INVESTIGATION" OF OTEBO BASIN FOR POTASH SALTS. 



TABLE I. Analysis ' of the water-soluble constituents of the loose gypsum sand over- 

 lying the mirabilite bed of Lake Lucero. 



1 Analysis by R. F. Gardner, Bureau of Soils. 



Tests for potash were also made on the icelike material of the 

 mirabilite bed itself and on the loose gypsum from South Lake, the 

 southern extremity of the old lake bed or sink. The latter sample 

 contained a trace of potash, the former none at all. These tested 

 materials occupy the lowest portions of the present playa, where 

 potash would accumulate if at all. Its absence is nearly conclusive 

 proof that it is present nowhere on or near the surface of the basin. 



The complete results of the study of the historical geology can not 

 be given here. It will suffice to say that the basin has shared the 

 history of most of the other undrained basins of North America in 

 that it is deeply filled with the debris of the surrounding mountains, 

 and has been, at several tunes during the Quaternary and perhaps 

 the Tertiaiy periods, the home of a fluctuating undrained lake. In 

 the long series of expansions and contractions of this lake, entailed 

 by its climatic vicissitudes, it probably often suffered complete or 

 nearly complete desiccation, and each of these periods of desiccation 

 must have been marked by the deposition on the lake bottom of all 

 or part of the salts which it contained. It is very probable, therefore, 

 that the buried beds of the valley will have considerable salinity. 

 This does not mean, however, that the included salts are likely to 

 exist in segregated and crystalline form. From a consideration of 

 the varying supply of insoluble alluvium to the ancient lake, and 

 from geochemical considerations concerning the concentration and 

 segregation of the various soluble materials, it seems much more 

 probable that any buried saline materials are in the form of saline 

 sands and clays rather than separate beds of salt. 



The direct evidence as to the chemical nature of the hypothetical 

 buried salts is so meager as to be unimportant. Three waters of 

 possibly deep-seated origin, have been analyzed and the results are 

 given in Table II, but the sources of these waters are unknown and 

 they offer no worthy evidence concerning the buried strata. 



