Library Copy ••• • 

IRC.181 Library Con 

GEOLOGICAL SURVEY CIRCULAR 181 

ELECTRICAL RESISTIVITY STUDIES OF 

SUBSURFACE CONDITIONS NEAR 

ANTIGO, WISCONSIN 

By H. Cecil Spicer 

U.S. Cat,- logical Survey 

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Cs:bAdrnbu s , „ II • 

006543 9 J#'7A" 014k y 

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Wiffnel'ir 

UNITED STATES DEPARTMENT OF THE INTERIOR 

Oscar L. Chapman, Secretary 

GEOLOGICAL SURVEY 

W. E. Wrather, Director 

GEOLOGICAL SURVEY CIRCULAR 181 

ELECTRICAL RESISTIVITY STUDIES OF SUBSURFACE CONDITIONS 

NEAR ANTIGO, WISCONSIN 

By H. Cecil Spicer 

Washington, D. C., 1952 

Free on application to the Geological Survey, Washington 25, D. C. 

ELECTRICAL RESISTIVITY STUDIES OF SUBSURFACE CONDITIONS 

NEAR ANTIGO, WISCONSIN 

CONTENTS 

Page Page 

Abstract 1 Summary of results 3 

Introduction 1 Conclusion 5 

Location and geology 1 Literature cited 5 

Field methods used in resistivity studies._ • 1 Interpretation of apparent resistivity curves 9 

Methods of interpreting resistivity curves... 3 Well logs 19 

ILLUSTRATIONS Page 

Figure 1. Map of the Antigo area, Wisconsin, showing the location of resistivity line centers and deep 

wells 2 

2. Cross sections B and C showing deposits based on resistivity interpretations 4 

3. Contours on pre-Cambrian rocks based on electrical resistivity measurements 6 

4. Contours on top of sand and gravel deposits based on resistivity measurements 7 

5. Contours on top of till deposits based on resistivity measurements 8 

6-23. Apparent resistivity curves, Antigo, Wis., Lines A 1-2; B 1-7; C 1-8; and BMC ..... 10 

ABSTRACT LOCATION AND GEOLOGY 

Resistivity measurements are reported for the 

glaciated area near Antigo, Wis., to locate buried 

sand and gravel deposits in the glacial drift, which 

might be developed as aquifers, and to determine 

depths to the pre-Cambrian bedrock. The results of 

the resistivity study are presented both as cross 

sections and as contour maps. The apparent resistivity curves, their interpretation in terms of the 

thickness and character of the geological materials, 

as well logs of the area are given. On the basis of 

the study a number of sites were selected that would 

be suitable for drilling water-supply wells, no drilling 

has been done on the sites selected. 

INTRODUCTION 

The resistivity studies in the vicinity of Antigo, 

Wisc., were made at the request of the Office of the 

Ground Water Branch of the U. S. Geological Survey 

in Madison, Wisc. , and in cooperation with Mr. Ernest 

F. Bean, State geologist of Wisconsin. Field measurements were taken during October 1948. 

The writer was assisted in the field measurements 

by George J. Edwards, geophysicist of the Geological 

Survey, by members of the Madison office staff, and 

by men employed locally. Cooperation and assistance 

were also given by Ernest F. Bean, State geologist, 

Frank C. Foley, geologist in charge of the Ground 

Water Office of the Geological Survey at Madison, 

Wisc. , and by Eugene Daniel and Wm. E. Price, Jr. 

The area in which the resistivity measurements 

were made is in Langlade County in the northeastern 

part of central Wisconsin. (See fig. 1.) The city of 

Antigo is located in the south-central part of this area, 

and it was partly in the interests of the city that the 

resistivity studies were undertaken. 

A large part of the area is farm land under 

cultivation, but there are also scattered areas of 

marshy and tree-covered land. The soil covering 

the area varies, but it is mainly sandy clay or sandy 

loam. The other geological materials overlying the 

bedrock are glacial deposits consisting of sand, gravel, 

till, silt, and clay. The bedrock underlying the area 

is considered to be pre-Cambrian. An exposure of 

the crystalline rock in the southwest corner of the 

area (fig. 1) is weathered coarse-grained pink granite. 

FIELD METHODS USED IN 

RESISTIVITY STUDIES 

The resistivity measurements were all made 

with the Gish-Rooney type earth resistivity apparatus, 

which has been modified by the present writer from a 

commercially available instrument. Power for 

driving the commutator in the instrument was obtained 

from the truck storage battery, and power for the 

current circuit to energize the earth was supplied by 

a bank of super "B" batteries. Taps for various 

voltages were brought out to a control panel, and 

rheostats were included in the circuit to adjust the 

1 
• • 

• • 11.1 M 

nor 

-Eq rg-115imi 

,i1111111111 Otto Gresch-well 

MAMMA"( 0 8-5, 

IN! 

T 3IN 

- - 

T3OK 

C-I 

0 

Resistivity line center 

• 

Deep well 

LANGLADE COUNTYRI 1E1 R tgrE 

RI IE St 12E .SHAVTATIO CaUNTY 

EXPLANATION 

Figure 1. --Map of the Antigo area, Wisconsin, showing the location of resistivity line centers and deep wells. 

2 
amount of current flowing in the earth and through 

the current side of the instrument. The electrodes 

used for making contact with the earth for both the 

potential and current were copper-clad steel rods 

about 26 in. long with a hexagonal steel driving head 

on one end and a sharpened point on the other. 

Stranded bronze wire with synthetic rubber insulation 

was used for connecting the electrodes to the instrument and was carried on duralumin reels. Each 

electrode was carefully "mudded in" at each interval 

so as to maintain good contact with the earth. 

Depth profiling was used throughout the study. 

Electrodes were set in the earth according to the 

modification of the Wenner arrangement as proposed 

by F. W. Lee. Measurements of potential were made 

by both the Wenner (1915) and Lee (1929) techniques 

thus giving three measurements at each interval. 

The apparent resistivity was computed by the Wenner 

(1915) formula Pa-=2 n ai for all the observations because it spreads the curves on the chart thus making 

them more accessible for interpretation; however, 

the curve form remains the same. The three resistivity curves thus obtained are shown (see figs.6-23) 

and are termed Full, P-1, P-2, and are indicated 

by s's, A's, and x's. Bearings for the depth profiles are referred to true north and are given for the 

P-1 direction. Altitudes are expressed as heights 

above mean sea level. 

METHODS OF INTERPRETING 

RESISTIVITY CURVES 

The resistivity curves obtained from this 

investigation (figs.6-23) were interpreted by procedures explained in the literature on geophysics, and 

pertinent aspects will be pointed out for convenience 

to the reader. These methods of interpreting resistivity curves are based on theoretical and mathematical 

considerations, primarily the theory of images which 

is given by Jeans (1925) and others. These methods 

apply to two, three, and more layers, and in the 

writer's experience have been found to be more 

reliable than any of the empirical methods of interpretation that have been advanced. 

The technique to be pointed out is not quick, nor 

is it easy, and it demands a knowledge of the theoretical aspects of apparent resistivity curves as will 

be found, for example, in Hummel (1931). Two-layer 

resistivity curves and two methods of interpreting 

them will be found in the papers by Roman (1931, 

1934, and 1941). Three-layer resistivity curves will 

be found in an article by Wetzel and McMurry (1937), 

and the use of the Roman (1941) two-layer curves and 

the Wetzel and McMurry three-layer curves to aid 

in the interpretation of three and more layer curves 

is completely explained in Watson and Johnson (1938). 

Some aid in the understanding of their treatment of 

potential theory will be found in the article by Watson 

(1934). 

The method of Tagg (1937) is useful at times 

for the interpretation of certain types of resistivity 

curves. Examples of its application will be found 

in the reference cited. 

It has been demonstrated by both theory and 

model measurements that surface resistivity curves 

should be a series of smooth curves for two, three, 

3 

four, and more layers and should be amenable to the 

interpretation procedures pointed out above. While 

the writer is cognizant of the fact that the earth is 

not so nicely bedded or layered as theory must assume, 

it has been his experience that this is a minor factor 

in comparison with the perversions of procedure that 

have entered into the taking of data for resistivity 

curves. If one does not get smooth curves then it is 

time to examine carefully the instruments in use, 

the techniques of measurement, and the site chosen 

for the observations. If the latter is at fault, select 

a better site to take the next line of observations, 

being sure that the measurements give a smooth 

apparent resistivity curve. If it is found that the 

instrumentation or techniques are at fault, try others 

or find the trouble and correct it. There are no doubt 

specific instances or certain localities where the 

generalization above will not hold, but an experienced 

operator will readily recognize such a geological 

condition. 

SUMMARY OF RESULTS 

Eighteen depth profiles were started in the 

.Antigo area, but two were abandoned-one because 

of leakage in the wires, and the other because of 

the indicated presence of a buried conductor. The 

centers of the depth profiles were located (see fig. 1) 

so that the results would give information concerning 

the subsurface materials along three north-south 

profiles. These are indicated on the figures and in 

the text by the letters A, B, and C prefixed to the 

depth profile number. — 

At the time the geophysical measurements were 

made sample logs were available for only two wells 

in the area and neither well penetrated bedrock. 

Both wells are near the city limits of Antigo (fig. 1), 

and logs for them are given on p. 19. It is apparent 

from these logs that there is a considerable variation 

in the glacial materials over a relatively short distance. 

A field test was made on the outcrop of preCambrian rock to determine its resistivity. As 

expected, it was very high averaging 1.5 x 106ohm 

centimeters (ohm cms). This value is higher than 

any of the resistivities computed from the apparent 

resistivity curves for the pre-Cambrian rocks, 

namely, 1.3 x 105to 1.2 x 106ohm cms. This is 

to be expected because of the dryness of the outcrop. 

The computed values of resistivity in ohm cms for 

the other materials are: soil. or near-surface materials, 12.3 x 103to 445.0 x 10 3; sand and gravel, 

9.5 x 104to 15.9 x 106; till, 6.8 x 10 3to 21.8 x 

103;clay, 2.8 x 103to 6.1 x 103. 

The interpretations from the apparent resistivity curves are presented diagrammatically in 

figures 2 to 5 inclusive. The numerical values are 

given in figures 6-23. 

Figure 2 shows cross sections along the series 

of electrical depth profiles B and C, respectively, 

and are plotted with altitude above mean sea level 

in feet as the ordinate and distance in miles as the 

abscissa. It is apparent from these two figures that 

the pre-Cambrian rock surface rises to the west, 

and that the till becomes thinner in this direction. 

The sand and gravel deposit is, however, quite 
_ A ltitude, in feet 

North 

B-I 

EXPLANATION 

B-2 

.5. 

•z 1300 

:4- 

1200 

C-7 

B-3 

South 

B-4 B-5 B-6 B-7 

(E-W Match line ) 

Sand gravel Soil 

Clay 

108 

892 930 

5 

Distance miles 

CROSS SECTION B 

862 707 

10 

C-5 C-4 C-3 C-2 

0 5 15 

Distance miles 

CROSS SECTION C 

10 

Figure 2. --Cross sections B and C showing deposits based on resistivity interpretations. 

Till 

x 

X 

Pre- Cam brian 

X 

1200 - 

1125 

0 

A' 

C-6 

X 

X 

X 

X 

X 

X 

1102 

Pre-Cambrian 

Ii 

x 

1070 

A 

A 

South 

C-I 

A 

X 

945 

Till 

and,grovel'. 

k 

1500 

1400 

-X 

Soil 

Clay 

Sand, gravel 

Till 

Pre-Cambrian 

North 

C -8 

1300 -- 

1500 

1400 

1045 

o' • Sond,Gravel 

"4:: 

965 

(E-W Match line) 

x

x 

870 

X 

Ic 

Ic 

Ic 
variable in thickness and does not show the definite 

trend to thin toward the west. At depth profile C-6, 

the till appears to be composed entirely of clay.- At 

depth profiles C-8, C-7, and B-7 thin beds of clay 

are present near the surface of the ground. 

The interpretations from the apparent resistivity curves are shown in a different manner in 

figures 3, 4, and 5. The area corresponds to that 

of figure 1 and shows the subsurface topography of the 

various deposits by means of contours drawn on their 

upper surfaces. No detail is included in these figures 

other than the data pertinent to the depth profiles. 

The altitudes on each of the subsurface deposits are 

obtained by subtracting from the altitude of each resistivity station the computed depths obtained from the 

interpretations to the several deposits. Both the 

surface and deposit altitudes are given in figure 3, and 

the surface altitude and deposit thickness are given 

in figures 4 and 5. Correct altitudes for the two wells 

shown in the figures were not available; so their altitudes were estimated. 

Figure 3 indicates a ridge of pre-Cambrian rock 

more than 100 ft high across the central part of the 

area that is flanked by troughs. The random thickness 

of the sand and gravel will again be apparent in figure 

4,and the tendency of the till to thin westward will also 

be seen. Little or no correlation seems to exist 

between the contours of the different deposits in this 

area, and as a result it would be nearly impossible to 

recognize high altitude bedrock from any surface or 

subsurface indications. 

Most of the sand and gravel deposits in this area 

will probably yield water, and in many places it is 

sufficiently free of clay so that considerable water can 

be obtained from it. For shallow wells in sand and 

gravel at depths less than 60 ft, the following locations 

are selected: A-1, A-2, B-2, B-4, B-5, B-6, C-3, 

C-4, C-7, C-87 BNE. For mediumdepthwellin 

Fandy-fill at depths less than 125 ft the selection is: 

A-2, B-2, B-4, B-5, B-7, C-3, BMC. For wells at 

depths greater than 125ft, the sandy till or gravel at 

A-2, B-2, B-4, and B-7 appears to be the best of the 

locations studied. No drilling has been done on this 

selected group of sites. 

Since this report was prepared, the city of Antigo 

has drilled two test wells in the NEi-NW+ sec. 29, 

T. 31 N. , R. 11 E. These wells are located in the 

city limits and are about 12 miles south of resistivity 

depth profile BMC. Other information about them is 

given on p. 19. 

Test well 1 did not reach bedrock at a depth of 

73 ft where drilling stopped, but the driller reported 

bedrock at 72 ft in test well 2. According to the 

estimated contours on bedrock by geophysical measurements (fig. 3) the depth to bedrock in the vicinity 

of the drill holes should have been about 125 ft. If the 

reported bedrock of test well 2 is not a large boulder, 

then the high bedrock area indicated by depth profiles 

C-4, BMC, and B-6 must extend southward from BMC 

thus causing the bedrock in this direction to have a 

clifflike drop. 

It is unfortunate, from the geophysical viewpoint, 

that drilling was discontinued before bedrock was 

reached in test well 1, and that a sample was not 

available for Mr. Thwaites, geologist of the Wisconsin 

Geological Survey, to examine to see if it was bedrock 

in test well 2. Such information would have eliminated 

any doubt about the correlation of geophysical measurements and drilling information. 

CONCLUSION 

The studies clearly indicate that it is possible 

to differentiate the glacial deposits in this area by 

means of electrical resistivity measurements and to 

determine the depths to and thicknesses of these materials, as well as the depth to the pre-Cambrian bedrock. It was also possible to evaluate the character 

of the glacial materials from their electrical resistivities and to recommend the most suitable sites for 

drilling water-supply wells. 

LITERATURE CITED 

Hummel, J. N., 1931, A theoretical study of apparent 

resistivity in surface potential method: Am. Inst. 

Min. Met. Eng. Tech. Pub. 418. 

Jeans, J. H. , 1946, The mathematical theory of 

electricity and magnetism, 5th ed. ,Cambridge [Eng.] 

Univ. Press. 

Lee, F. W. , Joyce, J. W. , and Boyer, P., 1929, 

Some earth resistivity measurements: U. S. Bur. 

Mines Inf. Circ. 6171. 

Roman, Irwin, 1931, How to compute tables for 

determining resistivity of underlying beds and their 

application to geophysical problems: U. S. Dept. 

Commerce, Bur. Mines Tech. Paper 502. 

1934, Some interpretations of earth 

resistivity data: Am. Inst. Min. Met. Eng. Trans. 

vol. 110, pp. 183-200. 

1941, Superposition in the interpretations 

of two-layer resistivity curves: U. S. Geol. Survey 

Bull. 927-A. 

Tagg, G. F. , 1937, Interpretation of earth resistivity curves: Am. Inst. Min. Met. Eng. Tech. 

Paper 755. 

Watson, R. J., 1934, A contribution to the theory 

of the interpretation of resistivity measurements 

obtained from surface potential observations: Am. 

Inst. Min. Met. Eng. Tech. Paper 518. 

Watson, R. J., and Johnson, J. F. , 1938, On the 

extension of two-layer methods of interpretation 

of earth resistivity data to three and more layers: 

Geophysics, vol. 3, no. 1, pp. 7-21. 

Wenner, F., 1915, A method of measuring earth 

resistivity: Nat. Bur. Standards Sci. Paper 258, 

pp. 469-478. 

Wetzel, W. W., and. McMurry, H. V. , 1937, A set 

of curves to assist in the interpretation of the 

three layer resistivity problem: Geophysics, vol. 2, 

no. 4, pp. 329-341. 
B-2 

0 

1565 00 

/333 

B-I 

0 

C-7 

0 

1525 

/432 

2 Miles 

Pre-Cambrian 

outcrop 

0 

Contour interval 20 feet 

RIOE RITE RITE R12E 

A-2 

C-B 

T32N 0 

— 

T3IN 

1502 

14/1 

B-3 

0 

1567 

1389 

1542 

/5('0 - /297 

— 1460 —C-4 

0 

66 

1505 

13-4/. Prosser well 

0 1510 

512 )1410 

1302 

tto G resch well 

• 8 -5 --—

(1510) 

1410 1242 EXPLANATION 

1240 C-I 

0 

Resistivity line center 

• 

Deep well 

4 

Altitude of surface 

in 

I

f

3

ee

2

t 

3 

Altitude on top of 

pre-Cambrian rocks in feet 

Index map 

O 

1470 

/

1317 

/329 

1300 8-7 

0 

1 320 1451 

C- I 

oO 

1445 

/322 

T31N 

T3ON 

T32N 

T31N 

A-I 

0 

1595 

C-5 

0 

1485 

1429 

T31N 

T3ON 

RICE RITE RITE R12E 

733N 

T33N 

— C-B T32N T321,40 

1545 

/423 

Figure 3. --Contours on pre-Cambrian rocks based on electrical resistivity measurements. 

6 
RIOE RITE RITE RI2E 

T33N 

T33N 

c=-8 T32N 

T32N 0 

1538 

50 

C-7 

0 8-I 

1514 0 

65 

B-2 

1561 

49 /560 

C-6 

A-2 

1559 

T32N 0 47 

1494 

T31 N 6 T32N 

8-3 T3IN 

O 

1533 A-I 

24 0 

C-4 8-6 

0 

1497 500 BMC 0 

1524 

3/ 1499 3PN 

// 

B-4 

0 • Prosser well 

1582 1440 

10 15 

C-3 

0 Otto Gresch wet 

1451 • B-5 

// 1450 

/0 

O 

1496 EXPLANATION 

40 C-I 

T3IN 

C-2 Resistivity line center T3ON 

0 • 

1466 Deep well 

/9 

1497 

Altitude of grovel in feet 

3/ 

Thickness of gravel in feet 

1436 

0,0 

118 

C-I 

1440 Index map 

0 2 Miles 

Pre-Conbrion 

outcrop 

1 

Contour interval 20 feet 

RIOE RUE RITE RI2E 

C-5 

4 

/460 

T31 N 

T3ON 

/480 

Figure 4. --Contours on top of sand and gravel deposits based on resistivity measurements. 

7 
R 10E RITE RITE RI2E 

RIOE RI IE RITE RI2E 

Pm-Zambian 

outcrop 

Gib 

T33N 

T33N 

C-8 T33N 

T32N0 

1487 

64 

B-4 

0 • Prosser well 

1492 1430 

190 )2/ 

EXPLANATION 

C-I 

0 

Resistivity line center 

• 

Deep well 

1447 

Altitude of till in feet 

/30 

T3IN 

T3ON 

Thickness of till 

in feet 

Index map 

0 I 2 Miles 

C-3 

1462 

56 

C-2 

0 

1447 

/30 

Otto Gresch well 

• 

B-5-

0 

1455 

2/3 

B-7 

0 

1408 

79 

C-I 

0 

1428 

/05 

T3I N 

T3ON 

C-7 

0 

1449 

/440 17 Th

B-I 

0 

6-2 

0 

1511 

778 

T32N 

T3I 

C-6 

0 

1490 

79 Irk) 

B-3 

0 

1509 

212 

C-5 

0 

1477 

48 

C -4 

0 BMC 

(none) 0 

1488 

62 

6-6 

0 

1492 

/06 

1500 

150' 

A-2 

0 

1512 

/23 

T32 N 

T3IN 

A-I 

0 

Contour interval 20 feet 

Figure 5. --Contours on top of till deposits based on resistivity measurements. 

8 
INTERPRETATION OF APPARENT RESISTIVITY CURVES 

9 
1 I I I I I I IIL 

Depth 

Electrical depth profile: (feet)— 

Sand, soil with gravel 0-8.3 

Sand and gravel . ... 8. 3-55_ 

Till, some sand and gravel .. .. 55-178 

Bedrock 178-500_ 

-..- . 

a 

• 

A 

• 

• C.. 

• 

• 

i• 

t 

• 

•• 

• 

•• 

• 

• 

• 

• 

' • A • ''. . 

I :• • 

A P 

0Full 

x P-2 

-I 

curve 

curve 

curve 

61 20 30 40 50 60 70 80 90 ICO 200 300 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

ipoopoo 

APPARENT RESISTIVITY, INOHM CMS 

100,000 

10,000 

5 

I I I 

Electrical 

Line abandoned 

erratic 

discovered 

the wires 

cause 

I 

depth 

results. 

was 

that 

profile: 

because 

It 

leakage 

the contributing 

I 

of 

in 

I 

was later 

I III_ 

Depth 

(feet) — 

_ 

_ 

0-260 

e 

I 

e 

• 

0 . 

• 

r 

• 

I 

• 

e 

• 

• 

I 6 

a . AA 

a 

• 

• 

x 

.Full 

e,P-1 

P-2 

curve 

curve 

curve 

20 30 40 50 60 70 80 90 100 200 300 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

Figure 6. --Line A-1, SWiSWI sec. 5, T. 31 N., R. 12 E. P-1 N. 1 - °E. Altitude, 1,595 ft. 

1,000,000 

cn 

2 

O 

100,000 

10,000 

Figure 7. ---Line A-2, NE+NE4 sec. 36, T. 32 N. , R. 11 E. P-1 N. 2°W. Altitude, 1,567 ft. The interpreted 

depths or thicknesses of beds given in this section are not to be considered accurate to tenths of a foot. Theso 

values are given primarily to assist those interested in following through the interpretation procedure as outlined in the text, because by using the method described, the values can easily be interpreted in tenths of a 

foot to depths of approximately 15 to 20 ft. 

10 
I [ I I 1 1 I I 1 1 Depth — 

Electrical depth profile: (feet) — 

Sandy clay soil with gravel 0-4.6 

Sand and gravel with some 

till or clay 4.6-54 — 

Till, some sand or gravel 54 7232 

Bedrock .... 232-600 ....... 

, 

• 

I 

I I I 

A 

• . 

♦ l — 

• 

f• 

• 

• • 

I 

ft 

• • 

. 

• •• 

• 

• 

• 

' •• , A ••• 

• 

6P

x 

°Full 

-I 

P-2 

curve 

curve 

curve 

ZO 30 40 50 40 70 80 90 100 200 300 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

10,000 

APPARENT RESISTIVITY, IN OHM CMS 

IlIV,VNI 

loopoo 

10.000 

• 

1 1 1 1 I 1 1 1 1 1_ 

Depth 

Electrical depth profile: (feet) — 

Line abandoned because of _ 

erratic results. Cause unknown 0:60 _ 

• 

• 

o 

• 

• 

. , _ . 

A 

• 

x o 

• 

,, 

AP 

Full 

-I 

P-2 

I 

curve 

curve 

curve 

I 

61 ZO 30 40 50 60 70 80 90 00 300 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

Figure 8. --Line B-1, SE+SEI sec. 16, T. 32 N., R. 11 E. P-1 N. 90°E. Altitude not taken. 

Figure 9. --Line B-2, NW+NWi- sec. 28, T. 32 N., R. 11 E. P-1 N. 5°W. Altitude, 1, 565 ft. 

11 
5 10 20 30 40 50 60 70 80 90 130 200 300 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

0 30 40 50 60 70 80 90 100 200 300 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

1,000,000 

APPARENT RESISTIVITY, IN OHM CMS 

100,000 

10,000 

100.000 

Electrical 

Moist 

Sand and 

till or 

Till, little 

Bedrock 

clayey 

depth 

gravel, 

clay 

soil 

sand and 

profile: 

.some 

gravel . 33-245 

245-650 

Depth 

(feet) — 

0-9.3 — 

9.3-33 _ 

• 

• 

. • 

. 

I 

• 

• 

I 

• 

• 

t " 

. 

• 

1 

A 

. 

1 

A 

• 

r 

. 

• 

• 

' • . 

A 

• • . 0 • 

• 

• 

• 

• 

• 

i . 

4 • , • 

v 

eFull 

c,P-I 

P-2 

curve 

curve 

curve 

Figure 10. --Line B-3, SE-1-NE+ sec. 4, T. 31 N., R. 11 E. P-1 N. 5°W. Altitude, 1, 542 ft. 

II I I I I I TlI 

Depth — 

Electrical depth profile: (feet) 4 -- 

Moist sand, little clay 0-10 — 

Sand and gravel 10-20 

Till with some sand _ 

and gravel 20-210 

Bedrock . 210-650 

• 

• 

A • I 

• • 

6 0 

A ' • 

• 

r 

4' 

. 

• 

. 

•.• .• .- . • 

. 

. 

A A 

• 

a x 

• " , 

A A 

, 

• 

. 

A 

v 

Full 

P-1 

P-2 

curve 

curve 

curve 

Figure 11. --Line B-4, NE4SVv4 sec. 22, T. 31 N., R. 11 E. P-1 N. 0° E. Altitude, 1, 512 ft. 

12 

1000 
1,000,000 

APPARENT RESISTIVITY, IN OHM CMS 

100,000 

0 20 30 4p 53 60 70 60 90 00 200 300 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

20 30 40 50 60 70 BO 90 100 200 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

1,000,000 

APPARENT RESISTIVI

TY, IN OHM CMS 

100,000 

10,000 

5 10 

11 I I I i I III 

Depth — 

Electrical depth profile: (feet) — 

Sandy clay and gravel 0-11.5 

Sand and gravel 11.5-52 — 

Till with some sand 

and gravel 52-265 — 

Bedrock 265-800 

._ 

• 

A . 4 • 

• 

• 

a 

v 

A. 

• 

A 

. 

• 

1 ' A 

. 

A. 

• 

. 

. • 

A 

. • • 

• •• 4 • 

• 

• 

• X 

A 

A 

• 

•••• 

A 

' 

. Full 

A P 

I 

v P-2 

. A 

-I 

I 

curve 

curve 

curve 

I 

Figure 12. --Line B-5, Center NW4 sec. 34, T. 31 N., R. 11 E. P-1 N. 4°W. Altitude, 1, 507 ft. 

1 

Depth 

Electrical depth profile: (feet) -, 

Sandy soil, some gravel 0-5.8 

Sand and gravel, some till 5.8-38 

Till with little sand and _ 

gravel 38-144 

Bedrock 144-600 _ 

. 

„.

• 

* A . 4 

= 

• . a 

d • 

. 

. . 

A 

• 

• • • 

.

• A 

• 

A 

• 

. 

. 

I • 

I' 

a ., 

• 

1 

t 

" 

• 

• Full 

A P 

X P-2 

-I 

curve 

curve 

curve 

Figure 13. --Line B-6, NWiStasec. 15, T. 31 N. , R. 11 E. P-1 N. 13°E. Altitude, 1, 530 ft. 

13 

10,000 

5 
1,000,000 

APPARENT. RESISTIVITY, IN OHM CMS 

100,000 

10,000 

5 C 20 30 40 50 50 TO 80 90 100 200 300 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

20 30 40 50 60 70 8090 100 200 300 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

Figure 15. --Line C-1, NE4SE4 sec. 16, T. 30 N. , R. 11 E. P-1 N. 55°E. Altitude, 1, 445 ft. 

14 

5 C 

I I I I I I III I_ 

Depth 

Electrical depth profile: (feet) — 

Soil, sand, gravel 0-10 

Till, probably clay 10-15 — 

Sand, and gravel 15-43 — 

Alternating beds of sandgravel and till (or clay? 43-122 _ 

Bedrock 122-400 

1 

• 

• 

• 

. • 

. 

. 

• • 

• 

• 

I 

I 

• 

it 

• 

I 

I 

• 

• 

I x , 

r 

• . • 

, 

• 

• 

• 

A 

•♦ 

• 

A• ' • ' •

A 

• 

• e 

A 

• 

A P 

Full 

x P-2 

curve 

-I curve 

curve 

Figure 14. --Line B-7, SWiNW4 sec. 7, T. 30 N., R. 12 E. P-1 N. 2°W. Altitude, 1, 451 ft. 

100,000 

ti 

2 

O 

6; 10,000 

tr 

1 000 

I I I f I I I IIL 

Depth 

Electrical depth profile: (feet) — 

Sandy clay soil with gravel 0-5 _ Sand and gravel, some till 5-17.5 

Till, probably clay 17.5-123 — 

Bedrock 123-500 

• • 

A • 

. 

• 

. 

'.. 

• 

A 

• 

. 

. 

. 

e 

x 

• 

, 

A 

A 

A 

• , x • • 

A . 

. 

/ A A 

A 

th . 

a 

x 

°Full 

P-I 

P-2 

curve 

curve 

curve 
300,000 

100,000 

APPARENT RESISTIVITY, IN OHM CMS 

10,000 

3 000 

I I 

Electrical 

Sandy 

Sand and 

Till, 

Bedrock 

I 

clay 

probably 

depth 

gravel, 

I 

soil 

profile: 

very 

clay 

clean.. 

I I 

153-600 

I I Depth 

(feet) 

0-4 

4-23— 

23-153 

. 

A 

. 

A A 

• 

A s 

1 

A 

A. 

• 

A 

a.' A A w 4. 

' 

. Full curve 

.P-4 

x P-2 

curve — 

curve 

5 20 30 40 50 60 70 60 90 100 300 400 500 1 000 

ELECTRODE INTERVAL, IN FEET 

Figure 16. --Line C-2, SEINE+ sec. 6, T. 30 N., R. 11 E. P-1 N. 5°W. Altitude, 1, 470 ft. There is an 

appreciable difference in depths to bedrock on the P-1 and P-2 halves of the measurements. This is interpreted as indicating that the center of the line lies near the edge of an old lake, which is now filled. The depth 

to bedrock increases to the north. 

I 

, Electrical 

Sandy 

Sand and 

little 

Till, 

Bedrock 

I 

and gravel 

soil 

till 

depth 

gravel, 

considerable 

I 

profile: 

very 

I 

sand 

I I I IL 

Depth 

(feet) — 

0-8 __ 

8-19 _ 

75-400 19-75— 

• • 

• 

. 

• 

• 

. 

•

• 

, 

oP-I 

oFull 

.P-2 

curve 

curve 

curve 

40 50 60 70 80 90 100 200 300 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

Figure 17. --Line C-3, SW-INEi sec. 26, T. 30 N., R. 10 E. P-1 N. 3°W. Altitude, 1, 470 ft. 

15 

APPARENT RESISTIVITY,IN OHM CMS 

1,000,000 

100,000 

10,000 
1,000,000 

RESISTIVITY, IN OHM CMS 

100,000 

10,000 

5 12 20 30 40 50 60 70 80 90 100 200 300 400 500 1000 

C 20 30 40 50 60 70 90 90 100 200 300 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

I I 1 I I 1 1 1 1.... Depth 

Electrical depth profile: (feet) 

Sand soil, little clay 0-8 _ 

Sand and gravel, little 

till .. 8-30-- 

Bedrock 39-250 

• s 

. 

. 

. 

f' 

. 

. 

4 e 

A 

r 

A 

A a 

— 

A 

. Full 

. P-2 

curve 

P -I curve 

curve 

ELECTRODE INTERVAL, IN FEET 

Figure 18. --Line C-4, SE-TINWi- sec. 14, T. 31 N., R. 10 E. P-1 N. 4°W. Altitude, 1, 505 ft. 

I I .1 I I I III Depth 

Electrical depth profile: (feet) — 

Sandy soil, dry 0-4.1 

Sand and gravel 4.1.-8.1 

Till, probably clay 8,1-56 

Bedrock 56-400 

I 

I 

A 

A 

X a 

A 

0 

• 

A 

° 

ro 

r 

° 

o 

A 

• 

4 

A ... 

A '.. 

e A 

A 

°Full curve 

&P-1 curve .-- 

. P-2 curve 

1 

1 

1 

Figure 19. --Line C-5, NWiNWi- sec. 10, T. 31 N. , R. 10 E. P-1 N. 1°W. Altitude, 1, 485 ft. 

16 

4 000 5 

400,000 

100,000 

APPARENT RESI

STIVI

TY, IN OHM C

MS 

10,000 
300,000 

100,000 

APPARENT RESISTIVITY,IN OHM CMS 

10,000 

. 

o 

I, I 

Electrical 

Sandy 

gravel 

Sand and 

Clay 

Bedrock 

soil 

depth 

gravel 

I 

with some 

profile: 

. 

I I I I I 

Depth 

(feet) 

0-6 _ 

6-12 

12-91 

91-400. 

.0 

, 

A 

0 

. 

o 

o 

o 

. 

0 

A x 

9 

4. 

• 

I 

o 

0 

a 

A A 

0 

• 

a 

0 a 

0 

• 

. 

. 

a . 

r 

A • 

a . 

,Full curve 

LP-I curve 

„P-2 curve 

0 20 30 40 50 60 70 e0 90 100 200 300 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

Figure 20. --Line C-6, SWISW+ sec. 35, T. 32 N., R. 10 E. P-1 N. 85°E. Altitude, 1, 502 ft. 

li___ I I • 1 L_1 I JL 

Depth 

Electrical depth profile: (feet) — 

Clay soil, some gravel 0-2.8 — 

Clay or till 2.8-11 

Sand and gravel, some _ 

till 11-76 

Till, probably clay 76-93 _ 

Bedrock, very hard 

and dense _ 93-400 

• 

, 

. 

• 

• 

• A 

• 

A 

' 

a 

A . 

[ 

a 

i 

x 

.Full 

z.P-1 

R-2 

curve 

curve 

curve 

0 20 30 40 50 60 70 80 90 100 200 300 400 500 1000 

ELECTRODE INTERVAL IN FEET 

Figure 21. --Line C-7, SEISE4 sec. 16, T. 32 N. , R. 10 E. F-1 N. 5°W. Altitude, 1, 525 ft. At some place 

between Lines C-6 and C-7, the till layer begins to thin so that at C-7 it is only about one-seventh as thick as 

at C-6. 

17 

3 000 

5 

APPARENT RESISTIVITY, IN OHM CMS 

100,000 

10,000 

1 000 
100,000 

APPARENT RESISTIVITY, IN OHM CMS 

10,000 

1 000 

5 10 20 30 40 50 60 70 80 90 100 000 

ELECTRODE INTERVAL, IN FEET 

200 300 400 500 

10 20 30 40 50 60 TO 80 90 100 200 300 400 500 1000 

ELECTRODE INTERVAL, IN FEET 

1,000,000 

APPARENT RESISTIVITY, IN OHM CMS 

100,000 

10,000 

I 

Electrical 

Sand with 

gravel 

Clay or 

Sand and 

Till, probably 

Bedrock 

I 

depth 

clays 

till 

gravel 

I 

and 

. 

profile: 

clay 

1 1 

4 

1 

3.8-7.5 

122-500 

1 1 1 

Depth — 

(feet) — 

0-3.8 — 

— 

7.5-58 

58-122 _ 

. 

• 

• 

. 

. . 

• 

. 

. ° 

• 

4 

A 

A A ' 

, A A 

• 

. . 

. • 

• 

. 

i 

a 

• 

0 Full 

,& P-1 

.P-2 

curve 

curve 

curve 

Figure 22. --Line C-8, NE-iNWi- sec. 4, T. 32 N. , R. 10 E. P-1 N. 12°W. Altitude, 1, 545 ft. 

1 1 I 1_ I I I I 1 1 

Depth 

Electrical depth profile: (feet) — 

. Clay soil with gravel 0-11_ 

Sand and gravel 13-22 

Till, some sand and _ 

gravel 22-84 

Bedrock 84-400 __ 

. 

. 

• 

• 

. 

' • 

. 

. . • 

• ','e ' 

. 

. 

.. 

., 

. 

. . 

• 

. • 

0 

P 

A 

- 

' X 

0 Full 

e, P

.P-2 

-I curve 

curve 

curve 

Figure 23. --Line BMC, NW1SW* sec. 17, T. 31 N. , R. 11 E. P-1 N. 4°W. Altitude, 1, 510 ft. 

18 
WELL LOGS 

[ Samples examined by F. T. Thwaites] 

Otto Gresch farm well, Antigo, Wis. , 

WiNE1 sec. 33, T. 31 N. , R. 11 E. Altitude, 

1,510 ft (estimated) 

Depth 

(feet) 

Sand, fine, silty 0-5 

Sand, medium; some pebbles 5-35 

Sand, fine to coarse 35-50 

Sand, medium to coarse 50-60 

Sand, medium; some pebbles 60-69 

Prosser farm well, Antigo, Wis. , SE3-4- sec. 22, 

T. 31 N. , R. 11 E.. Altitude, 1,510 ft 

(estimated) 

Antigo test well 1. --Continued 

Depth 

(feet) 

Sand, medium, light-gray 30-40 

Sand, medium, light-gray; some 

small pebbles 40-45 

Sand, medium to coarse, light-gray; 

some small pebbles 45-52 

Sand, medium to coarse, light-gray 52-581 

Sand, medium to very coarse, much 

silt, yellowish-gray 582-73 

Antigo test well 2. Near corner of Arctic 

Street and Graham Avenue. NE-WW-isec. 29, T. 31 N. , R.. 11 E. Altitude, 

Gravel, sandy 

Sand, coarse; some pebbles 

0-5 

5-20 

1,500 ft 

Sand, medium to very coarse 20-30 Silt, some sand, light brownish-gray 1-5 

Gravel, sandy, coarse 30-35 Sand, fine to medium, much silt, light 

Sand, fine to coarse 35-60 brownish-gray 5-10 

Gravel, sandy, coarse 60-65 Sand, medium to coarse; some silt, 

Sand, medium to pebbly 65-80 light-gray 10-15 

Till, very sandy 80-87 Sand, medium to coarse, light-gray 15-18 

Gravel, fine, stony 87-92 Sand, medium to very coarse, small 

Till, sandy 92-101 pebbles, light-gray 18-30 

Sand, medium, light-gray, very little 

Antigo test well Ii. Near corner of Graham coarse material 30-32 

Avenue and Fulton Street. NEWW)-i Sand, medium to coarse; pebbles to 

sec. 29, T. 31 N. , R. 11 E. Altitude, in 32-35 

1,500 ft Sand, medium, light-gray 35-47 

Silt, some sand, brownish-gray 1-5 

Sand, medium to coarse, some pebbles, 

light-gray 47-54 

Sand, fine to coarse, much silt, 

brownish-gray 5-10 

Sand, fine to coarse, light-gray 

Sand, medium to coarse, brown-gray; 

54-57 

Sand, medium to very coarse, light-gray .. 10-15 some silt 57-61 

Sand, medium to very coarse 15-20 Sand, medium to coarse; small pebbles 61-71 

Sand, medium, light-gray 20-30 Gravel, fine, sandy, light-gray; stones 

to 2 in 71-72 

Bedrock, no samples, driller's report . 72 

19 INT.-DUP. SEC., WASH., D.C. 27000 

t."", 

~4; 

Y 

~~ 

~•