Niobium (Columbium) 

and Titanium at Magnet 

Cove and Potash Sulphur 

Springs, Arkansas

GEOLOGICAL SURVEY BULLETIN 1015-B

Niobium (Columbium) 

and Titanium at Magnet 

Cove and Potash Sulphur 

Springs, Arkansas

By V. C. FRYKLUND, JR., R. S. HARNER, and E. P. KAISER

A CONTRIBUTION TO ECONOMIC GEOLOGY

GEOLOGICAL SURVEY BULLETIN 1015-B

Description of deposits and results 

of analyses

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON ; 1954
UNITED STATES DEPARTMENT OF THE INTERIOR 

Douglas McKay, Secretary

GEOLOGICAL SURVEY 

W. E. Wrather, Director

For sale by the Superintendent of Documents, U. S. Government Printing Office 

Washington 25, D. C. - Price 35 cents (paper cover)
CONTENTS

Pag*

Abstract_________________________________________________________ 23

Introduction. _____________________________________________________ 24

Location and general geologic features__________________________ 24

Previous work_______________________________________________ 25

Present work__________________________________________________ 26

Acknowledgments _____________________________________________ 26

Method of spectrographic analysis.______________________________ 26

Magnet Cove area-_-_-_-___----_-___-__--_-_______-______-____--__ 28

Description of titanium-niobium deposits _________________________ 28

General. _____________________________________________ 28

Magnet Cove Titanium Corporation rutile deposit-.___________ 29

Christy brookite deposit----__-____-_____-_-____-_-_______-_ 34

Kilpatrick brookite deposits_______________________________ 38

Mo-Ti Corporation property._______________________________ 39

Description of calcite rock bodies...__.____.____-__-__._________. 43

General._________________________________________________ 43

Kimsey calcite quarry area.________________________________ 44

Origin of the calcite rocks - _________________________________ 49

Economic factors-___-___---_---__-__________-___________-_-___ 49

Rutile and brookite deposits._______________________________ 49

Other possible sources of titanium and niobium______________ 50

Potash Sulphur Springs area._-_-__________-_____--___-_--__-_-_--__ 51

Location and previous work___________________________________ 51

Geologic relations.___________________________________________ 51

Sampling and analysis_______-________________-__--_____________ 53

Conclusions.--.-.___________________________________________ 54

Literature cited.__________________________________________________ 55

Index...._____________________________________________________ 57

ILLUSTEATIONS

PLATE 6. Topographic map of Magnet Cove, Hot Spring County, Ark___In pocket

Pag* 

FIGURE 2. Location map, Magnet Cove and Potash Sulphur Springs____ 24

3. Geologic map of the Magnet Cove Titanium Corp. deposit____ 30

4. Correlation of niobium and TiO2 , Magnet Cove Titanium

Corp. deposit.__-_-____-______-_-_____-_-_---_-__--__- 34

5. Geologic map of the Christy deposit_______________________ 36

6. Correlation of niobium and TiO2 , Christy deposit..-.________ 38

7. Geologic map of the Kilpatrick deposits.___________________ 40

8. Correlation of niobium and TiO2 , Kilpatrick deposits.________ 41

9. Geologic map of the Kimsey quarry______________________ 45

10. East part of the Kimsey quarry___________________________ 46

11. Correlation of niobium and TiO2 , Kimsey quarry. ___________ 47

12. Geologic map of the Wilson prospect-__-_-_-__----_-__-____ 52

in
IV CONTENTS

TABLES

Page

TABLE 1. Characteristic minerals of the igneous rocks, Magnet Cove

Titanium Corp. property, Magnet Cove, Ark______________ 31

2. Primary constituents of veins in the Magnet Cove Titanium

Corp. deposit_________________________________________ 31

3. Analyses of samples from the Magnet Cove Titanium Corp.

property, Magnet Cove________________________________ 32

4. Analyses of rutile crystals and rutile concentrates from the

Magnet Cove Titanium Corp. property, Magnet Cove_____ 33

5. Analyses of samples from the Christy property, Magnet Cove__ 37

6. Analyses of brookite crystals and composite samples of brookite

from the Christy property, Magnet Cove_________________ 39

7. Analyses of samples from the Kilpatrick property, Magnet

Cove_____ ___-__ --------__-__ 42

8. Analyses of channel samples from the Kimsey calcite quarry,

Magnet Cove-_____-----___--------------------------- 47

9. Analyses of single crystals from Magnet Cove_____________ 48

10. Summary of analytical data from the principal titanium deposits at Magnet Cove_______-_-_-------___----__------ 49

11. Analyses of samples from the Wilson prospect, Potash Sulphur

Springs_____________________________________________ 53

12. Analyses of samples of cuttings from churn-drill hole CH-1,

Wilson prospect, Potash Sulphur Springs _________________ 54
A CONTRIBUTION TO ECONOMIC GEOLOGY

NIOBIUM (COLUMBIUM) AND TITANIUM AT MAGNET 

COVE AND POTASH SULPHUR SPRINGS, ARKANSAS

By V. C. FRYKLUND, Jr., R. S. HARNER, and E. P. KAISER

ABSTRACT

Niobium (columbiuni) and titanium occur in several minerals and rocks of the 

Magnet Cove and Potash Sulphur Springs areas. Niobium is in demand for use 

in high-temperature and noncreep steels; titanium metal is becoming an important structural material.

The Magnet Cove and Potash Sulphur Springs areas are in central Arkansas 

between the communities of Malvern and Hot Springs. They are underlain by 

similar alkalic igneous complexes consisting of nepheline syemite, more basic 

alkalic rocks, and calcite rock or carbonatite. The igneous rocks transect sedimentary rocks of Paleozoic age and were truncated by erosion of Late Cretaceous 

age.

At Magnet Cove, deposits of rutile (TiO2 ) occur within the igneous complex, 

and deposits of brookite (TiO2 ) occur in quartzite of the Arkansas novaculite of 

Devonian and Mississippian age near the margin of the complex. Perovskite 

(CaTiOs) occurs in several places in the igneous complex.

Analyses of drill core and channel samples show that the larger titanium deposits contain 3 to 6 percent TiO2 in recoverable form. The Nb/TiO2 ratios in 

these samples are sufficiently constant to allow a fairly accurate calculation of 

the percentage of niobium from the percentage of titania. Concentrates of rutile 

and brookite average 1.2 and 2.0 percent niobium respectively. Single crystals of 

these minerals are surprisingly variable in their content of niobium. Brookite 

crystals contain from 0.8 to 9.6 percent niobium; rutile crystals contain from 0.0 

to 1.7 percent niobium. The vanadium content varies greatly, both in core and 

channel samples and in individual crystals of titanium minerals, and shows no 

correlation with the niobium content.

Drill cores of perovskite-bearing magnetite-pyroxene rocks at the Mo-Ti Corp. 

property contain 0.03 to 0.04 percent niobium.

The Kimsey calcite quarry area was mapped, and channel samples were analyzed and found to contain about 0.01 percent niobium. The niobium content of 

single crystals of perovskite from this area ranges from 5.1 to 8.8 percent. Rare 

earths of the lanthanum group occur in the apatite and calcite of the area.

Analyses of channel samples from the trenches in the Wilson prospect at 

Potash Sulphur Springs show 0.1 to 0.9 percent niobium.

23
24 CONTRIBUTIONS TO ECONOMIC GEOLOGY

INTRODUCTION 

LOCATION AND GENERAL GEOLOGIC FEATURES

Magnet Cove is a shallow topographic basin about 3 miles in diameter near the center of Arkansas in Hot Spring County (see fig. 2). 

It is 12 miles east of Hot Springs and 7 miles northwest of Malvern. 

U. S. Highway 270 passes through the center of the cove. The Hot 

Springs branch of the Chicago, Eock Island, and Pacific Eailroad 

skirts the southern edge of the cove. The Potash Sulphur Springs 

area is about 6 miles west of Magnet Cove.

\ "

\

GARLAND .- 

COUNTY I

Hot Springs

@ Little Rock 

POTASH SULPHUR SPRINGS

0 *Zr-^-r-MAGt/er COVE

o f'-' 

HOT SPRING """"" 

COUNTY

FIGDBH 2. Map showing location of Magnet Cove and Potash Sulphur Springs, Ark.

The Magnet Cove and Potash Sulphur Springs areas are underlain 

by igneous rocks which have intruded folded sedimentary rocks of 

Paleozoic age, ranging from Silurian to Mississippian. The sedimentary and igneous rocks were truncated by erosion of Late Cretaceous age and then covered in Late Cretaceous and Tertiary time by 

sediments of the Coastal Plain. The Coastal Plain sedimentary rocks 

crop out a few miles to the south of Magnet Cove.

The igneous rocks are unusually rich in sodium and titanium; they 

are part of an alkalic igneous province extending from the syenites in
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 25

the vicinity of Little Rock and Bauxite, Ark., to Magnet Cove and 

Potash Sulphur Springs. The diamond-bearing peridotites and 

associated rocks of Pike County, Ark., which are relatively rich in 

titanium, are part of this province.

The Magnet Cove rocks, and those of the smaller complex at Potash 

Sulphur Springs, consist chiefly of varieties of nepheline syenite and 

related rocks. They also include rocks of doubtful origin that consist chiefly of calcite; rocks of this type are sometimes called carbonatites. The Magnet Cove and Potash Sulphur Springs rocks thus 

are similar to the rocks in several other alkalic complexes that also 

contain nepheline-bearing rocks in association with calcite rock or 

carbonatite, as in Colorado, Norway, Germany, South Africa, and 

other places. Abundant titanium is a common feature of these complexes ; relatively abundant niobium is characteristic of many of them. 

The calcite rocks associated with these complexes have been interpreted as blocks of sedimentary carbonate, but in the last few years 

they have more commonly been described as material introduced by 

either hydrothermal or intrusive action.

Associated with the Magnet Cove complex are deposits of rutile and 

brookite, which contain not only titanium but also niobium. Rocks 

containing niobium and uranium have been found at Potash Sulphur 

Springs, but little is known of the occurrence of these elements in that 

area.

The element niobium (columbium) is in demand for use in hightemperature and noncreep steels. It is commonly referred to as 

columbium in commerce and in older American technical literature, 

and as niobium in foreign and recent American technical literature. 

Titanium is in demand for use as TiO2 in pigments, and as titanium 

metal in structural forms. Rutile (TiO2 ) is used in welding-rod coatings.

PREVIOUS WORK

The Magnet Cove and Potash Sulphur Springs areas were first described in detail by Williams (1891) whose monograph on the igneous 

rocks of Arkansas still remains a classic of geologic literature. Additional petrographic data were contributed by Washington (1900, 

1901) and more recently by Landes (1931) and Ross (1941). Williams described the various rare and unusual rocks and minerals in 

detail and presented chemical analyses. The presence of niobium in 

perovskite (dysanalite) was first reported by Mar (1890, p. 403).

Little geologic work was done on the rutile and brookite deposits 

until the work of Holbrook (1947) and Fryklund and Holbrook 

(1950), which depended in part on data made available by test pitting 

and by Bureau of Mines drilling (Reed, 1949a, b). This work has 

established the nature and approximate grade of the rutile and 

brookite deposits.
26 CONTRIBUTIONS TO ECONOMIC GEOLOGY

PRESENT WORK

As part of the U. S. Geological Survey's program of studying 

niobium resources, the rutile, brookite, and perovskite areas at Magnet Cove were studied, sampled, and in part mapped, in order to 

determine the approximate abundance and habit of the niobium. 

The Wilson prospect at Potash Sulphur Springs was also mapped 

and sampled. This work was done during February and March 

1952, by V. C. Fryklund, Jr., H. L. Sobel, and E. P. Kaiser. Splits 

of samples from drill cores were obtained from the U. S. Bureau of 

Mines station at Eolla, Mo.; splits of channel samples from pits were 

obtained from the Division of Geology, Arkansas Resources and 

Development Commission. Spectrographic analyses were made by 

B,. S. Harner, K. J. Murata, and R. G. Havens.

ACKNOWLEDGMENTS

The writers are indebted to the U. S. Bureau of Mines for a number 

of drill-hole samples of the Magnet Cove Titanium Corp. area and 

the Christy brookite property; to N. F. Williams, director of the 

Division of Geology, Arkansas Resources and Development Commission, for splits of samples taken by Fryklund on the Kilpatrick 

brookite property, for the use of a power auger, and for many other 

courtesies; and to Wynne Christy for samples from the Christy 

brookite property. It is a pleasure also to acknowledge the help of 

J. W. Kimsey and Lawton Kimsey of Magnet Cove. Part of the cost 

of this investigation was supported by funds for the columbium program from the Defense Minerals Procurement Agency.

METHODS OP SPECTROGRAPHIC ANALYSIS

The Spectrographic analyses were made under the following conditions :

Excitation: Ballasted d-e arc of 250 volts, run at 15.5 amperes. Arc 

gap maintained at 3.5 mm throughout the burning period. Arc image focussed on the collimator lens which 

was diaphragmed to permit only light from the central 

2 mm of the arc column to pass through the prism. A 

rotating sector, set at 20 percent transmission, was used 

to reduce light intensity.

Spectrograph : A large quartz prism instrument of the Littrow type. The 

region from 2520 to 3575 A was photographed.

Electrodes: High-purity graphite rod, ^-in. diameter, with thin-walled 

cavity as described by Myers (1951), used as the anode; 

a %-in. high-purity graphite rod used as the cathode.

Plate: Eastman III-O, developed at 20° C for 5 minutes in DK-50 

developer.
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 27

Plate calibration: Method of Dieke and Crosswhite (1943). Iron lines present in spectra of a quartz-microcliue mixture containing 

1 percent Fe2Oa were used.

Microphotometer: Projection comparator-microphotometer employing a scanning slit at the plate.

Limit of detection in weight percent 

Element Oxide

---_-___-_-_________________ 0.01 ___________

Nb 3194.98____________________________ .01 ___________

Ti 3088.03_-----__--_-_______________ .001 0.002

Ti 3261.61_____________________________ .05 .09

Ti3299.4l_____________________________ .1 .2

V 3183.41_____________________________ .002 .004

V 3183.98_____________________________ .001 .002

La3245.12_-__-________________________ .02 __.____._-_

La 3337.49___________________________ .01 ___________

La 4333.73 __________________________ .003 ___________

Y3327.88.----____________________ .002 _______

The line pair Nb 3163.40/Th 3124.39 was used for determining niobium 

in the single crystals of titanium minerals reported in tables 4,6, and 9.

The analytical curves for the various elements were established by 

means of two sets of standards prepared by successive dilutions to 

contain 1.00, 0.464, 0.215, 0.100, 0.0464, 0.0215, . . . , 0.00100 percent 

niobium, vanadium, lanthanum, and yttrium. The titanium percentage was tenfold higher than that of the other elements in each step 

of the standards. The first set was prepared with a pure calcite 

matrix and was used in the analysis of samples from calcite veins. 

The second set was prepared in a pegmatite-base matrix consisting of 

60 parts of quartz, 40 parts of microcline, and 1 part of Fe2O3 , and 

was used for analyzing all other samples.

The samples were prepared by crushing, quartering, and grinding 

in agate mortars to pass 150-mesh silk bolting cloth. Single crystals 

were picked out of one quarter of the original sample and weighed 

before grinding.

The samples from calcite veins were arced without further preparation. All other samples, excepting the single crystals of titanium 

minerals, were diluted with equal weights of pegmatite base, and 25- 

milligram portions were arced to completion. The spectra of a few 

steps of the appropriate standard were put on each plate to correct 

for any shifts in the analytical curves.

If a sample was found in the initial analysis to contain a high concentration of any of the elements it was further diluted with calcite or 

pegmatite base and reanalyzed. This dilution made the composition 

of the sample approach that of the standard used in its analysis and 

improved the accuracy of the determination.

A separate pegmatite base containing 2 percent thorium (incorporated as ThO2 ) was prepared for determining niobium in the

302324 54 2
28 CONTRIBUTIONS TO ECONOMIC GEOLOGY

single crystals of titanium minerals. The single crystals were diluted 

with 5 parts of this thorium pegmatite base and 4 parts of thoriumfree pegmatite base so that the thorium was 1 percent of the sample. 

An internal standard was needed for the single crystal determinations because the crystals were frequently so small that 25-milligram 

portions were not available for analysis. Thorium was chosen for 

the internal standard element because it does not occur in appreciable percentages in the rocks and minerals analyzed and movingplate studies showed that it has a volatilization rate similar to 

niobium.

Since the work reported in U. S. Geological Survey Circular 225 

(Fleischer and others, 1952), additional checks on the spectrographic 

determination of niobium have been obtained by means of X-ray 

fluorescence analyses. These checks are listed below.

Sample Analyses 

Mineral no. Spectrographic X-ray fluoretcew*

Rutile.. _______________________ 52-813a 2.2 1.70

Do...__._-.____.__.. 52-813b 1.2 1.16

Do...._________________ 52-813c 1.1 .91

Brookite . ___________________ 52-718e 1.9 2.03

Bauxite---.--.... _____________ 52-383 .098 .097

Do-----.--..___---.-.._ 52-390 .072 .084

Do-_____________ ______ 52-397 .030 .040

Do_-_____________________ 52-409 .020 .014

Dmeoiite _____________________ 53-149 .23 .25

Do__________________.____ 53-151 .14 .17

Do------------___-_..._-- 53-156 .16 .16

Do---_-_--.__-___-_______ 53-157 .11 .12

It has not been possible to obtain checks on vanadium, lanthanum, and 

yttrium.

The analytical results for niobium, lanthanum, and yttrium are 

given as weight percentages of the elements. The analytical results 

for titanium and vanadium in many of the samples had previously 

been given as weight percentages of the oxides (Fryklund and Hoibrook, 1950) so this mode of reporting has been retained for these two 

elements in order to facilitate comparison with previous results. The 

only exception is in table 11, where the semiquantitative results for 

titanium are reported in terms of the element.

MAGNET COVE AREA

DESCRIPTION OF TITANIUM-NIOBIITM: DEPOSITS 

GENERAIi

Niobium and titanium occur together at Magnet Cove, and in fact 

all the niobium of possible economic interest occurs as part of the crystal structure of titanium minerals. The two elements are, therefore-, 

described together.
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 29

The titanium-niobium deposits of Magnet Cove (pi. 6) consists 

chiefly of rutile and brookite deposits. The only known large deposit 

of rutile is on the property of the Magnet Cove Titanium Corp., which 

also includes unexplored areas where rutile is locally abundant in 

the soil. The major brookite deposits are on the Christy property 

and the Kilpatrick property. Other areas of rutile and brookite float 

are shown on plate 6.

Rutile-brookite-feldspar veins and molybdenite veins cut perovskite-bearing magnetite-pyroxene rock on the Mo-Ti Corp. property. 

Although none of these rocks crop out, they were studied in drill 

core. Because some of the perovskite in Magnet Cove contains as 

much as 8.8 percent niobium, the perovskite-bearing calcite rock and 

perovskite syenites are of interest and were studied during the current work.

MAGNET COVE TITANIUM CORPORATION RUTHJE DEPOSIT

Location and extent. The Magnet Cove Titanium Corp. deposit, 

the only major rutile deposit known in the area, is mainly in the 

east-central part of sec. 18, T. 3 S., R. 17 W., about three-quarters 

of a mile north of U. S. Highway 270 (pi. 6). The property was 

controlled by C. H. Scott of Denver, Colo. in 1952. About 5,188 

short tons of rutile concentrates were recovered from this property between 1931 and 1944. The mill has since been dismantled.

The deposit has been described by Eoss (1941) and Fryklund and 

Holbrook (1950). U. S. Bureau of Mines drilling projects have been 

described by Spencer (1946) and Reed (1949a). The main deposit 

(fig. 3) has been partly exposed in two shallow open pits. Information from outcrops and drill holes indicates that the known deposit 

has a long axis striking east and is about 2500 feet long and up to 800 

feet wide. The deposit has been proved to a depth of 188 feet by drilling. In an area about one-half mile southwest of the open pits, old 

shallow workings can be seen, and rutile is locally abundant in the soil.

Former mining operations utilized the weathered material in 

which some residual concentration had occurred. Most of this material has been removed. All drilling has been done in the vicinity of 

the open pits (fig. 3). The U. S. Bureau of Mines sank 16 churn-drill 

holes in 1945 and 27 core-drill holes in 1948. For the results of sampling and analyses see pages 32 and 33.

Character of the deposit. The bedrock consists of igneous rock, 

chiefly nepheline syenite of several types, cut by veins and irregular 

bodies of feldspar-carbonate rock. The most common igneous rock is 

aegirine-nepheline syenite porphyry, which contains scattered inclusions of various igneous and metamorphic rocks. Inclusions of igneous breccia are described by Fryklund and Holbrook (1950, p. 22) and 

are similar to those in Conway and Perry Counties, Ark., described by
30 CONTRIBUTIONS TO ECONOMIC GEOLOGY

S

OB 

o>

25

EH ° 

« §

£2 

u 3

Croneis (1930, p. 155-161). The igneous rocks and their characteristic 

minerals are listed in table 1.
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 31

TABLE 1. Characteristic minerals of the igneous rocks, Magnet Cove Titanium

Corp., Magnet Cove, Ark.

[For descriptions of rock types see Fryklund and Holbrook, 1950, p. 16-25]

phyry.

type).

type).

Nepheline tinguaite dikes _ ___ .

Monchiquite dikes ________ .

Fourchite dikes ___ .. ___ _ .

Amphibole fourchite dikes .... __

Feldspar

.....do.............

do

 ..do- .... ..

.....do... ..........

Minerals

Feldspathoid

.. do-.... __ _ ..-

__ do _ - .............

Analcime(?) ...........

.... -do ... ... ....... _

.....do .............

Ferromagnesian

Aegirine.

Diopside, aegirine.

Do.

Aegirine.

Do.

Titanaugite, barkevikite.

biotite,olivine(7).

In the main deposit the rutile occurs in feldspar-carbonate veins 

of several types that cut the igneous rocks and constitute 50-75 percent of the deposit. For a detailed description the reader is referred 

to Fryklund and Holbrook (1950, p. 26-35). The veins are tabulated according to constituents and rutile content in table 2.

TABLE 2. Primary constituents of veins in the Magnet Cove Titanium Corp.

deposit

Vein name

Coarse-grained biotite-apatitecalcite. 

Sugary-textured albite-dolomite.

Coarse-grained albite-perthitecarbonate.

Constituents

Coarse calcite, apatite, green biotite.

Euhedral albite, euhedral dolomite, 

pyrite, apatite, molybdenite.

sphene, pyrite.

Albite, microcline, perthite, carbonate (leached) quartz.

Average 

grain size (millimeters)

2-12

0.5 

.5. 

04

.5-1.0 

5-20

1

2 

2 

2 

5

.5

Rutile content

Absent. 

Up to 5 percent.

masses. 

Less than 1 percent.

seminated hi calcite.

The rutile occurs as single grains, aggregates of acicular grains, 

and as veins. The maximum length of acicular rutile crystals is 0.5 

millimeter; the average length is 0.1 millimeter, but some are barely 

visible at 360 diameters magnification. Probably 15 to 20 percent of 

the TiO2 in the carbonate veins is in the form of leucoxene.

/Sampling and analysis. The location of drill holes in the vicinity 

of the open pits is shown on figure 3. The results of analyses of the 

cores for TiO2 and V2O5 by the U. S. Bureau of Mines are discussed 

and tabulated in Fryklund and Holbrook (1950, p. 39-40, 82-130). 

Splits of 38 samples of cores from 18 drill holes were obtained in 

1952 from the U. S. Bureau of Mines at Rolla, Mo. These splits were 

analyzed spectrographically for niobium, TiO2, V2O5 , yttrium, and 

lanthanum (table 3).
TABLE 8. Analyses of samples from the Magnet Cove Titanium Corp. pr

[Spectrographic analyses by K. J. Murata; chemical analyses by Bureau of Mines (Eeed, 1949b). Kock type, Fryklu

zero indicates item looked for but not found at limit of sensitivity (Nb, 0.01; 

Drill hole no. 

(fig. 3)

B-2 ....... 

B-2_... ............ 

B-3 

B-3 - ....... 

BOC-1. .. .........

BCC-2-- - - 

BCC-2_... ........ 

BCC-2-- 

D-l. ... 

E-7 . ..... 

E-7 - -

E-7 -----

E-7 

F-1- . . -------

F-1... _._ 

G-2 ... -. 

G-2 ... ..... -.

G-2 .-. - -

G-4 ... .

1-1. ------

1-1 ... ..

I-1- . -

J-l . .

J-2 ... .

3-9.. ...... ........

J-3_ 

J-3 

J-3 .... --.

K-5 - ..... ----- ..

K-5 .... .

L-2 ... - -

L-2 .... -

M-5.. ..... .-

O-2 .... ------

O-2 .

O-2... ....... -----

O-2 -----

O-3 - -----

O-3 

O-3 

Depth (feet)

91-95 

110-115 

27-34 

73-79 

54-60 

30-36 

73-80 

80-86 

21-24 

48-49.8 

49. 8-52 

73-76. 5 

108. 2-111. 4 

10. 7-19. 4 

110. 4-120. 1 

53-56 

56-58 

115-118 

135. 8-145 

20-26 

36-40 

67-72 

32. 5-35. 9 

31. 8-39. 4 

33-39 

75-82 

96-103 

103-109 

24-29 

57. 5-67 

14-21 

21-28 

54-61 

9. 5-11. 7 

27. 1-29. 1 

29. 1-34. 1 

49. 1-52. 3 

23-26.5 

34. 3-35. 2 

59. 5-64. 5

Laboratory 

no.

52-782SW 

52-783SW 

52-784SW 

52 -7858 W 

52-789SW 

52-786SW 

52-787SW 

52-788SW 

52-7708W 

52-790SW 

52-791SW 

52-792SW 

52-793SW 

52-794SW 

52-795SW 

52-798SW 

52-796SW 

52-797SW 

52-799SW 

52-800SW 

52-801SW 

52-802SW 

52-803SW 

52-804SW 

52-805SW 

52-806SW 

52-807SW 

52-808SW 

52-809SW 

52-810SW 

52-811SW 

52-761SW 

52-762SW 

52-763SW 

52-764SW 

52-765SW 

52-766SW 

52-767SW 

52-768SW 

52-769SW

Sample 

no.

1333 

1337 

1758 

1765 

1557 

1553 

1560 

1561 

1633 

1396 

1397 

1405 

1418 

1716 

1727 

1218 

1219 

1234 

1816 

1189 

1192 

1200 

1911 

1846 

1865 

1872 

1875 

1876 

1491 

1496 

1965 

1966 

1885 

1289 

1296 

1297 

1301 

1347 

1352 

1365

Nb

0.039 

.028 

.036 

.021 

.009 

.022 

.12 

.026 

.021 

.041 

.039 

.015 

.021 

.020 

.023 

.014 

.042 

.022 

.037 

.013 

.012 

.014 

.026 

.026 

.012 

.019 

.016 

.029 

.016 

0 

.062 

.075 

.009 

.020 

.071 

.048 

.040 

.025 

.026 

.034

TiOj

Spectrographic

4.3 

1.1 

2.4 

1.2 

1.1 

2.6 

9.5 

1.7 

3.2 

2.7 

2.0 

1.2 

1.3 

1.3 

1.5 

1.4 

2.4 

2.6 

4.1 

1.2 

1.3 

1.0 

3.3 

2.1 

1.2 

2.9 

1.7 

2.7 

2.4 

.02 

2.6 

3.7 

.51 

2.9 

4.2 

2.9 

3.0 

.64 

1.2 

.97

Chemical

4.95 

1.70 

2.65 

1.05

2.50 

3.20 

2.70 

1.35 

2.30 

1.10 

1.55 

1.73 

2.90 

2.30 

3.78 

.88 

2.35 

1.15 

3.14 

2.38 

1.00 

2.62 

1.82 

3.04 

2.40 

.25 

3.08 

3.56 

.49 

3.26 

5.35 

2.67 

3.25 

.70 

.95 

1.15

VtOt

Spectrographic

0.065 

.042 

.086 

.025 

.028

.091 

.032 

.13 

.13 

.072 

.070 

.048 

.030 

.021 

.071 

.066 

.085 

.052 

.098 

.033 

.022 

.14 

.024 

.030 

.11 

.064 

.10 

.18 

.005 

.039 

.057 

.012 

.47 

.030 

.025 

.031 

.063 

.013 

.053

Chemical

0.11 

.19

.11 

.05 

.10 

.18 

.08

.05 

.07 

.05 

.08 

.07 

.05 

.05 

.09 

.07 

.08 

.08 

.09 

.09 

.15 

.07 

.08 

.07 

.08 

.19 

.07 

.05 

.15 

.11 

.09 

.05

Y

0.

.

.

.

.

.

.

.

0 

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

0 

0 

0
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS

. The original core samples were divided according to the length of 

core pulled, rather than according to lithology, partly to permit correlation of core and sludge analyses. The igneous rocks contain from 

2 to 5 percent TiO2 in rutile, ilmenite, and silicates, probably unrecoverable by milling. In the common case, therefore, where a sample includes both igneous rock and vein, the analysis cannot be interpreted 

directly and quantitatively. Adjustment of analytical figures on the 

basis of type of material indicates that in the main deposit about 

& percent TiO2 is present in recoverable form. Calculation of average 

grade of niobium likewise cannot be done directly, but a similar adjustment indicates that the deposit contains about 0.04 percent niobium 

in recoverable form.

The relation between niobium and titania in the samples is shown 

graphically in figure 4. The scattering of the points may be due 

partly to the mixed material analyzed. A more important reason is 

indicated in table 4, which shows the results of the analyses of rutile 

concentrates and single crystals. The single crystals of rutile from 

the west pit range from 0.4 to 1.7 percent niobium; those from the 

float area one-half mile southwest of the pits range from 0.00 to 1.4 

percent niobium. This variation is probably sufficient to explain the 

scattering shown in figure 4. Table 4 also contains analyses of two 

composite samples of rutile, 814-e and 815-f, and analyses of rutile 

concentrates. These analyses indicate that the average niobium content of rutile concentrates is about 1.2 ±0.2 percent niobium. '

TABLE 4. Spectrographic analyses of rutile crystals and rutile concentrates 

from the Magnet Cove Titanium Corp. property, Magnet Cove, Ark.

\~R. B. Harner, analyst, except where noted. Leaders indicate item not looked for; zeraindicates itemlobfced 

for but not found at limit of sensitivity (Nb, 0.01; Y, 0.002; La, 0.003)]

Laboratory 

no.

52-814SM

b

d

52-815SM

b

d

f

 51-13858

52-813SM

b

d

Description

Rutile crystals from west pit: 

Single-crystal samples:

8 mg... ............. ...... ............ .. .. ..

Rutile crystals from surface, J4 mile southwest of west pit: 

Single-crystal samples:

27 mg...... ........ . ... .... -......-.- ..

8mg.... -. _-.. -.. . .- .

Rutile concentrate from old mill, separated on Frantz 

separator:

Nb

1.3

.4

1.7

1.7

1.4

1.2

1.4

1.4

0

1.2

1.0

1.3

2.2

1.2

1.1

1.6

VjOs

0.52

.071

.30

.30

.54

.71

.071

.071

.073

.41

.80

1.5

.29

.17

.43

Y

0

0

0

0

0

0

.La

0

0

0

0

0

0

1 H. J. Rose, Jr., analyst.
34

0.13

.10 

.09 

.08 

2.07

'c 

<u

£.06

Q> 

Q.

.05 

 04 

.03 

.02

.01

CONTRIBUTIONS TO ECONOMIC GEOLOGY

(

'/

^

'

J

 /

1 \

/

/

'/J

 *

/

/

Coef

V

ficient i

/

if corre lotion = 0.806

l 234 567 8 IO

Percent Ti02

FIGURE 4. Correlation of niobium and TiO2, Magnet Titanium Corp. property,

Magnet Cove.

Vanadium content in the single crystals ranges from 0.071 to 0.71 

percent and it is not surprising that the vanadium content of the 

drill-core samples is also erratic. The lanthanum and yttrium are 

probably in the apatite.

CHRISTY BROOKITE DEPOSIT

Location, geology, and extent. The Christy deposit is near the 

eastern margin of Magnet Cove. It is about one-half mile, north of
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 35

the town of Magnet, in the SW^SW^ sec. 16, T. 3 S., R. 17 W. (pi. 

6). The property was owned in 1952 by the Malvern Lumber Co. 

of Malvern, Ark., and has been described by Holbrook (1947), Reed 

(1949b), and Fryklund and Holbrook (1950).

The deposit (fig. 5) contains primary brookite-bearing rock and 

enriched residual material. The primary deposit is in quartzite of 

the Arkansas novaculite of Devonian and Mississippian age. The 

primary deposit extends about 420 feet north-south and about 900 

feet east-west, and has been proved to a depth of 130 feet by drilling. 

Residual material has crept downslope from the primary deposit and 

forms a deposit about 900 feet long and at least 550 feet wide. The 

maximum thickness of the residual material is about 20 feet.

Character of the deposit. The primary material, as seen in drill 

core, is composed of brookite-bearing dark quartzite, separated by 

clay layers containing little or no brookite. The brookite grains 

average less than 0.5 millimeter in diameter and are rarely visible 

megascopically. In thin sections the quartz grains range from 0.05 

millimeter to slightly more than 1 millimeter in diameter. The dark 

color of the rock is due to the brookite, to abundant very fine-grained 

acicular rutile needles, and to altered taeniolite, a rare magnesian 

lithium mica containing a small proportion of titanium as an essential constituent (Miser and Stevens, 1938). Rutile inclusions in 

brookite show that the rutile formed earlier. In thin sections brookite occurs in quantities ranging from a few grains to 10 percent.

The residual material consists of porous quartzite fragments, 

quartz crystals, brookite crystals, and sand-sized material in a matrix 

of red clay. The dark quartzite forms at least one-third of the residual material. The largest brookite crystals of the deposit, some of 

which reach a diameter of 6 or 7 millimeters, are within or attached 

to quartz crystals.

No production from this deposit has been recorded. Exploration 

work has consisted of test pits financed by the Reconstruction Finance 

Corp. in 1944 and of 21 core- and bucket-drill holes put down by the 

U. S. Bureau of Mines in 1948.

Sampling and analysis. The location of drill holes and test pits 

is shown in figure 4. The results of analyses by the U. S. Bureau 

of Mines of drill-core samples are discussed and tabulated in Fryklund and Holbrook (1950, p. 63,131-151).

Splits of 5 samples from drill cores, and 29 samples of residual 

material from test pits, were analyzed for niobium, TiO2 , V2O5, and 

yttrium; the results are shown in table 5.

Calculations on the basis of the Bureau of Mines figures give an 

average grade of 5.9 percent TiO2 . Part of this is present in finegrained rutile, leucoxene, and taeniolite, and therefore is probably 

not recoverable.

302324 54 3
36 CONTRIBUTIONS TO ECONOMIC GEOLOGY

NVINVA1AS

-NN3d-iSOd NVINVA 

'3N3003-38d -1ASNN3d

NVIddl NVINOA3Q

 SSISSIH QNV

O NVINVA NVIddl nxsNN3d -ssissiw
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 37

TABLE 5. Analyses of samples from the Christy property, Magnet Cove, Ark.

[Spectrographic analyses by R. S. Harner; chemical analyses by Bureau of Mines (Reed, 1949a). Zero 

indicates element looked for but not found at limit of sensitivity (Nb, 0.01; Y, 0.002). Lanthanum content 

less than 0.005 percent in all samples]

Pit no. (fig. 5) Laboratory 

no. Nb TiO2 V.Oj Y

Pit Samples

A-l - . _.__...... ...._...__

A-2___. .................................

A-3 - - ...

A-4.. --- ...___ - - -._._ .

B-l .

B-2.._.._. ...............................

B-3.................. .................

B-4... .....__... ..._.-_.- ..-.._...._.

'B-6... ...................................

C-l

C-2.............. ........................

C-3-.-__- -... ._.-..-.......-.._..._

C- 4--.-.... . _ .-- .......

C-5

D-l

D-2... ..................................

D-3 -- -

D-4.. .-.-..... - ---.--..--.-.---.

D-5...... ..............................

E-2

E-3.. .--....-.....-..-..-. ..............

E-4..... ................................

E-5 . - . .

E-6-. . _ 

F-l.. .................. .................

F-2__.__ ........................ ______

F-3. .... _ ..

F-4.. ..-_..... .- ... ...-.--.....

F-5--- . . - .... .......

52-694SW

52-695SW

52-696SW

52-719SW

52-697SW

52-698SW

52-699SW

52-700SW

52-720SW

52-701 SW

52-703SW

52-702SW

52-704SW

52-705SW

52-706SW

52-707SW

52-708SW

52-709SW

52-710SW

52-711SW

52-712SW

52-713SW

52-714SW

52-721SW

52-715SW

52-722SW

52-723 SW

52-716SW

52-717SW

0.32

.060

.15

.072

.032

.042

.096

.086

.040

.058

.20

.080

.050

.086

.042

.028

.20

.086

.24

.40

.072

.20

.21

.086

.030

0

13

8.0

9.7

6.3

2.1

11

7.2

6.7

5.0

7.7

12

7.3

5.7

12

6.3

8.0

9.7

7.7

4.0

12

9.7

10

18

9.7

9.7

12

6.3

3.3

2.0

0.55

.29

1.8

.50

.079

.29

.40

.54

.34

.54

1.0

.43

.36

1.3

.82

.43

.43

.29

.28

.15

.21

.55

.89

.36

.26

.85

.21

.32

.33

0

0

.016

.016

.014

.028

0

0

0

0

.012

0

0

0

0

.011

.016

.016

.022

.016

.015

.013

.018

.013

0

.014

.016

.019

.026

Drill Samples

Drill hole

no. 

(fig. 5)

C-4 ..____.._

C-4 ....

C-8... ..... ..

C-8... ......

C-8-.. ......

(feet)

77. 5-80. 5

103-106

63. 5-66

85-86. 5

100. 5-102. 5

no.

52-727SW

52-728SW

52-724SW

52-725SW

52-726SW

no.

419

427

1012

1018

1025

Nb

0.18

.20

.088

.45

.33

Ti

Spectrographic

10

11

4.4

23

11

O2

Chemical

10.70

6.72

3.83

26.30

12.25

V2

Spectrographic

0.53

.20

.38

.25

.30

Os

Chemical

0.81

.31

.52

.38

.42

Y

0.040

.14

.024

0

0

The correlation of niobium and TiO2 is shown graphically in figure 

6. The lack of good correlation is explained at least in part by the 

data given in table 6. The single crystals range from 0.80 to 9.6 percent niobium. The analyses of composite brookite samples indicate 

that the average niobium content of brookite concentrates is about 2 

percent niobium.

The lanthanum and yttrium are probably in the apatite. The 

vanadium content varies greatly. The following analysis shows that 

at least part of the vanadium is present in brookite:
CONTRIBUTIONS TO ECONOMIC GEOLOGY

Analysis of brookite crystal from Christy property 

[Lee C. Peck, analyst, Rock Analysis Laboratory, University of Minnesota]

Constituent 

Fe2O3 

TiO2 

V2O5

Total

Percent

1.13

98.25

.41

99.79

.40

Z

c

0>

u

1_

o

Q-.20

.10 

0

c

1 1 ./

 ^/

 .f c

«

/

<

X

 

Coeffi

/

cient of

/

correlc

x

ation =

/

0.822

) 2 4 6 8 10 12 14 16 18 2

Percent Ti02

FIGURE 6. Correlation of niobium and TiO2 , Christy brookite property, Magnet Cove. 

KILPATRICK BROOKITE DEPOSITS

General. The Kilpatrick deposits are in sees. 16 and 17, T. 3 S., K. 

17 W., 1 mile north of the town of Magnet (pi. 6). The deposits have 

been described by Ross (1941) and Fryklund and Holbrook (1950). 

They have been known in the literature as the Hardy-Walsh deposits, 

but in 1952 they were owned by the estate of William Kilpatrick.
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 39

TABLE 6. Analyses of brookite crystals and composite samples of brookite from 

the Christy property, Magnet Cove, Ark.

[Spectrographic analyses by R. S. Earner, except where noted. Leaders indicate item not looked for; zero 

indicates item looked for but not found at limit of sensitivity (La, 0.003)]

Laboratory 

no.

52-718SM

b

d

IWS-254

Description

Small brookite crystals from surface:

....do....... ... ... . .. .. ....

-...do....... ................ . .. .................

Composite sample of brookite:

Nb

0.80

2.3

4.4

9.6

1.9

2.4±0.3

2.7

VaOs

0.58

Y

0.002

La

0

1 By K. J. Murata and E. L. Hufschmidt. 

s By J. I. Dinnin.

The deposits are exposed on a ridge of Arkansas novaculite of Devonian and Mississippian age, at the eastern edge of the cove. Igneous rocks of several types crop out a few hundred feet north of 

the deposit. The ridge consists of several knobs and saddles (fig. 7). 

The knobs consist of novaculite with small quantities of brookite, 

chiefly exposed in shallow trenches. The saddles are underlain by 

residual material whose depth is not known. The eastern saddle contains the largest residual deposit, which is at least 450 feet long and 

200-300 feet wide. The primary deposit is in quartzite of the Arkansas novaculite. The material of the primary and residual deposits 

is similar to that in the Christy deposit.

Exploration work has consisted of test pits and auger holes. The 

results of the auger drilling are not available.

Sampling and analysis. The locations of test pits and the results 

of analyses by the U. S. Bureau of Mines of channel samples are 

shown on plate 4 of Fryklund and Holbrook (1950).

The locations of test pits from which samples for niobium were 

taken are shown in figure 5, and the results of analyses of 33 samples 

are given in table 7. The average grade of the samples is 5.9 percent TiO2 and 0.06 percent niobium. The correlation of niobium 

and TiO2 is shown graphically in figure 8. No analysis of crystals or 

concentrate have been made.

MO-TI CORPORATION PROPERTY

The Mo-Ti Corp. prospect pit is in sec. 17, T. 3 S., R. 17 W., on the 

south bank of Cove Creek within Magnet Cove (pi. 6). The area 

has been described by Holbrook (1948) and Fryklund and Holbrook 

(1950). The pit was flooded in 1952, but drill-core obtained during 

a drilling program in 1947 was studied in Fryklund.
40 CONTRIBUTIONS TO ECONOMIC GEOLOGY
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 41

0.14

.13

.12

.10

.09

.08

-07 c

CD 

U

<U

Q. .06

.05

.04

.03

.02

.01

O 2 " 4 6 8 IO 12 14 16 18

Percent Ti0

FIGUBB 8. Correlation of niobium and TiO2, Kilpatrick property, Magnet Cove.
42 CONTRIBUTIONS TO ECONOMIC GEOLOGY

TABLE 7. Spectroffraphic analyses of samples from the KilpatricJc property,

Magnet Cove, Ark.

[R. S. Hamer, analyst. Zero Indicates element looked for but not found at limit of sensitivity (Nb, 0.01;

Y, 0.002, La, 0.003)]

Location (fig. 7)

14

21 -

26 

29 .. 

41. . . .... ........ .. __

42-............. ......

45 

47. .. ..... . . __

54 ......................

56. 

58 .. 

64 

75 .... .... .

76 

78 

82.. .... .. .

85 

95A.. .... .... ....

95B . . _

95D ... .

96 

120 

131 

134 . ........

137 .

139 

140

144 

144B ._ ..

145 ........

146... 

163 . . ......

173-174 ..

Laboratory 

no.

52-757SW

52-729SW

52-762SW

52-730SW

52-731SW

52-732SW

52-733SW

52-758SW

52-759SW

52-734SW

52-735SW

52-736SW

52-737SW

52-760SW

52-738SW

52-761SW

52-739SW

52-740SW

52-741SW

52-742SW

52-743SW

52-744SW

52-746SW

52-747SW

52-748SW

52-749SW

52-750SW

52-751 SW

52-752SW

52-753SW

52-754SW

52-755SW

52-756SW

Length of 

channel 

(feet)

5.0

1.7

10.0

5.0

14.0

7.0

O

7.0

8.0

14 0

0 ft

3.0

7.0

4.0

6.0

>; n

0

6.5

(3)

4.0

3.0

4.0

3.0

3.0

6.0

4 o

5.0

6.0

6.0

10.0

7.0

M2.0

Nb

0.008

.028

.017

.017

.032

.026

.052

.048

.011

.026

.008

.012

.040

.012

.20

.27

0

.084

.074

.12

.022

.060

.12

.042

.010

.022

.017

.46

0

.034

.32

0

.038

TiOz

3.3

6.5

6.3

4.3

5.0

5.7

3.0

5.0

4.3

9.4

3.3

4.3

3.7

4.3

14

9.0

.082

6.5

5.0

12.0

3.2

7.7

37

4.0

2.2

2.5

5.0

20

3.2

3.2

12.0

3.0

2.5

V2 O5

0.092

.15

.015

.14

.13

.15

.21

.21

.14

.17

.053

.14

.39

.21

.27

.16

.034

.21

.23

.39

.39

,29

.34

.61

.32

.20

.36

.27

.082

.25

.32

.19

.39

Y

0

0.009

0

0

.007

.004

0

0

0

.004

0

0

.017

.034

0

0

0

0

.030

0

0

.026

0

.011

0

0

0

0

0

0

0

0

0

La

0.009

0

.026

0

0

0

0

0

.040

0

.028

0

0

.076

0

.040

0

0

0

0

.019

0

0

.003

.003

0

.004

0

.004

.003

0

.004

.003

1 Grab sample.

2 Quartzite sample.

3 Chip sample.

4 Composite sample.

Veins containing rutile, brookite, and molybdenite cut pyroxenemagnetite rock. The results of earlier work suggest that mineralized 

and altered rock underlie a large area now covered by gravels. Pyroxene-magnetite rock containing nepheline and perovskite forms 

most of the drill core. The rock is dark green with a maximum grain 

size of 4 millimeters. The mode of one thin section is as follows:

Mineral

Nepheline and alteration products_ 

Diopside (?) and alteration products. 

Biotite, mainly primary_____________

Magnetite _________________ 

Apatite __________________ 

Perovskite ____________________

Others, mainly garnet and sphene_

Percent 

7

58 

6

16 

4

Total ______________________________ 100
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 43

The pyroxene is light yellow in color and pleochroic; XAc=52°; the 

extinction is anomalous and similar to the titanaugite of the area. In 

other thin sections the perovskite content ranges from 5 to 8 percent.

According to Johannsen's classification the rock is a perovskite 

melteigite, 3125P (Johannsen, 1938, v. 4, p. 327). It was included in 

the "eleolite syenite" group by Williams (1891, p. 188-189).

Perovskite-pyroxene-magnetite rock has been seen in drill cores 

from this property, but no outcrops were found. In three thin sections 

the perovskite content ranged from 5 to 8 percent. Material for 

analysis was drilled from one grain of perovskite in a thin section; it 

contained 0.56 percent niobium. Assuming that this is an average 

figure, the rock contains 0.03 to 0.04 percent niobium in perovskite. 

No analyses of brookite or rutile-bearing material have been made.

DESCRIPTION OF CALCITE BOCK BODIES 

GENERAL,

At several places in the cove the bedrock consists of coarsegrained calcite with scattered accessory minerals. The accessory 

minerals include perovskite that contains as much as 8.8 percent 

niobium. Rocks of this type and of doubtful sedimentary origin have 

been called "carbonatite" (Daly, 1933, p. 564) and have been found to 

contain appreciable concentrations of niobium in other localities.

Plate 6 shows the location of known bodies and the probable location of other bodies of coarse-grained calcite rock at Magnet Cove. 

Rock of this type is especially well exposed in and near the Kimsey 

quarry, which is on the west side of Cove Creek and on the north 

side of Highway 270 (see pi. 6). To the north of the Kimsey quarry, 

coarse-grained calcite rock crops out in two areas along Cove Creek, 

as shown in plate 6.

Power-auger drilling showed that the hill north of the quarry 

and west of Cove Creek (labelled "west tufa hill" on plate 6) is underlain by residual clay to the level of the surrounding gentle slopes. 

The surface of the hill is littered with boulders of cellular iron-stained 

apatite-rich material which was called "tufa" by Williams (1891, 

p. 183). Gradation from "tufaceous" material to calcite rock, which 

can be seen in the outcrop at the northwest corner of the quarry, indicates that the "tufa" is derived from the calcite rock by weathering. 

The "tufa" can, therefore, be used as evidence for the occurrence of 

coarse calcite in underlying bedrock. On this basis the hill west of 

Cove Creek and the hill north of the church, labelled "east tufa hill" 

on plate 6, are inferred to be underlain at least partly by coarse calcite 

rock. On "east tufa hill" the "tufa" float is not abundant and is 

accompanied by boulders of bleached igneous rock. A power-auger 

hole at the crest of the hill penetrated 40 feet of clay, to the limit of
44 CONTRIBUTIONS TO ECONOMIC GEOLOGY

.available drill pipe. The hill is only about 40 feet above the surrounding flat.

The hill labelled "middle tufa hill" on plate 6 has relatively few 

.float boulders; most of them are igneous rock and quartzite, and a few 

.are "tufa". On the flat south of the hill the soil contains abundant 

magnetite and some apatite and perovskite. A power auger struck 

irock at 20 feet and brought up fragments of apatite. The bedrock 

.is probably at least partly calcite rock.

Calcite rock crops out near the Baptist Church about 3500 feet

-southeast of the Kimsey quarry (pi. 6). According to J. W. Kimsey, 

.a well near the church penetrated about 50 feet of calcite rock. Ill 

.the field on the southern side of the highway, south of the calcite 

quarry, abundant perovskite in the soil indicates that calcite rock 

forms part or all of the underlying bedrock. This area is called 

"perovskite hill" in the older reports and on plate 6.

In addition to the areas just described, the southwestern part of 

the area near the pits on the Magnet Cove Titanium Corp. property 

(pi. 6) is underlain in considerable part by calcite rock. One drill 

"hole penetrated calcite rock to a depth of 161 feet. A water well, said 

to be about 90 feet deep, in the northwest corner of sec. 19 (pi. 6), 

penetrated calcite rock. There is no outcrop in the vicinity, but

-rutile is locally abundant in the soil. These data indicate that the

 total area underlain by calcite rock is very large.

KIMSEY CALCITE QUARRY AREA

General geology. The Kimsey quarry area was mapped and studied 

4n detail because of the presence of niobium-bearing perovskite, and 

"because it is the only good exposure of the calcite rock. The calcite

 rock has been described by "Williams (1891) and Landes (1931). The 

calcite body (figs. 9 and 10) trends roughly east and has a maximum 

exposed length of about 360 feet; the maximum north-south dimension 

is about 300 feet. Other calcite bodies are present to the north and 

south but are poorly exposed. One such body is in the southeast 

corner of the mapped area (fig. 9). The body exposed in the quarry 

is in contact with syenite porphyry on the northern and southern sides. 

Cover prevents determination of its extension to the east and west. 

An attempt to drill auger holes in the flat east of Cove Creek failed 

because the auger could not penetrate the coarse gravels.

The calcite rock has little obvious structure but locally does have a

faint layered appearance produced by color differences in the calcite,

by differences in concentration of apatite and monticellite, and by

' local concentrations of pyrite and molybdenite (figs 9 and 10). Acces-

; sory minerals, in approximate order of abundance and also in approxi-
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 45

mate order, of decreasing age, are apatite, monticellite, biotite, magnetite, pyrite, and perovskite. Zones containing abundant pyrite and 

those containing molybdenite are only locally present. Pyrrhotite is 

associated with magnetite and occurs only at contacts of calcite rock 

and syenite.

Contact, dashed where approximately 

located, short dashes where concealed

Dump

X 15

Source of sample

Topography not shown in quarry

Contour Intenral 5 foot 

Datum assumed

FIGURE 9. Geologic and topographic map of the Kimsey calcite quarry, Hot Spring County.

I-nclusions in the calcite rock. The calcite body contains inclusions 

of several rock types, ranging in size from fragments a few inches 

long to angular blocks 6 to Y feet long. Small aggregations of green 

biotite may represent digested or replaced inclusions. Reaction rims 

of varying thickness are present around the larger inclusions. Some 

inclusions have only a small remnant of the original rock at the center; 

others have a reaction rim only 1 to 2 inches wide. A typical reaction 

rim consists of the following zones:

1. A narrow outer zone, usually less than 1 inch wide, of magnetite and 

pyrrhotite lying in a medium-grained calcite matrix.
46 CONTRIBUTIONS TO ECONOMIC GEOLOGY

2. An intermediate zone rich in green biotite. Some biotite grains may reach 

1 centimeter in diameter.

3. A fine-grained idocrase-rich inner zone of variable width, in some cases 

including the whole block. A few large idocrase crystals, reaching 3 

to 4 centimeters in length, are present in these zones.

In thin section the altered rock shows total replacement of pyroxene 

by epidote, muscovite, and idocrase; and brown garnet is bleached and 

partly replaced by idocrase. Only a minor amount of carbonate is 

present.

CTumnel soanples and average grade. Twenty-one channel samples 

were taken from the sloping walls of the Kimsey quarry. The channels were cut along lines normal to the trend of the walls and are 

located as shown on figures 9 and 10. Quantitative spectographic 

analyses for niobium, TiO2 , V2O5 , yttrium, and lanthanum are given 

in table 8.

EXPLANATION

Contact

Strike and dip of joints

$om 

Strike and dip of vertical joints'

Pyrite vein, showing dip 

where determined

_j^_£. 

KteryBderrflTveinT showing dipo-IN 

Inclusions

»s

Concentrations of silicates., 

mainly monticellite

*»A

Concentrations of apatiteTop of cut

Foot of cut

X9 

Source of sample

Contour interval 5 feet 

Datum assumed

FIGURE 10. Eastern part of the Kimsey calcite quarry, Hot Spring County, showing the 

occurrence of accessory minerals in the calcite rock.
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 47

TABLE 8. Spectrographic analyses of channel samples from the Kimsey caldte 

quarry, Magnet Cove, Ark.

[R. S. Earner, analyst. Zero indicates element looked for but not found at the limit of sensitivity (Nb, 0.01) ]

Channel

No,

1 .... -

2 

3 -

4 - .

5

6 

7 --------------------

8 --------------------

9 ...

10 

11..-....-.... ..........

12 .

13 -

14 - . ......

15 ---------------

16 

n..... ..................... i&........ ....... ...........

19........ ................ ..

20 --

21 

Length 

(feet)

2.3

1.5

2.1

2.4

7.5

2.0

1.9

4.5

3.8

2.0

3.2

2.7

3.1

2.5

7.7

"1.9

7.0

4.4

2.4

1.8

2.1

no.

52-665SW

52-666SW

52-667SW

52-668SW

52-669SW

52-670SW

52-671 SW

52-672SW

52-673SW

52-674 SW

52-675SW

52-676SW

52-677SW

52-678SW

52-679SW

52-680SW

52-681 SW

52-682SW

52-683SW

52-684SW

52--685SW

Nb

0

0

0

0

0

.028

0

0

0

0

0

0

0

.025

.022

.048

.053

0

0

.070

0

TiOa

0.031

.020

.14

.053

.10

.20

.075

.022

.029

.019

.075

.019

.099

.40

.22

.91

.67

.080

.050

.97

.13

V2 05

0.009

.015

.022

.009

.017

.013

.012

.014

.008

.007

.011

.016

.009

.031

.023

.022

.023

.016

.011

.045

.010

Y

0.003

.006

.015

.003

.006

.006

.003

.003

.003

.008

.003

.008

.009

.007

.007

.007

.009

.007

.006

.015

.007

La

0.022

.037

.049

.019

.038

.034

.024

.024

.022

.014

.022

.033

.029

.029

.035

.046

.050

.026

.010

.062

.018

Niobium was detected in only six of the samples. The analyses confirmed the visual impression that perovskite, apatite, and monticellite 

tend to be concentrated in the same zones. The graph of figure 11

VJJO

.07 

.06

.05 

.0

Z

"c .04 

0>

u

k. 

0>

a- .03

.02

.01

°.

/

'

/

 /^

/>

/

/

/

Coeffi

/

cient o

/

\ corre

/

^

lotion =

/

0.909

3 .1 .2 .3 .4 .5 .6 .7 .8 .9 1.

Percent Ti02

PIGDKE 11, Correlation of niobium and TiO2, Kimsey calcite quarry, Magnet Cove.
48 CONTRIBUTIONS TO ECONOMIC GEOLOGY

shows moderately good correlation between niobium and TiO2 

analyses.

The average grade of the channel samples is 0.011 percent niobium. 

The average content of the calcite body is probably about 0.01 percent niobium.

Analyses of perovskite, apatite, and calcite. Niobium in Magnet 

Cove perovskite has been reported by several workers, beginning with 

Mar (1890, p. 403). Available analyses, including those made during 

the present study, are given in table 9. All values are given as niobium, 

rather than as Nb2O5 . Presumably the samples of Mar (1890) and of 

Rankama (1948) came from the Kimsey quarry-"perovskite hill" area, 

as this has been the only collecting ground for loose perovskite crystals. For comparison, an analysis of perovskite from the pyroxenerich rock at the Mo-Ti Corp. pit is also given.

The analyses of previous workers range from 3.1 to 3.3 percent 

niobium; those of the Geological Survey range from 5.1 to 8.8 percent niobium. Mar's very early analysis for niobium by chemical 

methods may be in error. The high percentage of tantalum (4.2 percent) reported by him has not been confirmed by later workers.

Analyses of apatite and calcite from the Kimsey quarry are also 

given in table 9. Magnet Cove apatite contains rare earths of the 

lanthanum group and is probably the source of most of the lanthanumgroup rare earths in the samples from the rutile and brookite deposits.

TABLE 9. Spectrographic analyses of single crystals from Magnet Cove, ArJe.

[R. S. Harrier, analyst, except where noted. Leaders indicate item not looked for; zero indicates item looked 

for but not found at limit of sensitivity (Nb, 0.01; TiOs, 0.05; VaOs, 0.002)]

Laboratory 

no.

0) ( 2)

IWS-202

52-686SM

b

d

62-942SW

62-1407SW

62-1408SW

62-687SM

62-688SM

Description

__.__do ____ _ _ ... ... __ _ ....

cite quarry .3 

Perovskite crystals from soil, "perovskite hill:"

.. do. 

.....do- ...................

. do . 

in thin section of perovskite melteigite from drill core, Mo-Ti Corp. 

property.

Kimsey calcite quarry. 

.....do ___ -.--._ __ -

 -.do.. ... ....

Nb

3.1

3.3

5. 6±0. 3

8.8

6.8

8.4

5.6

6.4

.56

0

0

.28

.30

Ta

4.2

.02 *0

TiOs

0

0

1.3

1.2

V3 0j

0.57

0

Y

0.1

0

0

La

1.2

.38

.008

1 Prom Mar, 1890.

2 From Eankama, 1948. 

> K. J. Miirata, analyst. 

* Lessthan0.2percent.
NIOBIUM AND TITANIUM DEPOSITS, AEKANSAS 49

ORIGIN OP THE CALCITE BOCKS

Bodies of calcite rock or carbonatite associated with and included 

in alkaline igneous complexes have generally been described as sedimentary inclusions, whose assimilation may have been a factor in' 

the origin of the alkaline rocks (Landes, 1931; Daly, 1933, p. 508-509y 

564-565; Shand, 1947, p. 303-328). Recent descriptions however,, 

have emphasized evidence that some calcite bodies of this type are 

introduced material, formed either as magmatic carbonate intrusives 

or by hydrothermal replacement (Bowen, 1924; Von Eckermannr 

1948; Strauss arid Truter, 1951).

Two lines of evidence indicate that the coarse calcite rock at Magnet Cove is introduced into the igneous rocks. The inclusions of 

syenite, rimmed by reaction products and veined by calcite, testify 

that the calcite material was both mobile and reactive after the formation of the igneous rocks, and most likely was introduced later 

than the igneous rocks. Also, coarse calcite bodies and veins cut 

the igneous rocks in drill cores from the Magnet Cove Titanium Corp. 

deposit, and it is apparent that widespread introduction of calcite 

has taken place here probably by hydrothermal action. The question 

of magmatic intrusion versus hydrothermal replacement has not been 

answered for the Magnet Cove calcite rocks, but the available evidence 

favors hydrothermal replacement.

ECONOMIC FACTOBS 

RUTILE AND BROOKITE DEPOSITS

The drilling 011 the Magnet Cove Titanium Corp. property and the 

Christy property has been sufficient to indicate the presence of considerable resources of rutile and brookite. It is probable that rutile 

and brookite deposits at Magnet Cove will be mined eventually.

The present work was done in order to determine the distribution 

and average grade of niobium in the titanium deposits and associated 

rocks. In addition the past work of the U. S. Bureau of Mines and 

of Fryklimd and Holbrook has been summarized, and average grades 

for TiO2 and V2O5 have been calculated for the deposits. This information is listed in table 10.

TABLE 10. Summary of analytical data from the principal titanium deposits at

Magnet Cove, Ark.

Locality

Magnet Cove Titanium Corp. 

property.

Do . - -..-..

Kimsey "calcite quarry area _____

Mineral of 

possible value

Rutile. -------

Brookite. _ .. 

 . .do ..---

Ruffle... ..

Perovskite. ... 

.. do ......

Estimated average recoverable grade of 

known material

TiOs

3

5.9 

5.9

"""26"

Nb

0.04

.07 

.06

.03 

.01

V2Os

0.09

.35

.21

........

Estimated average grade 

of titanium concentrates

TiOs

92

92 

92

........

Nb

1.2

2 

2

....

VsOs

0.5

.5 

 5(?)

- - 
50 CONTRIBUTIONS TO ECONOMIC GEOLOGY

The Bureau of Mines has made milling tests on rutile and brookite 

material from Magnet Cove (Fine and others, 1949; Fine and 

Frommer, 1952). These tests gave low recovery 46 percent for 

rutile, 55 to 60 percent for brookite but produced high-grade concentrates of about 92 percent TiO2 in rutile and brookite. As shown 

in table 10, the rutile and brookite concentrates contain about 1.2 percent and 2 percent niobium respectively.

The chief factor in the low recovery is the occurrence of TiO2 in 

several forms. In the rutile deposits, for example, nonrecoverable 

TiO2 occurs in ilmenite, leucoxene, and silicates. In addition, the 

rutile occurs in grains of widely varying size and shape and the finer 

acicular grains are easily broken down into clay sizes that are recoverable only with difficulty. In the brookite deposits, TiO2 occurs not 

only in brookite of widely varying sizes but also in very fine-grained 

acicular rutile grains and in taeniolite.

The vanadium content of samples from the rutile and brookite 

deposits varies widely, and the ratio of concentration of vanadium in 

rutile or brookite concentrates is much lower than that for TiO2 and 

niobium. This relation indicates that part of the vanadium is in 

minerals other than rutile or brookite. The recoverable vanadium 

is, however, of possible economic value. Extensive bulk sampling 

and mill testing under operating conditions will be necessary to determine accurately the recoverable grade of the deposits.

The data indicate the niobium is a constant companion of the titanium, and its average grade can be predicted within rather close 

limits.

It is probable that processes for making metallic titanium from 

the rutile and brookite concentrates will allow separation and recovery of niobium and vanadium. However, if the rutile and 

brookite are used for welding-rod coatings, the niobium and vanadium will be lost.

OTHER POSSIBI^E SOURCES OF TITANIUM AND NIOBIUM

Perovskite-bearing rocks in other areas have been considered as 

possible sources of titanium alone and of both titanium and niobium. 

The perovskite-bearing calcite rock exposed in the Kimsey quarry 

has been studied and sampled as described in this report, and the 

analytical data are summarized in table 10. Unless the perovskite 

can be recovered easily as a byproduct of other operations, the TiO2 

and niobium content of this material is probably too low to be of 

economic interest.

Two localities where perovskite-bearing silicate rock occurs are 

known: the Mo-Ti Corp. locality described in this report, and an area 

about 1000 feet east of the magnetite quarry on the north side of
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 51

Highway 270 (pi. 6). The quantity of perovskite-bearing rock in 

these localities is not known.

POTASH SULPHUR SPRINGS AREA 

LOCATION AND PREVIOUS WOBK

The Potash Sulphur Springs area is about 6 miles west of Magnet 

Cove (fig. 2). The area underlain by igneous rocks is on the north 

side of U. S. Highway 270 and is about one-half mile in diameter. 

The Potash Sulphur Springs area is more rugged than Magnet Cove 

and is cut by several deep valleys draining southward to the Ouachita 

Eiver. About one-half mile north of the highway, near the head of 

the deepest valley, are the hot springs that give the area its name. The 

Wilson prospect described in this report (fig. 12) is on the hillside east 

of the hot springs, above the Wilson residence.

No natural outcrop is present in the vicinity of the prospect. Several bulldozer trenches up to 10 feet deep expose only heavily weathered rock (saprolite). On the surface are several residual boulders, 

somewhat similar to the "tufa" boulders near the Kimsey quarry at 

Magnet Cove. One of these boulders is unusually radioactive and a 

grab sample analyzed in December 1950, by T. W. Carney, chemist of 

the Arkansas Division of Geology, was found to contain a notable 

quantity of niobium. Later analyses by the U. S. Geological Survey 

and the University of Arkansas have confirmed the presence of niobium and uranium. The bulldozer trenches were dug in 1951 for B. G, 

Wilson, the owner of the property. Shortly thereafter a churn-drill 

hole about 75 feet deep was drilled in one of the cuts.

GEOLOGIC RELATIONS

The Potash Sulphur Springs area, like Magnet Cove, is underlain 

by alkalic igneous rocks that have intruded sedimentary rocks of 

Paleozoic age. The geology of the area was described by Williams 

(1891, p. 344-366), and Purdue and Miser (1923). The scant outcrops 

and float material indicate that the rocks, like those at Magnet Cove, 

are syenite and more basic alkalic rocks. Calcite rock is exposed in the 

valley near the hot springs. Perovskite, rutile, and brookite have not 

been reported from the area.

At the Wilson prospect, which is on the eastern contact of the igneous complex, the trenches expose heavily weathered syenite and 

quartzite. The quartzite, probably part of the Arkansas novaculite of 

Devonian and Mississippian age, is exposed in the eastern part of 

the long east-west trench shown on figure 12. Elsewhere in the 

trenches heavily weathered syenitic rock is exposed. The presence of 

dikes of syenite in the quartzite, and of quartzite inclusions in the
52 CONTRIBUTIONS TO ECONOMIC GEOLOGY

EXPLANATION

LOCATION MAP

Topography not shown in cuts

100 

I

200 Feet

_1

Contour interval 10 feet 

Datum is approximate

PIGURH 12. Geologic and topographic map of the Wilson prospect, Potash Sulphur Springs,

Garland County.
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 53

syenite, indicates that the syenite is intrusive. The syenite is almost 

completely altered to brown, white, and green clay. Irregularly 

shaped blocks of clay are separated by stringers and veins of iron 

oxide and clay. Some of the rock may have been a breccia before 

weathering, or may have developed this structure during weathering 

and joint-filling.

In hand specimens the least altered material is cream-colored. 

Orthoclase and microcline phenocrysts up to 2 millimeters In diameter 

are common. In the southern trench biotite brooks up to 2 inches in 

diameter are abundant. In the northern trenches the rock is finer 

grained and biotite is rare or absent. In a thin section of the weathered syenite the groundmass consists of feldspar grains (averaging 

0.1 millimeter in diameter) and very fine-grained yellowish material, 

presumably composed of clay minerals. The feldspar contains abundant large apatite inclusions. The rock also contains a few grains of 

zircon and 1 or 2 percent opaque minerals. Ferromagnesian minerals, 

if originally present, have been altered to clay minerals. The rock 

was originally a syenite but cannot be identified further in its weathered condition.

SAMPLING AND ANALYSIS

A split of the original sample collected by the Arkansas Division 

of Geology was obtained and analyzed by the Geological Survey. In 

addition, 3 channel samples, 3 grab samples, and 5 samples of churndrill cuttings were taken during the present work. The locations 

where samples were taken are shown on figure 12, and the results of 

analyses are given in tables 11 and 12.

TABLE 11. Quantitative and semiquantitative spectrographic analyses of samples 

from the Wilson prospect, Potash Sulphur Springs, ArTc.

[R. O. Havens, analyst, except where noted, ell (equivalent uranium), the quantity of uranium in equilibrium with its daughter products that would produce the observed radioactivity. X, a figure other than 

zero: X indicates a value between 1 and 9 percent, O.X indicates a value between 0.1 and 0.9 percent, 

and so on. Leaders indicate element not looked for; zero indicates element looked for but not found at 

limit of sensitivity. Elements looked for but not found in any sample: Ag, As, Au, B, Bi, Cd, Co, Qe, 

In, Ir, Hf, Hg, Li, Mo, Os, Pd, Pt, Re, Rh, Ru, Sb, Sm, Sn, Ta, Th, Tl, W, and Zn]

Field no.

1143-Bi..-..

VF-PS-5..-

VF-PS-6___.

VF-PS-7--.

VF-PS-9-__

VF-PS-11...

VF-PS-14.._

Laboratory no.

51-10745

D-67153

D-67154

D-67155

D-67156

D-67157

D-67158

Description

der"; iron-stained, siliceous material.

1.5-foot channel sample.. ............

Nb

1.6±0.3

.OX

.X

.X

.X

X

.ox

Ti

X

X

X

X

X

.X

Y

0.05

.OOX

.OOX

.OX

.OOX

.ox

.OOX

La

0.05

.OX

.OX

.X

.ox

.X

.OOX

eU

0.011

.009

.007

.004

.13

.005

U

0.008

.005

.005

.005

.15

.002

1 K. J. Murata, analyst.
54 CONTRIBUTIONS TO ECONOMIC GEOLOGY

TABLE 11. Quantitative and semiquantitative spectrographic analyses of samples 

from the Wilson prospect, Potash Sulphur Springs, Ark. Continued

Field no.

1143-B .. 

VF-PS-5 -----

VF-P8-6-.. . ..-...

VF-PS-7 --

VF-PS-9 

VF-PS-11 .... 

VF-PS-14.. ------

Field no.

1143-B-. .............

VF-PS-5 ..-. ....

VF-PS-6- ........

VF-PS-7.. 

VF-PS-9 .. .

VF-PS-11 .... ...

VF-PS-14 

Field no.

1143-B........ -...

VF-PS-5 

VF-PS-6 .. .. 

VF-PS-7- - .

VF-PS-9 

VF-PS-11 _ -

VF-PS-14- -

Si

XX

XX

XX

XX

X

XX

Al

XX

X

X

X

K

X

X

X

Nd

o.ox

.ox

.ox

.ox

.ox

0

Fe

X

X

X

X

Ba

n v

.X

.X

.X

Ni

0

0

o.oox

0

Mn

O.OOX

.OOX

.OOX

.OOX

.OX

.ox

Be

Tr.

O.OOOX

.OOOX

.OOOX

.OOOX

Tr.

Pb

0

O.OOX

.OOX

.OOX

.OOX

0

P

o.x

0

.X

.X

X

0

Ce

O.OX

.OX

.X

.OX

.X

0

Sc

O.OOX

.OOX

.ox

.OOX

.OOX

.OOOX

Ca

o.x

.X

.X

.X

X

.X

Or

o.ox

.ox

.ox

.OOX

.OOX

.OOX

Sr

O.X

.X

.X

.ox

.X

.ox

Mg

O.X

.X

.X

.X

.ox

.X

Cu

O.OOX

.OOX

.OOX

.OOX

.OOX

.OOX

Zr

o.ox

.ox

.ox

.ox

.X

.ox

Na

o.x

.X

.X

.X

.X

X

Ga

O.OOX

.OX

.ox

.ox

.OOX

.OOX

V

O.X

.X

.X

X

.X

.ox

TABLE 12. Analyses of samples of cuttings from churn-drill hole CH-1, Wilson 

prospect, Potash Sulphur Springs, Ark.

Field no. 

5AR53K 

6AR53K 

7AR53K. 

8AR53K. 

9AR53K.

[Quantitative chemical analyses by A. P. Marranzino]

Depth of 

cuttings (feet)

___________________________ 6^-8

_ __ _ ____ _ _______ ___ 53

±65 

75

Nb (percent) 

0.20 

.11 

.11 

.05 

.06

Radioactivity is irregularly distributed in the weathered rock 

exposed in the cuts. Because of the irregularity, no systematic radiometric work was done. Sample No. VF-PS-11 was taken at one of 

the places where the rock is highly radioactive; it contained a notable 

quantity of niobium and uranium. Churn-drill hole CH-1 was drilled 

at this point. Samples of cuttings were taken from the cutting trough 

about a year after the hole was drilled. The only feature noted visually was the presence of abundant pyrite in cuttings from below 40 

feet. The results of analyses, given in table 12, show that niobium is 

present but in smaller quantities than in the saprolite exposed near 

the collar of the drill hole.

CONCLUSIONS

The lack of outcrops and the limited exposures in the trenches preclude definite geologic interpretation of this occurrence. Material of
NIOBIUM AND TITANIUM DEPOSITS, ARKANSAS 55

this type high in niobium and uranium, and relatively low in titanium is not known to occur at Magnet Cove, and therefore no analogies with that area can be drawn.

The results of sampling suggest that material high in both niobium 

and uranium is not abundant, but that material relatively high (0.1 

to 0.9 percent) in niobium may be abundant in the trenched area. It 

is possible that certain elements, including niobium and uranium, 

may have been relatively enriched by weathering processes in the 

saprolite, as compared to the unweathered rock. Another possibility 

is that the zones high in niobium and uranium represent weathered 

pegmatites that contained minerals such as samarskite.

Estimates of quantity of material present cannot be made with the 

information now available. Further work should include diamond 

drilling to test the presence of similar material below the surface 

and to reach unaltered rock.

LITERATURE CITED

Bowen, N. L., 1924, The Fen area in Telemark, Norway: Am. Jour. Sci., 5th 

ser., v. 8, p. 1-11.

 Croneis, C. G., 1930, Geology of the Arkansas Paleozoic area: Arkansas Geol.

Survey Bull. 3, 457 p. 

Daly, R. A., 1933, Igneous rocks and the depths of the earth : New York, McGrawHill Book Co., Inc., 598 p. 

Dieke, G. H., and Crosswhite, H. M., 1943, The use of iron lines as intensity

standards : Optical Soc. America Jour., v. 33, p. 425-434. 

Eckermann, Harry von, 1948, The alkaline district of Alno Island: Sveriges

Geol. UndersSkning, ser. CA, no. 36, p. 13-163. 

Pine, M. M., Kenworthy, H., Fisher, R. B., and Knickerbocker, R. G., 1949,

Titanium investigations: The laboratory development of mineral-dressing

methods for Arkansas rutile: Mining Eng., v. 1, p. 447-452. 

Pine, M. M., and Frommer, D. W., 1952, Mineral dressing investigation of titanium ore from the Christy property, Hot Spring County, Arkansas: U. S.

Bur. Mines Rept. Inv. 4851, 7 p. 

Fleischer, Michael, Murata, K. J., Fletcher, J. D., and Narten, P. E., 1952,

Geochemical association of niobium (columbium) and titanium and its

geological and economic significance: U. S. Geol. Survey Circ. 225, 13 p. 

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Spring County, Ark.: Arkansas Res. Devel. Comm., Div. Geology, Bull

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Div. Geology, Bull. 12; 16 p.

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56 CONTRIBUTIONS TO ECONOMIC GEOLOGY

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INDEX

Page 

Acknowledgments....__.---..._._..._ 24-25

Analysis, apatite-..--_-._._..._...__ 48 

brookite____________ ___.. 35-38,39 

caldte -. . -.---- 48

perovskite.._..__-.______.___ 48 

rutile -- 31-34

spectrographic, conditions of._.,-.-_--.. 26-27

Calcite rocks, hydrothermal replacement.. _. _ 49 

location of___._ .....______ 43-44 

magmatic intrusion.......________. 49

Christy brookite deposit, character of.. _... 35 

location and extent. ..___ __ 34-35 

sampling and analysis_______.___ 35-38

Dinnin, J. I., analyst. 39

Harner, R. S., analyst .-..----. 33,37,39,42,48 

Havens, R. Q., analyst..__________._ 53 

Hufschmidt, E. L., analyst-_______..-.. 39

Kilpatrickbrookite deposit, description...... 38-39

sampling and analysis ..._.-----.-. 39

Kimsey calcite quarry, analysis of apatite. _ 48 

analysis of calcite.- ...__ ._ 48 

analysis of channel samples___--___ 46-47 

analysis of perovskite .. . 48 

average grade of channel samples. ... 48 

geology of . 44-45 

inclusions in. 45-46

Literature cited-..___ . .. 55-56

Magnet Cove, geologic features__... 24-25 

location 24

Magnet Cove TitaniumlCorp. rutile deposit,

character of...___________ 29-31 

location and extent___________.. 29 

sampling and analysis______...___ 31-34

Marranzino, A. P., analyst.__.__ ..... 54

Minerals:

apatite___.___.._....__........... 46

biotite_________.__________ 45 

feldspar_________________ 31 

feldspathoid________________ 31 

ferromagnesian.._.._____...___ 31 

magnetite_____._______.___ 45 

monticellite________________ 45 

perovskite____..-.______.__.. 45 

pyrite.... .___ ....__ __ 45

pyroxene... . -... .. 43 

rutile.___________._______.. 29-31

Mo-Ti Corporation property, analysis of._. 42-43 

description of.___ _.... __ 39

Murata, K. J., analyst_____________ 39,48

Niobium, relation^to titania..____ 33-34,38,41,47 

use of __ _ _ 23

Potash Sulphur Springs, geologic features__ 51-53 

location..._.__ 24,51

Previous work, Magnet Cove_.__ __ 25 

Potash Sulphur Springs. ____-___ 26,51

Radioactivity_ . 

Rose, H. J., Jr., analyst.

- . - 54 

................ 33

Titania, relation to niobium... ... 33-34,38,41,47 

Titanium, useof...__________ __ 23

57

U. S. GOVERNMENT PRINTING OFFICE: 1914