POTASH SALTS AND OTHER SALINES IN THE GEEAT BASIN REGION. ' 



havp not rPf,r.hprl ,.,,-^'^^^fcatratioii sufficient to produce cr;.;t,„I!l.,a,lu.u oi mnii« ux 

 rJmno^mds wS" vP lit,"" "^ ^"^ concentration of pota,sfiium. The abgorption 

 compounds ^^ould g^^e litu. ^,,i ^^ ^ ^e^j^ j ^-ai^elecs brine Doubt: 



such a solution by desert sands wou.- - ^roM-finn - ,.^"f^^'^>"-^^«- •^"'^' ,. 

 further investigation will show many of the . . •'^-^^'^^■^JJfiicated above. 



Two general types in the desiccation phenomena ma^ . ^^ Clistinguished, the Sea) 

 type, in which a large, deep lake was evaporated, and the compar. ""-^'^iy thick bf 

 of saline material, restricted in area and saturated with residual brine, was form 

 and a second t^^pe, which is best illustrated by Death Valley, in which case we h; 

 the building up of a mass of muds and silts with interbedded salines, by the repea 

 formation and desiccation of a shallow lake. To the latter type belong most of 

 desert, dry lakes, or playas. The line between the two types is not a sharp one. 



The possibility of deposits at depth is still not completely disproved . The geolo, 

 cal evidence goes to show that several periods of desiccation occurred. Each peric 

 might have been characterized by deposits of the kind described above. Such evi 

 dence as we have, and it is meager, does not indicate deposits of this nature. The 

 evidence goes to show that the larger Quaternary lakes existed for a long time and 

 desiccation was a feature of their final stages. This would place the period of saline 

 formation at the end rather than at an intermediate time, and would argue for deposits 

 at shallow depths rather than otherwise. On the other hand, the geological evidence 

 is not necessarily complete. The obliteration by erosion of older lake lines than the 

 present ones is not improbable. Only by systematic deep boring could such a question 

 be settled. As the larger Quaternary lake basins are, in almost every instance, occu- 

 pied by lakes of considerable size and in some instances of considerable depth, the 

 difficulties of such work are apparent . 



The question of deep deposits being uncertain, the field becomes narrowed to the 

 deposits which might have resulted from the desiccation periods of the most recent 

 Quaternary lakes. Only in Searles have we surface deposits of this nature. In all 

 other basins, if older deposits than those at present forming exist, they must be sought 

 for at depth. The size of such a deposit would depend upon the area of the drainage 

 basin and the area and depth of the Quaternary lake occupying it. Desert basins 

 showing no signs of former lakes might well be placed in a separate and unimportant 

 class. Such basins can not be said not to have saline beds at depth, but the existence 

 of such beds and their value are doubtful. Upon the criteria stated above I have 

 grouped the desert basins in the following manner: 



Group I. — Basins formerly occupied by Quaternary lakes, 



A. Basins in which the Qxiaternary lake was over 300 feet in depth: (in 



order of magnitude on the basis of area) : Square miles, 



Carson and Humboldt 27, 575 



Black Rock and Smoky Creek Deserts 10, 500 



Searles (area includes Owens) 4, 850 



Panamint 1, 950 



B. Basins in which the Quaternary lake was 300 feet or less in depth: 



Railroad Valley 6, 340 



Columbus Marsh (including Big Smoky Valley) 5, 225 



Buena Vista (part of Caron and Humboldt) 4, 000 



Dixie Valley 2, 660 



. Basins which are now occupied by lakes : 



Bonneville Basin 54, 000 



Walker, Nev 3, 850 



Alvord, Oreg. 3, 200 



Pyramid, Nev 2, 975 



Owens. Cal 2, 825 



Honey Lake, Cal 2, 660 



Surprise Valley, Cal 2, 350 



Catlow, Oreg .- 2, 000 



Warner, Oreg , ' 2, 000 



Abert, Chewaucan, and Summer, Oreg 1, 500 



Madeline Plains, Cal 900 



Long Valley, Nev 775 



Mono, Cal 770 



Silver, Oreg_- 500 



D. Doubtful basins: 



Diamond Valley, Nev. 

 Danby and Bristol Lakes, Cal. 

 Franklin and Ruby Lakes, Nev. 



