Tritium Rainout over the 

United States in 1962 

and 1963

GEOLOGICAL SURVEY 

CIRCULAR 520
Tritium Rainout over the

United States in 1962

and 1963

By G. L. Stewart and C. M. Hoffman

Geological Survey Circular 520

Washington 7966
United States Department of the Interior

STEWART L. UDALL, Secretary

Geological Survey

William T. Pecora, Director

Free on application to the U.S. Geological Survey, Washington, O.C. 20242
CONTENTS

Page Page 

Abstract ___________________________ 1 Data interpretation _________________ 2

Introduction _______________________ 1 Summary __________________________ 5

Tritium rainout network ____________ 1 References ________________________ 5

Analytical methods _________________ 2

ILLUSTRATIONS

Page 

Figure 1. Graph showing tritium concentrations in 1963 precipitation at Salt Lake

City, Utah, and Ocala, Fla ____________________________________________ 3

2. Map showing weighted-average tritium coneentration _______________________ 4

3. Map showing total tritium rainout ________________________________________ 4

TABLES

Page 

Table 1. Tritium rainout data for 1962 ____________________________________________ 5

2. Tritium rainout data for 1963 ____________________________________________ 7

III
Tritium Rainout over the United States in 

1962 and 1963

By G. L. Stewart and C. M. Hoffman

ABSTRACT

This report describes the tritium sampling network established by the U.S. Geological Survey. Tritium rainout data 

are included for 1962 and 1963 precipitation collected at 15 

stations in the United States and Puerto Rico.

These data are presented graphically to show seasonal 

variations and geographic distribution patterns for 1963 

tritium rainout. Total tritium rainout during 1963 was considerably higher than it was in previous years. Peak tritium 

concentrations in late spring or early summer of 1963 were 

higher by a factor of three or more over concentrations measured in 1962.

INTRODUCTION

In recent years, because of the similarity 

of its physical and chemical properties with 

water, tritiated water (HTO) has proved of 

great value in water dating and tracer applications. Radioactive isotopes are advantageous as water tracers because they can be 

detected in relatively small concentrations 

compared to nonradioactive tracers. Tritium, a radioactive isotope of hydrogen, is 

probably the best radioactive tracer for water because it is incorporated directly into 

the water molecule, and its 12.26 years half 

life permits its use in both short- and relatively long-term experiments.

Small quantities of tritium are produced 

naturally by cosmic radiation in the atmos - 

phere. This tritium eventually becomes oxidized, and it is carried to the earth in the 

form of rain or snow. The tritium production 

rate is considered to be quite constant and is 

the basis for water dating, because the tritium concentration in water is proportional 

to its age. Various estimates of natural tritium activity in precipitation have been made;

these range from 2 to 10 TU 1 , the concentration depending upon location with respect 

to oceanic influences and other meteorologic 

phenomenon (Kaufman and Libby, 1954, p. 

1337; Libby, 1961; Thatcher, 1962).

Since 1952, natural tritium in precipitation 

has been masked by synthetic tritium placed 

in the atmosphere by thermonuclear bomb 

explosions and by nuclear facilities. This 

synthetic production has resulted in large 

quantities of tritium being added to the hydrologic environment and has thus produced 

a tritium pulse valuable for present and future hydrologic investigations.

Since tritium was first introduced as a water tracer (Kaufman and Libby, 1954, p. 1337) 

in analysis relating to hydrologic problems, 

several investigations dealing with tritium 

circulation in the atmosphere and in surface 

and ground waters have been conducted. In 

general, these investigations have been quite 

satisfactory and have further established the 

potential usefulness of both natural and artificial tritium tracer in hydrologic and meteorologic investigations.

TRITIUM RAINOUT NETWORK

Based upon the premises given above, the 

U.S. Geological Survey initiated a program in 

1958 to measure fluctuating tritium activities 

in precipitation, which subsequently provides 

a tag for surface and ground waters. Since 

that time, precipitation waters have been 

monitored systematically for tritium activity

* ! TU = 1 tritium atom/1018 hydrogen atoms ~3. 2 pico curies 

per liter.
TRITIUM RAINOUT OVER THE UNITED STATES IN 1962 AND 1963

by the Survey. Initially, three collection stations were established to monitor tritium on 

a regular basis, and supplemental data for 

other locations were provided as required. 

The observation network was expanded to. 

include 9 stations after the U.S.S.R. broke the 

3 -year moratorium and resumed nuclear test - 

ing in September 1961. To obtain more complete information about tritium rainout patterns and to document tritium data for future 

work, the network was again revised and expanded in January 1963. It presently includes 

15 stations collecting biweekly samples at 

the following cities: Albuquerque, N. Mex.; 

Baton Rouge, La.; Bismarck,.N.Dak.; Boston, 

Mass.; Denver, Colo.; Lincoln, Nebr.; Madison, Wis.; Palmer, Alaska; MenloPark, Calif.; 

Ocala, Fla.; Portland, Oreg.; St. Louis, Mo.; 

Salt Lake City, Utah; San Juan, Puerto Rico; 

and Washington, D.C.

Tritium rainout data reported herein covers 

a time period from July 1962 to December 

31, 1963. These data are almost complete 

except for a few samples that are missing 

because of a short discontinuance of sampling 

during part of July 1962 through March 1963. 

In March 1963 the station at Albany, N.Y.,was 

discontinued in favor of a station at Boston, 

which would be more representative of storms 

originating in the ocean or along the coast.

Precipitation samples were collected in a 

standard 8-inch U.S. Weather Bureau rain 

gage. The total amount of precipitation falling 

during the collection period was measured in 

the rain gage at the end of the collection 

period and recorded on the sample container 

at the time of collection. The network is 

operated by U.S. Geological Survey personnel 

of the various district offices. Each precipitation sample represents a biweekly composite 

of precipitation for the particular region. 

Precipitation collected in the rain gage is 

poured into polyethylene containers and shipped to the U.S. Geological Survey tritium 

laboratory for analysis.

U.S. Geological Survey tritium rainout data 

before July 1962 are listed in previous reports (Thatcher, 1962; Thatcher and Hoffman, 

1963, p. 5899-5901).

ANALYTICAL METHODS

All analytical work was done by the U.S. 

Geological Survey tritium laboratory in 

Washington, D.C. Where direct measurement

of samples was not feasible, the samples 

were enriched in electrolysis cells. Most 

precipitation samples collected during the 

time period covered in this report were of 

sufficient tritium activity that electrolytic 

enrichment was not necessary. In general, 

higher activity samples were counted directly 

with a liquid scintillation spectrometer and 

low activity by a gas-phase counting system 

employing Geiger-MUUer detectors. Counting 

and electrolytic enrichment methods, except 

for a few refinements, are the same as those 

reported earlier (Hoffman and Stewart, 1966).

The statistical counting error was + 5 percent or less; the maximum probable analytical error was generally less than + 10 

percent.

DATA INTERPRETATION

The spring rise and late spring-early summer peak observed in previous years was 

also characteristic of 1963 precipitation. The 

two curves on figure 1 are representative of 

the 1963 tritium rainout pattern. Peak tritium concentrations for areas included in the 

network were three or more times greater 

than in 1962. Complete tritium rainout data 

are not available for 1962 precipitation; 

therefore, only general comparisons between 

1962 and 1963 data can be made. The highest 

tritium concentration measured for 1963 precipitation waters was 12,950 TU for a sample 

collected at Denver, Colo. during May 5 18. 

Salt Lake City, Utah, precipitation for June 

2 9 and June 16 30 contained tritium concentrations of 11,450 TU and 10,440TU, respectively. If individual storms had been monitored for tritium activity, peak values would 

probably be higher than those reported here.

It is the total tritium rainout, calculated by 

multiplying the tritium concentration by the 

amount of precipitation, that is of greatest 

hydrologic significance. This product gives 

the total rainout of tritium radioactivity for 

a given time and ground-surface area in the 

vicinity of the collecting station (that is, 1 

Tu-cm per unit times 3.2 x 10~3 pico curies 

per cm2 per unit time). For meteorologic 

interpretations of tritium rainout data, tritium concentration in individual storms is 

important. Data for tritium rainout during 

1963 for the various stations and 1962 data 

not previously reported are listed in tables 

1 and 2. The "TU-cm" column represents
DATA INTERPRETATION

JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV

1963

Figure 1. Tritium concentrations in 1963 precipitation at Salt Lake City, Utah, and Ocala, Fla.

DEC

the total tritium rainout per cm2 of groundsurface area for the collection period specified. For comparison, the 1963 total rainout 

is given for each location. Where sample 

collection was not complete, particularly 

during parts of January and February for a 

few stations, estimates of tritium rainout 

were made. These estimates were based 

upon available tritium data for the location 

and trends observed at other stations. Because tritium concentrations in precipitation 

were low during the time when samples are 

missing, the error introduced by estimating 

tritium concentrations and amount of precipitation is insignificant when total 1963 

rainout weighted-average tritium concentrations are considered. Precipitation amounts 

for the missing data and for the Denver, 

Colo., station were.estimated from Weather 

Bureau records. All other precipitation amounts were taken directly from rain gage 

readings at the collection site. Samples from 

Denver, Colo., were collected at the Denver 

Federal Center, where precipitation amounts 

were not recorded but were estimated from 

Weather Bureau records for the Denver airport about 10 miles away. This introduces 

an error into computations of total tritium 

rainout and weighted-average tritium concentration.

The geographic distribution of tritium rainout for 1963 is shown on figures 2 and 3. 

Because of oceanic influences and other 

meteorologic phenomena, the tritium concentration in midcontinent precipitation is generally higher than that falling near coastal 

regions. Weighted-average tritium concentration increases with latitude going from 

south to north. The relatively low values for 

total tritium rainout and weighted-average 

tritium concentrations for Menlo Park are 

probably due to low rainfall during late spring 

and early summer when the atmosphere is 

normally high in tritium. Only 0.08 inch of 

rain was recorded during May 11 to September 11. Total tritium rainout for Denver and 

Albuquerque is also lower than expected and 

is due to low precipitation during the time 

when tritium in the atmosphere is high. Generally, the data indicate an inverse relationship between the tritium concentration of
TRITIUM RAINOUT OVER THE UNITED STATES IN 1962 AND 1963

Palmer, Alaska

Oca la 

620

San Juan, Puerto Rico 

240

Figure 2. Weighted-average tritium concentration (TU) calculated by dividing the total 1963 tritium 

rainout (total TU-cm, table 2), by the total amount of precipitation.

Palmer, Alaska 

124,410

0Portland 

129,240

Bismarck 

226,080

''Boston

Menlo Park 

21,630

Salt Lake City

167,910 Denver 

108,450

Madison \ \

o\i

140,310 \J

Lincolin

136,840 

St. Louis

111,100

Washington 

114,020°

Albuquerque 

°45,360

94,840

Baton Rouge

^Ocala 

\76,300

San Juan, Puerto Rico 

25,860C

Figure 3. Total tritium rainout (in TU-cm) during 1963.
REFERENCES

precipitation and the amount of precipitation. 

However, biweekly composites were collected, and this generalization does not always hold be cause individual storms were not 

monitored and the precipitation rate of deposition is important.

Although Portland, Or eg., Bismark, N. D., 

and Boston, Mass., are at about the same 

latitude, the total tritium rainout at Bismarck 

is considerably greater than at the other two 

locations because oceanic influences are not 

as great and precipitation patterns are different. The relatively low tritium rainout at 

Palmer, Alaska, is probably due to oceanic 

influences.

The primary purpose of this report is to 

document tritium rainout data and to discuss 

general observations. Subsequent reports 

will go into more detail on meteorologic influences causing these observed patterns and 

the hydrologic implications of tritium rainout.

SUMMARY

Locations for 15 sampling stations, collecting biweekly samples for tritium analysis, are listed. Stations in the network were 

geographically selected to provide representative tritium data for the continental 

United States, Alaska, and Puerto Rico.

Observations for 1963 tritium rainout are 

characteristic of previous patterns. A spring 

rise and late spring-early summer peak was

observed for all stations, and the total 1963 

tritium rainout was considerably higher than 

it had been in previous years. Peak tritium 

concentrations were up by a factor of three 

or more over 1962 reported values. It was 

also observed that total tritium rainout and 

weighted-average tritium concentration increase with northern latitude and that midcontinent values are greater than coastal 

regions where oceanic influences are important. In some places low tritium rainout 

is related to low precipitation during times 

when atmospheric tritium is high.

REFERENCES

Hoffman, C. M., and Stewart, G. L., 1966, 

Quantative determination of tritium in natural waters: U.S. Geol. Survey WaterSupply Paper 1696-D (in press).

Kaufman, S., and Libby, W. F., 1954, The 

natural distribution of tritium: Phys. Rev., 

v. 93, p. 1337.

Libby, W. F. } 1961, Tritium geophysics: Recent data and results a symposium in 

Vienna, Austria, May 3-10, 1961: Tritium 

in the Phys. and Biol. Sci., v. 1, International Atomic Energy Agency.

Thatcher, L. L., 1962, The distribution of 

tritium fallout in precipitation over North 

America: Internat. Assoc. Sci. Hydrol. 

Bull., v. 7, no. 2, p. 48.

Thatcher, L. L., and Hoffman, C. M., 1963, 

Tritium fallout over North America from 

the Soviet tests in 1961: Jour. Geophys. 

Research, v. 68, no. 20, p. 5899-5901.

Table 1. Iritium rainout data for 1962

Collection period

Amount

precipitation 

(cm)

Tritium

concentration 

(TU)

Tritium

rainout 

(TU-cm)

Collection period

Amount

precipitation 

(cm)

Tritium

concentration 

(TU)

Tritium

rainout 

(TU-cm)

Albany, N. Y.

June 26-July 3 __ _ 

July 4-1Q _______

July 24 ___ _____

July 31 __ ____

Aug. 7 14 _ _ ____

Aug. 15-21 __ ___

0.28 

2.62

1.52

1.57

3.99

1.67

1,240 

790

1,640

1,160

790

1,070

350 

2,070

2,490

1,820

3,150

1,790

Aug. 29-Sept. 4... 

Sept. 11-18 ____

Oct. 2-30 ______

Oct. 31-Nov. 28 __

Dec. 4-18 ........

Dec. 19-26 .......

3.33 

.81

9.73

8.79

4.77

1.50

450 

600

250

370

220

1,250

1,500 

490

2,430

3,250

1,050

1,870

Albuquerque, N. Mex.

July 1-29 ........

July 30-Aug. 4 .... 

Sept. 9-29 ........

2.90

2.16 

2.46

570

560 

190

1,650

1,210 

470

Sept. 30-Oct. 27 ..

Nov. 12-Dec. 2 __ 

Dec. 16-29 ____ .

5.44

2.11 

1.14

300

390 

530

1,630

820 

600
TRITIUM RAINOUT OVER THE UNITED STATES IN 1962 AND 1963

Table 1. Tritium rainout data for 1962 Continued

Collection period

Amount

precipitation

(cm)

Tritium

concentration

(TU)

Tritium

rainout

(TU-cm)

Collection period

Amount

precipitation

(cm)

Tritium

concentration

(TU)

Tritium

rainout

(TU-cm)

Lincoln, Neb.

July 3-30 ________

Aug. 2-31 ____ _

Sept. 3-30 _______

15.98 

13.33 

8.99

1,350 

410 

380

21,570 

5,470 

3,420

Oct. 1-31 __ _____

Nov. 1-27 _______

Dec. 4-24 ___ __

7.96 

1.75 

1.27

400 

590 

990

3,180 

1,030 

1,260

Menlo Park, Calif.

Oct. 12-14 _______

Nov. 19-27 __ ___

8.43 

.91

70 

190

560 

170

Dec. 3-17 ___ __ 1.55 160 250

Ocala, Fla.

June 28-July 4 ___

July 5 Aug. 1 ____ 

Aug. 2-Sept. 5 ___

Sept. 6-Oct. 3 __ _

3.68

25.58 

9.27

13.69

550

400 

160

90

2,020

10,230 

1,480

1,230

Oct. 4-31___ __ _

Nov. 1 Dec. 5____ 

Dec. 6-31 _______

4.17

5.87 

3.23

90

200 

120

390

1,170 

390

Palmer, Alaska

July 8 Aug. 4 ____

Aug. 5-Sept. 2 ___

Sept. 3-30 _______

2.24

6.17

3.18

910

560

540

2,040

3,460

1 79fl

Oct. 15-29 __ ____

Nov. 19 ____ ___

Dec. 2-23 _ ___ __

3.40

.25

1.39

340

850

440

1,160

220

610

Portland, Or eg.

Aug. 6-13 _______ 1.96 360 71D Sept. 10 _ __ _____ 0.38 170 650

Salt Lake City, Utah

Mar. 7 __________

Mar. 10 _________

Mar. 23 _________

Apr. 22 _________

Apr. 29 _________

May 13 . __ ____

0.51

2.03

3.00

2.39

3n

1,690

1,660

1,110

3,010

1,040

1,860

860

3,370

3,330

2,490

560

May 20____ ______

May 27 _______

June 3 __________

June 10 _________

June 11-24 _ _____

1 Qn

3.15

1.55

197

.89

2,260

2,460

2,480

2,030

4,070

4 9Qfl

7,750

3,840

2,580

3,620

Washington, D.C.

July 3-25_ __ __ _

Aug. 27______ __ _

1,150

190

Sept. 4_ __ ______ 390
TABLES

Table 2. Tritium rainout data for 1963

[Items marked with an asterisk (*) indicate no sample collected. Tritium concentration estimated 

and amount of precipitation taken from Weather Bureau records]

Collection period

Amount

precipitation 

(cm)

Tritium

concentration 

(TU)

Tritium

rainout 

(TU-cm)

Collection period

Amount

precipitation 

(cm)

Tritium

concentration 

(TU)

Tritium

rainout 

(TU-cm)

Albany, N.Y.

Jan. 1-15___. __ _

Jan. 16-22 ______

Jan. 23-29_______

2.70

.41

3.86

930

660

1,350

2,510

270

5,210

Jan. 30-Feb. 13 __

Feb. 14-Mar. 4 __

2.95

2.82

12.74

450

1,510

1,330

4,260

13,580

Boston, Mass.

Mar. 5-18 _______

Mar. 19-30 ______

Apr. 3-11 _______

Apr. 16-May 13 __

May 14 June 12 __ 

June 13-July 1 ___ 

July 2-Sept. 2____

6.96

1.42

.91

6.71

5.13 

5.00 

8.61

620

1,600

870

2,170

2,590 

3,320 

3,110

4 ^90

2,270

790

14,560

13,290 

16,600 

26,780

Sept. 3-Oct. 16 __

Oct. 25-Dec. 2___

Dec. 3-31 _______

Total, Albany 

and Boston __

7.87

22.71

9.25

74.57

87.31

1,080

470

1,280

8,500

10,670

11,840

109,620

123,200

Albuquerque, N. Mex.

Jan. 1 5 ________

Jan. 6-12 __ __ _

Jan. 13-l9_-____-

Feb. 1-15 .......

Feb. 16-28 ______

Mar. 1-15 ____ _

Mar. 16-31 ______

Apr. 1-15 ____ _

May 15-31 ____ _

June 1-30*_______

0.23

.05

.51

.74

.30

1.12

.96

.68

.03

*.28

1,420

1,200

2,080

1,480

2,120

1,590

2,370

2,920

3,690

*3,000

330

60

1,060

1,100

640

1,780

2,280

1,990

110

*840

July 1-15 _______

July 16-31 ______

Aug. 1-15 _______

Aug. 16-22 _ __ __

Aug. 25-Sept. 5 __

Sept. 16-30. _____

Oct. 16-31 ......

Nov. 1-15 ___ __

1.19

1.68

8.46

.89

2.18

1.40

2.41

1.12

24.23

2,520

2,140

2,180

2,410

1,310

1,060

770

1,600

3,000

3,590

18,440

2,150

2,860

1,480

1,860

1,790

45,360

Baton Rouge, La.

Jan. 1 Apr. 6 ____ 

Apr. 7-June 7____

June 8-23 _______

June 24-July 7 ___

July 8-13________

July 22-28_______

July 29-Aug. 11 ._ 

Aug. 12-25 ___ _

*21.00 

5.23

9.24

8.53

5.13

12.95

7.72 

9.44

*450 

920

980

1,960

930

1,980

880 

640

* 9,4 50 

4,810

9,060

16,720

4,770

25,640

6,790 

6,040

Aug. 26 Sept. 15. 

Sept. 16-22______

Sept. 23-29._____

Nov. 4-10 _______

Nov. 25-Dec. 1 __

Dec. 9-15 _______

2.51 

4.57

.78

9.73

8.28

10.49

113.80

790 

380

570

330

190

250

1,980 

1,740

440

3,210

1,570

2,620

94,840

Bismarck, N. D.

Jan. 1-Feb. 9 ____

Feb. 10-19 ______

Feb. 20-Mar. 3 __ 

Mar. 4 Aor. 1 ___

*0.33

.15

.91 

.99

*1,000.

1,070

1,350 

3.480

*330

160

1,230 

3.450

Apr. 2-15 ___ ___

Apr. 16-29 ______

Apr. 30-May 13 __ 

Mav 14-28 ______

3.35

1.24

*3.18 

2.49

3,690

4,400

*4,500 

6,210

12,360

5,460

*14,310 

15,460
TRITIUM RAINOUT OVER THE UNITED STATES IN 1962 AND 1963

Table 2. Tritium rainout data for 1963 Continued

Collection period

Amount

precipitation

(cm)

Tritium

concentration

(TU)

Tritium

rainout

(TU-cm)

Collection period

Amount

precipitation

(cm)

Tritium

concentration

(TU)

Tritium

rainout

(TU-cm)

Bismarck, N. D. Continued

May29-June 9____

June 10-23 _ __ ___

June 24-July 7____ 

July 8-20 ____ __

July 21-Aug. 4 __

Aug. 5-18 _____ _

Aug. 19-Sept. 1 ___

6.86

7.85

5.26 

3.73

5.13

2.59

1.12

6,790

6,950

3,740 

3,590

3,930

3,450

2,070

46,580

54,560

19,670 

13,390

20,160

8,940

2,320

Sept. 2-29 _____

Sept. 30-Oct. 27 _

Oct. 28-Dec. 8 __ 

Dec. 9-22 _______

Dec. 23-31 ______

1.42

3.33

1.02 

.76

.08

51.79

1,630

780

1,030 

2,150

1,240

2,320

2,600

1,050 

1,630

100

226,080

Denver, Colo.

Jan. 1-Feb. 9_____

Feb. 10-19 __ ___

Mar. 3-4__ _______

Mar 12

May 5-18 ___ .__

May 19-31 _____

June 1 14 ________

June 15 16 _______

July 8-22 __ __ ___

June 23-Aug. 3 ___ 

Aug. 5-12 ________

*1.07

1.02

1.91

2.29

.51

1.14

2.29

7.75

.33

1.24 

.41

*1,500

2,060

2,220

2,840

12,9*50

8,130

5,160

5,400

3,380

2,150 

2,580

*1,610

2,100

4,240

6,500

6,600

9,270

11,820

41,850

1,120

2,670 

1,060

Aug 4 _ _

Aug. 12-26 ______

Aug. 27-Sept. 8 __

Sept. 9-23.___ ___

Oct. 7-21 _ __ ___

Oct. 22-Nov. 4___

Nov. 5-18 ___ __ _

Nov. 19-Dec. 13 _

Dec. 14-29. _____

1.75

4.24

1.35

2.03

2.79

.41

1.22

.33

.74

34.82

1,520

1,490

1,020

970

1,210

1,430

1,020

1,490

2,130

2,660

6,320

1,380

1,970

3,380

590

1,240

490

1,580

108,450

Lincoln, Nebr.

Jan. 1-30 ________

Feb. 10-24 _______

Feb. 27-Mar. 12 __

Mar. 18-25.. __ _

Apr. 2-10 __ __ ___

Apr. 15-28 __ ___

May 4 15 ________

May 16-27 _______

June 1-16 ________

June 19-26 _______

1.63

^1

A Q?

1.75

.84

1.68

5.92

.51

1.32

15.95

1,200

1,520

1,070

1,250

3,490

2,090

2,080

3,460

4,150

3,370

1,960

770

5,280

2,190

2,930

3,510

12,310

1,760

5,480

53,750

July 2-12 ___ __

July 16-Aug. !___

Aug. 5-12 ___ ____

Aug. 16-27 ______

Sept. 1-10. __ ___

Sept. 16-24__ __

Oct. 16-31 ___ ___

Nov. 11-31 __ ____

Dec. 1-17 _______

3.63

3.63

2.16

3.51

5.89

2.99

1.83

.51

.84

60.03

1,790

2,520

1,720

2,470

1,540

1,650

1,440

1,110

1,960

6,500

9,150

3,720

8,670

9,070

4,930

2,640

570

1,650

136,840

Madison, Wis.

Jan. 1-Feb. 26____

Feb. 27_ ____ __

Mar. 1-7 __ __ _

Mar. 8-14. __ ___

Mar. 15-31. __ ___

Apr. 1-15. __ __

Apr. 16-30 __ ___

May 1-15 ___ ___

May 16-31 _ __ ___

June 1 1 5 ________

June 16-30 _______

July 1-18 __ ______

*2.31

.71

2.36

.27

3.28

.84

4.70

2.06

1.85

4.80

4.37

5.99

*1,500

1,550

2,210

1,680

1,490

3,690

2 94.O

2,100

4,620

2,320

2,550

4,700

*3,470

1,100

5,220

450

4,890

3,100

10,530

4,330

8,550

11,140

11,140

28,150

Aug. 1-15 _______

Aug. 16-31 __ __ _

Sept. 1-15 _______

Sept. 16-30 __ __ _

Oct. 1-15____ ____

Oct. 16-31 ______

Nov. 1 15___ ____

Nov. 16-30 ______

Dec. 1-15 _______

Dec. 16-31 __ __ _

3.48

3.17

5.56

2.57

.58

.86

.91

3.-96

.68

.63

55.94

3,510

3,100

2,260

1,900

1,450

1,540

1,310

540

1,870

3,140

12,220

9,830

12,570

4,880

840

1,320

1,190

2,140

1,270

1,980

140,310
TABLES

Table 2. Tritium rainout data for 1963 Continued

Collection period

Amount

precipitation 

(cm)

Tritium

concentration 

(TU)

Tritium

rainout 

(TU-cm)

Collection period

Amount

precipitation 

(cm)

Tritium

concentration 

(TU)

Tritium

rainout 

(TU-cm)

Menlo Park, Calif.

Jan. 29-Feb. !____

Feb. 9-16 _____ _

Mar. 14-31 __ ___

Apr. 10-15 _______

Apr. 19-25. __ ...

May 8-10 ..______

July 9

10.52

5.69

6.10

7.31

1.88

1.22

.08

130

410

870

700

800

1,540

1,770

1,370

2,330

5,310

5,120

1,500

1,880

140

Sept. 12_________

Sept. 17 __ __ ___

Sept. 30-Oct. 14 .

Oct. 15-28 . ___

Oct. 29-Nov. 11 _.

Nov. 12-25. .._..

0.63

.13

1.98

.81

1.85

6.50

44.70

410

970

290

650

360

280

260

130

570

530

670

1,820

21,630

Ocala, Fla.

Jan. 3-30 .. __ ...

Jan. 31-Feb. 13___

Feb. 14-27 _ ___ _

Feb. 28-Mar. 13 __ 

Mar. 14-2 7 _______

Mar. 28-Apr. 10 __ 

Apr. 25-May 8____

May 9-22 _ __ ___

May 23-June 5____

June 6 19 ________

June 20-July 4____

July 5-17 _ __ ____

4.90

9.93

4.60

5.05 

2.44

2.64 

7.29

6.32

3.99

4 14

6.04

6.15

140

310

170

280 

250

710 

660

660

680

1,420

870

1,410

690

3,080

780

1,410 

610

1,870 

4,810

4,170

2,710

5,880

5,250

8,670

July 18-31 ______

Aug. 1-14 ___ __

Aug. 15-28 ______

Aug. 29-Sept. 11 _ 

Sept. 12-25______

Sept. 26-Oct. 9 __ 

Oct. 10-23 __ __ _

Oct. 24-Nov. 6___

Nov. 7-20 _______

Nov. 21-Dec. 4 __

Dec. 19-31 ______

12.95

5.05

8.51

5.49 

9.65

1.47 

.23

.96

5.72

1.29

7.59

122.40

1,090

900

640

880 

360

370 

510

270

180

310

220

14,120

4,550

5,450

4,830 

3,400

540 

120

260

1,030

400

1,670

76,300

Portland, Oreg.

Jan. 1-Feb. 3_____

Feb. 4-18 ___ ___

Feb. 19-Mar. 4 ___

Mar. 5-18. _______

Mar. 19-Apr. 1 ___

Apr. 2-15 ________

Apr. 16-29. ______

Apr. 30-May 16___

May 27-June 10___ 

June 11-24 _______

June 25-July 8____

July 9 22

*12.88

2.62

2.28

1.73

13.00

6.57

3.84

9.39

1.09 

3.63

3.96

2.06

*400

820

770

1,480

1,010

2,100

1,620

2,340

1,270 

1,950

4,220

3,530

*5,120

2,150

1,760

2,560

13,130

13,800

6,220

21,970

1,380 

7,080

16,710

7 97O

Aug. 5-19 _______

Aug. 20-Sept. 3 __

Sept. 4-16__ _____

Sept. 17-Oct. 1 __

Oct. 2-15 _______

Oct. 16-29 ______

Oct. 30-Nov. 12 __

Nov. 13-26 __ ____

Nov. 27-Dec. 10 _ 

Dec. 11-24 ______

Dec. 25-31 ______

0.36

2.08

1.65

.84

1.12

5.03

8.84

8.56

4.39 

3.94

1.95

101.81

2,750

1,820

820

1,280

840

560

660

730

490 

Q^n

590

990

3,790

1,350

1,080

940

2,820

5,830

6,250

2,150 

3,740

1,150

1 oq 04.0

San Juan, Puerto Rico

Feb. ll-25_ __ ___

Feb. 26-Mar. 14 __

Mar. 15 Apr. 1 ___ 

Apr. 2-15 __ ______

Apr. 16-29 ___ __

Apr. 30-May 13___

May 14-29 _______

May 30-June 22___

3.05

3.05

10.52 

7.23

2.24

7.14

14.35

1.90

90

200

200 

190

210

220

330

430

270

610

2,100 

1,380

470

1,570

4 740

820

June 23 30 ______

July 2-18 ___ __ _

July 21-Aug. !___ 

Aug. 5 22 _______

Aug. 23-Sept. 5 __

Sept. 6 23. _

Qarif 94.__TV»+ 4.

Oct. 5-18 _ ______

8.89

1.42

2.87 

4 fil

9 1 9

5.51

4 on

4.11

4.90

190

170 

170

99n

230

990

260

3,730

270

490

7QO

2,010

1,270

1,080

1.070
10 TRITIUM RAINOUT OVER THE UNITED STATES IN 1962 AND 1963

Table 2. Tritium raiwout data for 1963 Continued

Collection period

Amount

precipitation 

(cm)

Tritium

concentration 

(TU)

Tritium

rainout 

(TU-cm)

Collection period

Amount

precipitation 

(cm)

Tritium

concentration 

(TU)

Tritium

rainout 

(TU-cm)

San Juan, Puerto Rico Continued

Oct. 25-Nov. 1 ....

Nov. 2-18 ........

Dec. 1-15 __ __ ..

6.65

4.88

4.72

200

150

140

1,350

730

660

Dec. 16-31 ...__.. 2.36

109.56

190 450

25,860

Salt Lake City, Utah

Jan. 1-12 ........

Jan. 13-Feb. 3____ 

Feb. 17-24 __ ....

Feb. 25-Mar. 3 ...

Mar. 10-17_______

Mar. 18-24.......

Mar. 25-31.......

Apr. 1-14........

Apr. 15-30 .......

May 4-12 ........

June 2 9 _________

June 7-15 ________

*0.20

2.08

1.45

.66

3.99

.25

1.29

5.77

7.34

.58

2.84

2.64

*2,000

3,100 

2,040

1,090

3,310

3,260

3,310

3,500

5,850

7,980

11,450

5,880

*400

6,450 

2,960

720

13,210

820

4,270

20,200

42,940

4,630

32,520

15,520

June 16-30_______

July 29-Aug. 4 ___ 

Aug. 5-ll________

Aug. 19-25_______

Aug. 23-^Sept. 8___

Oct. 6-13 ________

Oct. 19-27 _______

Oct. 28-Nov. 10 __

Nov. ll-24_______

Dec. 8-22__ __ ___

Dec. 23-31. __ ...

0.20

.53 

1.37

1.42

2.82

1.04

.94

3.45

2.57

1.57

.71

45.71

10,440

1,840 

1,250

780

960

3,600

1,490

830

850

2,210

1,430

2,090

980 

1,710

1,110

2,710

3,740

1,400

2,860

2,180

3,470

1,020

167,910

Palmer, Alaska

Jan. 1-21 . _____

Feb. 4-14 ____ __

Mar. 4-12 .......

Mar. 13-18 .......

Mar. 19-25__ __ __

Apr. 8-15 ........

Apr. 16-23 ___ __

Apr. 24-May 13___

May 14-27________

May 28-nJune 17___ 

June 18 24 _______

June 25-30 _______

4.57

4 17

.56

9**

9^

1.47

.76

1.14

.66

.81 

3.05

1.73

970

1,300

1,440

1,650

3,130

1,290

3,640

3,170

2,980

6,210 

3,690

4,070

4. 4.9O

5,410

810

410

780

1,900

2,770

3,610

1,970

5,030 

11,250

7,040

July 1-15 _ _____

July 16-22 _ ______

July 23-29 _______

July 30-Aug. 5 ___

Aug. 12-19. __ ..

Aug. 20-26_______

Sept. 15-30 ______

Oct. 1-7 _________

Oct. 8-^STov. 13 ___

Nov. 26 Dec. 9 ___ 

Dec. 10-23_______

1.07

3.33

2.13

1 19

5 ^^

3.76

1.32

.81

1.78

1.02 

1.02

42.11

7 1 9n

6,610

4,780

5,000

3,260

2,170

1,300

1,700

1,430

1,360 

980

7,630

22,000

10,180

5,600

1 7 3Qn

8,160

1,720

1,380

2,550

1,390 

1,000

124,410

St. Louis, Mo.

Jan. 1-Feb. 19____

Feb. 20-Mar. 7 ___

Mar. 8-18________

Mar. 25-31__ __ __

Apr. 13-29 ___ ____

May 1-15 ________

May 16-31 _______

June 10-13 _______

June 15-20 _______

July 2-13 ___ __ __

Julv 17-28 _______

*1.19

4.60

3.81

5.43

5.03

3'. 81

8.30

5.59

4.24

1.75

1.73

*500

640

1,490

610

1,680

1,030

2,530

1,680

4,200

990

1.080

*600

2,940

5,680

3,310

8,450

3,920

21,000

9,390

17,810

1 7?n

1.870

Aug. 9-l2_____ ___

Aug. 18-29 ______

corvi- 1 ic

Dr-t 1 1 1

Oct.l6-31________

MOV 1 1 5

Nov. 16-30 ___ __

Dec. 7-ll________

Dec. 17-18 __ ___

2.39

4.01

2.87

1.68

Ri RR

.38

fi QQ

1 ^n

.20

n nfi

1,420

2,450

1,660

1,170

1,080

1,070

870

840

3,560

3,390

9,820

4,760

1 070

6,000

410

6,080

1,260

710

111,100
TABLES 11

Table 2. Tritium rainout data for 1963 Continued

Collection period

Amount

precipitation 

(cm)

Tritium

concentration 

(TU)

Tritium

rainout 

(TU-cm)

Collection period

Amount

precipitation 

(cm)

Tritium

concentration 

(TU)

Tritium

rainout 

(TU-cm)

Washington, D,C.

Jan. 1 Feb. 1 __ .

Feb. 2-21 ........

Feb. 22-Mar. 9 ... 

Mar. 10-24.......

Mar. 25-Apr. 6 ... 

Apr. 7-14 ___ ...

Apr. 15-30... __

May 1-15 ........

May 16-June 5 ___ 

June 6-July 3_____

*4.83

5.84

3.30 

9.91

2.54 

.51

RQ

1.27

11.22 

3.30

*500

620

640 

920

1,100 

2,520

9 1 ^n

1,190

850 

3,150

*2,410

3,620

2,110 

9,120

2,790 

1,290

1,900

1,510

9,540 

10,400

July 4-16.... __ .

July 17-Aug. 7 ...

Aug. 8-Sept. 10 .. 

Sept. 11-26 .._...

Sept. 27-Oct. 9... 

Oct. 10-Nov. 15 ..

Nov. 16-Dec. 5...

Dec. 6-31 .......

1.52

3.43

15.75 

3.05

4.83 

10.80

9.14

8.38

100.51

4,800

3,490

1,500 

1,730

540 

680

510

750

7,300

11,970

23,630 

5,280

2,610 

7,340

4,660

6,290

113,770

* U. S. GOVERNMENT PRINTING OFFICE : 1966 O - 213-782

GEOLOGICAL SURVEY CIRCULAR 521

Mineral Resources of the 

Grandfather Mountain 

Window and Vicinity 

North Carolina

Mineral Resources of the 

Grandfather Mountain 

Window and Vicinity 

North Carolina

By Bruce Bryant and John C. Reed, Jr. 

GEOLOGICAL SURVEY CIRCULAR 521

Washington 1966
United States Department of the Interior

STEWART L. UDALL, Secretary

Geological Survey

William T. Pecora, Director

First printing 1966 

Second printing 1967

Fr«« on apptkation to fft* U.S. Geological Survey, Washington, D.C. 20242
CONTENTS

Page Page

Abstract_-_______-__________________ 1 Nonmetallic resources _____________ 9

Introduction __________ _ _______ 1 Mica and feldspar -- - -- 9

Summary of geology _________________ 1 Kaolin ____________-----_ _-- _- 10

Metallic resources _ ___ _______ 3 Asbestos. _ ___ - - - 10

Iron. __ ______ _________- 3 Road metal__ - _- -- H

Titanium _________________________ 4 Sand and gravel ____ - _________ 11

Uranium ___ ____ ___ ______ 5 Building stone _ _ - - H

Gold ___________________ 7 Other commodities 12

Zinc and lead _____________________ 1 References.-______ _______________ 12

Manganesse __ ____ _______ 8

Copper..-_________ __ _ ______ 8

ILLUSTRATIONS

Page

Figure 1. Generalized map of Grandfather Mountain area showing location of some of

the mineral resources ___________________________-_--_------------_--_-- 2

2. Sketch of uraninite veinlets at the foot of Bard Falls ___ ____ ___ - ______ 5

3. Map of uranium prospects on North Harper Creek-______________-__--__---_-- 6

TABLES

Page

Table 1. Metal content of selected specimens from iron prospects on Big Ridge,

Linville quadrangle ____________________________________ ___ _________ 8

2. Copper content of samples of Montezuma Member of the Grandfather

Mountain Formation _i___________________________________________________ 9

in

Mineral Resources of the Grandfather Mountain 

Window and Vicinity, North Carolina

By Bruce Bryant and John C. Reed, Jr.

ABSTRACT

The most valuable and largest mineral resources presently 

known in the Grandfather Mountain area are gravel, sand, 

road metal, and building stone. Mica, feldspar, kaolin, iron, 

titanium, and asbestos have been produced, and additional 

resources may be available in modest amounts. Uranium, 

lead, zinc, manganese, gold, and copper occur in small 

amounts, but no deposits minable under present economicconditions are known.

INTRODUCTION

This circular summarizes the information 

collected on mineral deposits during a study 

of the Grandfather Mountain window and vicinity in northwestern North Carolina and 

presents these data independently of the description and interpretation of the general 

geology of this large and complex area. The 

Grandfather Mountain area comprises the 

Linville, Linville Falls, Lenoir, and Blowing 

Rock 15-minute quadrangles and parts of the 

Marion 15-minute quadrangel and the Little 

Switzerland and Marion East T^-minute quadrangles. Geologic information on the area is 

in published geologic maps (Bryant, 1963, 

1965; Reed, 1964a, b) and in the open-file 

map (Reed and Bryant, 1964). Information in 

this report pertaining to the Linville and 

Linville Falls quadrangles has previously 

been published (Bryant, 1962; Reed, 1964b). 

The specific localities mentioned in this report can be found on the published quadrangles, for many of the geographic features 

are too small to be shown on figure 1.

SUMMARY OF GEOLOGY

From northwest to southeast the area is 

composed of the following tectonic units: 

the Mountain City window, the Blue Ridge 

thrust sheet, the Grandfather Mountain window, the Brevard fault zone, and the Inner 

Piedmont (fig. 1).

In the Mountain City window, weakly metamorphosed Lower Cambrian rocks of the 

Rome Formation, the Shady Dolomite, and 

the Chilhowee Group are exposed.

The Blue Ridge thrust sheet consists of 

upper Precambrian schist, gneiss, amphibolite, migmatite, and granitic rock formed 

during a metamorphic-plutonic event 1,000 

1,100 million years ago and intruded by ultramafic rock of early Paleozoic(?) age and 

leucogranodiorite and pegmatite of early or 

middle Paleozoic age. These rocks have 

been metamorphosed one or more times 

during the Paleozoic. In late Paleozoic time 

the Blue Ridge thrust sheet moved relatively 

northwestward at least 35 miles over Precambrian granitic rocks and migmatite and a 

thick sequence of upper Precambrian sedimentary and volcanic rocks that are now exposed in the Grandfather Mountain window. 

An intermediate thrust sheet, the Tablerock 

thrust sheet, occurs above the autochthonous 

rocks and beneath the Blue Ridge thrust sheet 

in the southern part of the window. The 

Tablerock thrust sheet is composed of the 

Shady Dolomite and rocks of the Chilhowee 

Group. The rocks in the window and the 

thrust sheet were pervasively metamorphosed at low grade during the Paleozoic.

The Brevard fault zone, a strike-slip fault 

of regional extent, truncates the Grandfather 

Mountain window and the Blue Ridge thrust 

sheet to the southeast. The fault zone contains slices of exotic rock, and the zone and 

adjacent rocks showing structural and metamorphic effects related to the faulting form 

a belt 5 miles wide. Right-lateral movement 

along the Brevard fault took place in late 

Paleozoic and early Mesozoic time and may
MINERAL RESOURCES OF THE GRANDFATHER MOUNTAIN WINDOW AND VICINITY. NORTH CAROLINA

36

82°00' LINVILLE QUADRANGLE BLOWING ROCK QUADRANGLE 81°30'

Park

f* CRANBER&Y MINE

- <WILKBS| 

\CO

LENOIR QUADRANGLE

Base from Army Map Service 

1:250,000 quadrangles

Thrust fault Strike-slip fault Plllllil

Teeth on upper plate Arrows show direction of Mica^>roducing area

, rslative movement

Figure 1. Generalized map of the Grandfather Mountain area showing location of some of the mineral resources: A, asbestos; Au, gold;

Fe, iron; K, kaolin; Pb, lead; Ti, titanium; U, uranium; Zn, zinc.
METALLIC RESOURCES

have been closely related to the northwestward transport of the Blue Ridge thrust sheet.

In the inner Piedmont, which is southeast 

of the Brevard fault, layered biotite and biotite-amphibole gneiss, mica, and sillimanite 

schist and concordant bodies of cataclastic 

augen gneiss of Precambrian or early Paleozoic age have been invaded by granitic rocks 

of early or middle Paleozoic age and by ultramafic rocks of early Paleozoic(?) age. 

These rocks were subjected to one or more 

episodes of metamorphism during the Paleozoic.

METALLIC RESOURCES

IRON

Historically, iron has been an important 

mineral resource of the Grandfather Mountain area. A belt of iron prospects and mines 

in the Linville quadrangle extends northwestward from near Newland through Cranberry 

and about 6 miles west into Tennessee. The 

principal producing mine in this belt was the 

Cranberry mine at Cranberry, N.C.

The first published description of the 

Cranberry deposit, including several analyses of the ore, was written by Kerr (1875) 

before any extensive mining had been done. 

Bayley (1923) gave a rather complete review 

of the literature on Cranberry mine. During 

the present survey the underground workings 

at Cranberry were only partly accessible; 

most of the description, therefore, is summarized from the literature.

The ore mineral is magnetite; the gangue 

minerals are, principally, pyroxene, amphibole, epidote, quartz, feldspar, and, subordinately, garnet, and calcite. According to 

Ross (1935), the country rock contains augite 

and the ore deposits hedenbergite. Other 

minerals in the gangue include biotite, pyrite, 

pyrrhotite, sphalerite, and chalcopyrite. The 

ore is nontitaniferous and low in phosphorus. 

The iron content is 30 35 percent.

Keith (1903) recognized that the ore occurs 

in separate lenses peneconcordant with the 

foliation of the Cranberry Gneiss; he believed that the ore was postmetamorphic. 

However, Bayley (1923, p. 67, pi. 4) found 

that the ore and gangue at the Cranberry deposit were sheared, indicating that the mineralization occurred before or during the

latest metamorphism. Goldich and Wedow 

(1943) considered the ore bodies as discusshaped tectonic lenses. The lenses mined 

ranged in thickness from a few feet to 200 

feet and were as much as 900 feet long. Kline 

and Ballard (1948, p. 11) referred to an unpublished report by Lucien Easton, which 

stated that the ore occurs in shoots that 

strike N. 57° W., dip 30° SW., and are elongate in a S. 70° W., 30° SW., direction of 

plunge.

Surface float from the Cranberry deposit 

was mined as early as 1820 (Bayley, 1923, 

p. 98), but systematic mining did not begin 

until 1882 when a railroad was completed to 

Cranberry from Johnson City, Tenn. (Nitze, 

1893). In 1884 a small blast furnace capable 

of handling 40 tons of ore per day was built 

at Cranberry. After 1900 the ore was shipped 

to Johnson City where a 100-ton-per-day 

blast furnace had been built. From 1882 to 

1930, about l£ million tons of ore was produced (Kline and Ballard, 1948). During and 

after World War II the U.S. Bureau of Mines 

made a geophysical survey of the Cranberry 

iron belt, did some core drilling, and processed ore in a pilot plant (Kline and Ballard, 

1948). Since 1930 the mine has not been 

operated except during the Bureau of Mines' 

test, although in recent years some ore has 

been salvaged from dump material which has 

been crushed for gravel.

The Cranberry mine was worked by opencut; it was also worked underground on two 

levels by an adit and slopes from the upper 

level. The workings underlie an area about 

3,700 feet long and 700 feet wide (Kline and 

Ballard, 1948). Goldich and Wedow (1943) estimated that between450,000and 600,000tons 

of ore might be taken from the mine by robbing the pillars if the mine were abandoned 

in the process. They estimated that there 

might be 1 2 million tons of ore below the 

present mine workings. Kline and Ballard 

(1948, p. 85) believed that there are more 

ore shoots at Cranberry like those already 

mined, and possibly others elsewhere along 

the iron-bearing belt.

Other iron prospects in the Cranberry belt 

in the Grandfather Mountain area have had 

negligible production, and many are overgrown and difficult to locate. The U.S. Bureau of Mines conducted magnetometer surveys in the Fork Mountain area northwest of 

Newlandand along a strip from the Cranberry
MINERAL RESOURCES OF THE GRANDFATHER MOUNTAIN WINDOW AND VICINITY, NORTH CAROLINA

mine to the Tennessee Stateline. One magnetic anomaly was drilled about half a mile 

west of Elk Park; as much as 44.5 feet of ore 

having more than 30 percent total iron content over a length of 52.5 feet was found in 

one hole (Kline and Ballard, 1948), but the 

other drill holes suggest that ore of that 

thickness and grade is of limited extent to 

the depth of 250-440 feet tested.

The origin of the Cranberry deposits is 

not really known. Keith (1903), who recognized that replacement played an important 

role in their genesis, attributed the ironbearing solutions to the Bakersville Gabbro 

and suggested the Roan Gneiss (his name for 

the amphibolites) as a possible source of the 

iron. Bay ley (1923) thought that the iron deposits were formed by intrusion of magmas 

composed of (1) magnetitic pyroxene pegmatite, (2) pyroxene-magnetite, and (3) magnetite. He also thought that the material of these 

intr isives originated by differentiation from 

Precambrian or upper Precambrian mafic 

magmas.

Megascopic and microscopic textures (Bayley, 1923; Ross, 1935) show that the magnetite 

and iron-rich silicates replaced the wallrock probably during the plutonic metamorphism when the Cranberry Gneiss was 

formed because the ore is cut by pegmatite 

and because both the ore bodies and pegmatite were sheared and partly metamorphosed 

to low grade along the wallrock. The ore has 

zones which lack much cataclasis and retrogression. The lenses at. a whole may be 

largely tectonic in their present distribution 

and shape. The linear distribution of the 

mines and prospects in the Linville quadrangle and 6 miles west into Tennessee suggests that their present position is related to 

Paleozoic tectonism, for they are subparallel with the boundary between rocks of low 

and medium-grade Paleozoic metamorphism. 

This boundary may be major thrust fault of 

Paleozoic age. Neither the distribution nor 

any possible stratigraphic or tectonic control on the emplacement of the ore deposits 

before the pervasive shearing is known. Any 

theory for their origin would be highly specculative. Perhaps the deposits were derived 

by segregation of iron from amphibolites and 

schists when those rocks were converted to 

Cranberry Gneiss during the plutonic metamorphism.

In the northern part of the Linville quadrangle, near Big Ridge, phyllonite zones in

Cranberry Gneiss of the Blue Ridge thrust 

sheet contain magnetite, hematite, and small 

amounts of sphalerite. Concentrations of 

hematite with or without magnetite are abundant in phyllonite zones in the Cranberry 

Gneiss throughout its outcrop area," but they 

are generally less than 10 feet thick and 100 

feet long. Some of the concentrations have 

been explored.

Hematite is also locally concentrated in 

phyllonite in the Wilson Creek Gneiss near 

Tar Ridge in the Blowing Rock quadrangle. 

We located only one of the four prospects 

mentioned by Nitze (1893, p. 118-119).

TITANIUM

A deposit of ilmenite and magnetite in the 

Wilson Creek Gneiss near Richlands in the 

Blowing Rock quadrangle has been known for 

a long time (Kerr, 1875). Selected ore contained as much as 41.21 percent TiC>2, but the 

average was 14.90 percent TiO2 and 36.00 

percent metallic iron (Nitze, 1893). The deposit was mined from 1942 to 1952 by the 

Yadkin Valley Ilmenite Co., a subsidiary of 

the Glidden Co. About 230,000 tons of titanium concentrates was produced.

The ore body consists of a. series of narrow, closely spaced lenses forming a nearly 

continuous vein which is about 1,000 feet 

long, and which, as shown by core drilling, 

extends to a depth of about 200 feet. Mining 

was discontinued after soft ore near .the surface was removed.

The main part of the mine is an open pit 

50-100 feet deep and about 400 feet long. Its 

bottom is near the level of the Yadkin River. 

The ore body trended N. 15° E. and dipped 

25°-45° SE. The ilmenite and magnetite occur in a gangue of epidote, amphibole, chlorite, biotite, talc, and accessory pyrite. Talc 

and biotite form segregations. The deposit 

has sharp contacts with partly layered cataclastic gneiss. The foliation in the gangue 

material and the enclosing gneiss is parallel. 

The ore contains concordant wisps of more 

felsic gneiss 1 inch to 4 feet long and as 

much as 3 inches thick. Locally, thin stringers rich in ilmenite are found in the wallrock.

In thin section a specimen of gneiss, which 

was included in the ore and which resembles 

typical Wilson Creek Gneiss, contains crystals and fragments of crystals of plagioclase
METALLIC RESOURCES

altered to albite from the originally coarser 

grained granitic rock in a matrix of recrystallized albite, quartz, biotite, epidote, and 

chlorite.

The ore body parallels the regional structural trend of both Paleozoic and Precambrian structural and lithologic elements in 

this area of the Grandfather Mountain window. The ore apparently replaced the Wilson 

Creek Gneiss along a linear zone and is 

younger than the gneiss, which was emplaced 

1,000 1,100 million years ago (Davis and 

others, 1962). The ore has been sheared 

along with the country rock and is pre-late 

Plaeozoic in age. The iron and titanium may 

have been derived from preexisting rock and 

segregated during the plutonism, but their 

source is unknown.

A similar, but low-grade, ore body threequarters of a mile to the southeast was reported by Hunter and Gilder sleeve (1946, p. 

81). It consists of ilmenite mixed with chlorite and serpentine minerals, and is as much 

as 25 feet thick and 3/4 mile long.

URANIUM

There was considerable prospecting for 

uranium in the Grandfather Mountain area 

in the middle 1950*s, but no minable deposits 

were found. The areas of greatest activity 

were in the Wilson Creek Gneiss in the Linville Falls and Linville quadrangles and in 

the Cranberry Gneiss north of the window in 

the Linville quadrangle. Radioactive minerals were prospected in (1) heavy mineral 

partings rich in zircon in the clastic rocks 

of the Chilhowee Group in the tectonic slices 

north and west of the window and in arkoses 

of the Grandfather Mountain Formation within the window; (2) small pegmatites (mostly 

less than 10 ft in diameter) in Cranberry 

Gneiss, especially in pegmatites rich in biotite and quartz; and (3) strongly sheared and 

phyllonitic zones in the Wilson Creek Gneiss.

The most promising of the three occurrences is that in the Wilson Creek Gneiss. 

The principal prospects were on Ripshin 

Ridge near North Carolina Highway 181 in 

the Linville Falls quadrangle, north of the 

road between Edgemont and Pineola in the 

Linville quadrangle (the Little Lost Cove 

prospect), and on and near North Harper 

Creek at and north of the boundary between 

the Linville and Linville Falls quadrangles.

These prospects were stripped and trenched, 

and the North Harper Creek deposit was core 

drilled.

The most abundant uranium minerals occur in scattered uraninite-filled joints in 

sheared pegmatites in phyllonite zones. The 

joints commonly dip steeply and strike almost parallel to the regional northwesttrending mineral lineation in the wallrocks. 

The joints are poorly developed in the surrounding phyllonite and are sparsely mineralized or barren in the phyllonite (fig. 2). 

Secondary uranium minerals are disseminated in the phyllonites; but their distribution is spotty, and the phyllonite zones themselves are discontinuous.

The following information concerning 

claims on the Wilson Creek Gneiss is summarized from unpublished data compiled in 

1955 and 1956 by S. J. Meliherscik of E. J. 

Longyear Co.

The uranium-bearing mineral in the phyllonites is torbernite. Selected samples from 

phyllonites contained as much as 0.28 percent

/

/ Light-colored cata- \\\v '

gneiss containing \\\ 

pods of pegmatite

1 FOOT

Figure 2. Uraninite veinlets at the foot of Bard Falls on North 

Harper Creek, Linville quadrangle. View downdip of foliation.. 

Mineralized joints shown as heavy lines.
MINERAL RESOURCES OF THE GRANDFATHER MOUNTAIN WINDOW AND VICINITY. NORTH CAROLINA

The prospects in phyllonite on Ripshin 

Ridge and Little Lost Cove were explored by 

bulldozer cuts. At Ripshin Ridge the radioactive rock was destroyed by the first cut of 

the bulldozer, and no more could be located 

in a pit 20 by 100 by 15 feet. Bulldozing at 

the Little Lost Cove anomalies showed that 

there the phyllonite lacked horizontal and 

vertical continuity. The torbernite showings

were interpreted as resulting from nearsurface weathering and secondary enrichment of disseminated uraninite.

The best surface showing is at North 

Harper Creek just below Bard Falls (fig. 3). 

The average analysis of 6 samples cut at 

10-inch intervals across the showing was 

1.01 percent UaQj. These samples contained

36 "'00'

Strike and dip 

of foliation

Strike of vertical foliation

Radiometnc readings 

twice background

phyllonite

containing

torbenite and >j^" 

some uraninite OOH 7

S3f FT

tao FT

Uraninite in 

northwesttrending

quartz veins

disseminated 

uraninite

36°00'

Figure 3. Map of uranium prospects on North Harper Creek showing locations of diamond-drill holes and surface radiometric anomalies. 

Lengths of lines of drill hole represent approximate projection of hole to surface along foliation planes. Numbers indicate, in descending 

order, length of hole, thickness of pegmatite in hole, number of uraninite-bearing veins penetrated, and number of radiometric anomalies indicating 0.1 percent UjOg in first 500 feet of hole. From map by E. J. Long/ear Co.
METALLIC RESOURCES

a trace of gold, silver, and ThC>2, and about 

0.1 percent copper. Channel and chip samples over a 4-foot width in brecciated granitic rock in Shatley Fork averaged 0.23 percent U^O8. The country rock has a radioactivity 1.5 times background.

In addition to the obvious northwest-trending veinlets, some paper-thin veinlets of 

uraninite occur on shear planes parallel to 

the regional structure. Pyrite, pyrrhotite, 

and chalcopyrite are also found on thin seams 

parallel to the foliation. Uraninite is also 

disseminated in a pegmatite about 350 feet 

downstream from Bard Falls.

Seven holes, totaling 3,055 feet, were drilled 

inclined steeply to the northwest (fig. 2) in 

order to intersect the zones of more sheared 

rock and phyllonite, which are parallel with 

the regional structural trend. They intersected the pegmatites which occur as tectonic lenses in and parallel to the zones of 

phyllonite and strongly sheared gneiss and 

the very thin seams of uraninite which are 

parallel with the shear planes. However, as 

the prominent minerals in the surface showings are in veins trending northwest parallel 

with the drill holes, the principal uraniumbearing structures were not intersected. 

Ratioactive logging showed only a few anomalies exceeding 0.1 percent U3O&.

Drilling and detailed surface mapping indicated that it was difficult to draw contacts 

between phyllonite, sheared gneiss, and less 

sheared granitic rock. These subdivisions 

are not continuous along strike or downdip.

According to our interpretation, the uranium mineralization occurred during and immediately after the Paleozoic retrogressive 

metamorphism of the Wilson Creek Gneiss. 

The high background readings on that rock 

unit suggest that the showings formed by 

local mobilization of uranium during the 

metamorphism and concentration in shear 

zones in the gneiss and joints in the pegmatities, which formed relatively brittle competent lumps in the shear zones.

GOLD

A few small gold prospects and mines are 

found on quartz veins in the rocks of the 

Inner Piedmont. At the time of our survey 

these workings were either overgrown or inaccessible. According to Bryson (1936, p. 

136), the quartz veins of the South Mountain

region, including the southern part of the 

Grandfather Mountain area, are generally too 

small to be worked profitably for gold, and 

no vein in the South Mountain region has ever 

been worked on a large scale.

Many of the gold prospects are northeast 

of, and alined parallel to, the northwesttrending diabase dike in the Lenoir quadrangle. However, Nitze and Wilken (1897) reported that the quartz veins in several of the 

prospects strike N. 50°-60° E. and are 8-10 

inches thick, although in the Baker mine the 

vein strikes N. 35° -45° W. and is 2 5 feet 

thick. The prospects we saw are in the belt 

of polymetamorphic rocks adjacent to and 

southeast of the Brevard fault.

The most recent prospecting has been near 

the Miller and Scott Hill mines on Celia 

Creek in the Lenoir quadrangle. There the 

small growth on the dumps and the state of 

preservation of the headframe suggest that 

work has been done since 1936.

Keith (1903) reported that a quartz vein 

containing gold-bearing pyrite was mined on 

the north side of Grandfather Mountain in the 

Grandfather Mountain window in the Linville 

quadrangle and that similar veins were prospected on the east side of the mountain. Several of these old prospects, at which little or 

no work has been done in this century, were 

located in our survey. Most of the prospects 

are in sericite phyllite and phyllitic siltstone 

containing quartz veins and lenses and some 

pyrite. Two prospects are in phyllonitic 

gneiss on the ridge south of Bellows Creek 

in the Linville and Blowing Rock quadrangles.

Placer mining has yielded small amounts 

of gold on the Blue Ridge upland on Howard 

Creek in the Blowing Rock quadrangle and 

near Gragg in the Linville quadrangle (Keith, 

1903).

ZINC AND LEAD

Disseminated sphalerite associated with 

small amounts of cuprite, chalcopyrite, pyrite, and some secondary copper minerals is 

found in the Shady Dolomite of the Tablerock 

thrust sheet near Linville caverns in the Linville Falls quadrangle. The ore minerals 

with quartz and calcite occur in veinlets and 

irregular replacements in dolomite. One 

small prospect trench has been opened on the 

hillside, and in 1943 44, four holes were
8 MINERAL RESOURCES OF THE GRANDFATHER MOUNTAIN WINDOW AND VICINITY, NORTH CAROLINA

diamond drilled. No further exploration was 

done between that time and 1958.

Selected samples from old iron prospects 

in phyllonite zones in the Cranberry Gneiss 

on Big Ridge north of Beech Mountain in the 

Linville quadrangle contain interesting amounts of zinc. The zinc occurs in black 

sphalerite associated with sericite, magnetite, epidote, albite, fluorite, chlorite, quartz, 

and accessory apatite and carbonate. No 

significant amount of copper or lead accompanies the zinc (table 1). A brief examination of surface exposures and the prospects 

suggest that the sphalerite has a spotty distribution; no minable bodies were seen.

Analysis of a somewhat mineralized graphitic phyllonite, from a graphite prospect 

south of Dark Ridge Creek in the Cranberry 

Gneiss lying above the Mountain City window 

but below the Blue Ridge thrust sheet, revealed 0.1 percent zinc and no unusual 

amounts of Fb, Cu, or Ni.

Galena reportedly was mined on the ridge 

where Buckeye Creek turns east to join 

Beech Creek in the Linville quadrangle 

(Keith, 1903). A shaft was still visible in 

1957, but no lead minerals were found in the 

phyllonite on the dump.

Galena, in euhedral cubes as much as 5 mm 

across, and small amounts of chalcopyrite 

and sphalerite were found in a 25- to 30-foot - 

thick vein of granular quartz on the north 

side of Upper Creek in the Linville Falls 

quadrangle. The vein strikes northeastward 

parallel to the foliation of the enclosing 

schist and gneiss of the Piedmont. It is exposed in several prospect pits over a distance of 200 feet; but no recent work has 

been done, and the pits are slumped and

overgrown. Reportedly, the galena carries 

small quantities of silver.

Reports of the occurrence of native lead 

are widespread in the area, but no specific 

localities are mentioned. Such reports have 

a long history, for Elisha Mitchell (1905), 

who visited the area in 1828, heard them and 

recorded in his diary: "Such in substance is 

the account that I received in so many different places and from so many different 

persons that I am ready to knock down the 

man who shall tell the tale again."

MANGANESE

Botryoidal psilomelane, clayey pyrolusite, 

and ocherous wad occur in alluvial and colluvial clay which caps a small quartzite knob 

0.5 mile S. 20° W. of the village of North 

Cove (formerly Pitts Station) in the Linville 

Falls quadrangle. The clay contains lenses 

of gravel. D. A. Brobst (written commun., 

1960) estimated that the manganiferous clay 

is at least 30 feet thick and that it is covered 

by a soil mantle 5 10 feet thick. Some prospecting and development work was done on 

the deposit between 1943 and 1950, and several carloads of ore were shipped. All the 

opencuts and small adits described by Brobst 

were caved, and the workings were partly 

overgrown at the time of our visit in 1959.

Concentrations of manganese oxides a few 

inches thick are locally found in alluvium 

and fan deposits.

COPPER

The Montezuma Member of the Grandfather 

Mountain Formation contains copper minerals at scattered localities. Malachite is the 

copper mineral more commonly visible in

Table 1 Metal content, in percent, of selected specimens from iron prospects on Big Ridge, Linville quadrangle

[Spectrographic analysis by J. C. Hamilton. Results are reported in percent to the nearest number in the series 1, 0.7, 0.5, 0.3, 0.2, 0.15, and 0.1, etc., which represent approximate midpoints 

of group data on a geometric scale. The assigned group for semiquantitative results will include the quantitative value about 30 percent of the time. M, major constituent, > 10 percent]

Lab. 

No.

291880 __

291881 __

291882 __

Field 

No.

G-70-l-b

G-70-l-d

G-71-l-a

Fe

5.0

M

M

Ti

0.2

.05

.07

Cu

0.015

.05

.02

Ni

0.01

.0015

.0015

Pb

0.002

.005

.02

Zn

0

2.0

M

Description

Phyllonite containing pyrite.

Mineralized phyllonite.

Do.
NONMETALLIC RESOURCES

Table 2. Copper content of samples of Montezuma Member of the Grandfather Mountain Formation 

[Determined by colorimetric method by Dwight L. Skinner]

Lab. no.

271275 ____

271276 __ ._

271277 ____

271278 ____

Field no.

RE-71-1 __

AC-14-1 ___

H-5-3-e ___

H-5-5 ____

Source

Outcrop . ... .. 

Prospect; no obvious evidence of copper minerals in

specimen. 

Outcrop; evidence of copper mineralization nearby ____ ..

Cu 

(ppm)

10

16

38

88

hand specimen; it occurs in amygdules, along 

fractures, and in epidote segregations. Azurite also occurs but is less abundant. No extensive area of mineralized rock of ore 

grade has yet been found. Analyses (table 2) 

show that the copper content of the Montezuma Member is very low, even in areas 

containing visible copper minerals. Several 

prospects were found in the upper part of the 

valley of Pigeonroost Creek in the Linville 

quadrangle.

NONMETALLIC RESOURCES

MICA AND FELDSPAR

Both sheet and scrap muscovite has been 

obtained from the granodiorite pegmatites of 

the Blue Ridge thrust sheet in the Grandfather Mountain area. Most of the production 

has come from the southwestern part of the 

Linville quadrangle and the northwestern 

part of the Linville Falls quadrangle. This 

area is part of the Spruce Pine pegmatite 

district. Most of the productive pegmatites 

occur in the mica schist and gneiss unit, 

some in the amphibolite, a few in the granodiorite, and a very few in the unit of mixed 

rocks. No pegmatites containing commercial 

muscovite have been found in the Cranberry 

Gneiss.

Some mica has been produced from pegmatites in mica schist and gneiss north of 

Boone in the Blowing Rock quadrangle. The 

prospects near Deep Gap do not appear to 

have been very productive. A few mica prospects and one mine reportedly are in rocks 

of the Blue Ridge thrust sheet southeast of 

the window in the Blowing Rock quadrangle, 

but we did not visit them.

Various mines in the Grandfather Mountain 

area have been described (Sterrett, 1923; 

Kesler and Olson, 1942; Olson, 1944; F. G.

Lesure, written commun., 1964), and the 

economic geology of the pegmatites has been 

summarized (Brobst, 1962).

Most of the pegmatites form peneconcordant lenses and pods, the largest a few hundred feet long and several tens of feet thick. 

Many small ones have been completely removed by mining. Most of the pegmatites 

lack conspicuous zoning, although a few have 

quartz cores. The smaller pegmatites have 

conspicuous cataclastic textures, and their 

muscovite books are bent and ruled; yet 

commercial mica has been produced from 

some foliated pegmatites only a few feet 

thick. The pegmatites in the Blue Ridge 

thrust sheet southeast of the window are on 

the average more strongly deformed than 

elsewhere, and the largest muscovite we saw 

there was about 3 inches in diameter.

Scrap mica is obtained as a byproduct of 

kaolin mining in the northwestern part of the 

Linville Falls quadrangle.

Feldspar is commonly recovered as a byproduct of the mica mines, but in some 

mines it is more valuable than the mica. The 

prospects and small mines in the mixed unit 

on Bellevue Mountain in the Linville quadrangle appear to have produced only feldspar. These pegmatites are rich in biotite' 

and poor in muscovite, and the micas are 

very deformed. A small amount of feldspar 

has been produced from pegmatites in the 

Cranberry Gneiss.

The value of sheet mica production fluctuates, depending upon the demand and on the 

encouragement given by the U.S. Government 

through its lending and buying policies. For 

instance, Avery County produced about 

$186,000 worth of sheet mica in 1958 under 

Government support (Vallely and others, 1959),
10 MINERAL RESOURCES OF THE GRANDFATHER MOUNTAIN WINDOW AND VICINITY. NORTH CAROLINA

but only $9,850 worth in 1962 after support 

was withdrawn (Beck and others, 1963).

The reserves of sheet mica in the Spruce 

Pine district probably are at least equal to 

the production to date, according to Brobst 

(1962, p. 19).

KAOLIN

Kaolin is mined from light-colored muscovite granodiorite saprolite along the north 

side of Brushy Creek in the northwestern 

part of the Linville Falls quadrangle. The 

deposits were opened in 1937, and several 

large open-pit mines are currently being 

operated. Scrap muscovite is recovered as 

a byproduct. Smaller deposits on the north 

side of Threemile Creek (Parker, 1946), at 

the west margin of the Linville Falls quadrangle, had not yet been mined in the quadrangle at the time of our mapping (1957).

Twelve samples from the Gusher Knob deposit (just outside the Linville Falls quadrangle north of Threemile Creek) contained 

an average of about 24 percent quartz, 16 

percent mica, 0.5 percent feldspar, 47 percent hydrated halloysite, and 12 percent kaolin (Sand, 1956). The hydrated halloysite is 

derived from feldspar and the kaolin from 

muscovite.

The kaolin is as much as 60 feet thick and 

is overlain in part by terrace gravels averaging 16 feet in thickness and in part by 

residual soil and stained kaolin averaging 6 

feet in thickness (Parker, 1946). The deposits have been formed by deep weathering of 

the light-colored granodiorite, which almost 

lacks mafic minerals. The deep weathering 

took place on broad valley floors, the bottoms of which now stand as gravel-covered 

terraces as much as 100 feet above the 

present streams. Commercial kaolin is found 

as high as 250 feet above Brushy Creek on 

relatively gently sloping valley sides (Parker, 1946).

Reserves in 1942 were estimated by Parker (1946) to be l| 3 million tons in the 

Brushy Creek deposits and % l^ million tons 

in the deposits north of Threemile Creek 

(Gusher Knob deposits). No records of production or estimates of current reserves are 

available.

A possible additional source of kaolin in 

the Grandfather Mountain area is near Deep 

Gap in the northeast corner of the Blowing 

Rock quadrangle. The rocks on the gentle 

slopes near Gap Creek appear to be deeply 

weathered and to contain numerous bodies of 

pegmatite and granitic rock, some of which 

are plagioclase rich and lack mafic minerals. Judged from exposures in the Stony 

Fork drainage, whatever bodies of kaolin are 

found would be relatively small compared to 

those in the Brushy Creek area and would 

have a width of only several tens of feet.

ASBESTOS

Small amounts of anthophyllite astfestos 

have been mined from ultramafic rocks in 

the Blue Ridge thrust sheet and the Inner 

Piedmont in the Grandfather Mountain area.

In 1957, just west of Cow Camp Gap in the 

Linville quadrangle, an ultramafic body 320 

feet long and 60 feet wide was being mined 

for anthophyllite asbestos. The fibers commonly are | 1 inch long, and some are as 

much as 4 inches. Most are slip fibers and 

are parallel to the fabric of the rock. Some 

veins of cross fibers, which are perpendicular to walls of veins, transect the mass; 

these veins are as much as 2 inches thick. 

The ultramafic body appears to be concordant with the amphibolite and hornblende 

gneiss which forms the wallrock. Talc is 

common at the margin of the body.

Other small ultramafic bodies on the south 

side of Hawshore Mountain and south of 

Hughes in the Linville quadrangle have been 

prospected unsuccessfully for commercial 

anthophyllite. Asbestos prospects on Snakeden Mountain in the Blowing Rock quadrangle appear to be much older because the pits 

are overgrown.

The prospect on Camp Branch in the northeastern Blowing Rock quadrangle contains 

veinlets of asbestiform tremolite with fibers 

several inches long parallel to the veins and 

one-fourth inch long perpendicular to the 

veins.

In the Inner Piedmont one small anthophyllite asbestos mine has been worked northeast 

of the junction of the Johns River and Wilson 

Creek in the Lenoir quadrangle. There the
NONMETALLIC RESOURCES 11

asbestos occurs in veins about 1 foot thick in 

a dunite which has been entirely serpentinized in its interior and converted to talc 

schist at its margins.

The mines near Cow Camp Gap and the 

Johns River have been more fully described 

by Conrad and others (1963, p. 21-22,42-44).

ROAD METAL

Road metal has been quarried from many 

different rock units throughout the Grandfather Mountain area. The largest active 

quarries in 1961 were in the Shady Dolomite 

at Woodlawn in the Little Switzerland quadrangle and in migmatitic gneiss at the 

Causby quarry in the southwestern part of 

the Lenoir quadrangle. The quarry at Woodlawn, which was operated by the State Highway Department, and an inactive one in Shady 

Dolomite at Ashford were described by 

Conrad (1960).

SAND AND GRAVEL

Sand and gravel is obtained from stream 

beds and flood plains at various localities 

throughout the area. Although many of the 

operations last only a few months in one 

place, they have been noted on the quadrangle 

maps where they were in progress at the 

time of mapping or had been recently completed.

The coarser grained deposits containing 

the fewest fragments of weathered rock are 

found in streams draining quartzite or arkose. Such deposits have been exploited at 

the head of the Watauga River and along the 

Linville River just west of the gorge through 

the Tablerock thrust sheet in the Linville 

quadrangle (where the deposits are as much 

as 15 ft thick) and along the Linville River 

and Paddy Creek in the Linville Falls quadrangle. In the pits on Paddy Creek and the 

Linville River in the Linville Falls quadrangle, the gravel is poorly sorted and consists 

of rounded pebbles to boulders of quartzite 1 

inch to 3 feet in diameter in a matrix of gray 

sandy clay. The deposit ranges in thickness 

from 4 to 10 feet and rests on bedrock. It is 

overlain by 2 5 feet of gray-yellow or brown 

sandy clay containing scattered pebbles and 

cobbles; the clay, in turn, is overlain by 

brown organic soil.

Most of the larger streams draining the 

steep southeast-facing margin of the Blue 

Ridge have considerable fresh sand and gravel in their alluvial deposits. In 1961, gravel 

operations at the junction of Buffalo Creek 

with the Yadkin River in the southeast corner 

of the Blowing Rock quadrangle exposed 

above water level 6 10 feet of sand, gravel, 

carbonaceous sand, and clay. Sand is the 

dominant material. The gravel consists 

mainly of pebbles and cobbles, and it has a 

maximum grain size of 1 foot.

Sand is obtained from the bed of the Catawba River near Morgantown.

Plentiful supplies of sand and gravel remain to be exploited on the flood plains of the 

major streams, such as Wilson Creek, the 

Johns River, Buffalo Creek, and Elk Creek. 

In 1962, sand and gravel was probably the 

most valuable commodity produced in the 

Grandfather Mountain area. Production for 

that year was valued at $122,000 in Watauga 

County and $208,000 in Burke County (Beck 

and others, 1963).

BUILDING STONE

In the Grandfather Mountain area, building 

stone is obtained principally from the meta-^ 

morphosed sedimentary rocks of the Grandfather Mountain window. The most actively 

worked quarries are in the lowest arkose of 

the Grandfather Mountain Formation south 

and east of Grandfather Mountain in the Linville quadrangle. The arkose most used for 

building is medium grained, light greenish 

gray, has cleavage parallel with bedding, and 

is known as "Grandfather Stone." Council 

(1955) described the quarries on the road 

between U.S. Highway 221 and Gragg, and 

also the Green and Taylor quarry east of 

Linville. Other small quarries are found in 

the arkose unit north of Foscoe in the Linville quadrangle and north and east of Shulls 

Mills in the Blowing Rock quadrangle.

Slices of Chilhowee quartzite which are 

quarried for building stone are along the 

Linville Falls fault in the Linville Falls 

quadrangle near North Carolina Highway 181 

(Causby and Dula quarries of Council, 1955), 

on U.S. Highway 221 at the south edge of the 

Little Switzerland quadrangle (Woodlawn 

[Teastor] quarry of Council, 1955), and at
12 MINERAL RESOURCES OF THE GRANDFATHER MOUNTAIN WINDOW AND VICINITY. NORTH CAROLINA

other places in that vicinity. The quartzite 

in these quarries is light gray to light greenish gray and has bedding parallel with cleavage.

On Timber Ridge in the northwestern part 

of the Linville quadrangle a well-foliated 

medium-grained phase of the Beech Granite 

is quarried for building stone.

Along the Blue Ridge Parkway, Blowing 

Rock Gneiss was quarried for bridge construction. The inactive quarry in this unit 

near Spruce Knob was a building stone quarry 

rather than a road-metal quarry, as was 

shown on the Blowing Rock quadrangle map. 

This quarry was the source for the bridge 

materials.

North of Rock View Church on Elk Creek 

in the northeastern part of the Blowing Rock 

quadrangle, a layer of coarse-grained uniform well-jointed cataclastic biotite-quartz 

monzonite gneiss, at least 30 feet thick, is 

quarried for building stone.

East of Turkey Knob in the Blowing Rock 

quadrangle, soapstone was quarried from an 

ultramafic body.

OTHER COMMODITIES

Graphitic phyllonite has been prospected 

for graphite, but none of the deposits is of 

sufficient grade or tonnage to be considered 

minable.

Quartz crystals have been found in the 

Blue Ridge thrust sheet in the southwestern 

part of the Linville quadrangle, but few of 

them are salable for manufacture of oscillator plates (Mertie, 1959, p. 281). The better 

ones have value as specimens. Well-shaped 

but small crystals are also found locally in 

some veins in the rocks of the Grandfather 

Mountain Formation in the Linville quadrangle.

Small amounts of pure silica might be obtained near the Bradshaw School in the Blowing Rock quadrangle where a lens of almost 

pure white granular quartzite 10 30 feet 

thick and at least 500 feet long is found in 

Wilson Creek Gneiss. Similar but mostly 

less pure quartz bodies are found on White 

Rock Ridge.

In a study of high-silica materials in 

North Carolina, Broadhurst (1949) listed 

analyses of the upper quartzite of the Chilhowee Group in the Tablerock thrust sheet 

that range, in percent, from 96.7 to 91.0 

SiCfc; 2.7 to 7.2 AlaOa; and 0.12 to 0.27 

Fe2 Oa. He pointed out that A12 OQ content 

should be less than 0.5 percent in material 

for silica refractory industries.

The sillimanite schist unit in the southeastern part of the Lenoir quadrangle was 

investigated by Hash and Van Horn (1951) as 

a potential source of refractory material. In 

the laboratory they were unable to make a 

satisfactory concentrate of marketable grain 

size.

Agricultural lime has been quarried from 

the Shady Dolomite in the North Cove area 

in the Linville Falls quadrangle (Conrad, 

1960). It is somewhat impure to be ideal for 

many industrial uses, but geographic location in relation to the industry needing dolomite is usually of prime importance in determining the economic potential of a dolomite deposit. Partial analyses of the Shady 

show the following ranges, in percent: MgO, 

10-21; CaO, 27-31; ignition loss, 41-46; Fe, 

0.25-0.6; and acid insoluble 0.7 8.6 (Hunter 

and Gildersleeve, 1946, p. 27-28). Complete 

analyses show the following ranges, in percent: SiO2 , 0.60-5.96; A12 O3 , 0.60-1.76; 

Fe2 C>3, 0.49-0.73; CaO, 29.13-30.93; MgO, 

19.56-21.22; K2 O, 0.26-0.41; PgOfe, 0.01-0.02; 

and COa, 40.07 47.10 (Loughlin and others, 

1921).

REFERENCES

Bayley, W. S., 1923, The magnetic iron ores 

of east Tennessee and we stern North Carolina: Tennessee Div. Geology Bull. 29, 252 p.

Beck, W.A.,Stuckey, J. L., and Rivers, M. E. 

1963, The mineral industry of'North Carolina: U.S. Bur. Mines 1962 Minerals Yearbook, v. 3, p. 775-794.

Broadhurst, S. D., 1949, A general survey of 

some high silica materials in North Carolina: North Carolina Dept. Conserv., Div. 

Mineral Resources Inf. Circ. 7, 30 p.

____1955, The mining industry in North 

Carolina from 1946 through 1953: North 

Carolina Dept. Conserv. Devel., Div Mineral Resources Econ. Paper 66, 99 p.
REFERENCES 13

Brobst, D. A., 1962, Geology of the Spruce 

Pine district, Avery, Mitchell, and Yancey 

Counties, North Carolina: U.S. Geol. Survey 

Bull. 1122-A, 26 p.

Bryant, Bruce, 1962, Geology of the Linville 

quadrangle, North Carolina-Tennessee A 

preliminary report: U.S. Geol. Survey Bull. 

1121-D, p. D1-D30.

____1963, Geology of the Blowing Rock quadrangle, North Carolina: U.S. Geol. Survey 

Geol. Quad. Map GQ-243.

____1965, Geology of the Linville quadrangle, North Carolina-Tennessee: U.S. 

Geol. Survey Geol. Quad. Map GQ-364.

Bryson, H. J., 1936, Gold deposits in North 

Carolina: North Carolina Dept. Conserv. 

Devel. Bull. 38, 157 p.

Conrad, S. G., 1960, Crystalline limestone of 

the Piedmont and Mountain regions of North 

Carolina: North Carolina Dept. Conserv. 

Devel., Div. Mineral Resources Bull. 74, 

56 p.

Conrad, S. G., Wilson, .W. F., Alien, E. P. and 

Wright, T. J., 1963, Anthophyllite asbestos 

in North Carolina: North Carolina Dept. 

Conserv. Devel., Div. Mineral Resources 

Bull. 77, 61 p.

Council, R. J., 1955, Petrography and economic aspects of the miscellaneous commercial rocks of North Carolina: North 

Carolina Dept. Conserv. Devel. Inf. Circ. 

13, 26 p.

Davis, G. L., Tilton, G. R., and Wetherill, 

G. W., 1962, Mineral ages from the Appalachian Province, North Carolina and Tennessee: Jour. Geophys. Research, v. 67, 

p. 1987-1996.

Goldich, S.S., and Wedow, Helmuth, Jr., 1943, 

Preliminary report on the magnetic iron 

ores of western North Carolina and eastern 

Tennessee: U.S. Geol. Survey open-file 

report.

Hash, L. J., and Van Horn, E. C. 1951, Sillimanite deposits in North Carolina: North 

Carolina Dept. Conserv. Devel., Div. Mineral resources Bull. 61, 52 p.

Hunter, C. E., and Gildersleeve, Benjamin, 

1946, Minerals and structural materials of 

western North Carolina and north Georgia: 

Tennessee Valley Authority Report C, 94 p.

Keith, Arthur, 1903, Description of the Cranberry quadrangle [North Carolina-Tennessee]: U.S. Geol. Survey Geol. Atlas, Folio 

90, 9 p.

Kerr, W. C., 1875, Report of the geological 

survey of North Carolina; v. 1, Physical 

geography, resume', economical geology: 

North Carolina Geol. Survey, 325 p., map.

Kesler, T. L., and Olson, J. C., 1942, Muscovite in the Spruce Pine district. North

Carolina: U.S. Geol. Survey Bull. 936 -A,

p. 1-38. 

Kline, M. H., and Ballard, T. J., 1948, Cranberry magnetite deposits, Avery County,

North Carolina, and Carter County, Tennessee: U.S. Bur. Mines Kept. Inv. 4274,

85 p. 

Loughlin, G. F., Berry, E. W., and Cushman,

J. A.,1921,Limestones and marls of North

Carolina: North Carolina Geol. and Econ.

Survey Bull. 28, 211 p. 

Mertie, J. B., Jr., 1959, Quartz crystal deposits of southwestern Virginia and western

North Carolina: U.S. Geol. Survey Bull.

1072-D, p. 233-298. 

Mitchell, Elisha, 1905, Diary of a geological

tour in 1827 and 1828: North Carolina

Univ. James Sprunt Hist. Mon. 6, 73 p. 

Nitze, H. B. C., 1893, Iron ores of North Carolina: North Carolina Geol. Survey Bull.

1, 239 p. 

Nitze, H. B. C., and Wilkins, H. A. J., 1897,

Gold mining in North Carolina and adjacent

south Appalachian regions: North Carolina

Geol. Survey Bull. 10, 164 p. 

Olson, J. C., 1944, Economic geology of the

Spruce Pine pegmatite district, North

Carolina: North Carolina Dept. Conserv.

Devel., Div. Mineral Resources Bull. 43,

67 p. 

Parker, J. M., lEt, 1946, Residual kaolin deposits of the Spruce Pine district, North

Carolina: North Carolina Dept. Conserv.

Devel., Div. Resources Bull. 48, 45 p. 

Reed, J. C., Jr., 1946a, Geology of the Lenoir

quadrangle, North Carolina: U. S. Geol. Survey Geol. Quad. Map GQ-242. 

_____ 1964b, Geology of the Linville Falls

quadrangle, North Carolina: U.S. Geol. Survey Bull. 1161-B, p. B1-B53. 

Reed, J.C., Jr., and Bryant, Bruce, 1964, Geologic map of part of the Grandfather Mountain window, North Carolina, Sheet 2 Southwestern extension of the window: U.S. Geol.

Survey open -file map. 

Ross, C. S., 1935, Origin of the copper deposits of the Ducktown type in the southern

Appalachian region: U.S. Geol. Survey Prof.

Paper 179, 165 p. 

Sand, L. B., 1956, On the genesis of residual

kaolins: Am. Mineralogist, v. 41, p. 28 40. 

Sterrett, D. B., 1923, Mica deposits of the

United States: U.S. Geol. Survey Bull.

740, 342 p. 

Vallely, J. L., Stuckey, J. L., and Rivers,

M. E., 1959, The mineral industry of North

Carolina: U.S. Bur. Mines 1958 Minerals

Yearbook, v. 3, p. 681-699.

U.S. GOVERNMENT PRINTING OFFICE : I9«7 O 256-885