I D E N T I F I C A T I O N O F K A O L I N M I N E R A L S I N T H E

P R E S E N C E O F C H L O R I T E B Y X - R A Y D I F F R A C T I O N

A N D I N F R A R E D A B S O R P T I O N S P E C T R A

by

HID~.o~ KoD~A* and KAORU O I N ~ Tokyo Universi ty of Education, Tokyo, J apan

ABSTRACT

Experimental da ta are presented to show tha t the current auxilliary procedures adopted for identification of kaolinite in the presence of chlorite are not generally valid because the procedures often fail to give an explicit condition for distinguishing both the minerals.

As the result of an examinat ion of numerous infrared spectra in the OH region of clay minerals, obtained by using Nippon Bunko DS-401G Grating Speetrophotometer, it turned out tha t the absorption band at 36984-2 cm -1 is effective for dist inguishing kaolinite from other clay minerals wi thout the use of any additional techniques. The absorption band seems to be less affected by variation of particle size and erystallinlty than is the X-ray diffraction pattern. The band is detectable to a few weight percent of kaolinite in total amounts of clay minerals. Identification of kaolinite by its absorption spectrum in clay samples from sedimentary rocks was successful.

I N T R O D U C T I O N

In the course of studies on clay minerals in recent marine sediments and sedimentary rocks, we often encounter difficulty in identification of kaolinite in the presence of chlorite by X-ray powder diffraction methods. In such a case additional techniques such as critical heat treatment and hydrochloric acid treatment are frequently used. Though X-ray powder data obtained after these treatments provide valuable information for identifying kaolinite, it is often conditional because the treatments generally furl to give an explicit condition.

The infrared method has not yet been applied to the above problem. Recently the writers examined in detail features of absorption bands in the hydroxyl region for each clay mineral and noticed an effective absorption band for distinguishing kaolinite from the other clay minerals. Consequently they could easily develop their research on this problem.

The purpose of this paper is (1) to direct attention to the difficulty in obtaining useful differentiation by X-ray analysis involving additional

* Present Address : Mineralogy Laboratory, Soft Research Inst i tute, Canada Depart- ment of Agriculture, Ottawa, Ont.

236

IDENTIFICATION OF KAOLIN MINERALS 237

techniques and (2) to propose the use of an infrared method for rapid, exact and sensitive recognition of kaolinite.

The writers wish to express their sincere thanks to Prof. Dr. Toshio Sudo of the Geological and Mineralogical Insti tute for his comments and also to Prof. Dr. Koji Nakanishi of the Chemical Insti tute for the use of spectro- photometers.

C R I T I C I S M OF X - R A Y I D E N T I F I C A T I O N M E T H O D S

Characteristic Reflections of Kaolinite

In principle, detection of kaolinite is possible by the presence of 003 reflection, d = 2.383 A, and 060 reflection, d = 1.490 A. However, since the 003 reflection is fairly weak and the 060 reflection is often modified by 060 reflections from other dioctahedral minerals, the exact detection of small amounts of kaolinite admixed with chlorite and other minerals is very difficult. In such cases the detection by the above reflections is indefinite. Thus, further analysis is necessary.

Thermal Technique

A combined thermal and X-ray method has been generally accepted as a method for distinguishing kaollnte and chlorite. However, as pointed out by Nelson and Roy (1953) (see also Brindley, 1961) there is a difficulty in this method in that a temperature (generally 600 ~ ~ 450~ and a length of heating period (generally �89 ~ 1 hr) used in the treatment, must be carefully chosen in accordance with particle size and degree of crystallinity. In addition, consideration must be given to variations in thermal behaviour of kaolin mineral varieties and chlorite mineral species. This s tatement is based on the following experimental results.

By using the oscillating-heating X-ray powder diffraction method, an experiment was made on detailed thermal change of 001 and 002 chlorite reflections and of 001 kaolinite reflection. The reference specimens used are sedimentary and hydrothermal kaolin]tes, dickite, ripidolite, leuehtenbergite and thuringite. They are well-crystallized materials except for sedimentary kaolinite with somewhat lower crystallinity. The intensity of each basal reflection was measured at intervals of 5 ~ to 10~ as the temperature was being raised 10~ per minute. Figures la and lb are graphs of the change in intensity of the basal reflection against the change of temperature. In the experiments with the kaolin minerals, the 001 reflections disappeared entirely between 500 ~ and 720~ In the experiments with the chlorite minerals, the 002 reflections disappeared between 580 ~ and 660~ and the 001 reflections gave their maximum intensities between 610 ~ and 710~ Since these critical temperatures were measured in continuous heating experiment, the tempera- ture at which the basal reflection disappears tends to be somewhat lower if thermal t reatment is maintained over a longer period of time. I t is noteworthy tha t these experiments have produced varied behaviour and overlap of critical

238 ELEVENTH I~ATIO:NAL CONFERENCE ON CLAYS AND CLAY ~INERALS

800

/ 700

z . / �9 1 / "

/ / ."

600 500

Ternpereture 1 ~

" ~ 7 ~ reflection

'

g 3

400 300

J .0

! r • !

\:i !

- i \ \ f . . . . . . . . . . . . . . o ~ t W r . - '" t i T , : , / \ / ~ " d 14,7 ~ refllcll . . . .

[~ t ! /_~ / - : < - . . . . . . . . ~ . . . . . . . . . . .L . . . . . . i 7 . . . . . . . / - . < " I / ' ,

-.--- ! 4 .l:-f T .............. I ...... i . . . . . . . . . .

800 700 600 500 "400 300

Temperature,

FIGURE 1.--(a) The change in intensities of bhe 001 reflections of some kaolinites against the change of temperature. 1, Dickite (Kasuga Mine). 2, I-Iydrothermal kaolinite (Kampaku Mine). 3, Sedimentary kaolinite (Hara, Gifu Prcf.).--(b) The change in intensities of the 001 and 002 re- flections of some chlorites against the change of temperature. 1, Ripidolite (Hitachi Mine). 2, Leuchtenbergite (Wanibuehi Mine). 3, Thuringlte (Ichino-

koshi, Toyama Prefi).

temperatures. Because of this, it is still more difficult to choose the best temperature for distinguishing kaolinite and chlorite.

Hydrochloric Acid Dissolution Technique

Hydrochloric acid treatment has often been used. In this treatment chlorite is decomposed, whereas kaolinite remains behind. This treatment is generally carried out with 6N hydrochloric acid in a boiling water bath. Though a poorly crystallized chlorite or iron-rich chlorite is easily decomposed by the treatment in a period of time as short as 10 rain, generally treatment for 1 hr is required to achieve complete decomposition of most chlorites. However, according to Kobayashi and 0inuma (1961), experimental results suggest that it is difficult to choose with certainty the best period of time for treatment to differentiate between kaolinite and chlorite, regardless of variations of chemical composition and of erystaUinity. Therefore, the following case frequently comes into question.

Figure 2 exemplifies X-ray diffraction patterns of four clay fractions from sedimentary rocks before and after hydrochloric acid treatment for one hour. All the patterns after treatment have no distinct 14.5 ~ line, and have a

N27

IDENTIFICATION OF KAOLIN ~/[INERALS

Untreated. Treated,

K.C

7.2 ,'~

!

l ..'-' s C 4

K

7.2h

239

T022

A29

840J

a. lo o ~5o(2o) ~'o '1~~ '"' 15o(20)

F I auR~ 2 . - - X - r a y diffract ion p a t t e r n s of four spec imens before a n d a f te r hydrochlor ic acid t r e a t m e n t for one hour . (Ni-filtered CuK~ radia t ion .

weaker 7 A line than untreated specimens. This fact suggests the presence of chlorite and kaolinite. Figure 3 shows X-ray diffraction patterns of two other clay samples before and after treatment for 10 rain. The pattern of specimen A04 after treatment has no 14.5 • and 7 .~ lines, but that of speci- men A03 has a weak 7 A line. Therefore specimen A04 does not contain

240 ELEVENTH NATIONAL CONFERENCE O1~ CLAYS AND CLAY MZNERALS

3

4

- I I ~ I JO" 2o" 5o" 4~'

FIOUICE 3 . - - X - r a y diffract ion p a t t e r n s of two spec imens before and af te r hydroch lor ic ac id t r e a t m e n t for 10 rain. (Ni-filtored CuK~ radia t ion) 1. A04 un t r ea t ed , 2. A04 t rea ted , 3. A03 un t r ea t ed , 4. A03 t rea ted .

kaolinite, but specimen A03 may contain both kaolinite and chlorite. As seen in the X-ray patterns of specimens A03, A29, and 8401, the presence of a weak 7 A line cannot give a clear definition of kaolinite. This is because it is ambiguous whether the weak line is caused by the presence of a small amount of kaolinite, or imperfect decomposition of chlorite. This is a serious weakness of the hydrochloric acid t reatment method.

IDENTIFICATION BY INFRARED ABSORPTION ANALYSIS

Experimental In their s tudy on infrared absorption spectra of clay minerals, 0 inuma and

Kodama (1962) pointed out tha t kaolinite has a characteristic absorption band in the OH region, and that the band may be effective for distinguishing kaolin minerals from the other clay minerals. Recently the efficacy of the band to the identification has been reconfirmed on the basis of results of further

IDENTIFICATION OF KAOLIN MINERALS 241

e x p e r i m e n t s . T h e e x p e r i m e n t s h a v e b e e n m a d e u s i n g N i p p o n B u n k o D S 4 0 1 G G r a t i n g S p e c t r o p h o t o m e t e r h a v i n g e x c e l l e n t r e s o l u t i o n p o w e r . F i n e l y p o w d e r e d s p e c i m e n s o f t y p i c a l c l ay m i n e r a l s we re p r e p a r e d as m u l l i n N u j o l a n d m o u n t e d b e t w e e n s o d i u m ch lo r ide c o v e r sl ides. T h e r e g i o n f r o m 4000 c m -1 t o 3200 cm -1 was s c a n n e d s lowly. T h e f r e q u e n c y of e a c h a b s o r p t i o n b a n d w a s c a l i b r a t e d w i t h t h e a b s o r p t i o n b a n d o f p o l y s t y r e n e a t 3027 c m -1.

Results

T h e i n f r a r e d s p e c t r a o b t a i n e d a r e r e p r o d u c e d in F i g s 4 (a), (b), (c), (d), a n d (e). T h e w a v e n u m b e r s a re l i s t e d i n T a b l e 1. T a b l e 2 s u m m a r i z e s f e a t u r e s o f

TABLE 1.--LIST OF THE WAVE-NUMBER OF INFRARED ABSORPTION SPECTRA IN FIO. 4 (a), (b), (c), (d) A_~D (e).

Wave-number (ella -1 ) Fig. 1~'o. Mineral Origin 1 2 3 4 5 6

4(a) 1 Dickite 2 Diekite 3 Naerite 4 Nacrite 5 Kaolinite 6 Kaolinite 7 Kaolinite 8 Kaolinite

4(b) 1 Kaolinite 2 Metahalloysite 3 Metahalloysite 4 MetahaIloysite 5 Halloysite 6 Halloysite

4(e) 1 Leuchtenbergite 2 Mg-chlorite 3 Mg-chlorite 4 Ripidolite 5 Chamosite 6 Thuringite

4(d) 1 Illite (2M-t3Te) 2 Illite (IM-type) 3 Montmorillonite 4 Montmorillonite 5 Montmorillonite 6 Montmorillonite 7 MontmoriUonite 8 Montmorillonite

4(e) 1 Vermiculite 2 Allophane 3 Pyrophyllite 4 Tale 5 Serpentine 6 Serpentine

Nikkyo Mine Kasuga Mine Nikkyo Mine Kasuga Mine Kura ta Mine Kampaku Mine Nikkyo Mine Hara, Gifu Pref. Sanage, Aichi Pref. Zao Mine Joshin Mine Azuma Mine Kusatsu, Gumma Pref. Chitose, Kanagawa P. Wanibuchi Mine Hanaoka Mine Hanaoka Mine Hitachi Mine Arakawa Mine Ichinokoshi, Toyama P. Shiraishi Mine Abeshiro Mine Endani Mine Togo, Tottori Pref. Hanaoka Mine Aterazawa, Yamagata P. Hojun, Gumma Pref. Maeyama, Aki ta Pref. Uzumine, Fukushima P. Kanuma, Tochigi Pref. Honami Mine Manshu Haruyama. Fukushima P. Kamuikotan, Hokkaido

3700 3654 3626 3700 3660 3628 3696 3654 3624 3700 3660 3628 3696 3656 3626 3698 3662 3630 3696 3658 3628 3696 3659 3624 3698 3663 3630 3696 3670 3630 3696 3632 3696 3624 3696 3624 3698 3630

3664

3680 3685 3674

3630 3642 3635 3644 364I 3631 3630 3633

3570 3420 3570 3410

3414 3575 3420 3574 3412 3582 3414 3584 3454 3560 3420 3540 3380 3550 3390

3394 3406 3416 3414 3416 3424 3428 3360 3410

242 ELEVENTH NATIONAL CONFERENCE ON CLAYS AND CLAY MINERALS

TABLE 2.--LIST OF FEATURES O~' II~FRARED ABSORPTION SPECTRA FOR EACH CLAY MrNERALS

Mineral

Dickite, Nacrito

Kaolinite

Metahalloysite

Halloysite

Leuchtenbergite

Ripidolite

Chamosite

Thuringite

Illite

Montmorillonite (common)

Vermiculite

Allophane Pyrophyllite Talc Serpentine

Wave-number (cm -1 )

3696-3700 3654-3660 3624-3628 3696-3698 3656-3663

3624-3630 3696 3670 3624-3632 3570 3410-3420 3696-3698 3624-3630 3575 3414-3420 3664 3574 3412 3560 3420 3540 3380 3550 3390 3630-3642

(3394) 363O-3644 3406-3428 3360

Order of Relative Intensi ty

3 s

2 s 1 s 1 s 3 s

2 s 2 s

(5) ind. 1 s

3 s

4 v br. 3 s 1 s 4 br. or ind. 2 v br. 3 ind. 1 br. 2 br, 2 br. 1 br. 2 v br. 1 v br. 2 br. 1 v br. 1 s

v br. 1 s 2 br. 1 v br.

3410 3680 3685 3674

1 v br. 1 s 1 s 1 s

Remarks

Shoulder-like peak in some cases.

Indist inct shoulder-like peak i~ some eases.

In one case.

The richer the content of iron, the lower the frequency of the absorp. tion bands. The relative intensity of iron-rich chlorite is reverse to tha t of magnesium-rich chlorite.

Due to absorbed water. Similar to absorption bands oi illite containing absorbed water. Similar to absorption band of allophane.

NOTE : S : sharp, br. : broad, v br. : very broad, ind. : indistinct.

s p e c t r a for e a c h o f t h e i n v e s t i g a t e d m i n e r a l species or var ie t i es . As eas i ly s een in t h e s e d a t a , a r e m a r k a b l e f e a t u r e r e v e a l e d in all s p e c t r a o f kao l in m i n e r a l s is t h e p r e s e n c e o f t h e b a n d a t 3698 + 2 c m -1, w h e r e a s n o n e o f t h e o t h e r c l ay mine ra l s e x a m i n e d h a v e such a b s o r p t i o n b a n d . T h e b a n d is a c t u a l l y one m e m b e r o f t h e t r i p l e t in t h e r a n g e o f 3700 ~ 3600 c m -1 o f kao l in i t e a n d o f d icki te , as r e p o r t e d in p r e v i o u s i n v e s t i g a t i o n s ( R o y a n d R o y , 1957), a n d is also c h a r a c t e r i s t i c o f nac r i t e . T h e va r i ous h y d r o g e n i c s t r e t c h i n g f r e q u e n c i e s

2.5 3,0 r, [ J i I i i

1

4s

2

~4(7

4(

2~

[ I = [ 40 36 32 XIO0

W A V E L E N G T H

2.5 1 r 3 ~ 0 J , i

3' 5,

4(

40

4~ 6

I ,~ i i

W A V E N U M B E R

P 2.~ 3,0

I ] I I [ I I ]

J

/ I i I . I 2

40 36 . x IO0

c m - I

Z �9

Z

b~

F~ Z

0

2.5 3.0 I I ] I ~ r r

201

8

J ' l [ l 4(I 36 3:? X 10

zi, ' 1 6(

4 0 36 32 X l O 0

60/ 4 0 : �9

WAVELENGTH /4

2.5 3.0 [ I ! I I I

4 0

~o ~ 4

80 - �9 ~

40 ,

201 . " �9 i

40 36 32 X 100

W A V E N U M B E R c m "1

2.5 3.0

4 0

8a[ 6 . . . . .

ill) ,J 40 a6 gz xloo

FIGURE 4 (b ) . - - I n f r a r e d abso rp t i on spec t ra in the O H region of some kaol in minera ls . Corresponding wave num be r s are l i s ted in Table 1.

2 . 5 3.0

l

80 i

FIGURE 4 ( a ) . - - I n f r a r e d abso rp t ion spec t ra in the O H region of some kao l in minera ls . Corresponding wave num be r s are l i s t ed in Table 1.

2 4 4 ELEVENTH NATIONAL CONFERENCE ON CLAYS AND CLAY MINERALS

Z 0

< e~ [.-,

2.5 3.0 l | I I I [ 1 1

1 8C .0 4C

2C

2

8( ~ ~

60

4o

I 316 I I 4 0 3 2 X l O 0

WAVELENGTH

2.5 3.0 I I 1 I I I ] I

3

6G

411

/z

2.5 3.0 I I I I I ] ] I

5 | �9

8o

60 - - ' ~ '

4 0

4

6f

4(

[ I 4 0 3 6 312 1 O 0

W A V E N U M B E R cm "1

6 80b

60[[

40i

20t"

I I I | 4 0 3 6 3 2 100

FIGURE 4 ( c ) . - - In f r a red abso rp t ion spec t ra in t he O H region of some chlori te minera ls . Cor responding wave n u m b e r s are l is ted in Table 1.

observed in kaolin minerals can be tentatively assigned on the basis of Nakamoto, Margoshes and Rundle (1955) study as follows:

F r e q u e n c y A s s i g n m e n t O H . . . . O Dis t ance

3700 ~ 3696 em -1 Free O H 3670 ~ 3656 cm -1 Assoc ia ted OH* 3.2 (A) 3632 N 3624 cm -x Assoc ia ted OH* 3.1 (A) 3575 N 3570 cm -1 Assoc ia ted OH* 3.0 (A) 3420 ~ 3410 cm -1 Assoc ia ted OH~ 2.8 (A)

* Due to hydrogen ic s t r e t ch ing be tween h y d r o x y l ion a n d i ts su r round ing o x y g e n ions. The lower t he f requency , the s t ronger t h e h y d r o g e n bond.

D u e to a s y m m e t r i c a l s t r e t ch ing of in te r l ayer wa t e r molecule.

IDENTIFICATION OF KAOLIN MINERALS 2 4 5

Consideration of the variabili ty of X- ray da ta on the kaolin minerals used in the writers' experiments leads to the conclusion t h a t the absorption band at 3698__ 2 cm -z due to free hydroxyl stretching seems to be less affected by variat ion of crystallinity than is the X- ray diffraction pat tern.*

0 L'I Ir

0

2.5 3.0 [ ( [ i , i |

4(

2f

2

6 0

40

20

i ! z l 40 3 6 32 xlO0

W A V E L E N G T H /~

2. 5 3 .0 l i z i t I i 1 1

80 -

60|

40t

2ol !

2 . 5 3 .0 n i z i i ~ ~ i [ ;

51 ~ i

.o i " ~

!, 6~ i i Y

40

T

4 . 6 ' '

/ , ', , ', 1 i

40 ~ 3'2 x l o o 40 36 32 : .WAVENUM BE P, c m ' l

2.5 3.0 I l l I i i * I

7 : !

8( ~ -

6( -

4c 4~-- : - - - - - t

.i 8

15r

4C

i 1oo 40 3'. ' 3[z x l o a

FIGURE 4 (d).--Infrared absorption spectra in the OH region of some illites and montmorillonite minerals. Corresponding wave numbers are listed in

Table 1.

The absorption spectra for artificial mixtures of kaolinite and other clay minerals in various mixing ratios give information on the detection limit. (Fig. 5). Even in the spectra of a mixture of chlorite (1), illite (1), mont- morfllonite (1) and kaolinite (0.14), the band at 3968___2 cm -1 is visible as a shoulder-like peak. I t s approximate detection limit was est imated to be a few weight percent of kaolinite in the total amount of clay minerals. This seems to be about the same detect ion limit as in the X - r a y method. However , infrared absorption analysis has an advantage in t ha t there is no necessity for using any additional t reatment .

Examples of Identification of Kaolin Minerals

The above-mentioned six hydrochloric acid t reated specimens were re-examined by infrared absorption analysis. The results are shown in

* S e e a l s o , f o r e x a m p l e , H i n c k l e y i n t h i s v o l u m e .

17

246 E L E V E N ~ N A T I O N ~ CONFERENCE ON CLAYS AND CLAY MINERALS

o

03 Y:

ro i:=

B O

60

4(]

80

6O

4O

2.5 3.0 l I ! I i i i

~*-i i i "t

2

�9 i i i i 40 36 32 xlO0

WAVELENGTH /~

2.5 3.0 i i i i i i |

3" ~ i

41

t i ,

4

6C

4C

40 36 32 :100

WAVENUMBER cm -t

2,5 32 i . ! . I I I i I

5 '

8t ~ '

61 J ~ 4(

- " t i t

1.6

41 / - - "

21

"~ i i i 40 36 32 1 0 0

FIGURE 4 (e).--Infrared absorption spectra in the OH region of vermiculite, serpentine and some other minerals. Corresponding wave numbers are

listed in Table 1.

Figs 6 (a) and (b). Infrared spectra in the usual infrared region of 4000 650 cm -1 were recorded by using a Nippon Bunko IR-S spectrophotometer. Results in the hydroxyl region were recorded with the DS-401G Grating Spectrophotometer. The spectrum of the specimen N27 shows other character- istic absorption bands of kaolinite in the range of 1100 ~ 900 cm -1, but these bands can not be found when only a small amount of kaolinite is present (< 15 ~ 20 per cent) (Oinuma and Kodama (1962)). On the other hand, the absorption band at 3698 +_ 2 cm -1 was clearly observed in the specimens N27 and Y022, and even in the specimens A29 and A03 showing a very weak 7 X-ray diffraction line even after acid treatment. Thus, it can be concluded that the weak 7/~ line is caused by the presence of a small amount of kaolinite. A very weak 7/~ line in the specimen 8401 is still doubtful since the absorption band is very faint. Even if the specimen contains kaolinite, the amount might be less than a few weight percent. These results prove that infrared absorption analysis facilitates the identification of kaolinite, particularly in the presence of chlorite.

I D E N T I F I C A T I O N O F K A O L I N M I N E R A L S

W A V E L E N G T H

247

0

G9 Z ,<

E-,

Z r ~

: . s : . e 2 . = ~ e 2 9 3 o 3 z

j I ! : , I i

I ' i [ : 8 c ~ " 1 _ ,

)oc ~

I I ,

4000 3SO0 3100

?s 2e 272e293.0 3.= .I0~ I I I [ ]| l

. _ ! 2 . . . . "

I

8C I 1 7 ,

i I 6~ . . . . . t ~

! i |

8 O - - , * .

, I

4 0

4000 3SO0 1200

W A V E N U M B E R c m - Z

F m U ~ E 5 . - - I n f r a r e d a b s o r p t i o n s p e c t r a o f m i x t u r e s o f s t a n d a r d c l a y m i n e r a l s i n t h e O H r e g i o n .

1. I : K = 1:1, 2. I : K = 1 : 0 . 5 , 3. I : K = 1 : 0 . 2 , 4. I : K = 1 : 0 . 1 , 5. C h : I : K = 1: 1: 1, 6. C h : I : M : K = l : l : 1: 1, 7. C h : I : M : K = 1: 1 : 1 : 0 . 5 , 8. Ch : I : M : K = 1 : 1 : 1 : 0 . 1 4 . I . . . I l l i t e ( S h i r a i s h i M i n e ) , C h . . . C h l o r i t e ( W a n i b u c h i Mine}, M . . . M o n t m o r i l l o n i t e ( H o j u n , G u m m a P r e f . ) , K . . .

K a o l i n i t e ( H a r a , G i f u P r e f . ) .

2 4 8 E L E V E N T H NATIONAL CONFERENCE ON CLAYS AND CLAY MINERALS

~,lili|lO i II Ill I

WAVELENGTH s

I

~,.r. F

l o l l 11 11 l i l l

rH l , s il.,I 1.7 l l . i i o 1.o l . : ~ ' ~ 1 i I I I I 1 1

, ~

Z 0 U~

Z ,<

Z

Ilg

f

r "

Jl !A2~

�9 .,,x... f/G .... ,,

-._./

k,,-, f

f

" f

\ I /

,lJ \_

I

/ 400O :~SO0 ~200 ;ZIO0 2400 ~000 l l o 0 l e o 0 1400 x=o0 I 1 0 0 IOO0 900 ~00 700 ' tO00 3 e o O ' ~ t O 0 : 1 4 0 0 : l O ~

W A V E N U M B E H cm. "~"

FIGURE 6 (a) . - -Infrared absorption spectra of four specimens from sediments and sedimentary rocks.

0 I/)

C/) Z

c-I

1 ~ 2 ~ 2 a 3 o

I1,{11

IDENTIFICATION OF KAOLIN ~/~JIERALS

WAVELENGTH

4 ~ S 7 a ~ 10 I* )2 13 14 ~

249

/

/-,,. f

+ .

4000 3600 3200 2ano 2400 2coo 18oo 16oo ~4oo 12oo lloo ~ooo ~oo

W A V E N U M B E R c m -1

I . . . . I . . . . .

i i i i i ~o~ ~oo

I

'4000 aeOo 3eO0 a400 3200

FIouaE 6 (b) . - - Infrared absorption spectra of two specimens from sedi- mentary rocks.

REFERENCES

Brindley, G. W. (1961) Kaolin, serpentine, and kindred minerals, and chlorite minerals: in The X.ray Identification and Crystal Structures of Clay Minerals, 2nd Edit ion, G. Brown, cd. Mineralogical See., London, p.84, and pp.260-266.

Kobayashi, K., and Oinuma, K. (I961) Clay mineral composition of the core sample obtained from the bot tom of the J a p a n Trench by Takuyo in 1959: Contribution from the Marine Research Laboratory. Hydrographic Office of Japan , v.2, pp.109- 117.

Nakamoto, K., Margoshes, M., and Rundle, R. E. (1955) Stretching frequencies as a function of distances in hydrogen bonds: J. Amer. Chem. Soc., v.77, pp.6480-6486.

Nelson, B. W., and Roy. R. (1954) New data on the composition and identification of chlorites: in Clays and Clay Minerals, Natl. Acad. Sci.-l~atl. Res. Council, pub. 327, pp.335-348.

Oinuma, K., and Kodama, H. (1962) Infra-Red absorption spectra of clay minerals: (in Japanese with English abstract). In press. J. Geol. Soc. Japan.

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