding 

 rocks have furnished at least a large part of the materials found 

 in the various veins, replacements, etc. The list includes the 

 names of most of the leading geologists of the past and many of 

 those of the present day. Many have held that this was the domi- 

 nant process in the concentration of our metallic and non-metal- 

 lic mineral deposits ; others recognized that there were limitations 

 to the theory and believed that some deposits, especially of the 

 metals, were best explained as having been formed from solutions 

 rising from considerable depths and probably originating from 

 igneous rocks. There are those who believe that this is essen- 

 tially the only means of deposition. 



