斜長石累帯構造が示すマグマ溜まりの分化過程

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(3) . ,**- 3 3 ,**. 2 ,0 . Magmatic Di#erentiation Process Inferred from Plagioclase Zoning and Its Pattern Akira TSUNE῍ and Atsushi TORAMARU῍ Relationships between whole rock composition of magma and plagioclase zoning were investigated on volcanic rocks from the Shirahama Group, Izu Peninsula, Japan, which have the various chemical compositions of tholeiitic series produced only by crystallization di#erentiation. The plagioclase zoning can be divided into the following three zoned regions, (+) oscillatory-zoned, (,) patchy-zoned, and (-) unzoned regions, based on Anderson(+32.)’s classification. We described the flatness of zones and the spatial distribution of zoned regions from core to rim of the phenocrysts, and found the relations between the characteristics of plagioclase zoning and the whole rock compositions. As the whole rock SiO, increases, (+) the number of resorption zones, defined as zones with resorbed track, increases ; (,) the frequency of plagioclase with patchy-zoned region decreases ; (-) the frequency of plagioclase with the patchy-zoned region in central parts of crystals increases ; (.) the diversity in the zoning pattern becomes smaller. In basalts, various zoning patterns can be observed whereas in dacite, oscillatory zoned regions are dominant. Our observation can be explained by a simple model involving the homogenization processes of heterogeneity in a magma chamber, associating with the crystal growth or dissolution processes. According to the model and the observations of natural plagioclase zoning, we can give a constraint on the characteristics of homogenization process developed in an evolving magma chamber : parameters of the characteristics f, the volume ratio of relatively di#erentiated part in the magma to homogenize and g, chemical contrast of the magma. At the initial stage (basalt magma), the homogenization process with large f and large g is dominant. At the later stage (dacite magma), the homogenization process with large f or small g is dominant. Key words : plagioclase zoning, heterogeneous magma, homogenization process, the Shirahama group. +ῌ ῐ ῎ ῑ ῏. ST5U89)<=>VWX5 YZW[\]V. !"#!$%&'. WX$^_`$abcd89.:); YZW ef. ()*+ ,-. /012'34)*+56. ghi$<=>jkclf mno5pq9 rs. 789.:); <=>?:"#@A5BC)5. t34)uv5Gw.aAK9)v:xuvcyz!5. DE9.BFGHIJK9.:) LMN Vance, +30, ;. 6789.BF (Tsuchiyama, +32/), {|5}x. Wiebe, +302 ; Anderson, +32. ; Stamatelopoulou-Seymour. ~$mn"v-.M89.:). et al., +33* ; Pearce and Kolisnik, +33* ; Singer et al., +33/. (Kawamoto, +33, ; Murphy et al., ,***). <=>\]V. ; OP QR ,+33/ ; Hattori and Sato, +330 ; Umino and. WXA (Shore and Fowler, +330) E. Horio, +332 ; Kuritani, +332 ; Murphy et al., ,*** ; Stewart. F5BC) (Singer et al., +33/) [ . and Fowler, ,**+;. !$<=>ῌ/ (L’Heureux, +33-). 3,*ῌ++3, > ##T# ¡ Graduate School of Natural Sciences, Kanazawa University, Kakuma-machi, Kanazawa 3,*ῌ++3,, Japan. ¢ : 2+,ῌ2/2+ £¤£¤¥¦§¨ 0ῌ+*ῌ+ ©ª###«¬®¯#°±. Present address : Department of Earth and Planetary Sciences, Graduate School of Sciences, Kyushu University, 0ῌ+*ῌ+, Hakozaki, Higashi-ku, Fukuokashi 2+,ῌ2/2+, Japan. Corresponding author : Akira Tsune e-mail : [email protected].

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(293) +jk- 9F_`_Ca &' ^- /,4 l( /o, p4 m9 "#no) pdV q*+),- ) p q*+<.r9sN) o q*+<tu9sN)^- /D4. SiO, wt.ῌ _. `_Ca v )/Fh$b! YZGF)] _`_fgh$b!. , 0 _`_ /12) _`_12 )3 =_`_4 wNb!+= f gh$b! . _`_4x5 f , . _`_5 g R \*-. yzR 4x. 5 f, {|5 g <.r9h$b!<6}^-. . ~z) 4x5 f <.r9& C 5 g <tu 9h$b!<6}^- ῏. ῎. JAMSTEC 789:;)? < . =A P=R >)=

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(297) K.rPu, £P¤¥C^. 265. ῌ ῑ ῐ ῍ Anderson, A. T. Jr. (+32-) Oscillatory zoning of plagioclase Nomarski interference contrast microscopy of etched polished sections. Amer. Mineral., 02, +,/῍+,3. Anderson, A. T. Jr. (+32.) Probable relations between plagioclase zoning and magma dynamics, Fuego, Volcano, Guatemala. Amer. Mineral., 03, 00*῍010. Cashman, K. V. and Marsh, B. D. (+322) Crystal size distribution (CSD) in rocks and the kinetics and dynamics of crystallization II. Makaopuhi lava lake. Contrib. Mineral. Petrol., 33, .*+῍.*/. Couch, S., Sparks, R. S. J. and Carroll, M. R. (,**+) Mineral disequilibrium lavas explained by convective selfmixing in open magma chambers. Nature, .++, +*-1῍ +*-3. Hattori, K. and Sato, H. (+330) Magma evolution recorded in plagioclase zoning in +33+ Pinatubo eruption products. Amer. Mineral., 2+, 32,῍33.. ST ¦nJ v (+33/) U§¨©Z_ª«¬_ `_a®¯¨©V°±²W ¨© .* -1/῍ -3-. Jaupart, C. and Tait, S. (+33/) Dynamics of di#erentiation in magma reservoirs. J. Geophys. Res., +**, +10+/῍+10-0. Kano, K. (+323) Interactions between andesitic magma and poorly consolidated sediments : Examples in the Neogene Shirahama Group, south Izu, Japan. J. Volcanol. Geotherm. Res. -1, /3῍1/. Kawamoto, T. (+33,) Dusty and honeycomb plagioclase : indicators of processes in the Uchino stratified magma chamber, Izu Peninsula, Japan. J. Volcanol. Geotherm. Res., .3, +3+῍,*2. Kingery, W. D., Bowen, H. K. and Uhlmann, D. R. (+310) Introduction to ceramics. John Wiley and Sons. Kirkpatrick, R. J., Klein, J., Uhlmann, D. R. and Hays, J. F. (+313) Rate and processes of crystal growth in the system anorthite albite. J. Geophys. Res., 2., -01+῍ -010. Kuritani, T. (+332) Boundary layer crystallization in a basaltic magma chamber : Evidence from Rishiri volcano, northern Japan. J. Petrol., -3, +0+3῍+0.*. t³±´; (+320) µXg_`_¶g_`_wN ·fg=_`_¸ ¨©Y¹ -* .+῍ /.. t³±´; (+321) _`_wN)G-fg_`_ b! º»F 3 ./῍.3. L’Heureux, I. (+33-) Oscillatory zoning in crystal growth : A constitional undercooling mechanism. Phys. Rev. E, .2, ..0*῍..03. Lofgren, G. E. (+31.) An experimental study of plagioclase crystal morphology : Isothermal crystallization. Amer. J. Sci., ,1., ,.-῍,1-. Lofgren, G. E. (+32*) Experimental studies on the dynamic crystallization of silicate melts. In Physics of Magmatic Processes. (Hargraves, E. B. ed.) Princeton University Press. .21῍//+..

(298) 266. FG H$IJKL. McBirney, A. R., Baker, B. H. and Nilson, R. H. (+32/) Liquid fractionation. Part I : Basic principles and experimental simulations. J. Volcanol. Geotherm. Res., ,., +ῌ ,.. Mullins, W. W. and Sekerka, R. F. (+30.) Stability of a planar interface during solidification of a dilute binary alloy. J. Appl., phys., -/, ...ῌ./+. Murphy, M. D., Sparks, R. S. J., Barclay, J., Carroll, M. R. and Brewer, T. S. (,***) Remobilization of andesite magma by intrusion of mafic magma at the Soufriere Hills Volcano, Montserrat, West Indies. J. Petrol., .+, ,+ῌ.,. (+330)

(299) Adobe PhotoshopTM 3+ ,-/ῌ ,.+. Pearce, T. H., Gri$n, M. P. and Kolisnik, A. M. (+321) Magmatic crystal stratigraphy and constraints on magma chamber dynamics : Lazer interference results on individual phenocrysts. J. Geophys. Res., 3,, +-1./ῌ+-1/,. Pearce, T. H. and Clark, A. H. (+323) Nomarski interference contrast observations of textual details on volcanic rocks. Geology, +1, 1/1ῌ1/3. Pearce, T. H. and Kolisnik, A. M. (+33*) Observations of plagioclase zoning using interference imaging. Ear. Sci. Rev., ,3, 3ῌ,0. Shore, M. and Fowler, A. D. (+330) Oscillatory zoning in minerals : A common phenomenon. The Can. Mineral., -., ++++ῌ++,0. Singer, B. S., Dungan, M. A. and Layne G. D. (+33/) Textures and Sr, Ba, Mg, Fe, K, and Ti compositonal profiles in volcanic plagioclase : clues to dynamics of calcalkaline magma chambers. Amer. Mineral., 2*, 110ῌ132. Stamatelopoulou-Seymour, K., Vlassopoulos, D., Pearce,. T. H. and Rice, C. (+33*) The record of magma chamber processes in plagioclase phenocrysts at Thera Volcano, Aegean volcanic arc, Greece. Contrib. Mineral. Petrol., +*., 1-ῌ2.. Stewart, M. L. and Fowler, A. D. (,**+) The nature and occurrence of discrete zoning in plagioclase from recently erupted andesitic volcanic rocks, Montserrat. J. Volcanol. Geotherm, Res., +*0, ,.-ῌ,/-. Tait, S. R.(+322) Sample from the crystallizing boundary layer of a zoned magma chamber. Contrib. Mineral. Petrol., +**, .1*ῌ.2-. Tamura, Y. (+33.) Genesis of island arc magmas by mantle-derived bimodal magmatism : Evidence from the Shirahama Group, Japan. J. Petrol., -/, 0+3ῌ0./. Tamura, Y. (+33/) Liquid lines of descent of island arc magmas and genesis of rhyolites : Evidence from the Shirahama Group, Japan. J. Petrol., -0, .+1ῌ.-.. Tsuchiyama, A. (+32/) Dissolution kinetics of plagioclase in the melt of the system diopside-albite-anorthite, and origin of dusty plagioclase in andesites. Contrib. Mineral. Petrol., 23, +ῌ+0. Umino, S. and Horio, A. (+332) Multistage magma mixing revealed in phenocryst zoning of the Yunokuchi Pumice, Akagi Volcano, Japan. J. Petrol., -3, +*+ῌ+,.. Vance, J. A. (+30,) Zoning in igneous plagioclase : normal and oscillatory zoning. Amer. J. Sci., ,0*, 1.0ῌ10*. Wiebe, R. A. (+302) Plagioclase stratigraphy : A record of magmatic conditions and events in a granitic stock. Amer. J. Sci., ,00, 03*ῌ1*-. !"#$%&'( (+31,) )*+,-./0123 456789: ; +1 +2ῌ,/. <=>?@ ABCDE.

(300)