 J. Hot Spring Sci. /2 +.2ῌ+/0 ,**20+ +῎ῒῌΐ῏ῐ῍ῑ῔h ij+Contact Point of Hot Spring and GroundwaterTadashi TANAKA+AbstractIn order to clarify the contact point of hot spring and groundwater, the author considered the origin of hot spring waters using the d diagram of hydrogen and oxygenisotopic ratios of hot spring waters. The d diagram provides us an important informationon the origin of hot spring waters from the hydrologic stand point of view. The resultsindicated that the hydrogen and oxygen isotopic ratios of the most of hot spring watersin Japan are plotted along the meteoric or local meteoric water lines on the d diagram,suggesting the origin of such hot spring waters is mostly the meteoric water. However,the isotopic ratios of several hot spring waters are shifted from the meteoric water lineand distribute along the mixing lines bounding the weighted mean value of the meteoricwater and the end member sources such as sea water, fossil sea water and volcanic thermal waters. The mixing ratio of the component of meteoric water in such mixing watersis usually higher than that of the end member sources except a few particular examples.
Those results imply that it is reasonable to consider the origin of hot spring waters inJapan might be the meteoric water, namely the naturally occurring the hydrologic cyclewater in basically. This stand point of view on the origin of hot spring waters maybeimportant for considering the conservation of hot spring resources in sustainable asshared resources as well as groundwater resources.
Key words : hot spring water, groundwater, stable isotopes, d diagram, meteoric waterline, origin

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J¶") +,- VW8./KLF0"vo stu#F¼!
")+ stu#F34 !"^IFM½N+149 Fig. + Schematic diagram showing fractionation processes of isotopicwater molecules during evaporation and condensation processes.
 + ῌFig. , d diagram of meteoric waters in the world (Craig, +30+, partially corrected).
 ,  !"  d #$%&'( )Craig, +30+ *+,-.

-/ " 01 d #$%&'(   !"#$%&%'()*+,-./0(1234563789: 5 Craig, +30+Craig 3CD@"12E/ dD

2 d+2O  +* ; , / 6<=12>?@"AB45FGHIEBJK9 LM meteoric waterline NO9: 5 IP ; , .?K9: 5 closed basins / QRῌQD>S"ITUQV >WX@:PY 698QV.PZ5/#$3[\BI "] ^_`.a\bc>dZ e'()*+,/LMfYgh.ijklK95; , .?K9"12; mI^nop. +2O )*+, qp. D )*+,>ijkl@";150 /2  ,**2Fig. -Schematic diagram showing d diagram.
 - d  d   - d !"#$%&'() *+,-./010234567  89:;<$=>?@ABCDE :;FG HI 2 JKLMN&'O LJP-Q D  +2O 456RSFGT$U>?

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2 UO[Dk^ p'3Gq +* JKLrsDEQJPtu$U>?Vp'Z vw$ xEyEW$U>?X3Gqz {^ ῌ|} ~*234567F  , :;UO<$E? dD2d+2O+1./ FL|aE &'L>? UO #$:;  dD2d+2Od DE X , q'dz pd-parameter }E? X d z  JKLrsDEQJPtu$U>?VpO JPtuLt$ #$ d z Qk^ p' ./{^456ssR./L&' x010234567 *fzsR4567N;<$@ABCDE LkῌaE$   ¡¢10456£¤ oxygen isotope shift Lr¥XL¦aE?
§O Xlmno'4567  - $%-U¨$ 104567©oLª«-¬<X\aR\U¨$ d  ./@A­®¯|$&? °k±²³´&?kE.

    ! "#$%&.

 µ¶· ¸¹· º»·$¼½- ./  d %&'()151 Fig. . d diagram of hot spring and spring waters in the northern parts of Kanto region(Minagawa, +331, corrected and revised).
 . d   +331 

  2   !"  d #$%&'()*+,-.
/ 012* dD 2d+2O+1 1 342567891 :; +33+ <*-./ =>>=?@ A BC dDῌd+2O DE, F91G,/= H/.91I.J<CK-./CLB=/  /  M?NOPCQRSTUVWDE<*)2H/ XV7OPLPY8/F,-TUVWLZY8/[\LH] 4\=@LK-TUVWLZY8/[\L^_>,/ @[\ OPC`QTUVWCDEM.-)^_>, aPbcde4cd<fg)2H/C.h/ i8jk *TUVW l,m,noMp/9TUVW?K-qr+,-./C=> sY9 a <tuC)2H/C.h/ vwxF.-)T8yzL8+,-./ ;ῌ{ +33+
 . M.-  F.- dDῌd+2O DEL91=>ee|,-}~+,-./ xῌ M?NxῌL ,> / M.-)XV78[\1=>|,-./L^_>,/ C QC`QTUVWJLP.C $b)P.

F.1,/** mgῌl Cnon 7=>-LYDjK-./CL +,/ 0  no9JC- J< . C TUVW<d #$%&'(2i/¡)2H/ 1<¢£i/C dD J2* d+2O J2, ¤¥TUVW dD JC d+2O JC) * 2H/=>`QTUVW2, |,L¦/C8/ §¨©?@ ªn«eLn«YPῌP¬«2­®>,/¯ °±C²2`QTUV³´L¦/CLµ>,-M] C¶·°C¸¹º»2+32/152-/* 2, `QTUV³´L¦/CL¼½+,-./Bowers and Taylor,/2  ,**2Fig. / Relationship between altitude heights and hydrogen isotopic ratios of hot spring and springwaters in the northern parts of Kanto region (Minagawa, +331, corrected and revised).
 /   +331  !"#$Fig. 0

d diagram of the Itsuura and Hiragata hot spring waters (Minagawa, +331, corrected and revised).
 0 %&'(d )*+,-.  +331  !"#$153

 

Fig. 1 Relationship between chloride ion concentrations and hydrogen isotopic ratios of hot springand spring waters in the Itsuura and Hiragata areas (Minagawa, +331, corrected and revised).
 1 ῌ
!"# +331 $%&'()*+ 1  ῌ !"#$%&'()*+,-./(012345678 9: ( ;<=(>= dD *, Cl+3,2** mgῌl 2?@AB-CDE(FG9 45FHI EῒJKL(>(MNOHIPῌDE(F7Q RMNSN LF 0 T4I>F . 78ULVWSNFXY 2  Z[ῌ \(ῐ d ]#^_`a2345678 Eb:cῐ2?@dA LA(efgQ2῏4 R=῎ ,.1/ 78 E= hijklJmn,-.opOHI L2qr(Ds d ]#^_`agQ - f(YnPῌ t;ῌuv +330 (wxyzD {5 EdA|} ~his)O),-./ dD ,*.* d+2O 02 uῑ +323 4 Eb:JKL(his(MNOHIPῌ b 494 Eb:,./LA9:Qb67f hisMNSN978(:b c 6hi(0ΐD78U his2F:bF RSNXI /῍ '(6:bIY uῑ +323/, - . / 0FYI Eb{7 ¡ b5 d ]#^_`a ¢£¤¥¦N§¨©ª«¬­®§¨¯%°± ,**1 f² 2῍³´3D( 3 Onf Eb{7µ+ b5)O)*+,-./ RXFLA¶HI·¸¹º b qrFL Df»¼2qr(D½­78E(234IY {5 ELA9:b154

 /2  ,**2Fig. 2 d diagram of hot spring and spring waters in the Nasu and Shiobara areas(Minagawa, +331, corrected and revised).
 2 ῌ d   +331  !"#$

 3

Fig. 3 Schematic diagram showing d diagram of hot spring waters in Japan(Ueda, ,**1, originally by AIST, corrected and revised).
%&' d () *+ ,**1 , AIST$ !"#$

   !"#$%&'()*+,-.
/0(+ *123 4(056789:;<(+ . !"#=>*+4?@A<(BCD0(+ EFGH>  !=>I>155  /*῎   & % '( )*+,-./0 !"#$%#$.1234)56078 d 9:;)<= >?&@AB#$%  ,***C

#$D/AEF GH&IHJ(& KLM

>? &A%N OP  KLAJQRS0TU V $(& % WXYZ CZA%U([C:\, !%I"@A0TU##$(&A]N@A&^d 9:;)<= $_`$>?0a%  b?& ῌ&c]N&d'N$ OP  KLb?& e%f 8$gh(0)*i+b?& '( b?& ῌ&c]N0,(U   QA-.0j/kKLl0b?&A1mn&oE῏῎

2p  ,**2 3 3 q ,. 4,1 40r5stu&vw#$(42x6 0+ yx07% 78z{AJ9:J(;<`'A|(& 9:}x'N%(~%(x=>? 042xx=@|AxD07ABJ'ῌῑῐ῍Bowers, T.S. and Taylor, Jr. H.P. (+32/) : An integrated chemical and stable-isotope model ofthe origin of midocean ridge hot spring systems. Jour. Geophys. Res., 3*, +,/2-ῌ+,0*0.
Craig, H. (+30+) : Isotopic variation in meteoric waters. Science, +--, +1*,ῌ+1*-.
Fukutomi, T. (+30+) : Rates of discharge of heat energy from the principal hot spring localitiesin Hokkaidou, Japan. Jour. Facal. Sci., Hokkaidou Univ, Seri. VII, + (/), -+/ῌ--*.

C D +32* : E  ,1, p., FG H
C D +323 : AI  +2* p., JKL HMN  +323 : -OP _(Qs  -3 ,-ῌ,2.
MN  +33+ :C  +-3 p., R HMatsubaya, O., Sakai, H., Kikuchi, I. and Satake, H. (+31-) : Hydrogen and oxygen isotopicratios and major element chemistry of Japanese thermal water system. Geochem. Jour.,1, +,-ῌ+/+.

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