 /+  ,**,

175

ῑ

ῒ





 +,  ++  ,   +.  +  +/ Distribution of Minor Elements in Banded
Structure Formed in Hokutolite Crust
Nobuyuki SASAKI
Department of Chemistry, Faculty of Education, Kagawa University

Abstract
Banded structure of hokutolite with brown and white crystal layers is often observedin Tamagawa Hot Spring, Akita, Japan, and in Peito Hot Spring, Taiwan. Two types ofthe banded structure are found : one shows higher Pb content in brown layer than inwhite layer, and the other shows higher Pb content in white layer than in brown one.
Chemical analyses of Sr, Ca, Fe, as well as the major metals of Ba and Pb, and X-ray
di#raction measurements of each crystal layer of this mineral obviously showed thedistinct di#erences in their chemical compositions and unit cell parameters.
As a result, relationships between chemical compositions of each crystal layer wereclassiﬁed into - types. And two types of formation mechanisms may be possible for thisbanded structure. One is the changes of chemical compositions in the crystal growth.
The other is the phase separation through two types of ion migration (exchange) after
precipitation.
Key words : banded structure, hokutolite, crystal layer, partition, phase separation :  ! "#$ %&' () *(++ῌ ῏ ῍ ῐ ῎,-./01234."#0156789:;<="#$9>?@A BCD5EF.GHI
9JKLDMD.GHNOPC@?=N  +331 "#$.Q9ARS.%&' RS'

TUS.%&' US' NVW9XYZ[\]^>^.N_`C@aK bc +3-* 2
deῌfg +30. 9JKhiLC@?=j /01:.^.9>?@A RS'AUS'9kl=T m n.opqNrF s9US'Atuvwopq2xyvwOz9J={|}Nr?BTNbc +3-* 9JK~LC@?=j

 2

176

Fig. + Banded structure hokutolites C and D formed at Tamagawa Hot Spring (+ a, + b). (+ c) A viewof banded structure hokutolite sample D.
 + 
    ῌ  ! "#$%&'()&*+,- !./
0& 1234 - ! 56 78+!9"#$% :&; <=>&?+@ABC
0D EF GC 78HI J,K34
LK0MNO&PQ4RS0TU!
VWBCXG YOXZ0[\]^_`
abcde`a <=>HfB
CKD
ghiX! XJj X kF

 [\]^_`abcde`a4lHmnFYO 123
4XJjopqrstq u$O+#$O

Fig. , Banded structure hokutolites E and F formed at Peito Hot Spring, Taiwan (, a, , b).
 , 


12vwLsf xy z{ |}s~S0++H 4U

HFD,ῌ ῑΐ῍῏῎ῒῐ,ῌ+ ῑ ΐF !
Fig. + a

H s Figs. + a, + b, + c  

C !

JK % #$O C+ &XJ + mm
sHD Figs. + b, + c H s Figs. , a, , b SD  4RFH sFH #$+u$ % u$O C, &XJ +./ mm

D !#$O ,. mm u$O -. mm,O



 MNO&Q

Os4X  u$ D+ #$ D, u$ D- #$ D. u$ D/ #$O D0

0 O  Ou$O& OF&#$O &SJ,» /+ ¼ -,**,.

·¸$¹6 

 

177

   !"# $%&' Fig. , a  E () *) , + ,()+ -E+. /01 . mm 2*)+ -E,. /01 +2 mm 34
Fig. , b  F *) ) *) - +055 ,*)+ -F+. 67)+ -F,.

2*)+ -F-. /01 - mm 34 

,, ῌ

,8 . 9':+; <=>?5@5 AB CD E>F  
GHI 0J  C  , +  D  0 +  E  , +  F  - +K +- +'LM>F 

ENOCPQR0 S >  Ba, Pb TUV ICP

W W

E Sr, Ca, Fe TUVXYZW E05LM>F [  ,8 -+- +. 'ῌ\ ]^05]^_`>ab cYMdLM>F LMDefghThijklmn Rint +,** >  o +./.+2 p CuKa+ \ -Ni jqr

si.  teu .* kV te ,. mA vwxy +zῌmin/*zF  TQ

 > cYMd>

Md + s {| LM}y , q~+/z-a~/..+30 p. >

]^}>F  - 
ῌ\]^<+ >G il]^_`>  <= >' >  C /0 D CD E<> Table +  

E /0 F CD E<> Table , G y6:i V¡ -wtῌ.   ¢£¤¥R¦ .

'©r  -molῌ. y

y>RC§¨  Ba, Pb, Sr, Ca ' [  ῌ\]^05 <>cYMdª> Table -  «¬#

­  Vegard ®¯CD °±² ³´>  µ  > K

Table + Chemical compositions of each crystal layers of banded structure hokutolite formed at
Tamagawa Hot Spring.
 + ¶%·¸$¹CDBaO(wt4ῌ) (molῌ)*

PbO(wt4ῌ) (molῌ)*

SrO(wt4ῌ) (molῌ)*CaO(wt4ῌ) (molῌ)*Fe, O-**(wt4ῌ)

C+
C,

.-423
./432

3.4-1
2/4*2

-41+*4/2

/4/+
+-4./

*4*,
*4,.

*4*0
*400

*4*+
*4+0

*4*0
*42+

*4,*
*4+,

D+
D,
DD.
D/
D0

-24*2
.-4+3
.*4.*
.*41.
-24./
.-4+0

2/4,2/4++
2041.
2.4-3
20420
3*4.*

243+
+*4+143/
341,
140/
04.2

+-41*
+-41+
++41+-42++421
34-,

*4+.
*4,,
*4,2
*4-2
*4+3
*4*1

*4.0
*40.
*423
+4+0
*40.
*4,,

*4+*
*4+*
*4++
*4++
*4+*
*4*+

*40+
*4/.
*40/
*40+
*40*4*0

*4.+
*4+0
*4*0
*4*0
*4./
*4+0

Sample No.

* Composition in molῌ as to barium, lead5 strontium and calcium. Molῌ was calculated on thebasis of BaºPbºSrºCa~+**ῌ.
** Fe is not in the crystal structure of barite.

\[?

178

Table , Chemical compositions of each crystal layers of banded structure hokutolite formed at
Peito Hot Spring.
 , no\[nop>?@5
Sample No.

BaO(wt4ῌ) (molῌ)

PbO(wt4ῌ) (molῌ)

SrO(wt4ῌ) (molῌ)

CaO(wt4ῌ) (molῌ)

Fe, O(wt4ῌ)

E+
E,

.+402
..41-

224-/
214/,

/430
24-1

2402
++4,/

*401
*4,.

,4+*
*403

*4+/
*4+*

*421
*4/-

*4*3
*4+*

F+
F,
F-

-*4*.
-*4*1
,+4,/

014/1.420+43/

+0403
+,42,
+04,1

,/411
,+43,
-,4/2

+421
*421
+4+2

04,,
-4,*
/4*3

*4*2
*4**2
*4/

*4.2
*4*/
*4-2

*41/
+43+
+40.


  C C+ C,    !"#$%&' ()*+,-./0 123/0#$%!&'
45678/0#$%9  :;<=
>?@5ABCDEFGH  IJ +3-*
*+,-./0CKL MN!O PQ

RSG TUN VWXR +33, YDZ[\[]RB^\_O`a_!Gbcde>?@5AB:;<=GHNf  :gGhiYDjkGB^b5lm!Gb5Nnop>?@5q  rs\[tuῌ\[]Rb
5Nnop , v S+, S, >?@5
Table .

 wxno\[tsGb5Nnop , v P+, P, >?@5 VWX
yz +322  Table /CMS :gRg!YcZ[\[]RB^\_

Table - Lattice constants (a, b, c) and cellvolume (V) of each crystal layers of banded
structure hokutolite.
 - nop
Sample
No.

a ()

b ()

c ()

V (-)

C+C,

2.2.- (.)
2.13/ (-)/..., (,)/..-3 (,)

1.+-. (,)
1.++, (,)-.-.. (.)-.*., (-)

D+
D,
DD.
D/
D0

2.130 (/)
2.2*+ (-)
2.2*/ (0)2.12/ (.)
2.2*0 (,)
2.2,3 (,)/..-, (-)/...- (,)/...2 (,)/..-0 (.)/.../ (+)/..., (,)

1.+*/ (-)
1.++- (,)
1.+,+ (,)
1.*3/ (/)
1.++2 (+)
1.+,, (,)--3./ (/)-.*.1 (-)-.+.0 (/)--2.3 (0)-.+.- (,)-.,., (-)

E+E,

2.2-+ (/)
2.2+. (,)/...- (-)/...2 (+)

1.+,, (-)
1.++1 (+)-.,.- (0)-.+.2 (,)

F+
F,
F-

2.1,* (/)
2.103 (3)2.1+. (/)/..., (.)/..-0 (-)/...+ (.)

1.*0/ (-)
1.*22 (-)
1.*0+ (.)--/.- (0)--1.3 (1)--..2 (0)* The numbers in the parentheses show thestandard deviations.
*   CA


O{|} `a} !GdeN!GH  S+ C S,~  " *+,-./0 123/0#$%&'^N  P+ C P,^ :gC C+  C, AB'Yc;<=GH~  " *+,-./0 123/0  g#$%!&'

 :gCG D/  D0 ABYc;<=GH   D GH  D+  D, S"#$%C D,  D+  &'  C  CGH: N *+,-./0#$%! D,&'   123/0#$%C9 :   D,  D- GCOC D, "#$%&  _C*+,-./0O123/0#$% g!9  N D-  D.

C D+  D,  Yc' OC  D. "#$%&' *+,-./0#$%CG&  123/0#$%CG9  D.

' /+ ( ),**,*

" #$ % %&179

Table . Chemical compositions of hokutolite formed on Yubana conduits at Yukawa downstream,
Tamagawa Hot Spring.
 .   ῌ Sample No.

BaO(wt4ῌ) (molῌ)

PbO(wt4ῌ) (molῌ)

SrO(wt4ῌ) (molῌ)

CaO(wt4ῌ) (molῌ)

Fe, O(wt4ῌ)

.14,0
.143/

+-4/*
3400

*4-/
*4-,

*4+1
*4++

*4++
*4/,

S+
S,

2,4+1
2040,

+04++,4**

*43*
*420

*42+
*4/-

S+ : Brown crystals formed above the surface of hot spring waters in Yubana conduits from +31/ to+323 (sampled in Oct., +323).
S, : Yellowish-brown crystals below the surface of hot spring waters in Yubana conduits from +31/
to +323 (sampled in Oct., +323).

Table /

Sample No.

Chemical compositions of hokutolite formed at Yukawa5 Peito Hot Spring4
 / 
 BaO
(wt4ῌ) (molῌ)

PbO(wt4ῌ) (molῌ)

SrO(wt4ῌ) (molῌ)

CaO(wt4ῌ) (molῌ)

Fe, O(wt4ῌ)

.*410
.*4/+

,-40,
+34*1

+4/3
+4-*

*4+.
*4*3

+4+0
*41-

P+
P,

024,0
1,40,

,14+2
,-4.2

-43-4./*40*4./

P+ : Grayish light brown crystals
P, : Whitish brown crystals

Table 0 Di#erences between chemical compositions of adjacent di#erent color layersof banded structure in hokutolite formed at
Tamagawa Hot Spring.
 0  


Ba

Pb

Sr

Ca

Fe

C+

W
B

W
!
B

W
!
B

W

C,

W
!
B

D+

B

D,

W
!
B

B
!
W
B
!
W

B
!
W
!
B
!
W

B
W

DD.
D/
D0

W
!
B
!
W

W : white crystal layer
B : brown crystal layer

Table 1 Di#erences between chemical compositions of adjacent di#erent color layersof banded structure in hokutolite formed at
Peito Hot Spring.
 1  


Ba

Pb

Sr

Ca

Fe

E+

W

W

W

B

E,

B

W
!
B

B

B

W
!
B

B

B

F+

B

B

B

W
!
B

W

F,

B
!
W

B

F-

B

W
!
B

W
!
B

W
!
B

B

W
!
B

W
!
B

W

W

W

W : white crystal layer
B : brown crystal layer

B
!
W
B



180

 D/  D-  D.   D      !"#$ %&'()*+,$-"# . /0ῌ12345678

Table 2 Relations between chemical compositions of adjacent di#erent color layers of
banded structure in hokutolite formed at
Tamagawa Hot Spring.
Z 2 f!ST"#Ba

9:;*+,<=> < ?@ D/  D0

$A!B D0 C

C+-C,<D!B D/ 9. EFGHIJK L

D+-D,
D,-DD--D.
D.-D/
D/-D0

MNJKOP Q6 C  9:;RST UVWX"#YZ'[ Table 0, Table 1
9:;
 \]^! _`JK"( <aC<D!ba
Y!cd <aC<D!bO

Pb

Sr

Ca

Fe

n-c

n

n

abn

abn-c
abn-c
abn-c
abn-c
n-c

n
abn
n
n
n

abn
abn
abn
abn
n

abn
n
abn
abn
n

n : normal
abn : abnormal
n-c : normal color
abn-c : abnormal color e! Y!fdgh[ C+  C, T $!cd"# D+-D,,
D,-D-, D--D., D.-D/ T $!fd"#D/-D0 T$!cd"#; ) EFGHIJKijkl$mnomn[Yc^"Y cdg

Table 3 Relations between chemical compositions of adjacent di#erent color layers of
banded structure in hokutolite formed at
Peito Hot Spring.
Z 3 f!ST"#Bap -qr[Ys^"Y

Pb

Sr

Ca

Fe

fdgh[ C+  C, T $

E+-E,

n-c

abn

abn

n

EFGHIJK LMNJK$t8

F+-F,
F,-F-

n-c
n-c

n
n

n
n

abn
abn

cd"# . u$fd"# :< v 9:;RST UV"#w9p!"#Y
x Table 2, Table 3, Table +* 9:;
8yZY( f; , STU
Vlz"#Yl{[ Table ++ 9:WvP -  ;( /  l|< v }*+, + $~dy8*+, mn EFGHIJKLM

Table +* Relations between chemical compositions of hokutolites formed under di#erent conditions4(S : Tamagawa hot Spring5 P : Peito Hot
Spring)Z +* f;
()T "#
Ba

Pb

Sr

Ca

Fe

NJKmn( u$mn[qr[

S+-S,

n-c

n

n

abn

 , {  Q$ $ D 

P+-P,

n-c

n

n

n

? B\] D/-D0
( Table /'() P 8)

 @$
( Table .

<8^$ C  F <8^'() S *+,

[ *+, , $mnEFGH

» /+ ¼ 7,**,9YZ[\¹º`

181

Table ++ Classiﬁcation of the relations between chemical compositions of adjacent di#erent color
crystal layers of banded structure in hokutolites.
 ++ YZ[\8!¬]^_`,-
Ba

Pb

Sr

Ca

Fe

Examples

Type +
Type +’

n-c
n-c

n
n

n
n

n
abn

D (D/-D0), P
C, F, SType ,
Type ,’

n-c
abn-c

abn
abn

abn
abn

n
n

E
D (D,-D-)

Type -

abn-c

n

abn

abn

D (D+-D,, D--D., D.-D/)

  !"# $!"# , %& '()*+ E  E+-E,, E,-E,-.+ D  D,-D- ,-/0 .+)1!

,-23456 7!839 ,-& :; <=> - ?@A
B 



<=> '()

D  D+-D,, D--D., D.-D/ ,-<=>/ <=>!CDEF!83<=> GHI 0 JKL 7+30.9 MN# OLP<=> , <=> !83QRST
UV '(WXOYZ[\80]^_`,-"abF cde - f;O g h0YZij"OL OklfmnEmoh
pkl +qrsnELkl + ftu`v mewxy`z{ 7|} ~}09 cde
 OOyO 45R0L80_`tu]80 y` O [\tu`v} *.+*., mmῌGL 7
+33/9, mm ^tu] +* UV`v O 0

 +32+Lr  Oh0kldOoL)_`GLom<=> + /& <=> , <=> - h0_`,-;m0 G
L <=> + YZijh0tuy`z{^ h&yo;O 79 nELpkl ,qg h0 7=B9  7 ¡¢ 9 h&OL;O 7£¤ +3329 nEmoh 0TP ¥¦y` Otu§¨& YZijdO 45©]^h0 7 ª9 ¨XOnE
L«G ¬ , fQ 7tu]9 a  b ^­b"]^ª®¯ Ba, Pb, Sr, Ca  . %fmDEF 1 2& ª®¯nEL°±HI 7!F9  ++ #;h - <=>o r²³,-" 7=B9ª®¯´" mgh0

<=> + "µ ª´
7Ba9a¶x7Pb9b¶y7Sr9b¶7+·x·y97Ca9b¸7Ba9b¶x7Pb9a¶y7Sr9a¶7+·x·y97Ca9a

ῌ

¬¼

182

 , 
x Ba a Pb by Sr a +xyCa ax Ba b Pb ay Sr b +xy

Ca b

῍

Ca b

῎

 - 
x Ba ay Pb b +ySr b +xCa a

x Ba by Pb a +y

Sr a +x *x, y+    !
"#$%& '()*+ Ba ),-+ Pb, Sr, Ca .

/ * 0"1 234" +156$#7$

ῌ 8%

9 + 

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Ichikuni, M. (+31-) : Partition of strontium between calcite and solution : E#ect of substitution of manganese. Chem. Geol., ++, -+/ῌ-+3.

RSTU7 D+331F : VWXYZ [;<=\ +** ]^_ `abc .1 ++/ῌ+,.(Sasaki, N. and Watanuki, K. (+32-) : Variation in chemical composition of naturally occurring
lead-bearing barite (hokutolite) having crystallized since +3/- at Tamagawa Hot Spring.
Miner. J., ++, ,31ῌ-*,.

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