DEPARTMENT OF THE INTERIOR 

FRANKLIN K. LANE, Secretary 

UNITED STATES GEOLOGICAL SURVEY 

GEORGE OTIS SMITH, Director 

Professional Paper 95 

SHORTER CONTRIBUTIONS TO 

GENERAL GEOLOGY 

1915 

DAVID WHITE, CHIEF GEOLOGIST 

WASHINGTON 

GOVERNMENT PRJ;NTING OFFlCE 

1916 
SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1915. 

THE COMPOSITION OF MUDS FROM COLUMBUS MARSH, NEV ApA: 

By w. B. HICKS. 

INTRODUCTION. 

The investigation of the dry lake of Columbus Marsh, in Nevada, which had for ·its 

economic motive the · discovery of potash, was continued by the United States Geological 

Survey during the summer of 1913 under the supervision of Hoyt S. Gale. The work done 

included the drilling of a shallow well near the old well 400 and the collection of a set of surface 

samples of muds from the marsh. This exploration, togeth~r with the chemical investigation 

of the samples thus collected, has furnished further data concerning the . character of the mud 

flat and thrown additional light on the conditions there. 

The writer was associated with Mr. Gale during his study of this region and the field 

observations here recorded were made jointly and are results of mutual discussion. The 

accompanying m·ap (fig. I) is based on a plane-table survey made by Mr. Gale, and for this 

and other assistance the writer wishes to express due acknowledgment. 

LOCATION. 

Columbus Marsh is situated on or near the line between Esmeralda and Mineral counties, 

Nev.1 Coaldale is a railroad station at the southeast corner of the marsh, and the Tonopah & 

Goldfield Railroad skirts the eastern margin of the mud flat itself. The marsh covers an area 

of 35 to 40 square miles and is roughly elliptical in outline, being about 9 miles from north to 

south and 6 miles or more in width. It is a broad mud plain with a rough, lumpy surfacea typical playa, the lowest part of the basin of a distinct drainage system, a physiographic 

feature characteristic of the Great Basin region. Little salt shows on the mud surface except 

about the margins of the plain, where several borax-producing plants were located in the earlier 

days of the borax industry. An accurate representation of this ·basin is given on figure 1. 

PREVIOUS EXPLORATIONS FOR POTASH IN COLUMBUS MARSH. 

EXPLORATIONS BY THE UNtTED STATES GEOLOGICAL SURVEY. 

LOCATION OF WELLS AND METHOD OF .EXPLORATION. 

I 

In searching for potash during 1912 six shallow wells were put down by the United States 

Geological Survey in Columbus Marsh to depths ranging from 32 to 50 feet. Later two ot;her 

wells were sunk to a depth of about 80 feet. These wells were located as follows: 

Well No. 100, sec. 13, T. 2 N., R. 36 E. 

200, sec. 12, T. 2 N ., R. 36 E. 

300, sec. ·35, T. 3 N ., R. 36 E. 

400, sec. 8, T. 2 N., R. 36 E. 

500, sec. 31, T. 3 N., R. 36 E. 

600, sec. 15, T. 3 N., R. 36 E. 

700, sec. 9, T. 2 N ., R. 36 E. 

800, sec. 5, T. 2 N., R. 36 E. 

1 Gale, H. S., Potash tests at Columbus Marsh, Nev.: U. S. Geol. Survey Bull. 540, p. 422, 1914. 

1 
2 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1915. 

The location of the wells is shown accurately on figure 1, which gives a clear conception 

of the area and extent of the mud flat as well as the distribution of the wells. The drilling 

7 

0 

J ..... , 

I "-..... 

R. 36 E. I II \ 

/ 

30 \ \ 29 

34 35 36 31 32 

R.36 E. R.37 E. 

(Note : Large numbers (.3 )rerertosurracesamples) 

2 3 Miles 

FIGURE. 1.-Map of Columbus Marsh, Nev. 

and sampling were done by Charles .E. Watson under the direction of Mr. Gale. The samples 

when received at the laboratory were air-dried. They were powdered without making a mineralogic study and preserved for analysis. 
COMPOSITION OF ;MUDS FROM COL1_JMBUS MARSH, NEV. 3 

METHOD OF ANALYSIS. I 

The analysis of the samples from Columbus Marsh 'las concerned primarily with the 

estimation of the total soluble salts and the potassium. . On extracting the muds with water, 

suspensions of a colloidal nature were obtained which would settle only after long standing, 

if at all. For practical analytical purposes in the estimation @f the water-soluble salts it became 

necessary to clarify these suspensions by artificial means. Fdr this purpose~ ammonium chloride 

was used, because of its volatility. The method was as follo~s: · 

The mud was digest~d on the ~team bath for half an hour/with 25 c_ubic cen_timeters of w~ter and 0.25 gram of ammonium chlonde for each gram of sample 1

taken, this quantity of ammonium 

·chloride being necessary in most cases for the clarification of the solution. The extract was 

either filtered and the residue washed with water, or made up to definite volume, filtered, and 

aliquots taken for analysis. In either case the filtrate which1 represented the extract from 2 to 

4 grams of material was evaporated in a tarred porcelain dish (porcelain being used because of 

the lack of platinum), ignited to dull redness to drive off I all ammonium salts, co.oled, and 

weighed, the result being reported as total soluble salts. 'llhe ignited residue was dissolved in 

dilute hydrochloric acid and filtered, and the potassium was lkletermined in the filtrate by what 

has been called the modified chlorplatinate method.1 

· Although it was presumed that the above-outlined procedure for the estimation of total salts 

would give somewhat high results, the method was thought I to be sufficiently accurate for the 

'work in hand. Being found rapid and practical, it was used in the earlier ·work on the muds 

that were of such a nature as to require artificial clarificatio:q. of their extracts. 

SUMMARY AND DISCUSSION. 

The analytical data obtained in connection with .the eLploratio:Q-. .9f Columb~s Marsh for 

potash during 1912 are summarized in the following t~ble: 2 I · 

Summary of previous analyses of muds from Columbus Marsh, Nev. 

[ W .B. H' IC k 1 s, ana ys. t] I .. 

'j·'l Soluble salts (ter cent of 

' S0luble potash as K. · samp e). I . . ~ 

Well No. 

Depth 

of well Per cent of salple. ( P~r :C~nt of total salts. 

(feet). Maxi- Mini- Ayer- mum. mum. I age. Maxi- Mini- I Aver- Maxi- Mini- Aver- mum. mum. age. mum. mum. age~ 

I 

1-

100 ....... 25 3.62 1.67 2.12 -------- -------- ................. ................ .................. -------- 200 ....... 49 22.30 4.67 9.73 0.68 0.06 

I 

0.54 8.46 0.34 5.52 

300 .... 0 ••• 50 26.91 14. 10 1-3.27 1.01 . 43 . 65 ' 4 .. 69 2.40 3.58 

400 ....... 38 17.30 5.17 8.66 1. 31 . 22 . 84 20.90 1. 67 9. 75 400 a ______ 38 6.30 5.17 5.96 1. 31 . 85 

I 

1.02 20.90 13.69 17.07 

500 ..... -- 48 15.50 11.10 12.84 . 84 . 35 . 55 6.69 2.38 4.30 

600 ... -- .. 46 19. 12 10.51 13.46 . 86 . 26 . 57 5.94 1. 37 4.23 

Average .. -------- ............... ................... 12.59 .................. .............. . 70 ---··--- -------- 5.46 

a Part below depth of 18 feet. j 

N OTE.-The complete data relative to wells 700 and 800 have ot been published and so are not included here. 

These data, exclusive of those for well 100, whic was Jhallow and located at th~ extreme 

edge of the flat, show that well300 has the highest an well400 the lowest percentage of soluble 

·salts. The reverse is true of their potash content. ells )0, 500:,· and 600 show intermediate 

1 Hicks, W. B., A rapi~ modified chlorplatinate ~ethod for the estimation ofpo assium: Jou~. ~~~- ~~ E~~~ Chern.~ ~ol. ~ p. 650, 1913. 

J See Gale,H. S., op. cit., pp. 423-424. 1 · 
4 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1915. 

values in regard to both determinations. In all cases, however, high percentages of soluble 

salts correspond to low percentages of potassium in the salts. Accordingly, the average content 

of soluble potash is approximately constant for all the wells except well 400, in which it is unusually high. The percentage of soluble salts in the section from 18 to 38 feet of well 400 is 

low, but the percentage of potassium in these salts is exceptionally high. The maximum and 

minimum percentages of soluble salts from wells 300, 500, and 600 vary much less than the 

percentages from the other wells. This is true to a less degree in regard to the potash content. 

Although the muds from some of the wells average nearly 20 per cent in soluble salts, no salt 

beds or distinct saline horizons were found. 

Only one sample of water was collected. and analyzed from each of wells 300, 500, and 600. 

These samples were strong brines containing from 18 to 25 per cent of salts, of which 4 to 1.5 

per cent was potassium. Six water samples were analyzed from well 400. These averaged 

0. 73 per cent of salts, of which 3.90 per cent was potassium. Four of these waters, two representing strong flows, came from the section between 18 and 38 feet, in which the salts extracted 

from the muds showed surprisingly high values in the. percentage of potash. These waters were 

very dilute and nearly uniform in composition, containing on an average 0.4 7 per cent of salts, 

of which only 4.31 per cent was potassium. These low figures are at variance with the results 

obtained for the muds from the same horizon. The low concentration in salts might be explained by assuming that the waters came from strong flows and had not remained in contact 

with the muds long enough to extract large amounts of the salts. This would require the further assumption, in order to explain the low values for potash, that the potash in the muds was 

present in a relatively less soluble condition than the other salts. In any event discrepancies 

in the analytical results obtained for the muds and waters from the same horizon in well 400 

· p,re evident. 

EXPLORATIONS BY THE RAILROAD VALLEY CO .. 

Subsequent to the investigations by the United States Geological Survey, described above, 

the Railroad Valley Co., of Tonopah, Nev., in its search for potash put down five holes in Columbus Marsh. These were shallow holes comparable to the wells of the Survey already described 

and were located as indicated on the accompanying map (fig. 1). So far as the writer is aware 

the results obtained by the Railroad Valley Co. in exploring Columbus Marsh have not been 

published. 

UNITED STATES GEOLOGICAL SURVEY WELL 900. 

LOCATION AND DETAILS OF DRILLING. 

In order to discover the cause of the discrepancies mentioned above and to obtain more 

information concerning the character of the muds in Columbus Marsh, well 900. was put down 

in August, 1913, under the direction of Mr. Gale. This well was located in sec. 8, T. 2 N., 

R. 36 E., about 100 feet east of well 400, and was drilled to a depth of 67 feet. The drilling 

was done by Charles E. Watson, who used a small modified Empire core drill, the casing alw~ys 

following within a few feet or even going ahead of the bit. In a general way the muds encountered . to the depth of 26 feet consisted of alternate layers of sand and clay; below this depth 

material much more consolidated was also encountered. Several water flows, some of which 

appeared to be rather strong, were observed as the drilling progressed. Only one, howeverthat struck at a depth of 3 feet-could be considered a brine, all the others being very dilute. 

A superficial examination of the muds as they came from the well was made by the writer, but 

no distinct saline horizons could be detected, the muds apparently being thoroughly washed 

with water and containing very little soluble matter. The sampling was also done by the 

writer, care being taken to obtain the most representative set of samples possible under the 

conditions attendant on the drilling. The muds were collected by averaging all the material 

representing a distinct layer as it came from the well. These were preserved in tin cans and 

shipped with the water samples to Washington for analysis. 
.· 

COMPOSITION OF MUDS FROM COLUMBUS MARSH, NEV. 

RECORD OF THE WELL. I 

A detailed record of the well is given below. It agrees with that of well 400. 

Record of United States Geological Survey well900, Columbus Marsh, Nev. 

· Muds. I . 

. . I 

Surface, crystl1lhzed salt and sand . . ......................... . . . .................. .. .... . Sand with small amount of clay, greenish yellow ......................... . _I_ ••........... • . 

Clay, light gray and black, wet ...... . ...... --------------------------- -1-· · · · · · · ·- · ·-· · · Sand, black w~th foul o~or, very wet ....................... ---------- --- .

1

.-------- ---- · · · Clay, black, sticky ....... . ... -.- .. -- ---------------------·-········ · ·· ·1· · · · · · · · · · · · · · · · Sand and gravel, dark gray, m01st. .................................................... . . Sand with a small amount of clay, light gray, moist ....................... J ............... . 

Clay, with a small amount of sand, hght gray ........................ . . . ................. . Sand, fine, light gray, very moist......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .............. . Hardpan, clay and consolidated material. ...... : . . . . . . . . . . . . . . . . . . . . . . . . . .............. . Sand, nearly black, wet, without saline taste ............ . .............................. . Clay, greeniSh gray, smooth ........ . ........................................ . .......... . Sand, black, very moist ............. . ............................................. . ... :. Hardpan, alternating layers of clay and more consolidated materiaL ...... . ..... . .......... . Clay, alternating layers of light gray and black ... . ........................ . ............ . Hardpan, alternating layers of clay and more consolidated materiaL.... . . . . .............. . Sand, coarse, nearly black........................ . ..... . . . ............. . ........ . ..... . Clay, black, sticky, soft ............................... . ................................ . Hardpan ................................ . ................. ____ . . ___ . __ . ..... _. ____ ... __ 

Sand, quicksand, nearly black, foul odor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . .......... . Clay, light gray, soft, sticky .............. . ........... . ... . .. . ......................... . Sand, quicksand, nearly black .................. . ....... . .............................. . Clay, light gray, very sticky ................ . .............. . .......................... . . . Sand, mostly quicksand, w1th some fine gravel ............................... .. .......... . 

Sample 

No. 

Water encountered. 

1....... Strong brine ...................... . . . ................ . · ...................... . 2 ....... Water, nearly fresh, strong flow, rising within 1.5 feet of surface ................ . 3....... Water, nearly fresh, moderate flow............. .. .............. . . ... . ......... . 4 ....... Water, nearly fresh, strong flow; rising within 2 feet of surface ..... . ... ~ ......... . 5... . ... Water, nearly fresh, weak flow ........ ~ .................. . ..... l ...... ......... . 6 ....... Water, nearly fresh, strong flow, rising within 1 foot of surface, f1ul odor .. : . ..... . 7....... Water, nearly fresh, weak flow ......... . . · ...................................... . 8....... Water, nearly fresh, strong flow, rising within 16 feet of surface, foul odor .... ...... . 9 a..... Water, nearly fresh, weak flow ......... . ............... . ....................... . 9 ............ do ..... . .......................... ." .............. . ....... L ••• • : ••••••••••• 

. I a Not sampled. 

CHEMICAL DATA. 

Thickness. 

Feet. 

0. 2 

4.0 

.5 

5.0 

.5 

7.0 

2.5 

.5 

3.5 

2.5 

3. 0 

. 5 

1.0 

6.5 

2.5 

5.5 

3.0 

4.0 

1.0 

1.5 

7.0 

.5 

.5 

4.5 

Temperature. 

oc. 

~1. 7' 

14.0 

16.0 

16.5 

17.0 

14.0 

(?) 

15.0 

(?) 

17. 0 

5 

Depth. 

Feet. 

0.2 

4.0 

4.5 

9.5 

10.0 

17.0 

19.5 

20.0 

23.5 

26.0 

29.0 

29.5 

30.5 

37.0 

39.5 

45.0 

48.0 

52.0 

53.0 

54.5 

61.5 

62.0 

62.5 

67.0 

Depth. 

Feet. 

2.5 

15.0 

23.0 

27.0 

37.0 

42.0 

47.0 

54.0 

61.0 

66.0 

CLARIFICATION OF THE MUD EXTRACTS BY THE USE I OF AMMONIUM CHLORIDE. 

In the chemical investigations relating to Columbus Marsh and more particularly to well 

900, the samples have been analyzed for soluble salts and potash, first by the method described 

above, in which ammonium chloride was used to clarify the olution, and then by a method in 

which the clarification was effected by filtration through Pai teur-Chamberland clay filters, the 

potash in all cases being determined by the modified chlorpl tinate method already mentioned. 

In addition more complete analyses of some of the samples have been made, and the ·total 

potash in a number of them has .been determined. The results of the analyses in which ammo- . 

nium chloride was used as the clarifying agent are given on page 6. With the exception of the 

moisture determination the percentages in this paper refer td the material dried at 100° C. 
6 SHORTER CONTRIBUT!:ONS TO' GENERAL GEOLOGY,_ 1915. 

Results of analyses of muds from well 900 with ammonium chloride as the clarifying agent. 

[W. B. Hicks, analyst.] 

Soluble 

Potash asK. 

Sample Depth salts Moisture 

No. (feet). Character of material. (per Per cent Per cent (per cent). cent of of of solu- sample). sample. ble salts. 

I . ..... . . 0.5 Surface ................. .. .. 21.02 0.27 1.27 13.4.6 

2 ........ 4.0 Sand ........ . .......... . ... 8. 20 .28 3.45 18. 60 

3 ...... . . 4.5 Clay ....................... 12.07 . 57 4.77 20.60 

4 ..... ~ .. 9.5 Sand ....................... 7. 74 .34 4.34 18. 75 

5.------- 10.0 Clay ........ . ......... . .. . . 8.63 .45 5.17 25.65 

6. ---- --- 17.5 Sand .......... .. ........... 3.61 .55 15.10 4.91 

7------- - 19.5 ..... do ........ . . . .. ... ..... 5.50 .86 15. 65 18.30 

8. -- -.--- 20.0 Clay ............ . . . .... . . .. 6. 75 1.04 15.33 23.70 

9.------- 23.5 Sand ............. . ... . ..... 3.35 . 91 17.00 16. 44 

10 .. -.. --- 26.0 Consolidated material. ...... 6.22 . 92 14.77 19.27 

11 ........ 29.5 Clay ................. .. ... . 6.15 . 93 15.13 21.85 

12. ------- 30.5 Sand ....................... 6.65 1.21 18.25 23.10 

13 .. -- .... 37.0 Consolidated material. ...... 6. 71 1.29 19.22 25.90 

14 ........ 39.5 Clay ....................... 7.86 1.46 18.60 29.30 

15 .. ------ 45.0 Consolidated rna terial ....... 4.15 .45 10.68 16.65 

16 ..... .. . 52.0 -?!~~d~---: ~ ~:::::::::::::::: 5.65 .55 9.65 26.20 

17 ........ 58.5 5.80 .41 7.05 41.70 

18 .. ------ 62.0 Quicksand ............. . .... 2.28 .15 6.67 27.80 

19 .. -- .... 67.0 ..... do ..................... 2.70 . 36 13.12 24.90 

Average .. ................ ...................................... ... 6.90 . 68 11.33 .......... . ... 

These results are in complete agreement with those obtained from well 400. Except in 

the surface material the percentage of soluble salts is low and nearly constant, while that of 

potassium is comparatively high, increasing at first with increasing depth to unusually high 

values in the section between 17 and 39 feet, and then falling off again. The samples for the 

whole well average 6.90 per cent in soluble salts and 11.33 per cent in potassium, against 8.66 

and 9.75 per cent, respectively, for well 400; while in the section: between 17 and 39 feet the 

muds from well900 average 5.87 per cent in soluble salts and 16.12 per cent in potassium, against 

5.96 and 17.02 per cent, respectively, for the muds from the corresponding section of well 400. 

In fact, the analytical data concerning the two wells are concordant in every particular. The 

unusually high percentage of potassium in well400 is found at corresponding depths in well900. 

Contrary to expectations, the percentages of both soluble salts and potash decline with increasing depth below 40 feet. · · · 

The muds from well 900 vary greatly, being composed of sand, clay, or material much 

more consolidated, or c;>f mixtures of these, and a most surprising fact is that the analytical data 

give no indication whatever of such differences in the character of the material represented by · 

the samples. 

CLARIFICATION BY FILTRATION THROUGH PASTEUR-CHAMBERLAND FILTERS. 

In searching for a method for the clarification of the extracts that would yield a clear solution containing without question only that material which water alone would dissolve from 

·the muds, filtration through porcelain filters suggested itself. Experiments carried out by 

the writer 1 have shown that only slight changes result to moderately concentrated solutions 

on passing through Pasteur-Chamberland clay filters and that the alkalies from very dilute 

alkaline solutions are more or less absorbed by such treatment; therefore mud extracts that 

are alkaline and very dilute are likely to show appreciable changes in composition after being 

subjected to this method of clarification. As the mud extracts from the Columbus Marsh 

1 Jour. Ind. Eng. Chern., vol. 6, pp. 829-831, 1914. 
COMPOSITION OF MUDS FROM COLUMBUS MARSH, sEV. 7 

samples were not excessively dilute, were composed largely of chlmides and sulphates, and 

were only slightly alkaline, it is believed that the values for the w ter-extractable material 

obtained by this method of clarification are nearly correct, some of them probably being a 

little low 

The following procedure was used: A 20-gram sample of the m1: d which had been dried 

and powdered was heated with occasional stirring for 1 hour on t e steam bath with 400 

cubic centimeters of w~ter. It was then transferred to a measuring flask, cooled, and made 

up to 500 cubic centimeters, and 10 cubic centimeters of water was added to correct for the 

volume occupied by the mud. After mixing and allowing to settlE the extract was filtered 

through a Pasteur-Chamberland clay filter using strong suction. .After discarding the first 

100 cubic centimeters of the filtrate, aliquots of 100 to 200 cubic cetltimeters were taken for 

analysis The results are given below. 

Analytical results obtainedfrom mud samples ojwell900 after clarification of the water extrc ct by filtration throu gh PasteurChamberland clay filters. 

[W. B. Hicks, analyst.] 

Ratio of valuet obtained by use 

Soluble potash as K. of ammonit m chloride to 

values obta ned oy use of 

Soluble Pasteur-Chai pberland fil~ers. 

· Sample No. Depth salts (per 

(feet). cent of S Dluble potash. sample). Per cent Per cent 

of of Soluble 

sample. soluble salts. In am- In soluble salts. p e . salts. 

1.--------- 0.5 18.26 0.11 0.58 1.16 . 45 2.19 2 __________ 4.0 4.96 .09 1.83 1. 65 .11 1. 88 3_. ______ --- 4.5 7.03 .15 2. 13 1. 72 . 80 2.24 

4 . . .. . ..... 9.5 4.80 .11 2.29 1.61 . 09 1. 46 5 __________ 10.0 3.77 .12 3.16 2. 29 . 75 1.64 

6.-- ------- 17.5 . 56 .04 6.62 6. 45 1 . 75 2.26 

7. --------- 19.5 .49 .04 5.70 11.22 2 .50 2.09 

8 _____ ----- 20.0 . 61 .04 6.50 11.05 2 .00 2.36 

9.-- ------- 23.5 . 74 .03 4.64 7. 23 3). 33 3.66 

10.--------- 26.0 .54 .03 5.32 11.50 3). 66 2. 68 

11.------ --- 29.5 • 75 .04 4.72 8.20 2 .25 3.21 

12. --------- 30.5 . 79 .04 5.11 8.42 3).25 3.57 

13- -- -~ --- -- 37.5 . 76 . 03 5.56 8.83 4. 00 3.46 

14.--------- 39. 5 . 94 .04 3.78 8.36 3p.50 4.92 

15. --------- 45.0 . 52 .03 8.66 7.98 1~.00 1.23 

16. -- ~------ 52.0 1.30 . 07 5.45 4.35 17.86 1. 77 

17.--------- 58.5 1. 36 . 12 9.52 4.27 ~.42 . 74 

18.--------- 62.0 . 52 .03 6.59 4.38 p. 00 1.01 

19.--------- 67.0 . 39 .03 10.15 6.93 1~. 00 1.29 

Average . .... .................... 2.84 . 06 5.17 ....................... ...... .. .............. ............................ 

According to these data the amount of material extracted by w!tter alone from the mud 

samples. in well 900, exclusive of the surf~ce material, is small, amounting on an average ~o 

only 2.84 per cent. The average content of potassium is 0.06 per ce 1t of the sample, or 5.17 

per cent of the soluble salts. The results from the section of the welJ between 17 and 39 feet, 

which yielded unusually high values for potassium by the other met 1od of analysis, a:re even 

more strjking. Here the average content of soluble matter is 0.69 pe cent and that of potassium 0.04 per cent of the sample, or 5.32 per cent of the soluble sal s. These figures are exceptionally low compared with those obtained by the use of ammoniLim chloride-a fact that 

becomes more evident by an examination of the columns of ratios in tthe table. Here it is seen 

that by the method in which ammonium chloride was used for clarific~tion, from 1 to 10 times 

as much soluble matter and from 2 to 40 times as much potassium is dissolved from the muds 
8 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1915. 

as by the method in which the samples are extracted by pure water and clarified by filtration 

through clay filters. It is also evident that the ratio of the potassium extracted is in general 

from 2 to 4 times that of the soluble salts. In other words, the soluble salts extracted from the 

muds by the use of ammonium chloride contain a much higher percentage of potash than the 

pure water extract. The variation in the results obtained by the two methods is greatest in 

the case of the muds that contain the least amount of soluble salts. No appreciable changes 

corresponding to differences in the character of the material appear in the results of the analysis, 

or in the variations by the two methods. 

A consideration of these data shows conclusively that the high figures obtained for potash 

in the samples from wells 400 and 900 have resulted from the method of clarifying the mud 

extracts with ammonium chloride. It further furnishes an explanation of the discrepancies 

observed above i~ the analyses of muds and waters from the same horizon. 

TOTAL POTASH IN THE MUDS. 

The total potash in a number of n1uds from well 900 was determined· by the J. Lawrence 

Smith method. 1 . The samples were selected from those showing high percentages of potassium 

in the ammonium chloride extract and represent the various kinds of material found in the 

well. The results a:.;e given in the subjoined table, which include also those for one sample from 

well 200, for comparison. 

Total potash in muds from well900 and percentage extracted with ammonium chloride and with water. 

[W. B. Hicks, analyst.] 

Total 

Per cent of total potash extracted bypotash 

Sample No. Depth Character of material. asK 

(feet). (per cent Ammoof nium chlo- Water. sample). ride 

solution. 

200+9 .... 29 ........................................... 3.55 19.20 ---------- 900+2 .... 4 Sand ... : ... , ............... 2.84 9.88 2.82 

900+3 .... 4.5 Clay ....................... 2.96 19.25 5.07 

900+9 .... 23 Sand ....................... 3.26 27.90 . 92 

900+12 ... 30 ..... do··-·····---··--··--- 3.30 36.70 1. 21 

900+13.-. 37 Consolidated material. ...... 3.46 37.30 .87 

900+14 ... 39 Clay ....................... 3.72 39.20 1. 08 

900+16.-- 52 ..... do ..................... 2.64 20.80 2.65 

900+19 ... 67 Sand ....................... 2.84 12.68 1. 07 

According to these data the potash content of the muds is roughly constant without regard 

to the character of the material. Although only a small percentage of the total potash was 

extracted by water, from 10 to 40 per cent was carried into solution by ammonium chloride, 

the high values again being shown by the muds which came from the section of the well between 

17 and 39 feet. 

ANALYSES OF WATERS. 

Incomplete analyses of the waters from well 900 were made. The results, which are set 

forth on page 9, are sufficient to give a fair idea of the character of these waters and to show 

the close similarity in composition of their dissolved salts. · 

1 Treadwell, F. P., Analytical chemistry, 3d ed., vol. 2, p. 496, John Wiley & Sons, 1911. 
COMPOSITION OF MUDS FROMCOLUMBUS MARSH, NEV. 

Depth (feet) ....................... 

01 ................... -· ............ 

so4············ · ··················· B407············· ·················· 003························ · ······ K .................. . .............. Na' ca_f(by difference) ........... . ..... 

Analyse ojwatersfrom well900. 

[V • B. Hicks, analyst.] 

1 2 3 4 

2.5 15 23 27 

= 55. 18 54. 90 53.36 53.00 

6.19 4.29 6.70 6.83 . 39 1.03 1.12 1. 30 

-------- .44 .44 . 66 

1. 91 3.45 3.53 3.65 

35. 89 36. 33 34.85 34.56 

5 6 

37 42 

51. oo 1 52.48 

9.48 6.19 

1. 44 1. 61 

.48 . 63 

3.04 3.59 

34.56 35.45 

7 

47 

48.62 

8.30 

1. 22 

. 36 

3.00 

38.50 

100.00 100. 00 100.00 100.00 100.00 100.00 .100. 00 

Total salts ....... .. ................ 20.52 . 62 . 59 . 50 . 66 . 38 . 87 

All the samples contained a small amount of c lcium. No test was made for Mg or Si02• 

9 

8 9 

54 66 

49.40 49.28 

6.85 9.63 

3.28 1.56 

2.38 1.02 

3.36 3.73 

34.73 34.78 

100.00 ioo.oo • 31 .47 

With the exception of sample No. 1, which is a strong brine, the waters from well 900 are 

very dilute and of the same order of c< ncentration. Their soluble salts are very similar. in 

composition, consisting largely of sodiur[l chloride with moderate amounts of sulphates, and 

containing borates,. carbonates, and sahs of potassium and calcium. Apparently the percentage of sulphates and borates tends o increase with depth. The potash is not unusually 

high and is approximately constant for :Lll the waters. 

ABSORPTIO ~ OF POTASH BY MUDS. 

From the preceding data it is evident that the muds from well900 contain a high percentage 

of potash. It is also known that only t small quantity of this potash is found in the water 

extract after fi.J.tration through porcelain filters, while a large amount is dissolved by solutions 

of ammonium chloride. Many investigators 1 have shown that rock-forming minerals are 

dissolved to a slight degree by water and to a larger extent by salt solutions. The magnitude 

of such solubility, however, is small. 

From a consideration of these facts tis believed that a large percentage of the potash in 

the muds of Columbus Marsh is held in ~ loosely combined form, though the exact manner of 

retention is not known. 2 It is probable, however, that a large portion of this potash has been 

absorbed from solution and is held by colloids either mechanically or in a weak chemical 

combination. At the same time it is cerl!ain that a small amount of the soluble potash shown 

in the analyses has resulted from the solvent action of an ammonium chloride solution on the 

minerals present. This conclusion is mnphasized by the fact that both the sands and the 

clays from well 900 contain approximat( ly the same quantities of potash and give up similar 

amounts to solutions of ammonium chloride. However, the sand as well as the clay samples 

which gave the high potash values con ain considerable colloidal matter. Furthermore, the 

muds from Columbus Marsh are still capable of absorbing considerable quantities of potash. 

Two grams of clay sample 200 + 9, fron well 200, absorbed 0.0287 gram of potassium from 

a 0.5 per cent potassium chloride solutio This corresponds to an absorption of 1.43 per cent 

of the mud, an amount greater than · th~ t extracted by solutions of ammonium chloride from 

any of the samples from well900 except No. 14. 

Considering all the facts at hand, i is believed that large amounts of potash with small 

quantities of other salts have been abs )rbed from surrounding or percolating solutions and 

are held in a loosely combined form by tl e muds of Columbus Marsh, and perhaps by the muds 

of the desert basins in general. Such a conclusion is in accord with the fact, which has been 

long recognized, that clays selectively a )Sorb potash, and perhaps it offers the best explana1 For a bibliography on the solubility of rock-forming min rals see Clarke, 1<'. W., The data of geochemistry, 2d ed.: U.S. Geol. Survey Bull. 

491, p. 454, 1911. 

2 For bibliographies on the absorption of salts by clays see an Bemmelen, J. M., Die Absorption, 1910; Clarke, 'F. W., op. cit., p. 477; Blanck, 

E., Landw. Zeitung (Fiihling's), vol. 62, p. 560, 1913. 
10 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1915. 

tion of the apparent disappearance of considerable quantities of the potassium salts from natural solutions or from the salts associated with the desert-basin saline deposits. Attention 1 

has been repeatedly directed, through the analysis of many brines, saline incrustations, and 

muds, to the low content of potassium .in comparison to that of sodium in these deposits. It 

is possible that in the desert basins the potash has been gradually absorbed from solutions 

by the muds, while the other salts, being less completely absorbed, have been gradually concentrated through ev11poration, this process yielp.ing the natural brines and salt incrustations 

with low potash content found in these regions at the present time. 

CONCLUSIONS. 

The data relating to~ wells 400 and 900 agree very closely. Water, as a rule, removes 

from. the muds of well 900 only small amounts of soluble matter, but solutions of ammonium 

chloride extract larger quantities. The high percentages of potash found in the soluble sa:lts 

from the muds of well 400, as well as the discrepancies between the results shown by the 

waters and muds from the same horizon, were a result of the method of analysis, in which 

the clarification was effected by ammonium chloride. High percentages of soluble salts in 

the muds usually. correspond to low percentages of potassium in the salts. In such cases the 

variations in the water and ammonium chloride extracts are not so great. 

The muds of Columbus Marsh are capable of absorbing more potash. It is believed that 

a large part of the potassium in the muds has been absorbed from surrounding or percolating 

solutions and is held in a loosely combined form, probably by colloids. Such a conclusion 

offers an explanation of the apparent disappearance of the potassium from the brines and 

saline deposits of the desert-basin regions. 

SURFACE MUDS FROM COLUMBUS MARSH. 

SAMPLES. 

In order to determine the variations in composition of muds from different localities in 

Columbus Marsh, a number of samples of the surface material were collected in 1913. It 

was also thought that some relation between the composition of the muds and the "self-rising 

ground" of the marsh might be found. The samples represent the surface material to a depth 

of about 6 inches. They were . collected by the writer and preserved in tin cans. The samples 

were taken at the plane-table stations established in mapping the fiat and therefore represent 

for the most part the edge of the marsh. The localities from which these samples came are 

des~ribed below and are also indicated accurately on figure 1. 

Localities from which surface s'amples were collected. 

Sample 

No. Location. 

900+1.... Sec. 8, T. 2 N., R. 36 E., at well900~ .. 

3 ......... Sec. 36, T. 3 N., R. 36 E .............. . 

Sec. 27, T. 3. N., R. 36 E .............. . 

5 ......... Se~.- 13, T. 2 N., R. 36 E .............. . 

6 ......... Sec. 8, T. 2 N., R. 36 E ............... . 

. 7 ......... Sec. 31, T. 3 N., R. 36 E .............. . 

8 .............. do ............................... . 

Character of surface material. 

Sand and clay, moist. Surface smooth, moderately compact, and 

covered with thin layers of crystalline salts. · Clay and sand, brownish, moist, sticky, containing salt crystals. 

Surface covered with film of crystalline salts. 

Sand with some clay, brownish, loose, containing salt crystals. 

Surface dried to a rough, nearly white, crust. 

Sand, brown, moist. Surface smooth, loose, and contains no crystalline salts. Many fragmentary volcanic rocks scattered over surface. Area formerly worked for borax. 

Sand, brownish gray. Area covered with salt grass and formerly 

wo:rk:ed for borax. Sample taken from smooth surface between 

the ridges. 

Sand and clay, brownish. Surface smooth, compact, and cov- ered with film of crystalline salts. 

Sand and clay, brownish yellow. Surface rough and very loose, 

like freshly plowed ground, and covered with a thin film of 

crystalline salts. 

1 See Clarke, F. W., op. cit., pp. 142-247; Dole, R. B., Explorations of salines in Silver Peak Marsh, Nev.: U. S. Geol. Survey Bull. 530, 

pp. 33Q-345, 1913; Gale, H. S., Prospecting for potash in Death Valley, Cal.; and Salt, borax, and potash in Saline Valley, Inyo County, Cal.: 

U.S. Geol. Survey Bull. 540, pp. 407-421,1914. 
COMPOSITION OF MUDS FROM COLUMBUS MARSH, NEV. 11 

ANALYSES. 

Only partial analyses of the surface samples from Colu:q1bus Marsh were made, but the 

data are complete enough to show the composition of water-soluble matter in these muds. The 

results of the analyses, made on the material dried at 100° C., are tabulated below, 

Analyses of surface muds from Columbus Marsh. 

[W. B. Hicks, analyst.] 

900+1 3 4 5 

CL ............ . ...................... 40.30 53.30 48. 15 49.20 

804-------------.-.---------- ~----.- .. 21.30 2.31 4.15 5.78 

~0~~~ ~ ~ ~ ~ -_ -_-_- -~ ~ ~: ~: ~ ~ ~ ~ ~ ~ ~ ~ ~ ~::::::::: 1. 14 2.21 1. 45 6.21 

None. None. 4.67 . 75 

SiOa--------------·----------------------- . 23 3.20 2.60 .43 

K-------------------------------- ---- . 58 . 50 .47 . 51 

Ca ..... -----·------------------------ 5.89 None. None. . 37 

N a (by difference) .. _ ......... _ .. _ ..... 30.56 38.48 38.51 36. 75 

Mg .............................. J • ••• None. Trace. Trace. None. 

100.00 100.00 100.00 100.00 

Soluble salts ............... _ ........... 18.26 11.27 20.00 11.75 

DISCUSSION AND CONCLUSION. 

6 

34.15 

4.44 

25.88 

. 92 

1.53 

1.91 

2. 72 

28.45 

None. 

100.00 

6.53 

7 

53.20 

3.45 

3.30 

None. 

1. 30 

2.08 

. 29 

36.38 

None. 

100.00 

7.24 

8 

45.40 

2.92 

3.01 

4.93 

4.80 

.67 

None . 38.27 

None. 

100.00 

10.96 

From these results it will be seen that the soluble salts in the surface muds of Columbus 

Marsh, while containing a large amount of sodium chloride, vary widely in composition. All 

contain small quantities of potash and silica and varying amounts of sulphates and borates. 

Sample 900 + 1 shows exceptionally high sulphates, sample 6 high borates, and samples 4 and 8 

considerable carbonates. According to the composition of the soluble salts, the mud samples 

may be classified as follows: 

Samples 3 and 7, consisting largely of chlorides. 

Sample 900+ 1 consisting largely of chlorides and sulphates. 

Samples 4 and 8, consisting largely of chlorides and carbonates. 

Samples 5 and 6, consisting largely of chlorides and borates. 

Samples 3, 7, and 900+ 1 came from smooth, rather compact areas; samples 5 and 6 from 

localities formerly worked for borax, in which the surface material is more or h:;ss loose and 

covered in salt grass; and samples 4 and 8 from rough, very loose surfaces known as" self-;rising 

ground." These facts indicate that the presence of carbonates in the s-urface material is a 

factor in causing the "self-rising ground," and that borates and perhaps alkalies in general 

tend to produce similar effects. The data, however, are not conclusive, because too few samples have been examined.