,-./ J. Hot Spring Sci. /2 ,2,ῌ,3- ,**3ῌ῍
0


,*

++

1


1 2+
 

,*

+,

,/



Relationship between Geology and Water Chemistry
Observed in Deep Wells in the Kanto Region
Yoji SEKI+

Abstract
Relationship between water quality and geology in deep wells (bottom hole depths
ranging from GL-+,*** to -,,*** m) in the Kanto region was studied mainly based on
published data. Four types of geology were investigated as representative host rockgeology for deep wells in the Kanto region. Characteristics in each geological unit aresummarized as follows. (+) Deep water in the uppermost Tertiary and lower Quaternary
Kazusa Group, host layer for Minami-Kanto gas ﬁeld, is characterized by neutral pH,
sea-water equivalent high salinity, and high homogeneity. Among all geological units
herein studied, Kazusa Group has highest concentrations for Na, Mg,, Cl and dissolved CO, species. On the contrary, SO., concentration shows the lowest. Deep waterin Kazusa Group is explained as fossil sea water evolved in sedimentary sequence rich inorganic material with signiﬁcant inﬂuences from microbes. (,) Deep water discharged
from granitic rocks is characterized by dilute and alkaline pH, with dissolved CO, species
as a dominant anion. This water is thought to be a water-rock interaction product mainly
bu#ered by calcite (CaCO-). This type of water is scattered even in the other host rockgeology. (-) Arakawa Group, Tertiary marine sediments mainly deposited in Kinugawa
graben, discharges deep water with neutral pH to slightly alkaline pH and relatively
higher salinity. This water seems fossil sea water origin but is much matured and may
be diluted as compared with that in Kazusa Group. (.) Yamizo Group, distributed in andaround Yamizo mountains, has at least two types of deep waters. One is similar to (,)
granitic rock types, the other is slightly alkaline with SO., as a dominant anion.
Homogeneity of water quality is the lowest in the four geology types, which may berelated to wide range of host rock mineralogy and fracture-related hydrology.
Key words : Deep wells, Kanto region, basement depth, dominant anion, fossil sea water,
Minami-Kanto gas ﬁeld.
+
+

282

-*/ῌ2/01 !"#$%&'( +ῌ+ )*+ 1.

Geological Survey of Japan, Advanced Industrial Science and Technology, Chuo-1, Higashi +ῌ+,Tsukuba, Ibaraki -*/ῌ2/01, Japan.

/2  ,**3

   +,*** m     
  ! ῌ "#$%&'( )* NaCl + , -./ 0 1!"2#$%345&*
'(34 ῍ 6)7* ( 89:;)+<=,>?@A
B  -./0-CDE)FG13 H2 7& 3 -I4J!
K '(34 ῎ L56M78"$N6O (%89:;
) * 9P:$;Q#,RG O <5&* STUῐ7&4J=V $%W0X0 3 >YZ[\>]-C ^_D4 ῏ ?M`@ $?MO (A< a BCbDc Ed
FYe$%7&5fῌgG/Hh 4i34 ^_D4
jklkm : no  IJ ,>?@AB 5&*

"#+    
Kp`q ` ,**. ( rLMbstuN%POPv
 )( PQR wS-13x TRU(yz13 ^_D4) ST{=5|V}$ ~\=VGW)CX-, !z ( 2YZ[$%  7&4J=V{ !" 34!* >\.ῌ] ^_%4i &4)GA9n-34e   +,***ῐ,,*** m novG` +** T- G/-a34

D,**+ ; nD,**+ ; D,**. ; D ,**1 bcD ,**2 %  n( d#Kp`qwSYe34!z p`{#,fbD34gc;ThE#i$Nj-k% !z NrC(NG)C)( lqD;Q#E#me-k%k -) ! nDopq$"#\ +30+ )( nrsGA93t"#¡¢n-ῌ£V34e 4DuvR w ¤{

 ¥xGA yD +30, ; ¦b +301 ; zῌ§ +32, ; zD +322 ; r6 +33+ ; ¨©D+330 ; ªn,**+ %  3D

 $a G{"34C,«ῌ¬| +33, ; ­}D ,**, ; ®D ,**- ; D ,**. ; ¯n ,**2 % °_ 
~M ®±IJG rL²%³-D4C ,**, ; ,©D ,**/ % 

(D$ ( f ST{

D(.q TR%Eµz)¶·C

´/0d3

_ d )( ῌ kY¸Ye-,x%v!~I ¹ .

%~fDI7Yed/34º`)X1»¼lq  $

,



d )( »¼lq$D  - +,***ῐ,,*** m 
n 3t"#¡¢n $ 4Dnf( +,*** m ½Ye
283

 



    !"#$%&'()*+,)-
*. /01!23)4567.182 "9:; ῌ<#7.=* $>?
!"#$2.@AῌBC2.D !A*E2F)*45!"#$G* HI8!JKL EMN(OP Q!*$R STQUVWXYZ[O\\]^Z[_O`I$!:97.18E]a_.
bc(% : ,**. de!fghihjk : ,**+l&: ,**+

mn: ,**2 !opqr(O- "#$% &'()*
: ,**. % "s.45$t!u8( #v(O+ pH Ewxy)*(z{|}y~y% , g !  - !!!4_)"^G - ih% Na !7.!E4.!/(ih%#y7
"!!"G*% $  : ,**+x mn: ,**2%" l&: ,**+ qr_. 1[:!&x!'5 +,***ῌ,,*** m !45%! - G!Ew(:[ [:E"!45w)7.!.
8*k.

.

+,-./012+3

"!45$* g E4_*% ih%*)`+E7. :,**.

"!!45

!op :,**+ ; l&:,**+ ; mn:*,#,**2!E-(:[ 1!E"w!45.%\.18E9. 45$!g 8/ ¡7.`+
!0% 12!"#3
7.¢£¤¥¦!u 45 !5 3
67 ,**, ; Fig. + 85*¡E§5"# .,*** m ¨7.

u45!5 2©ª8«"¬­R®¯°±N ²-13 ")³(:[.´µ)u45!¶"`+0!·*45E
3(*. Fig. ,%!«¸  ¹99::
;<!x$!º1=»8>?
37.@¼A ½A +30+
284

Fig. + Depth contour map of pre-Neogene basement in the
Kanto region. Pre-Neogene sedimentary rocks and/or plutonic rocks are distributed in areas with oblique lines.
 + 
  ,**,

 !

 /2  ,**3

    !"#$%&'"#$012345()*+,-.

6

/789:

NaCl;)<=  >7:?@A  9=BCD2

E* Cl+*,*** mgῌkgF G

HGIJῌK LMῌNOῌPQR  SR ῌT U
VSῌWXRY

ZQ[\4]4^&4*_ ` a[  [ bc dEe f"ghi!"

+,***ῌ.,*** m jk[E` [   lm

nop%&oq#r: F7s tusvwx$ %& y'z({7 7|}~}=
)*R +L,   4* )  0 Q   /+33, 23- } ./

4 9 ῌ  1f"ghi!" NOῌ.4RY ZQ[%&NOῌ

Fig. , Spatial distribution of chloride ion concentration in the eastern Kanto region.
 , 



MῌPQR m)5,67   8   }0 9 :* ,**, 0Q/\ 0 
;%&m)<< 9 / ῌn=- p +30, U<+ <&4 \>23

i!>j}=7

 ,,*** m¡> /? ¢£¤¥ "gh Q-. 5¦"gh §Q-.Ue@(34 §Q-.
%& :?@A  ¨ +,*** mgῌkg >9:?FAB©q34 Fig. ,

WXR C2DIJEªm[ <%&EF)*i!" [G«)<= Fig. + 0Q/H¬< ` [­D K®

I .~F¨J~}=:?@A 7 bcL¯}~¨ +,*** mgῌ

kg >)<= Fig. ,/  !" #$%&   M@AP

3/῍ ³´ & ,**. `

7


NaK

NaK N&O

1/῍ °+>±p  ² Na }  M@Aµ¦ Na

Q¶

E` ·R d ¸@A µ¦ :?@A Q¶J=7 S¹º Q¶7 sT¹Z 7 7|}~}~ ¸@Aµ¦JUz78`
4iWX}»34* ` ¸@Aµ¦ JUz ° U{ V´&

BCD2 YZ[¼)<e ½\=<Q¶¸@A
285

 



Fig. - Plots showing relationships between key-diagram and electric conductivity,and key-diagram and pH.
 - 
 pH   ,**.

 !"#$%
ῌ&' ,**. ( )*+,-./0123 pH !45,89:;<=/῎>?@# ABCDEFGH!45
(,89L:;<=/῎>?@M !"#N Fig. RST+UV῍/ X-Y 0123

pH 3 67/,89

I%DEFGH/JKH

OP pHWXY+U!45

DEFGH MQ

WXY+UZ [\]\01237/^_/῎>?@M `"O\N P ,**. ; Fig. .

MQR <ab+UWXMJKH/Jcd( @eST+UV῍(fg`/'PhijklmnCop :;WXM`/(q$ ,89elN(r,89e[/JcdST+U
(fgῌ;s!WXY+U M`/(pH `ST+UV῍`t , u/@vw

^x!`y \P/WXY+U/z{wd|!}
z<ab+UWX=~ z>w lN:;WX=z_O\$ OPῌ;sWX=zzM P\ Fig. /~z/~c6/JKH P ,**+ ; P ,**2 ; P ,**+ y%$`7#N~c A/ ¡P\ WXY+UJKH/i¢/4£ (~zq¤¥#$`¦§

0

!"!#$~z~c/JKHy%$( i¢ z¢ /¨ #$ + Na-Cl =cWX# [/©ªh«¬­®¯ ­°¯@/a±hi, ,89e²³H Na-HCO- =´µz¶CP\ [/©ª·¸¢¹«º »¼#N½i286- ,89e@ /2  ,**3 .





Fig. . Diagram showing dominant anion type on the two-dimensional space of pH
and total dissolved ion.

pH    ,**. !

NaῌCa-SO.  !"#$%& '()*+,-./ 0+,

1"23/456789:;<=>&?@ % ,**. A 
 CD ;

E FGHIJKL MN% ,**1 O&PQRSTFGUVWXRSTYZ RST[E5?\_`UVWRSTXab5?VWc d\
ab5?YZB]RSTK ^@]RSTK e@_`UYZ RSTd: f g 8hij

k8U !"[lm) nopqdr?@stdp[puvw[x5 () yGz{|}@?~j 
jpU  Kp " "!/ !p O"!p89
ῌ "#$

KpU  +ῌ- .[$ pq89 
 8U  v@?

05@5?

) 

5?@
::8U Kp5?% ,**.  +* )   ¡  ¢ £¤g¥¦§ [~j :&%U ¨©8ªe@Y[«}:[¬ tdvwj E ]G ­®¯°±² Fig. 0 U :³´I¯µ@e@¶©[«r?@:[xj ¶©U Na  Cl @?ve@ W· U) ¸8¹@ºt »¼½&
287

 



  NaCl  Ca ῌ Mg ! "B ῌ Cl!  #$%&'() *+,-.
/0123456789:;<=>?@ABCDEFG)> DJ) +322 ; KL ,**+ &'HI)+30, ;



MNOPQRS?TUV
WVXY ZE [\]^,_`-.abYcdeBCDZE,fgh
0 @A,ieEjDFGEkljD e
mBnYTo pqr !sY +ῌ- tu&v pqwxyz{|}
~D  +301 ; ) ,**- &' B=>D O

V=>D!sqYZ>@%B

CDZEEFGDE 5678>?7R~0?q@% +301 ; ῌ +322 &' Y=> D?¡EFGDY¢£BC¤¥
Fig. / Spatial distribution of dominant anion types
in the eastern Kanto region.
 / 

h¦D§¨MY ©()ª©«¦U©@jDZE¬­()®)> ? ¯G° ±² +32,

Fig. 0 Concentration patterns of major dissolved components for the Minami-Kanto gas ﬁeld.
Thick line shows average. “epm” is equivalent per million (me/L).
 0  !"#$%&'()*+ ,-./01
2345 epm .6789:;<ῌL.

288³´ µOB¶·=>?¸Y¹MOº» /2  ,**3



Fig. 1 Concentration patterns of major dissolved components for granitic rocks origin.
Thick line shows average. “epm” is equivalent per million (me/L).
 1 

!"#$%&'() epm "*+,-./0ῌL.

!"# $%&'()ῌ*+,-.'&/0,1234,

567 ,**2 Fig. 0 89:;8<=3>&ῌ ?@A7BC@

8 ;D#'8EF8>&G HIJ

KL8 M NOP#'Q >RSTU>V'& ?@A7

#' 7 ,**.  . ;  W XY Z[\5] ^  _1C Fig. 1 `37abL8 cIdeI?@,
fgh>V' 98ijklmLnopqr,st'u&`_Jv>wx
C  &y3n^  G + z{|}#' `~jG&&m_ `, A #'8 93Ts_># Cl Na

 G7 K A7BC?@'Gu&K*>ijklm,EF73 `873' 

+313 ; 67 +32+ > 9^#'734 GL@!

 ,23'&

 "7 +32,

, .F>V'G ?@¡

L8#¢£L,¤^23'& L¥¦ ?@fC 8 §¨¦©ªg«dcg«> $G%t73  &y#G?@L>FG ¬'d­® &( )¯°*(d*±(²,n³#>&´)8 ?@¡#,¤^23 µ¯73 
῍ 1234+ ;D_¶·¸d#'.4,¹&'fgh#'EF;_BC g,©ªg«L ``L8 ©ªg«A7BC#'7 ,**.  2 ; -º »¼ ½.ª
289

 



Fig. 2 Concentration patterns of major dissolved components for Arakawa Group origin.
Thick line shows average. “epm” is equivalent per million (me/L).
 2 

!"#$%&'() epm "*+,-./0ῌL.

    
,-./(0 1%2  + 3  4 *5
2 =>?@ABC Fig. 2 '!"#$%&' ()*+67689* :;< D-E@%&FG&(' >HIJKL3

M* N ;OPQHRS*TU  ' KL3V)WX+
Y%&67 Z[I\V"]%' ^_`ab]>V"c5 
%*d0'efg6 h3'*i7VFj8k lm Z[I\0' nOPQ0k Na  Cl  8 >HIoW6 +ῌ, p* lY Mg,i CaῌMg

8q!3

8>HIoW6 ,ῌ- p6r* S"3stu  "#v$%w +322 ' 1%oW6 , p&*6 >HI Mx , p&*Z[I\0' 'yz 8KL3({|)* J'}%uef~c8i
V0k  "#v$%w +322 )V" )*)866 )VYV
8+xW3*+3k,(8"! -I.8>HIoW6 + p*
0

CaῌMg

S/x}1%LOPQ)FG08+x*

8NS! T1 stu 8Si)* ' -I0 )i61W')VY,(8* Na  Cl 

81%JefoW6*' EC ¡)I¢%J*) 0£¤Y%3o¥¦ §2 +301 ¨©6kªd8
¤-IV"KL«O@%6c  3%¬U¥4)%3o¥¦6
+x*,(8*ῌ 12

5­I\' ®6¯-8°±+x*Y-173²*x . U2³J+x*
0' 5­I\V"c]+x" ,**.  3 U ´µ¶ 89 :;·¸ ¹¶ <# =§ R[ >?>º 

!"#$%&'»,-./(0@y n¼OPQz6²o½,-./(0'yz n¼OPQz
290 /2  ,**3



Fig. 3 Concentration patterns of major dissolved components for Yamizo Group origin.
Thick line shows average. “epm” is equivalent per million (me/L).
 3 

!"#$%&'() epm "*+,-./0ῌL.

  ,   !  "#$%& '()*+,- Fig. 3 .
/  0123*45 678 9: . ;<=>?@ #ABCD
EF@G H IJ KLM 7 NOPQR9:.;

STP 

 UVW9:7FXY=Z  [V\][^@_ `aU_bcd_#e9@fg7 hci.jklABC
NOmA*.n9 U_o:7cd_.pqTfg cr.jkABC
i 1s3Cmtu vw +32+ R9: x` !  yzu{|}Q ~TU$6F!@ x` ! 0 1 2 3
=7  . 0}Q "#$$;@


!.9 UVW.HT=

"b #e 0%8 ${x#=Z 0.n $7 \o ! 

9:


ῌ % ¡ ¢£(DT7 <6=W&¤^@ NaCl

.; 6^@¥'¦(  #ABCD 7Z § <=>^ Cl .jkACABCi  Na Cl Mg, ¨` hci Z § <=>^@ cr 7"
$<=>?@ )©ª«¬­ ®@ #*q¯°<T±~F! U
VW9²+F! ῍ NO~ 7 ³2´s6=#$D Z § <=>?@ hci.

jkACABCi9 45 67^@ µ¶·$O¸¹9:9
²+=®  NO~  7 º»TbST¼G  !
 ,½9NO= UVWb[V\][^@_ `aU_
291

 



    ῌ   ! "#$%& ' (( + )*

+,-,( ! Cl +./012 3!  !"45#($ 6%&($'7(' 89)+,-

῎:(*;(+<, =>- .(?//@( 0 1A2BC῍ 3D  ! "#$%& +./012 E4:F0G H=

I5"#$%&J+./012
K%L2FMN( , 6O,7P

(2Q8 ! 9R(S:T;&U,< =>V?N( @WA=X ;(7BC(DY 
](=8
]&

ZO*[\R; (E;^(S:+ EF;_+`aG+*PHIJ=X+P(bc dC@W-R(=XKeLfM!g&C h! $

 (/iNO Pc(jQ RV(SkAHRNO\lm&O $
(;n(NO^H T UoV7W(;XY Z[\p(;]
HR,q^_`RrO&s&Ct8῏῎abuc 0+ vuwxyzdT#efgh! u{|}2~Hm(@ubij(@u+kTR$lmnaῌῑῐ῍
2K +33+ : op((7 H=I45#qr (7C   ., ,,῎-..

s# @ #t +32, : ab( uNWv (wxuy .1 +02῎+2/.
s# @ #t z{| +322 : "}T(;n; ;~ ;  -+ /῎.*.
3 z{  f  +32, ::(2QO(CR("#$%  ;7 +0 ,/῎,3.
K  *t 2K +330 : op+T;_( H=I45#qr (7H=I7012?1  .0 03῎12.
(6 +30, : "}T(6% (wxuy ,1 0+/῎0.*.
 +301 : 45#qr ( R20(-R  :(vuy /2 +22῎,**.
:> n  d    ,**- :  2v(d¡ ¢:%(7£¤¥ ";_Hm, ¦§( ῌ:(ῌ¡}5¨(U  ;7 -1
1+῎2,.

©ª¢ ,**+ : £«45#(;n ?¬W(bc­¤ Pc;  /+ +./῎+/+.
®¥¦ ,**2 : ¯§(;; WA°(¨c+\±  ¯§²© 2/p.,³´µ +30+ : !"45#-R(v;  (wxuy ,0 ,+,῎,00.
¶tª« # · ¬¸­® ,**, : op£«45#(;n;  u, 45ῌW(¯-R (wxuy 01 2-῎30.
¹° º«K± ² ³« ´» ,**+ : "¼µ½($;n  ab ¶uy -+
+῎3.
292

 /2  ,**3


 +32+ :  

   -+ .1ῌ/0.

! " #$ %&' ,**- : ()(*+, -. /012
3 4567289:; <=>?@ 02
+++ῌ+,-.

AB ! C"! D#$ EF%G &'(H )IJ' F* + ,-K L./0 ,**1 : 1- M1- N1- 21- OPῌQ3ῌ4R   /1 33ῌ++..
56S TBU7 VW XY8Z ,**2 : 1-)[9 :\I]9;<=^_ `?@ /* +./ῌ+0,.

I>0 ,**. : a b?9:; 

c@A BC ?D defg

hiE 03ῌ3- jF
 kl G H' maIn ,**+ : 1-`]5 BC J ?@-+ ++ῌ,..

 Ko )Lpq rT s ta M u)v0 w5xy ,**. : 9
 Nz   /. +ῌ,..

{BOS |C/} ~#0 {  +30, : P+,  Q  +,=R  S5T
#Vv

U9:; +301 : BCῌ+,

@ 03 01ῌ2+.
 Q <=>?@ -, ,20ῌ

,30.

4WyX ,**, : 1- ` _Y Z <=[ 0- +ῌ+3.
4W\l +313 : e])     +- ,/ῌ-+.
4W +32, : P+, ]^+,_R` N aw[ -/ 000ῌ001.

EF G H  ' ab c b) d e¡ ,**/ : 1-`f2)¢£¤¥¦§¥¨©ªg ` _Y ¢«¬h Z <=[ 01 +-ῌ,1.
E­H `1jl ®F>¯ |Tij +32+ : °k±lm

 n=2S    +/ 03ῌ10.
E² > ³#¡o +33, : ´pbµl    ., ++.ῌ+,..
qW¶rs· +322 : qW¶ ` +.*p., ¸FAt¹º »b ¼ +322 : Cuῌ+,l]^+, 2 Q <=>?@ /- ,+-ῌ,,,.
,**2 v 3 w ,0 B BC ? 0+ ½?;?g

293