

J. Hot Spring Sci. /2 +-.ῌ+.1 ,**20+   +

Some Implications on the Hot Spring Research
Joyo OSSAKA+

Abstract
A rock alteration process is made up of dissolution of water soluble components andremaining of insoluble components. However, each rock component is not leached out
disorderly. Water soluble components in rocks make temporarily secondary minerals
that are stabilized under the environment there. For example, we can ﬁnd commonly
alunogen and halotrichite as secondary minerals at around volcanic fumaroles. Changein chemical composition of rock in an acidic alteration process will be more easily explained by considering the formation of such secondary minerals.
On the other hand, acidic spring water from submarine volcano supplied to seawater
makes suspended substances which show yellow, brown or reddish brown colors. Thosesuspended substances are amorphous minerals like allophane and hisingerite. The colorof the suspended substances depends on their mineralogical and chemical compositions.
These observations suggest that a mineralogical approach must provide us the better
understanding on the changes in chemical compositions in nature connected to geothermal ﬂuids.
Key words : rock alteration, secondary mineral, submarine volcano, colored sea water  !"#$%"&'("$%)*'+,-./012 3
345  6$$%789:"&;2<04= >?@:ABC:DEFGH'42IJKLM6$;2N-512 O'PQ RSTUV0 IJKL'3FWXYZ[\]^_`abc`4dMe2f'50g2 h#:ij+$k Alj4IJKLm$Mno;2f'0 lpqr:st;2f'!u012'v.w2
>x yzRS h#{|5}~w2'   4d LMy|52 fw  L '3FW_\]\[c`lj4'dKL:l2<'v.w2 $;2 LAKL+$Dlk +$:
+

134


 +/,ῌ**+,  ,ῌ/ῌ1 + Professor Emeritus of Tokyo Institute ofTechnology, ,ῌ/ῌ1 Senzoku, Meguro, Tokyo +/,ῌ**+,.

 /2  ,**2    !" #$% pH &'( #$%)* + ,  -. /01 2%3 4 56789:;$%<=>?@%# #: 1A5$B-%C DEF2%
GHIHJ : K L M,  67 3OP4Q " M ,N/R*S + T+ U  KVW L

, # DX 4C+U  67Y+ NZ[ 4\% 3 ,U] ^-!_`@2_ +Ta2%: QU4\%3 3OPbcR*S% C14\%

 !"#+++ 



67d?@%K L=>5 halotorichite ? e alunogen  f" F +300 5gh +302 ij/k$ l_ gh +33/ CmDn2_f675 o H,S 5 SO, /pq6789/r_1 sVW/r_1"f%t:\% 3 +-d4 5!""uv"E"?Fw xK#B L/y@"z{N $N |$N/%"f% 3 +-d/67}& ~4f%
 +  +3 H4k"\%
3 +-d4FB :F-f'(:)f_ +- (-t-4 $N-f*zN5aF`f,+ 32:67,:"f%/]``F-f +@%:4(%4\a2"f% FeAl, SO..ῌ,, H,O 5H

 Al, SO.-ῌ+0./ H,O 4\%  ,   - k$ +-+f,-/-"r"?1 $ -!":%5aF`f, 4  B.@% H  .  + $N/04/-"?1 123445/-"f%
32Cl_

B.@%,4\% 2F67C#89:/; + k_: 3; < + 5 ¡ -  +¢=£fC¤ ¥¦£fH4\1
¡ , 5>? B  +§=£fC¥¦£fC4\% 3@¨©
C 3@, A©8/B$%C4\%
32F#8/ Al,O-FeOSO-  - 8ªk$ ª + C-1 H alu hal A©C<«$%:  1 Fe 8Df¬­ mel FeSO.ῌ1 H,OA©8C 3®E4«-f F

c4GH$% ª , H /0 X I¯JK4\%: L°±M
 X I¯Jªª -  +-1 ; + k$A©8C fw2CN8H
5O-%Z²

4\1 A©³.P´F-f3:a`!

_Lµ67}&-4 K:sVW¶4 L$% ( _ EKA Al 5 Fe -V.@·f8: QR¸ S¹T.@r V.@Uf Si :ºV$%4-B  Al 5Fe 4».-5H:¼n2 2:.W"L: qC D

EF2% 3½X/ SiO,Al,O-FeO  - 8ª f"DX$%  ª .  +-% 3135

ῐ῏ῑΐ

136

ῌῒ῍῎

 /2  ,**2

Photo + Landscape of a volcanic altered area.
 + 
Photo ,
 ,Halotrichite and alunogen in a volcanic altered area.
  

Photo  -Halotrichite.
Photo . Alunogen.
 . 
Photo / The outside of the reactor for the alteration experiment.
 / 
Photo 0 The inside of the reactor for the alteration experiment.
 0  !"#Photo 1 Colored seawater observed with the submarine volcanism in Japan.
 1 $%&'()*+',-.(/01'2
Photo 2 Acidic hot spring at the seashore of Satsuma Iwo Jima, Japan.
 2 34567'8(9:;+<=>
Photo 3 Colored seawater found at the coast of Satsuma Iwo Jima, Japan.
 3 34567'8(?@A+1'2  !"#$% R &'()  !*+ H,SO. ,-./0

1234567 8 9:% Fe
EDFB*Al ;<=>?@=+A"B*  !*+C(D6 R "#$;<=>?@= GHI(JK  LML"#$ .
137





Table + Chemical compositions of halotrichite* and alunogen** collected from several volcanicand hot spring areas in Japan.
 +Water-insoluble
residues
H,O
SOAl,OFe,OFeO
MgO
CaO
Na,OK,O

FeῌAl***

Water-insoluble
residues
H,O
SOAl,OFe,OFeO
MgO
CaO
Na,OK,O

FeῌAl***

halotrichite*, alunogen**

Kusatsu +Yakedake -Hakone B

Tamagawa A

Yakedake +

*4,0

*4+/

*4,.

*4.0+4+,.040.
-04*.
+.42.
*4-*4-/
*4**
*4**
*4,.
*4*3./41*
-042*
+04-+
+4.,
*4**4**
*4,3
*4,,
*4**

..42*
-04/1
+-403
*4,+,413
*4**
*4**
*400
*4*-

//4,.
,342.
+*4-*
+423
,4.3
*4**
*4++
*4*.
*4*-

.04.*
-.43.
++4//
+401,423
*42,
*4,3
*4-1
*4+0

32413

+**43,32433+**4.*+**4,+*4*0ῌ,*4++ῌ,*4-+ῌ,*4/2ῌ,*4/.ῌ,Yakedake .

Nasu +

Beppu B

Yakedake ,

*42,

*43/

+4-*

*4/-

.-41*-04+.
+,41.
,410
.4*,
*4+.
*4+0
*4+2
*4+,

..4.2-/422
+,4+.
*4-1
/4-+
*4**
*4**
*4+*4*/.04,2--4*++4,+41//41/
*4-.
*4+.
*4*2
*4*-

..412
-.4.34*+
+4/0
24..
+4+,
*4-+
*4/*4*++**412

334-+

3343-

+**41,*41-ῌ,*400ῌ,*43-ῌ,+4//ῌ,* halotrichite : FeAl, (SO.).ῌ,, H,O** alunogen : Al, (SO.)-ῌ+0./ H,O*** “[Fe] / [Al]” means the moleculer ratio of iron to aluminium.

 Al,O-FeO  !"#$ Al,O- % FeO & + : + "'()*+, -,&./0,12 FeO &3)+,45678589 :;"$< SiO,Al,O- =>?@0 +ABC&.1 DE Al,O- FGHIJKL#$6 -,&MN0":;"$<OPLBQ7 SiO,Al,O- =>L Al,O- %RS"TO UV9 SiO, OW7XY6Al,O- 3)+,456Z< SiO, "[\@67 ]^_ SiO,ῌnH,O "`&Da0b%

8 66cd< FeO &858E7AFGHIJK&e$0"<85 fg"hi !&e$67 FeO &jk6<l% mnFGHIJK"#$&oV9 !%pe6 -"FGHIJK&qrst6 b"uv"w('(&xy6<l8 -"Z<b"w(z"$<{ . C "|} !AFGHIJKOE7
138

 /2  ,**2

Fig. + FeOAl,O-SO- ternary plots for halotrichite and alunogen collected fromseveral volcanic and hot spring areas in Japan.
 + 


Fig. , XRD patterns of halotrichite and alunogen.
 ,  X     !"#$ %&'( )*+ &,'( -./0 12) )34'5/67 8 9 !: ;6<= >./ SiO, ? @A> !: $B CD'E F8* 0 G HIJKL M&N&,'(4OPQ/RSQTU !"VWQX6 8Y>6Z R5[\]^ L Q/_`abcdaNefghijUkI Y T 50\UlD8mn
8o./* opq Y( Q/!"rs8o" tuv*w6T  !:>CD'E
xy z6/* L M&U{| 8Y>6Z R5[\>z}8Y&,

Q/ FeAl 4 ~TDLQ/Y_`abcdaef139





Fig. - Schematic XRD patterns of halotrichite
and alunogen collected from several volcanic and hot spring areas in Japan.
 -  $%&'() X *+,Fig. . SiO,Al,O-Fe,O- ternary plots for rocks alteredunder strongly acidic environment.
The interpretation of this ﬁgure is described in thesection +.+.
 . 
 SiO,Al,O-Fe,O!"#A B C 

 !"# $%&'()*+,-. /01 Ca 231 CaSO.ῌ, H,O 45Mg 231 MgAl, SO..ῌ,, H, O 6789:;< Na 231 Na,SO.ῌ+* H,O =>?@;<2A ,BC.DE" F*G&2HI*JKL0-MNOPQR#SKPRTU+#,  V-./0

W , - XYZ[\S]3C" ^_`abc*+,-deC"fN ghijSkl- $abmn $CVopq*deC".SkP"r $abstuvw2A x
140 /2  ,**2!"#$%&'"()*+ ,-(.$,/&0&12#+ 34 +32+ $56789"!:+;<=>?@0AB+ -CD($ EF
+GHIJKLMNOP&/!9Q 56 RSTUVWXYZ[Q,\]^0_Q\` ab / [\cdefghijkl0IJKLMNmne0 !"#NopegqK1rs+ ,tu$ab 0 [\'*!9Q vwnexyo1&y*+mne$ltz ,{)`+|1& }/# jkl~$ 
3 0i3 y/! !9 nejk}s#[\+ ^X-3 0
Q  v ^u0Q$!jk0}s# +jklxy}/+mneF 0 ,  + '&?@ 2  -2 1+ Q

+

0 -  9[ X 0/¡+  - ($[# Al,O-, Fe,O-, MgO, CaO, Na,O, K,O ¢"£¤[Q ¥¦2# SiO, O§¨©ª«2# ¬­ ®¯9`#F 0 §°±²2#³O´µ'#+ ¶·H" SiO, 0^k'"! ^9 ,/¸/¹º(F  SiO, »¼0½! ,0Table ,0 ¡+ ,/[# SiO, -/+Chemical composition of fumarolic gas at Owakudani, Hakone, Japan.
 ,Sampling date
December ,-, +30/

Temp.
H,OVol.ῌ

+**4.

3243



Composition exclusive of H,O (Vol.ῌ)HClSO,H,S

CO,

R*-4.

34,

14,

134*

+4,

* “R” means the gas consisting of the components that can not be trapped bybasic solution (/ mol dm- KOH).

Table - Changes in the chemical composition of the andesitic rock(Kamiyama lava, Hakone volcano) subjected to the alteration experiment with the fumarolic gas at Owakudani, Hakone, Japan.
 - !" 

* day

2 days-2 days1+ days

SiO,
Al,OFe,OFeO
MgO
CaO
Na,OK,OH,O
H,O
TiO,
MnO

/04-+24.2-40+.4+0.41.
24,3
,422
*41.
*4+*4*,*42/*4+//341,
+/43,
*4,2
04.3.41,04/3,43.
*40++40.
*42.
*413


034-,
243.
*401
-43+.4,*-4*,+41*40/,40-41/*43**4++11401-431
*4++
,430
-4*3+4..
*4-*4+/-401/42+
*43.
*4*2

Total

+**4-2+**4/.

3342-+**4,,wt.ῌ

141



Fig. / Changes in XRD pattern of rocks subjectedto the alteration experiment with the fumarolicgas at Owakudani, Hakone, Japan.
A, original rock ; B, -2 days ; C, 1+ days. Cr,cristobalite ; Q, quartz ; Pl, plagioclase ; Py, pyroxene.
 / 
 X A :  B : -2  C : 1+  Cr :  Q :  Pl :  Py :Fig. 0 Changes in the chemical composition ofrocks subjected to the alteration experimentwith the fumarolic gas at Owakudani, Hakone,
Japan, regarding the content of SiO, had been
constant through the experimental period.
 0 
 !
" #SiO, $%&'()

 !"#$ TiO, %&$'()*+,  -))./012 3)!456789:;<=>?@ABCD' E'F / 56 GH0) Pl CI?JKLM$NO1PQ8 
R$ Q S

Cr ?TE1UV<=>?W@8'CX-)YZ))T -)[\)[])[^_`?SS_ab8''cB de fgh)i?j ++* kllm8 n +,2 SO, ?op8 HF 2qrpsD'68''c H)tu2789vw)1

C$Bx.yz{'? |}~8-)/tuBD' -{  TBA=x<=n 0xIv8C

3* ῍ kl)%1X6 3{?)'c01 Yῌb8CBD''cxA{ H)tu  -))? tu))!4$BC%$=B%z A{'2)1¡=, *+,-./23 0*14 56,+ *+,-./' 0*1¢£ 1¤¥¦)¥§)¦¨_`)l©BA)¢£1¡=? ¦¨)_`ª  xIx«D5$I -)¬¦?t­<=)?®cA{= k -)t­)­?¯­142 /2  ,**2!""  #$"%&'()*!+",&-" ./012345*! 6789 : ;&<=> .8? 6" @! 139 Fe ABC3DEF%9. GH !<8-"
/0IJ92KLMNOPAQ+ RS/22TUV% WX W,Y8Z["123A\]^+ E_`Aa-"bc 6d_9e 1 8fgh(8 i! Si, Al, FeWjkl3DEF%&? " Hm no  +320 6!p" 238qr+ Z
+sH<=t>",, 

@! 1233DEF9e 2 8fgh(8 2TUVuv8w+ 27Ux. yDzUVz{3  2378|$*! 6!8}+< Si, Al, Fe ~Wd_z23 +  3DEFA[ @!qr+Zg<%9.
" .@lDz{$9i!278&<"  Dz36A23
A+]^g<=9 O8/ ",8927#U("  @9+Ag<=9$.-"
@' ¡¢£¤¡2¥¦K. §¨ 2 h(8yDz{$+©?
6!28!ª%Z[ 238r?[+<!" "«¡2¥.

¬8.+§¨ 3 h(Wj123­ +" yDz3®¯d_9° . 8fgh(%&-" @!9*2TUV%927%a±!+< ²³

K%´²+< GH ! µ¶·¸¹Aº»" no  +311g±¼@3 23AWj

kl%l ["A ½+6d_A_`gFig. 1 Si-Al-Fe ternary plots for the suspended substancescollected from colored seawater around submarine
volcano in Japan.
 1    SiAlFe

Fig. 2 Conceptual scheme for the formation ofcolored seawater at submarine volcanoes.
 2  143  !"#$%& ' 3 ()*+,"#-. /0
1 + 2341)*5$ 6078)* pH 9 Al, Fe $:& 7; pH (41)<5=>?3@ABC 417;DE9F3 G&
H Al, Fe (41)<5>IJ
Table . Chemical composition (mg/L) of thestrongly acidic hot spring water at SatsumaIwo Jima.
 .

Sampling date
Water Temp. ()
pHNa
K
Mg,
Ca,
Mn,
Fe,
Fe-
Fe
Al-
Cl
SO.,
CO,
H,SiO-

 mgῌL KLMNO PQ3= RS
TUM 7;MVWXE+O!YZ$&[\=]W^!A& G&' +* -( 41)<MYZ& pH 9

Eastern hot spring$/0M 78_H Al, Fe R

August ,, +31//04*+40-,.
/1400/41+..4.
2/43
0,4+.24,/./
3*0.32*/,4*-**

S`$60A7ab$:& 7;
 pH ,  - - Si =RS pH - - Fe-
=RS$cd e;fA Al =ghJR3
 VW pH ..- i- Al =I5RS j(7;kl$ m Fe- gh=JR
Al =no[RS&p pH 0./ i^WFe, =RS3qr 7;s;U= 7tuRS`M vw=kl
*A ^!Mx!A&RSyO$:3\=]
W^!A& e;(7;WzU=RS3
.&A no[{|}DEX"|}
~-. SiO, ῌ Al,O- ῌ nH,O SiO, ῌ Fe,O- ῌ nH,O TU=JR$e3V;
Fig. 3 Changes in chemical composition of mixtures of seawater and strongly
acidic hot spring water in Satsuma-Iwo Jima.
 3 

144

 /2  ,**2

Fig. +* Changes in pH and the degree of precipitation in the mixture experimentwith seawater and hot spring water.
 +* pH
 Fig. ++ Si-Al-Fe ternary plots for the suspended substances collected from colored
seawater around submarine volcano in Japan.
The double circles show the samples collected from Fukutoku-Okanoba.
 ++  

,-  !"#$ %&'#( )*+,-./012341567 8 ++ SiAlFe  - &'89 :;"<15=>? Si @"AB?9 )+,-CDE 0FGHIJKL .12MB?9A> )N=> Fe, Al "OP&'Q"

RL CSET1M?9ABUCVWG"X!J"KY2Z5 [\ +33+ [\ +320 "=N] ^_]`a

Q9? 8 ++ Rb=c"de)&'C:;f"A> )*"145



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Fig. +, Schematic ﬂowchart of transport of rock components to hot spring waters by rock alterationand formation of colored seawater.
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147