Nd, Sr and Noble Gas Isotopic Compositions of Alkali Basaltic Rocks and Mantle Xenoliths in the Baegryongdo

전체 글

(1) , 35, 6 , 523-532, 2002 Econ. Environ. Geol., 35(6), 523-532, 2002.

(2) Nd-Sr

(3) 1. 2. 1. 2. 1. ,

(4)

(5) . 1. 2. Nd, Sr and Noble Gas Isotopic Compositions of Alkali Basaltic Rocks and Mantle Xenoliths in the Baegryongdo Kim Kyu Han1, Nagao Keisuke2, Jang Hyung Sook1, Sumino Hirochika2 and Chung Jung In1 1. Department of Science Education Ewha Womans University, Seoul 120-750 Korea Laboratory for Earthquake Chemistry, Graduate School of Science, University of Tokyo Tokyo 113-0033, Japan. 2. The rare earth elements (REE) and Nd, Sr and noble gas isotopic compositions (3He/4He, 40Ar/36Ar) for the Quaternary alkali basaltic rocks and mantle xenoliths in the basaltic rocks from the Baegryongdo were investigated to decipher the origin of alkali basaltic magma and xenolith beneath the Sino-Korean craton. Analytical results are summarized as follows; (1) The alkali volcanic rocks with voluminous xenoliths which are represented by the Mg-olivine and clinopyroxene dominant spinel-lherzolite in the Baegryongdo consist mainly of the basalt-mugearite and basaltic andesite. (2) The REE pattern of alkali basaltic rocks characterized by high HREE is similar to that of oceanic island basalt (OIB). Relatively concordant REE patterns of the basaltic rocks suggest that the alkali basaltic magma be formed by the identical source materials. (3) The Nd-Sr isotopic data of the alkali basaltic rocks suggest that the alkali basaltic magma be originated from the depleted mantle source with a little contamination of the continental crustal materials. (4) The 3He/ 4 He ratios in olivines of xenoliths ranging from 5.0±1.1Ra to 6.7±1.3Ra are lower than that of MORB (ca. 8.0Ra). It suggest that the xenolith be derived from the subcontinental lithospheric mantle. However, the high 3He/4He value of 16.8±3.1Ra at 1800oC fraction (sample no OL-7) might be resulted from the post-eruptive cosmogenic 3He. The 40Ar/ 36 Ar ratios in olivines of mantle xenoliths are comparable to that of atmospheric argon, and are much lower than that of the MORB type mantle. These facts can lead to conclusion that the olivine of the xenolith in the Baegryongdo is affected by the post-eruptive atmospheric contamination during the slow degassing process.. Noble gas isotopic composition, Nd-Sr isotopes, mantle xenolith, alkali basalt, Baegryongdo.

(6) REE Nd-Sr, !"#$ % & '()

(7) * +,+ !- .& /0. 123$ 456 07 80. (1) 9 :;-<=>?@ - 0A BCD

(8) E FG -HI>?@(mugearite) * J KG 2)L M0. (2) NE HREEOP- QR

(9) REESTE OIBST CU0. ,

(10) V W?D XYZ [ #\] ^_D REESTE

(11) * +,+Q _ !`* Ca/7- XbV M0. (3) Nd-Sr !"#

(12) * +,+Q Rc`* def? g 3h !i- QjkV M0. (4) l mn& op !"#( He/ He) 5.0q1.1Ra~6.7q1.3Ra G MORB r(ca. 8.0Ra) s0 tK u vRc w

(13) "9:L O)- xyV M0. ,<x XY OL-7 mn& NE He/ He(16.8q3.1Ra) rE %z {F| ! He deKG }~0. mn& j !"#( Ar/ Ar=300~500) MORBr (10,000~30,000)s0 tE j !"#(295.5) Q0. ? mn&? +,+ % z Q9 ~ d(? M7- X V M0. !" )%, Nd-Sr !", ,

(14) , 3. 4. 3. 3. 40. *Corresponding author: [email protected]. 523. 36. 4.

(15)

(16)

(17) , w>?, 3>? & w

(18) N ' 9 U TK ab IJI $ 4\ F(tracer)j z7 Di35(Kaneoka, 1995; , , , , Hilton et al., 1993, 1999). A Kx p{ -!", #$, % &

(19) ' () *+ ,-. /01 *23# 45. 67 % , #$, , K| w8 M~"U 1

(20) j w K"l &

(21) 8 ()8 ,-. 9:/0 ; < H8 SA 7 Di35(Sumino et al., = >?2@/(mantle xenolith)A 5B CD3# 45. 2000). <=' ' % *23# 4 ,,-. /0E >? 2@/

(22) F G ,-. 9:/H IJI8 K", $LM

(23) . 9:/ >?2@/8 REE, Nd-Sr Ar, He & NE8 O$ J.# 3 >?8

(24) F 6P 8 p{K|(noble gas)M~"y *mA 3 , QR STU V5. 67, WXK$ >?2 . 9:/H IJIE 2@/8 K"A m35. @/YZ IJI 2@[\

(25) ] ^_7 `3K ab >?8 N$ STU c Td3# 45

(26) 524. . (Kushiro et al., 1976)..

(27) e fg hiYZ j 9:/ >?2@/ kl, /m

(28) F 5(b " nKo, 1987; p, 1995; qrs qtu, 1996; "vO &, 1998). % ,-. 9:/H IJ I8 K" w>? ST , & . Kx

(29) e8 4K LM8 6$8 y z7 QR35. p{K|1}(He, Ne, Ar, Kr, Xe)8 M~"y. % *23

(30) Z w"t y[ $F/ % U O /0, ()8 9:/ J.# Fj [\ 45(Fig. 1). %Z M U % 8 8 e *23# 4 j $F/ ¡¢, £ ¤/, ¥/ &j $[\ 45(b" nKo, 1987; ¦§¨ &, 1998). . The simplified geologic map showing the sampling sites of the Baegryongdo, South Korea (Lim et al., 1998)..

(31) !" #$ Nd-Sr %&'( )*+, -. 525 %A O, *+ ,-. 9:/( ©9:/) µ35. *m ¹ 5% h5. Nd, Sr M~"y *mZ *·Í µGU 140~ Z % Mª ©. IAA Q«j ¬ 4 km Fj *23# 45. i/08 ® ¯1 ° 160 C' HFE HClO j iµé# HClA Âi ' ± 10 m S 8 zj +[ 9: ]r Ïê ëÛ

(32) j Sr REEU *.35. Nd /0h ²³ 5~10 cm(± 30 cm) ´K8 >? 2 HIBA(α-hydroxy isobutylic acid)iìj 2 * @/ 5B CD[\ 45. .3(Dosso and Murthy, 1980; Tatsumoto et al., ©9:/8

(33) Hµ 4Kj S[¶n( 1987) í n#î

(34) g$ ïê H b" nKo, 1987) qtu&(1996) 8 K-Ar B*mK(Thermal Ionization Mass Spectrometry) 1 4.7~5.0 Ma((3K·, ¸=¹)j T#[¶5 Finnigan MAT262RPQU i3 Nd Sr8 M~" . ©9:/ º»¼8 ¢N=(lherzolite) >? yU ðS35. Nd/ Nd Sr/ Sry 2@/ 5B 2C[\ 4½ 6PF5. ¼8 , Nd/ Nd=0.7219E Sr/ Sr=0.1194j ]r3 -. ¾m8 S 9:/h +3K 5. ]rµG NBS 9878 Sr/ SrñZ 0.7102530ò 0.000010(2σ) La JollaE n#î N ]rµ

(35) G JNdi8 Nd/ NdñZ 0.5118291ò ©M *23 ,-. 9:/0 j ¿ 0,0000009(2σ)E 0.5121025ò0.0000008(2σ)5. Àm, TÁm, Â¾m, !m, Ãm &j $[ >? 2@/ µG' *.Í ¿Àm kl µG Â¾m TÁmZ ¹ÄÅ N²A Æ5. b" (óô)

(36)

(37) õ' W# V wÒ nKo(1987)Z ,-. 9:/0U ¾m9:/ Z ' *öËç(Stuart et al., 1994) ztF 1ïËç SH9:/j *3# qrs qtu(1996)Z (Nagao et al., 1997)j 1}U + HB*mKj ¿Àm w ZSH 9:/A 1 35. % 8 klh 2CÍ p{K|Q Ar( Ar/ Ar), He( He/ ,-. 9:/0 SN²(µGÇÈ, B-10, B-5U, B- He), Ne, Kr, Xe &8 M~"yU *m35. 0.5 6U, B-8, B-3) N/ N²(B-1, B-9)A nxh# ~2.0 mm ´K8 (f ¿Àm ÷S 1~3 g µGU 45. 9:/-É= 0.5~1.5 mm ´K8 Ê VwÒ' hydrouric press type crusherU Âi *ö ¿Àm 1 mm S 8 xÊ8 ÂËÁm S 4 mm 35. 70 MPaÕ

(38) øÔA ùúß 1* +ß S ´K8 -.¾m8 w OÌÍ5. (Nakai et al., 1997)Í 1}U HB*mK(VG-5400)U 9:/H ¯/Z 0.5~1.5 mm ´K8 Ê ¿À Âi M~"yU ðS35. *m ¹ ¬ 10% m 0.5 mm8 zÂÁm ¾m S &j $[ h5. \ 45. 9:/- É='E Î 5Ï ´K 8 WXK$ >?2@/0U 2@3# 4 , ÐlÑ S(16 cm h)8 ,-. ¾m S 2@5. > ? 2@/8 ÊÒ ÓÊ' ÔÊÕ

(39) 5Ï35. >? 2@/Z j ¿Àm, ÂËÁm, zÂÁm, ´Ö % 8 9:/0 $* " *m ÷ }Ä×j $[ }Ä×-ØN=(spinel-lherzolite) Table 1 Î5. 9:/H/8 SiO CBZ 49.39~ 5(p, 1995). 61.11 wt%j T 9:/ y 5 ùZ Ü5. Na O+K OCBZ 3.63~7.70 wt%(ûü, 5.23 wt%)5. èB" Cr(197~348 ppm), Ni(118~239 ppm), Zr (174~371 ppm), Sr(592~1249 ppm)&8 ý 1 ù5. ÙÚÍ µG ]8 Û 8 ¹XlYA / *0(Le Bas et al., 1986) <þ % 8 3K ~3 ¬ 2~3 cm ´K8 /ÜA ÝÞ ß àZ /YZ ,-.t8 9:/-É=(mugearite) X 24µ á. 5½ â0Û W½ã äåN E 'ÿ,-.t8 9:/H ¯/ DÊ Í5 (Fig. 2). ß *· 35. ÈS"(compatible element) Ni, Co, Cr, Sc, V pæ Royal Holloway and Bedford, New College, & ,-. 9:/ [\ 45. 9:/08 University of London8

(40) H J. N. WalshqÂ1 MgO CB ÈS"8 MgO â1 ICP-MS *mçj $* èB ", REE *mA 2. o. 4. 143. 146. 144. 86. 144. 86. 146. 87. 86. 88. 88. 144. 38. 36. 4. . . 2. 2. . 2. 3.

(41)

(42) . 526 . Sample No. Rock type. Major and trace elements of basaltic rocks and mantle xenoliths from the Baegryongdo. B-1. B-2. B-3. B-5U B-5L B-6U B-6L. B-8. B-9. B-10. B-11. B-12. Ol-7. Ol-8. Basaltic Basaltic Basalt Basalt Basalt Basalt Basalt Basalt Basalt Basalt Basalt Basalt Iherzolite Iherzolite andesite andesite. Major elements (wt.%) 54.63 51.63 56.47 49.39 53.4 50.58 52.9 61.11 SiO2 Al2O3 15.25 12.80 9.71 12.93 10.95 13.55 11.91 9.73 9.01 13.10 12.25 13.01 12.68 12.55 12.27 9.44 Fe2O3 MgO 6.41 7.90 6.56 7.67 7.80 7.46 7.37 5.56 CaO 7.44 6.56 7.09 6.71 6.59 6.45 6.79 7.58 Na2O 3.42 3.83 2.67 4.54 3.77 4.13 4.02 2.47 1.83 1.08 2.64 3.16 2.16 2.72 1.96 1.16 K2O TiO2 1.67 2.43 1.93 1.65 01.94 1.59 1.84 2.67 P2O5 0.22 0.52 0.53 0.76 0.55 0.81 0.78 0.17 MnO 0.12 0.15 0.15 0.18 0.16 0.16 0.16 0.11 trace elements (ppm) Ba 198 250 Co 36 48 Cr 250 244 Cu 39 37 Li 10 12 Ni 149 194 Sc 19 12 Sr 592 1149 V 153 161 Y 17 18 Zn 79 124 Zr 174 297 Rb 20 34. 250 36 263 29 14 165 10 1021 123 19 142 407 15. 211 38 197 33 16 183 9 1249 99 21 153 380 19. 227 40 307 30 15 216 11 1117 125 17 140 371 14. 194 37 252 34 15 207 9 1160 99 20 148 339 23. 231 41 242 34 14 197 11 1103 124 20 138 306 14. 290 38 248 26 7 118 16 1226 158 15 112 344 9. 50.15 13.09 12.31 9.48 7.94 3.42 1.11 2.01 0.32 0.17. 57.8 12.37 9.82 5.85 7.48 3.10 1.17 1.96 0.33 0.12. 215 45 445 40 11 239 24 994 179 21 105 260 16. 243 34 348 31 9 157 21 1050 158 18 85 262 13. 57.33 53.95 12.55 16.17 9.55 9.47 6.07 6.24 7.79 7.24 3.19 3.00 1.11 1.83 1.97 1.78 0.32 0.21 0.12 0.11. 43.06 0.17 9.01 47.29 0.25 0.05 0.04 0.01 0.01 0.11. 43.38 0.29 9.97 45.8 0.31 0.05 0.04 0.02 0.01 0.13. 245 36 341 29 11 161 22 1063 163 19 87 258 8. 7 91 270 3 3 2726 2 2 7 0 51 2 5. 7 91 255 2 2 2579 2 2 8 0 47 3 4. 204 37 235 38 10 145 19 578 159 21 83 177 20. The SiO2 contents are the simply calculated values.. <= â13# 45. ÎZ ³Z ¿Àm8 * ÷S8 p abj mÍ5. Ni Co8 ¿ ¿ Àmn zÂÁm ÎZ kl8 S+A p3# 4 5. Ü, Ba, Sr & ÈS"(incompatible element) MgO â1 <= ¿3 ³ 45. %. /08 0"(rare earth element, REE)8 * m ÷ Table 2E Î5. % ,-. 9:/Z 1 0 "Y(LREE)ñZ m y3 30~200 S j [\ 4#, Q0 " (MREE)ñZ mñ y 10~50 , : 0 "Y(HREE)ñZ 4~7 S j [\ (−)8 w OOtU T# 45(Fig. 3). 0" CB 9:/-É=' 9: /H ¯/j C <= | REECB F j

(43)

(44) # LREE1 HREET5 wFj [# 45. ¿Àm, Â¾m ÂËÁm &8. ÷S*i8 ÷ abj mÍ5. Fig. 3'E Î % 8 ,-. 9:/8 0 " Z z7 DÂ3 ,-. 9:/H IJI1 DÂ K"lH' D3½A 8è3# 45. J.# LREE1 Í ÊÒj Ï 9:/(OIB, oceanic island basalt)8 DÂ35. ,-. 9:/h8 ¿Àm >?2@/Z SiO 1 43.06~43.38 wt% MgO(45.80~47.29 wt%)E Fe O (9.01~9.97 wt%)U Al O (0.17~0.29 wt%), Na O . 2. 2 3. 2 3. 2. (0.05 wt%), CaO(0.25~0.31 wt%), K2O(0.04 wt%), P2O5. &8 $*Z

(45) 5(Table 1). j Mg-¿Àm(forsterite)j $Í >? 2@/Z Ni(2579~2726 ppm) Cr(255~270 ppm) CB ù5(Table 1).. (0.01 wt%), MnO(0.01~0.03 wt%).

(46) !" #$ Nd-Sr %&'( )*+, -.. 527.

(47) Data of rare earth element (REE) for alkali basaltic rocks and mantle xenoliths from the Baegryongdo, South Korea. Element (ppm). B-1. B-6U. B-10. Rock type. Basaltic andesite. Basalt. Basalt Iherzolite Iherzolite. 16.31 (49.44) 110.95 (39.19) 12.74 (28.4) 45.05 (27.76) 6.34 (18.32) 1.27 (20.18) 3.56 (13.78) 1.76 (9.88) 0.26 (9.39) 0.55 (7.59) 0.41 (6.8) 0.05 (6.78). 26.91 (193.47) 51.75 (144.71) 6.27 (107.31) 22.24 (90.68) 3.38 (48.23) 1.24 (42.51) 2.28 (26.96) 1.38 (14.06) 0.21 (11.53) 0.55 (7.61) 0.39 (4.39) 0.04 (3.8). (Eu/Sm)n. 0.20. 0.37. 0.25. 0.16. 0.15. ΣREE. 242.96. 116.64. 163.8. 218.65. 115.8. LREE/ HREE. 16.11. 11.32. 17.61. 9.37. 16.55. La Ce Pr Nd Sm.

(48) Chemical classification of volcanic rocks from the Baegryongdo, South Korea. Field boundaries of the total alkali versus silica diagram after Le Bas et al. (1986). The curved lines subdivide volcanic rocks into alkaline and subalkaline (Kuno, 1968).. Eu Gd Dy. Ð= ñj ]r >?2@/ ¢N= 8 0"8 ³Z LREE1 HREE y [\ ¬ (−)8 KKU T5. ¢N= µG(µGÇÈ OL-7, OL8-2)8 REE 'j DÂ35(Fig. 3).

(49) e w>? lH8 üH$ A 8è3# 45. JØn 9:/8 REE 9 U nxh# 45..

(50) ! "# . % ,-. 9:/08 Nd, SrM~"y. 143. Nd/144Nd=0.51273~0.51294,. 87. Sr/86Sr=0.7034~7043. Ho Er Yb Lu. Ol-7. Ol-8-2. 43.00 51.19 (70.07) (1.92) 77.00 101.12 (54.84) (1.52) 10.51 (41.33) (0.87) 35.00 33.81 (40.76) (1.36) 5.20 5.62 (25.58) (1.12) 1.30 0.87 (26.2) (0.38) 5.07 (18.13) (1.61) 1.80 3.61 (10.37) (0.21) 0.74 (10.65) (1.15) 2.26 (7.37) (0.42) 0.50 2.45 (6.3) (0.61) 0.36 (5.81) (0.69). 33.20 (2.34) 58.00 (2.01) (1.26) 18.00 (0.7) 3.40 (1.96) 0.50 (0.57) (2.44) (0.33) (1.13) (0.66) 1.90 (0.91) 0.3 (0.95). Numerals in parenthesis indicate chondrite normalised value based on Nakamura (1974).. Sr and Nd isotopic compositions of some basaltic rocks from the Baegryongdo. Sample No. B B B B B B B. 1 3 6L 6U 8 9 10. Rock type Basaltic andesite Basalt Basalt Basalt Basalt Basaltic andesite Basalt. n.d: not determined.. Rb (ppm) Sr (ppm) 20 15 14 23 9 16 13. 592 1021 1103 1160 1226 994 1050. Rb/Sr. 87. Sr/86Sr. 0.034 0.015 0.013 0.020 0.007 0.016 0.012. 0.70432 0.70343 0.70340 0.70336 0.70342 0.70353 0.70370. Sm (ppm) Nd (ppm) 6.34 n.d n.d 3.38 n.d n.d 5.20. 45.05 n.d n.d 22.24 n.d n.d 35.00. Sm/Nd 0.141 n.d n.d 0.152 n.d n.d 0.1491. 143. Nd/144Nd. 0.512729 0.512926 0.512941 0.512939 0.512927 0.512923 0.512897.

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(52) . 528. Chondrite normalized REE patterns of the alkali basaltic rocks from the Baegryongdo. REE abundances were normalized by the data of Nakamura (1974). MORB data from Humphris et al. (1985). OIB data from Basaltic Volcanism Study Project (1981).. j yF Z U T5(Table 3). Nd-SrM~" y , , , , ,-. 9 :/ y ÷Í 6$A T5(Fig. 4). Y 9:/08 >? "

(53) 8 6$ IJI S8 U p3# 4 j mÍ5. µGÇÈ B-1( Sr/ Sr=0.7043)A ,-. 9 :/08 Sr/ SrZ 0.7034~0.7037, Nd/ NdZ 0.51290~0.51294j' yF /w Ot M~"y1 DÂ35. Y MH8 " lH' D3½A

(54) µ3 " IJIj *[\ *+[ 8 SM¯

(55) lH 8 ¹X[

(56) ½A

(57) µ5. J Øn µGB-18 Sr/ SrZ 0.7043, Nd/ NdZ 0.51273j Sr 5 [\ 45. Rb/Sry(0.034). KxµG(0.007~0.012)' T5 ´5.

(58) l H 8 1$A µr3# 45. % 8 9:/0 >? ïf(mantle array) p e µ[ ÷>? K"(depleted mantle source) 6$A c nxh# 45(Fig. 4). % 9:/8 Rb ý 1 9~23 ppmj z7 Rb/Sry(0.007~0.034) 5.

(59) lH8 j mÍ 8 /08 ³ Rb8 ý. 69~249 ppmj T5 97 ù Rb/Sry eµ 0.1~15.6j z7 ù5(Kim et al., 1999). ÎZ Â' % 8 9:/0 Sino-Korean 87. 87. 86. 86. 143. 87. 87. 86. 143. 144. 144. Variations of 87Sr/86Sr vs. 143Nd/144Nd for alkali basaltic rocks in the Baegryongdo (Isotopic data of the Jungog, Ulreungdo and Chejudo (Kim et al., 1999), Dogdo (Kim, 2000) and Baegdusan (Lee, 2000). OIB data after Saunders et al. (1988). Slashed area: Baegdusan, dashed area: Jungog, shaded area: Ulreungdo, double line area: Dogdo and blank area: Chejudo.. craton

(60) A 3 *+3½

(61) lH8 X z7 Z j mÍ5. Zindler and Hart(1986)1 ¯ >? z$*Y y ! a, % 8 9:/0 Í >? z$ * EM"n EM#T5 $% ÷Í 6$A T5. qrs qtu(1996)Z % 9:/0 Sr M~"y( Sr/ Sr)U 0.7033~0.7037 0.7041~0.70488 J&j *3# 'j 5' ( IJIj *3n, )h ë³'8 ï. OÍ l= m * 45. JØn Sr/ Sr y 0.7033~0.70438 (IJI K" lH8 =K T5 IJI )$ß

(62) lH 1$ + abj mÍ5. 87. 86. 87. . 86.

(63) $ %&'( ! "#. Q,% 9:/(MORB)n ¸(plume) O ) h' *+ 9:/ Î >?' D µG 2@Í p{K|(He, Ne, Ar, Kr, Xe) "8 M~"yU

(64) , >?, -, K8 $* E OÍ QR ST1 .\/5(Ozima and Podosek, 1983; Porcelli and Wasserburg, 1995; Matsumoto et al., 2001).. Ø Y 83 >? F\ .

(65) !" #$ Nd-Sr %&'( )*+, -. . Isotopic compositions of noble gases in olivine of the mantle xenoliths from the Baegryungdo.. Sample. Iherzolite (OL-7). Method. Crush. 500oC. Weight (g) 4 He(×10−9) 3 He/4He(R/RA) 20 Ne(×10−11) 20 Ne/22Ne. 0.7764 1.35 <0.6 0.941. 0.4753 3.23 1.83±0.91 <1.0. 21. Ne/22Ne. 36. Ar(×10−10). Iherzolite (OL8-1). 1800oC. 500oC. Crush. Iherzolite (OL8-2). 1800oC. 500oC. Crush. 1800oC. 0.4753 0.9541 0.6112 0.6112 0.9938 0.4449 0.4449 2.64 1.53 4.72 9.67 0.509 2.86 8.26 16.8±3.1 <0.6 0.96±0.78 5.0±1.06 <0.2 0.86±1.41 6.69±1.3 11.0 3.03 7.4 5.99 2.56 <1.0 8.16 9.85±0.18 9.83±0.15 9.97±0.19 0.0312 0.0322 0.0341 ±0.0025 ±0.0032 ±0.0039 0.0968 0.699 3.25 0.215 0.722 2.34 0.184 0.546 2.85 0.1908 0.1891 0.1888 0.1877 0.1888 0.1889 0.1883 0.1882 0.1886 ±0.0014 ±0.0012 ±0.0007 ±0.0024 ±0.0020 ±0.0010 ±0.0016 ±0.0019 ±0.0008 500.6±1.5 347.7±1.0 320.4±0.6 312.8±0.8 307.3±0.6 301.2±0.5 299.9±1.2 311.5±1.3 299.4±0.5 0.346 13.4 11.4 0.524 9.3 9.4 0.361 7.1 10.9 0.084 0.24 3.69 0.063 4.89 3.31 0.042 1.72 3.56. 38Ar/36Ar 40. 529. Ar/36Ar. 84Kr(×10 −12) 132Xe(×10−12). Unit for concentrations is cm3 STP/g. *Normalized to the atmospheric ratio=1.4×10−6 (Ozima and Podosek, 1983).. 08 p{K| 1} ¾1 d13 j 1S3 # 45. 2, wFj 31}1 4 \n# 4 w>? ¾ MORBÊ( He/ Hey=8.18ò0.73Ra, Hilton et al., 1993 Ar/ Ary 1500w, Sumino et al., 2000) 5' DÊZ T5 ùZ M ~"y(9~32Ra, Porcelli and Wasserburg, 1995)E Z

(66) þ5 M~"yU 6 ï ÎZ LM 8 31}1 7 \n >? ¾5. Sumino et al.(2000)8 í 58µI >? 2@/ ' MORBÊ( He/ He=7.0Ra, Ar/ Ar= 2000) ¸Ê( He/ He=16.6, Ar/ Ar=400)j *35. í ' % 8 >?2@/ p{ K |8

(67) þ5(Ar), (He), 9ê(Ne), ´:(Xe), ´ ;<(Kr) &8 M~"yU ðS 35(Table 4). ,

(68) þ5 8 M~"8 *mG mZ í ' 5=

(69) 5. 3. 40. 3. 3. 4. 36. 4. 40. 4. 40. 36. 36. 8 Ï M~"y <= 08 >? ¾8 d1U 1S3# 45. 2, Z He/ Hey8 (8.0Ra) MORB8 K" [ ¾E ùZ He/ Hey(35.7 Ra )U 1

(70) ) hn ¸ O ¾5(Kurz et al., 1982; Allegre et al., 1983; Rison . 3. 4. 3. 4. 6. and Craig, 1983; Staudacher et al., 1986; Sarda et al., 1988; Hiyagon et al., 1992; Sumino et al., 2000).. SwF >?' He8 )$ [

(71) K ab >? K"8 µG' T He WK8 ñ= > 3. 3. Û 45. j He >?8 =?(U) (Th) 8 ËÂ$ @A 8 )$Í5. JØj MORBE OIB µG8 He/ Hey1 5Ï Z >?8 =? "µ ( He/U+Th)8 y1

(72) Hµ <= 5Ï3½A 8è5. He/ He1 wFj Z MORB8 K" >?Z wFj 31}1 4 g[¶n, " ùZ He abj He/ Hey1 ´# 31}1 FZ ÊF ¸K"8 >?'T5 Z He/U+ThyU 1 5(Allegre et al., 1983; Kurz et al., 1983; Hart et 4. 3. 4. 3. 3. 4. 3. 3. 4. 3. al., 1985).. áB M~"y( He/ He) 3>? $*A D3 QR Fj i[# 45. F j Q,%9:/(mid-oceanic ridge basalt, MORB) Z z7 ü He/ Hey(8ò1 Ra, Ra K8 He/ Hey 1.4C10 A 1þD)U 1

(73) 3E,

(74) }EÐ, .FGê(Reunin) &8 ï K"8 He/ He y 9~32 Raj + ñA nxh# 45(Porcelli and Wasserburg, 1995). Sumino et al.(2000) 83 'H í 58µI8 >?2@/8 ¿Àm' + M~"y( He/ He)1 9.4~16.6Raj

(75) e LM >?¸(mantle plume) K" j m35. % 8 >? 2@/8 ¿Àm' ðS M ~"y( He/ He) W Vãöç 500 CE 1800 C 8 zt 1ï+ õ' 0.86ò1.41 Ra~16.8ò 3.1 RaÕ

(76) 1 45(Table 4). 1800 C' +Í 3. 3. 3. 4. 4. −6. 4. 3. 4. 3. 3. 4. 4. o. o. o.

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(78) M~"y( He/ He) 5.0ò1.06~16.8ò3.1 Ra5 (Table 4). µG(OL8-1, OL8-2)8 He/ Hey MORBñ DÂ3 ñZ

(79) 3 .}Ä \ >?(subcontinental lithospheric mantle)K" lH [ ñ5(Fig. 5). 8 2@/8 M~"y(Sumino, 2000) MORBT5 5 5 (Fig. 5). JØn ¿Àm µG(µGÇÈ, OL-7)8 He/ He y 16.8ò3.1Ra(Table 4)j MORBñT5 $% +ñj T « >? ¸K"j m[ ñ5. JØn ñZ IJI1

(80) ]j *+ß f K"8 He(Craig and Poreda, 1986)abj He/ He ratios plotted against He concentrations )> Û 45. IJ3 ãö +ç8 He/ He for xenoliths from the Baegryongdo. Data of the Chejudo Sumino (2000). Shaded area indicates the He/ He y1 z7 K ab5. ~8 µG OL8-1 OL8- after ratio of MORB (8.18±0.73Ra, Hilton et al., 1993). 2 µG8 ûü He/ Heñ 8C10 A OL-7µG8 WK He/ He ñj 1S3 fK"8 3He8 BZ 4.1C10 ccSTP/gj tÍ5. )K(4.1 . Ozima(1994) 31}1 7 Í >?' Ar/ C10 ccSTP/g)A Âi3 10000L S Ý

(81) ] Ary 3,000w S P =# ÷N

(82) ¶5. J °+[\ OL-7µG8 He/ HeñZ f He8 M Øn 4Z >? lH *+ ß ËÂ$K" $* Fj 13 5. lN IJI *+ ß8 ËÂ$ f K" $* 8 ¹XA YK ab > K"8 He 8 1 #O P Û 4

(83) Ý, %

(84) ? K"8 µG U

(85) lH8 p{K|1}8 e8 2@/Z

(86) 3 .}Ä\ >?' D Fi3K Ðµ ÎZ 2 $*8 p A #Oî5. 1$ + j mÍ5. OIBE MORB' KE yZ p{K| 1}8 K" Û L M¯ :8[\ [#, KE yZ !

(87) þ5Z

(88) lH8 K K" lH8 OIB8 p{K| 1} Û8 K¹Xj \]

(89) QR STU F(tracer)5. >?8 [¶5(Patterson et al., 1990; Honda et al., 1993; Burnard et al., 1994; Matsumoto et al., 2001). ^# Ar/ Ary

(90) 8 31} (Q' R ¤ 0Û1 [\, KT5 ñ ´ Rþ' 8 j >? 2@/8 Ar/ Ar 651~4426j S 31}U 8è3# Z ñZ T.# S w>? K8 Ê Í5(Sumino, 2000). 31}U 8è5. <=' Ar/ Ary8 ' % 8 >? 2@/A Ê$ w>?

(91) ê K 8 ¹X 8 pA S> Û 45. 4 Ï

(92) ê _5(p, 1995). Qæ M Z /8 2@/8 Ar/ ArZ K8 ñT5 ùÑ

(93) e' +[ >? 2@/Y ÎZ ÷U T nxU5(Steiger and Jager, 1977). % 8 >?2@ # 45(Fan and Hooper, 1989). /8 Ar/ ArZ 300, 310, 490j *m[¶# Z ¹X[

(94) Z MORB8 Ar/ Ar(10,000~30,000; Staudacher and Allegre, 1989; Ozima, 1994)ñT5 wFj $% Z ñj K8 ñ( Ar/ Ar= %

(95) e8 4K ,-. 9:/ >?2@/ 295.5E µG 3 $*, èB$*, 0"(REE), Ar/ Ary=0.1880, Ozima and Podosek, Nd, Sr &8 M~ " *mA µ35. 67 9: 1983) DÂ35. Fj Ar/ Ary1 MORBE y' Ñ nxn Z µG1 K8 ¹X p / h 2@Í >? 2@/ ØN=h8 p{ A V½A 8è5. Matsuda and Marty(1995) K| 1}8 M~"y( He/ He, Ar/ Ar, Ar/ Ar &) *mj

(96) e8 w>?8

(97) F 6$ He/ Ar- Ar/ Ar, He/ Ar- He/ Ar8 JWU i 3 3 >?'8 Ar/ Ary 3,000 28,000 ,-. 9:/H IJI8 K"8 O$A _ 3 Â8 ñj K8 ñT5 Xî 5# ¯35 5. *m ÷ 5½ Î5. 530. 3. 4. 3. 3. 4. 4. 3. 3. 3. 4. 4. 4. 3. 3. 3. 4. −8. 4. 4. −14. 40. −14. 36. 3. 4. 3. 4. 40. 36. 40. 40. 40. 40. 36. 36. 36. 40. 36. . 40. 38. 36. 36. 40. 36. 3. 4. 40. 36. 36. 40. 4. 40. 40. 3. 36. 40. 4. 38. 36. 40. 36.

(98) !" #$ Nd-Sr %&'( )*+, -. 531 ?E´ (2000) µ

(99) ¢A!" R2 1. % 8 9:/0 É=E ÎZ ,-./ Nd-Sr !" =). ?©\ \¶ tï 9:/H ¯/8 y,-./ tïj *Í ! &U ·®, 49p. 5. ,-. 9:/h >?2@/ 5B +[ 2 ?D (1995) °D ¸

(100) % &] 12: Ww ¹ º»} @/Z Mg-¿Àm(Mg=45.8~47.3%) ÂËÁm ~. &R, 4, p. 104-123. }Ä×-ØN=(spinel-lherzolite)5. i¼½, _, ½¾, ~¿ (1998) %RÀ Á] X9 Â 12(Ã)-!¦ ÄÅ ÆJÄ. DÇ©!12 2. ,-. 9:/08 REE Z HREE1 LREE ", 98VC 1ÈsV, p. 17-38. T5 + ñA 1

(101) Ï 9:/(oceanic island Allegre, C.J., Stardacher, T. and Sarda, P. (1983) Conbasalt) DÂ3 , DÂ REE ³Z DÂ K straints on evolution of Earth's mantle from rare gas systematics. Nature, v. 303, p. 762-766. "lH' D3½A µÂ5. Basaltic Volcanism Study Project (1981) Basaltic volca3. % 8 9:/08 Nd-Sr M~"y ÷ nism on the terrestrial planets. Pergamon press, New york 1286p. >?K"(depleted mantle source)A

(102) µ3#,

(103) l Burnard, P., Stuart, F.M., Turner, G. and Osakarsson, H. H8 pA V

(104) Z j mÍ5. (1994) Air contamination of basaltic magma: Implications for high He/ He mantle Ar isotopic compo4. >?2@/8 M~"y( He/ He=5.0~ sition. J. Geophys. Res., v. 99, p. 17705-17715. 6.7 Ra) MORB(8.0Ra)ñT5 5. % 2 Craig, H. and Poreda, R.J. (1986) Cosmogenic He in ter@/

(105) 3 .}Ä\ >?(subcontinental restrial rocks: the summit of lavas of Maui. Proc. Natl. Acad. Sci. U.S.A. v. 86, p. 1970-1974. lithospheric mantle)K" lH' D3½A 1þ` Dosso, L. and Murthy, V.R. (1980) A Nd isotope study of 5. J.# ùZ He/ Hey(16.8Ra)U nxh µG the Kerguelen islands: inferences on enriched oceanic mantle sources. Earth Planet. Sci. Lett., v. 48, p. 268(OL-7) IJI *+ß f K"8 abj mÍ5. >? 2@/8 ¿Àm8 Ar/ Ary Fan,276.Q. and Hooper, P.R. (1989) The mineral chemistry of ultramafic xenoliths of Eastern China: Implications for (310~490) K8 ñ DÂ35. ,-. 9: upper mantle composition and the paleotherms. J. /H IJI1 waµ K8 pA VZ Tb 31 Petrol., v. 30, p. 1117-1158. }1 4¶c j ÂOÍ5. Hart, S.R., Hogan, I. and Dymond, J. (1985) The closed. 3. 3. 4. 4. 3. . 3. 4. 40. 36. ) ) d e1z

(106) " y(ÇÈ: 8 Ûg[¶5. Nd, SrM~" *m fÔ3r í n#î

(107) g$ g h iÛÑ Â8U ]5. :b «Âµ Dj 8kA ( *® Â8U ]5. KRF-2001-0079-1). *+,D (2000)

(108) K-Ar1 NdSr =). R*R, 36, p. 313-324. , l, ?), b, , ?, ~, D~, ?&, | (1996) R* .¡XY ¢ A=) 2=%&£ 12(II). 'R!12", ¢ ¤[ 12sV, UCPN 00016-070-4, 254p. b, (1996) D¥ lw ¦

(109) D & &)] 12(I): &§, ` ¨ F)%!". ©!ª«R*, 32, p. 223-249. !¬, ?®!, )¯, Vs^ (1998) §F °w ± |R² R2] OP. R*R, 34 , p. 172-191. ?®!, x (1987) ³ §4

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