Title Sedimentary Cyclicities and their Implications of the
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Title Sedimentary Cyclicities and their Implications of the
Title Sedimentary Cyclicities and their Implications of the Junicho Formation (late Pliocene-early Pleistocene), Central Honshu, Japan Author(s) Arai, Kohsaku; Konishi, Kenji; Sakai, Hideo Citation The science reports of the Kanazawa University=金沢大学理科報告, 36(01): 49-82 Issue Date 1991-07 Type Departmental Bulletin Paper Text version publisher URL http://hdl.handle.net/2297/34108 Right *KURAに登録されているコンテンツの著作権は,執筆者,出版社(学協会)などが有します。 *KURAに登録されているコンテンツの利用については,著作権法に規定されている私的使用や引用などの範囲内で行ってください。 *著作権法に規定されている私的使用や引用などの範囲を超える利用を行う場合には,著作権者の許諾を得てください。ただし,著作権者 から著作権等管理事業者(学術著作権協会,日本著作出版権管理システムなど)に権利委託されているコンテンツの利用手続については ,各著作権等管理事業者に確認してください。 http://dspace.lib.kanazawa-u.ac.jp/dspace/ Sf . :LRep~ Kv , na , z al ; Va{ ]n iv T y o. l3 6 }1 ¥ 1 0 .. 3p p .4 9 8 2 J u J y1 9 9 1 0 S, edimentary andt } j信i rI~~mRi catJi()l"8 ftheJunichoFormat . ! 1 J l 1 1 l , ] ( OateP H' [ l ¥c , 況l e-eady KohsakuAR/ ' d", KONISr I l * andHideoSAKA了 氏 J J e t a r i J n c n t0 /E a y t hS c i e n . c e s .. 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B .X i n l U n 11 モg r e s s i o ns t a g e ): 1 0o u t e rs h ε l fOnt h emaximum: i nm 呂g r 巴3 5 1 0 ns t 3 g e ト Sludyo fm a g n e t o s t r a t i g r a p h i cp o l a r i t yc o n f i r m st h日t( 1 )t h己 P l i o -P l e i s t o c 日n eboundaryi s l o c o . tedi nt h eupperp o r : i i o no ft h em i d d l ep a r to ft h eJ u n i c h oFormation,and( 2 )t h el o v ! e r t om i d d l日 p a r t sc h a r a c t e r i z e dw i t ht h enormalp o l a r i t ya了日目 smg 口ε dt ot h eOld u v a iSubchron i nt h e! V latuyam. oC h r o n .B a s e c lont h i sa g eぉ s i g n n 1 e n t,s e d i n l e n t a t i o nr a t ei sr e e s t i r n a b ピ ヨ1t o bεabout3 0cm/l000yn n d e rt h ea s s u m p t i o no fi t sc o n s t a n c y Sedimentaryc y c l e so f i : h eJ u n i c h oFor 口 、 o .t i o n,'.'1h i c hdemonstr . o t enpidr i s e sandf a 1 1 8i n E己a l e v e larεmosし I ik e l ya s c r i b e dt ohaveforme 1 cun 1 ce ramajorc o n t r o lo fg l ac i .o吃 u s t a t i c s e al e v e lcha 口gεAc l e p o s i t i o n a lmodelo ft h enont r o p i c a l( t 巴m p e r a t e )c a r b o n a t e司ndm i x e c l s e d i m e n t so ns h e l fi sp r o p o s e c lw i t hr e s p e c tt og l a c i o -巴u s t a c y I 1 1a c l d i t i o n,s t r a t i g r a p h i c a lc h a n g e so fr o c k r n a g n e t i cp r o p e r t i e s( e .g .s u s c ε p t i bi Ii t y )o ft h e c y c l i cs e d i n l巴n t so ft h em i d d l ep a r t二 (y c l巴 1andI I )r e v e a lamuchh i g h e r f r 己q u e n c yc y c l et h a n t h a to ft h el i t h o -andb i o f a c i e s _I ti se x p e c t e dt h a tt h i sa n a J y s i scanb巴 u s e da sas e n s i t .i v eand e t f e c t i v ei n c 1i c a t o rf o rt 巴1 立p o r a lv a r i a t i o n so fs e d i m e n t a r y compon とn t( e s p日c i a l l yo ff e r romag 孔e t i cmine 白 ぉ ぺ フ 同 ← 4 9- K .ARAIe taL 5 0 LK n t rl[))ducHm! E u s t a t i cs e a l e v e lchanges h o u l dt e n dt ol e a v esomev a r i a t i o ni ns e d i m e n t sands e d i o fs ε q u e n c es t r a t i g r a p h yh a smaderemarkablep r o g r e s si n mentaryf a c i e日. The e n e f i t t e dt o ε s t a b l i s h e u s t a t i cs e al e v e lc h a r t sb a s e d r e c e n ty e a r s,andb t ont h e o Id e p o s i t i o n a ls e q u e n c e so n t o continentalτV A I Le and 1 9 8 7 ) . and o ff i r s t -t ot h i r d o r d e r c 1bvo n l a Do f o ft h ee u s t a t i cs e a l e v e l a r ew e l ldocumente ti s d i f f i c u l tt odetectεs t h a nt h et h i r d o r d e r,b a s e don s e q u e n c e,i に tb o u n d a r i e so f c, , , , , , 'u; o i n d i s t i r andt h eC Oi1s e P l e i s t o c e n ε E p o c hi sc h a r a c t e r i z e d t h ev ¥ l o r l d w i d ec l i m a t i c o fs u c h o r d e r s q u e n t s e a l e v e lchan疫を w i t hp e r i o d i c i t vand some g e o The s e a l e v e J duγtheP i e i s t o c e n eh a sb e叩 色xamined chemicalεsandp a l e o m a g n e t i cp a r a m e t e r so f c o r e s SHACKELETON ばS , and,f o rl a t e bym u l t i d i s c i and i N I L L I A l c 1i e so fr n a r i n et e r r a c e s, o fc o r a lr e e f s . s t u 吋 s e q u ei1c eon2mdo f f n O V l m Shallowmarine s ona c t i v ec o n t i n e n t a lmargins andNe v v canb e: . r ti 1 iz e dt oc o n s t r u c t e v e lc h a n g e,b a s e d ont h ec o n c e p t s e q u e n c e t h e s e s e ai o ri n s t a n c et h e s e q u e n c eo f a p a r tfroms e q u e n c es t r a t i g r a p h y,f e p r e s e n t a t i v eo ft h em i d d l et ol a t eP l e i s t o c e n e,o f仁e n t r a lHonshu, t h eShimosaGroup,ar Japan,wasd e s c r i b e d s e v e r a la u t h o r s AOKIand 1 9 7 31 9 8 u ;TOKUHASHIand 9 8 9 ) .E a r l yP. 1 e i s t o c e n e s e a l e v e l a l s o b e e ndocument KONDO,1 e d from a l i m i t e d number o fHwrine s h e l f b o t hi n Ne ' v vZ e a l a n d (BEU and 1 9 8 4 )and H o η s h u ;KITAMURAandKmmo,1 9 9 0andN o r t h e a s t 1 9 9 0 ) Thep r e s e n t wasi n t e 日d e dt od O C U I ヨ 1 e n tt h es i m i l a r l n s h a 1 1 0 wmarines e q u e n c eo fn o n t r o p i c a lc a r b o n a t eand t h e Formation P l i o c e n e[ 0 o fC e n t r a l abackgroundo fs e q u e n c e O t h e rt h a nl i t h o -andm o l l u s c a nb i o f a c i e s i 口 s t u d i e swere w i t ht w o f o l1 cp u r p o s e s ;( 1 )t o an r a t eo fs e d i m e n t a t i o n f o rap a r to ft h e and( ρ 2 )t ot e s t o fs e d i m 白 l e r 日 日i c i 社 t ya s s i g n m e n t叩v羽~凡\山ザ f o rs h 剖 a 10 ¥ 羽 W 1 九 ' 1伺司 w 奇 1 可 ' 巾 1此 a l 沈 t e 町Y 仁 討i t 匂s . 同 o > 也 ヲ ヲ 。 2 .TheJunich心]fi'iJI:rmatlon TheJ u n i c h oFormationwasf i r s tnamedandd e s c r i b e d HASEGAWA l f t e ri t s 日 S e d i n 1色孔t a r yC y c l i c i t i e sa n dt h e i r l m p l i c a t i o n so It h ε Jl1n i c h oF o r m a t i o n 5 J t y p e J u n i c h oi ns o u t h w c 5 t e r na r己a( ) fH i n l i wherci ti s i nt h e3 X e ao f a b o u t2 5k r n2 ( F i g Thi5f o r m a t l o n o v e r l i e st h eAoFormation Miocenet oe a r i yP l i o c e n e )t h a tc o n s i s t so fm a s s i ¥ ぽ s i l t s t o n e,and i s 0'1ε r l a i nwitht h e " l i a n y u "Formation fana l t e r n a t i o no f s i l t s t o n ea n c l 1 9 8 6 ) f i n es a n d s t o n e(HASEGAWA and ぅ , 。 , 1 題璽 Jil1l臼i.c l ,也氏 感D Aoft". F i g LI n d e xa n dg ε n e r a l i z e dg e o l o g i cmaps h o w i n gt h es t u d i e da 了 日 aa n df i v er o u t ε s( 1; 5 ),w h e r e c 1e t ai !e c 1s t r a t i g r a p h yi sc a r r i e do u t , 0 了t o ft h es t u d i e da r e a, Thicknesso ft h ef o r m a t i o na t t a i n st o1 6 0m i nt h en o r t h e γ 1 1pa v v h e r ei thasa t t i t u d eo fs t r i k e so f, ' 11 4 5E andd i p so f1 5 2 0 SE .I nt h i s i ti s mainlyo fc a l c a r e o u sc o a r s es a n d s t o n eandc a l c a r e o u sf i n es a n d s t o n ev v i t hawide 0 0 K .ARAIe ta l cC :)6 a r ei n t e r c a l i . l t e di nt h i s f a c i e s . t u f fb e c l s cmt o1r ni n f o r m a t i ol1. 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J ! 1d ance0 ( Dl'r γ o w sp e rL l I 1t !a r 邑a ! ob e d d i r t思 「 信 F i g .1 0 .Theabundancr :o ft h eg l a u c o n i t i cm i n e r a !g r a iロsando ff o r a m i n i f e r a lr a t i oo fp ! a n k t o n i c / ft 1 1 色 m iddlep a r t( fromp o i n tc o u n t i n go ft h i ns e c t i o n ) .;andnumber b e n t h i ci nt h eCyd巳 1o o fburrowsp巴 u n i ta r e ap巴r p e n d i c u l a rt ob e d d i n gp l a n e . 勾 S e d i m e n t a r yC y c l i c i t i e sa n dt h e i rl I n p l i c a t i o n so ft h eJ u n i c h oF o r m a t i o n 6 0 s k e l e t a lc o n t r i b u t u r sv v i t h1l1 I n O fb u tc o n s l s t e n t ι d d i t i o n sf r O n l . c h i n o i d si nc a l c a r e o1Jsf i n とs a n d s t o n記 f a c i e s .T h ε n 1 0 1 1 u s c s乳 nde I lei n d u f 2 J e dbedso ft h ef a c i ε sF 'a r espon g : e s01" e c h i n o i d s t 噌 , witht h er e s t,t h i si n d u r a t己dbec 1ss e ε 1 1 1: 1 0havεchね なc t巴r i s t i cfeawrεSo t h e r : :pong;εechinoiddとb r i s .日Sf o l l o'Vv ザ 丹 ;I ar 克己下交τ a J ns i z e( s D e c i a l l v .i n t h a nt h edcmiηanceo f2 o c c u r r e n C l : :0 1rockf r a ' : ; ! l T I ε日t s and 司 守 s t r u c t u r e . Ther e1 a t i v eabundanceo f m i n ε r a 1 i nt h ξ , 1 eI .i ssummu ' j z e di n 仁 1 0 .H i n d i c a t e sa i nt h ef a c i e s 日ndt 日n ds: 1 0d e c r e a s e fromf a c i e sGt o 、o c c u r r e β c eo fl : I 1e m i n e r a l si nf a c i ε sGi sa s c r i b e dt o f a c i ε sF .Theconsidεrabk thεverylowr a t eo Is e d i r n ε n t a t i o n and 7 2, v . . l J . , f ! N ! . ' rp C I ; r : i Atl e a s tf o u r a r e i nt h eupperp a r t:εach i s d " of In e c l v v i t ht h ebaseo fw e l l s o r t e df i n es a n d s t o n e b u t d i f f ε r e n t i a : i edi n t o f i v ef 3 d ε s ;f a c i e sA f i n e f a c i e sB v e r yf i n es a n c l c a l c a r e O U 3f i n e sand facie~, C mediuHl s a n d s t o G δ ),f a c i e sD 1 d e l ¥ and f a c i e sE c o a r s es a γ I1 cS l 0 n e ii n i n♂ach o ft h el i t h o l o g i e sandmolluscanf o s s i l 0 1 。 句 ・ m D し三孟士三「二;コ「ニコ F i g .11 .C o l u m n a rs e c t i o no ft h eu p p e rp a : c ta l o n gt h er o u t e4 ,A ;w e l ls o r t巴df i日es a n d s t o n e .B、 p o o r l y s o r t e dv e r yi i n es 2 , n d s t o n e,C ;c a! ca r e o u smediums a n d s t o n , 日D ;m a s s i v ec a l c a r e o u s ;c a l c a r e o u sc o a r s es a n d s t o n e f i n es a n d s t o n ea n dE 7 0 K .ARAIe ta . l i nd e t a i la sf o l l o w s .Exceptf o rt h eboundarybetweenC y c l e3and4 ,w herenoe x p o s u r e s a r eo b s e r v a b l e,t h eboundarybetweenc y c l e si sw e l ld e f i n e dw i t has h a r pc o n t a c t .The f a c i e sboundaryi ne a c hc y c l ea l s ot e n d st ob ed e f i n e dc l e a r l y( F i g .1 1 ) . ( 1 )C y c l e1 T h i sc y c l ea tl e a s t6m t h i c ki s composed o ff a c i e sA o f2 . 5m t h i c k,f a c i e sA ' ( w e l l s o r t e df i n es a n d s t o n ew i t ht h i nmudl a y e r )o f1 .5m t h i c kandf a c i e sBo f1m t h i c k i na s c e n d i n go r d e r .Hummockyc r o s s s t r a t i f i c a t i o n(HCS)i so b s e r v e di nf a c i e sA,w h i l e manyburrows( S k o l i t h o ss p . )a p p e a ri nf a c i e sA¥ ( 2 )C y c l e2 o n s i s t so ff a c i e sA o f1 .5m t h i c kwhichi so v e r l a i nbyf a c i e s T h i sc y c l e3 . 5m t h i c k,c Bo f2m t h i ck .A l t e m a t i o n so ft h i n( a b o u t5cm)l a y e r e dp l a n a rs t r a t i f i c a t i o nandwave r i p p l ea r eo b s e r v e di nt h el o w e rs e c t i o no ff a c i e sA .C o n c h o c e l eb i s e c t aa s s e m b l a g ea p p e a r s i nf a c i e sB . ( 3 )C y c l e3 t h ef a c i e sc h a n g e supwardsfromf a c i e sA o f3 0 I nt h i sc y c l ea tl e a s t8m i nt h i c k n e s s, cmt h i c k, f a c i e sCo f2m t h i c k, f a c i e sDo f4m t h i c kt of a c i e sEo fa tl e a s t2m t h i c k .The m o l l u s c a ns p e c i e s,s u c ha s Chlamys sw併が andM i z u h o p e c t e ny e s s o e n s i si nf a c i e sC a r e remarkablyd e f a c e dandf r a g m e n t e d .Both"HoukiZuna"s t r u c t u r eandA c i l an a k a z i m a i a s s e m b l a g ea p p e a ri nf a c i e sD .L i t h o s k e l s(READ,1 9 7 4 )i nf a c i e sC anddominance o f b r y o z o as k e l e t a l si nf a c i e sEa r ed e t e r m i n e dfromt h i ns e c t i o na n a l y s i s . ( 4 )C y c l e4 T h i sc y c l ew i t hat h i c k n e s so fa tl e a s t1 0m, i scomposedo ff a c i e sAo f2m t h i c k, f a c i e s Bo f2m t h i c kandf a c i e sEo fa tl e a s t6m t h i c k .Macomac a l c a r e aa s s e m b l a g ea p p e a r si n f a c i e sB .Thes h e l l so fm o l l u s c a ns p e c i e s,s u c ha sL i m o p s i ss p .andV e n e r i c a r d i af e r r u g i n e a i nf a c i e sEa r ee x c e e d i n g l ya b r a d e dandf r a g m e n t e d .P l a n a rc r o s ss t r a t i f i c a t i o ni so b s e r v e d i nf a c i e sE . G r a i ns i z ea n a l y s i sshowse a c hsamplei nt h ef a c i e sA i sf i n e g r a i n e d( 2. 48t o2 . 7 3O ) andw e l l s o r t e d( s o r t i n g c o e f f i c i e n ti s0 . 3 3t o0 . 6 4 )w i t ht h emudc o n t e n to f1 .0 8t o4 . 2 6% ( A R A I,1 9 8 9 M S ) . 田 8 .MagneticI n t e n s i t yandS u s c e p t i b i l i t yi nt h eC y c l e so ft h eM i d d l ePart Magnetics u s c e p t i b i l i t yi st h er a t i oo fi n d u c e dm a g n e t i z a t i o nt o ana p p l i e dweak m a g n e t i cf i e l d .Magnetics u s c e p t i b i l i t ymeasurementsi nd e e p s e as e d i m e n tc o r e shaveb e e n u t i l i z e da sas e n s i t i v ei n d i c a t o ro ft e m p o r a lv a r i a t i o n si nt h ec o n c e n t r a t i o no ft e r r i g e n o u s m a t e r i a ls u p p l i e dt ot h es e abed(BLOEMENDALandDEMENCAL,1 9 8 9 ) .I nt h i ss t u d y, m a g n e t i ci n t e n s i t yands u s c e p t i b i l i t yo ft h es e d i m e n t sa r emeasuredi no r d e rt oi n t e r p r e ta s t r a t i g r a p h i c a lc h a n g eo ft h et r a n s p o r t a t i o np r o c e s so ft e r r i g e n o u sg r a i n sanda l s ot ot e s t ac o r r e l a t i o nbetweenl i t h o -andb i o f a c i e sc h a n g e . F i g .1 2showst h er e s u l to fm a g n e t i ci n t e n s i t yands u s c e p t i b i l i t ymeasurementi nt h e : う 己c l i m巴n t a r yC y c l i c i t i e sヨn dt h e i ri m p i i c 3 t i o n so ft h eJ u n i c h oF o τ m a t i o n 7 1 ' J 1 己n t o fn a t u r a lremz 合t i cm i n e r a I s and s i z e and c o n c e n t r a t i o no f magn two o fs a t u r a t i o ni s o t h e r m a lremanent s i z e and c o n c e n t r a t i o no f c h a r a c t ε r i z e e lv v i t h j~s t h er a t i oo f m withs t e p so f150α f i ε l d sεemst os u b s t a n t i a t e t obec o n s t ε n t t h i sobserved v a r i a t i o no ft I lec onc合n t r a t i o no f m i n e r a l si nt h es e d i m e n t s 2.008-7 lI ( g ) (SJ. れ! 田 : 概糊離欄翻麟i S.I./UJI " S. 1 . /リ門 s 日 常 争 1.008-7 ω {emu/I く + SIPJ1-1501¥ l l SIR門-5-150/¥ 1 1 S I R I V I /以/ Sll~ 刊 S/W 目 トm門 1 7.57 NRI つ5/0.969 F i g .1 2 .T her o c k m a g n e t i ci n t e n s i t y(NRM .a n dSIRM)a n ds u s c e p t i b i l i t yi nt h eC y c l e1a n dI Io f t h em i d d l ep a r L K .ARAJe ta . 1 7 2 円 A ザ ロ mb n u 一 一4 VA D日 -dMa nhu RM 5F ハ U ハ リ fs 一 M ρ り 内 ど 。 ハ 口 qu 4・ 叶 一 一 VJ PMHHHHbHMHHH 司心 {同刷出¥割程 回 1 F E品 F配一一山 O (UJ 。置怠 り の お 。 A~ O8 圃 " 1 .0 " 1 ,2 同 F i g .1 3 . SI R .M 1 5 0 / V i fp ! o t t巴da g a i n s t S I RI V ! / ' v Vf o rs a m p l e so fl a r g 巴 t y p e,s h o w i n g l i n 巴a r r e l a t i o n s h i p . S l oD i s c u s s i 心H S . NSa ni d e a l i z e dschemeo fa 1 4s h o ' r ,a t i o nand For了 iηthemiddlep a r to ft h e o feachf a c i e s .F a c i e sG r e p r e s e n t s s t a g ec h a r a c t ε r l z e dwitht h eleastε口o u sm a t e r i a l sand t h emaximum l a; ; acsediments over a wi1 c ea r e ao ft h e andj)e s n t v / i t hmost abund. 三三註一一一 ー一一一一一一一一一一一一一一 一一一 S . L 百三三三九 宗主主-一一一 一室士三与一了一下三 F i g .l 4 .S ummaryS h O'i'l i n ga ni d e aI iz e ds c h e m a t i cs e d i m e n t ayc y d eo ft h em i c l d l ep a r t . T' S e d i n 口 1 巴 仕n t乱r ヲ γ 必yC γ己l i d 託 出 t i己凶古 l J 了 口 I dt h 己i r1 江" t p バ E c司tJ円 n so f れ巴 J l 1 l ιchoF す 口r r n日U) n ヨ ヨ ♂ ア , 仁 ひ 7 3 t . h ef u r r n a t i o no fa".~.on(l.ei" lS'三 d 3 e c t i o n ' ¥ w h i c hi s r n0~:d: e : ' x : t . コ . f1 1 3 1 V e 仁t.t l e ft h es h o r ci i . n . と Concentra . i ono ft h e i nt I 1ef a c i : : : sG andseems: 1 0r e f l ε c taV, = T ' /l o ¥ v t abundance0 ;b i o t u r b a t i o nemd r a t i oo f s e d i r n c n L a t i c r nr a t eo ft h i sf a c i e s ψ 1 n ' r r ef a c i e ss u p p o r tt h i s Thusf a c i e 3Cmay t ob ' e n t h l cf o r a r n : n i f e r s) ] 1t t h er n a x i r n u r n γ a n ; : ; 1 h2s h e l fε s必r n e n t sr e t ε r a h l et oc o n d e n s e ds e c t i u f l r e p r e s ε n t: 。 Ther e s u l t so f b e t v v f ι e nt h ei n d u r a t e db e d si nt h ef a c i e sF ando t h e rf i n e ! s( i nt h tf a c i e s D8 . n c ! i n d i c z t ε t h a tt h ei n d u r a t e db e d shave ; 3 a n d s t o n ebec fεatuJ.~e~, a sd e S C lU x ; dabov心 1 ' h e s 三 : t c h a c a c t ε r i s t i cI e a t u rとs; ; u g g e s tt h a tt h ei n d u r a t e d e d i mヨn t a r yp r o c e s sd i f f e r e n t1 r 0 1 1 1t h a to f: I hεotherf i n 吃 b e d ss h o u l dh a v e ε d s s a n d s t o n ef a c i e s o1 'o Q "e t h e rw i t ht h e s ef e a t u r e s .C O n SlJi C U O L 叫 vf i n i n定一 u m λT;e l r ds e q u印 C巴 i n a sa ci n d i c a t日c) t h a ti l 1t 色nn . i t t e n ti nf 10 v v(Jf t h ei n d u r a t e db e1 storm i no r i g i n tf~, ok 仁 accumulation o ft h ef a c i e sF.τhesep o r o u s e n d e d: 1 0bεindl1r a t e ds e l e c t i ¥ l e l vb vc : a r b o n a t eC f : D i e n t . s a n d sbavヒ t ・ ι,e t C ユ thεone a sb o t h ~ゐ o f i 1 1t h er n i d d l ep a r tmanifes'~s t h 日 1 J e n ' I l r u n r n e n t sf r ul n t ot h日 s h aJ lo wero n e t h a ntbεstonnv v a v eb a s e GandD)i ;].ndεevidence 1 'h 1 8 C l fI i t h o .a sw ε 1 1a s 日n df o r a m i n i f 目 canb eb e s t r el ; 抗l V日 changeo f i e s b i o . fc s e a . l e v e l v a r i a t i o no ft hピ concen i tS e 8 f l l St h a tr ε l a t i v es e a . l e v e i t r a t i o no f m i n e r a l s .1 nt h emaximum t h a ta o f t色 Z~Ta ; l 1S f a c i e s i t i~: m i n e r a l st ε n d st o decreasεand b er e s t r i c t e dt o more landward The r e l a t i v e e 1 e lf 2 : l I t h i ss t a g emayt e n d: 1 0i n c r e a s et h ec o n c ε n t r a t i o no f s e al t h e f a c i e s工 si nt h e 人 a ndf u r t h ε r faci~s F ¥ m i r v e : r a l,) a ,i nt h emiddle 1andn 巳n t vind~cat合 the p r e s r ed e l i n e a t e d t h ef a c i e s b u ta l s oseεmt or e v e a lamuch D a r ! :,whicha S ' _ 'w hicho t h e n v i s eh a sno : lb e e nd e t e c t e d i : h e r e c o r do fr e l a t i v es e a . j日 7巴 '..H.2"I' c c n v e n t i o n a ir n e a n s .I tc a n s t r e s s e dt h a i :t h i s mag 町 t o s t ユ 叫 台r t h a n 砲 m ethod t ou n ε a r t hf i n e i 1 1t h e d a t i n g s . t t h a t i n t e n columnso Is e d i m e n t sO l lando f fs h e l v e s oI r n e a s u r eu e n : l so fs ε d i m e n t scanbεusεda sas e n s i t i v eande f f e c t i v ε 2nd 0 1 1 : 1 0 co n c e n t r a t i o no f i n d i c a t o ro ft e m p o r a lv a r i a t i o n si nt h e: d e l i n ε a t e d t h es 問 f l o o r,v v i t h問 。b a b l vmuchh i g h e rr e s o l u t i o nt h a nt 1 日 t ol i t h o .andb i o . f a c i e s N l o r ee x t e n s i v e t : t ec o n v ε n t i o n a l 1 0s u b s t a n t i a t et h i sc Ol1c e p t b o t hdeeDs e a2 . n ds h a l l o wmarines ε d i m e n t sa r en e c e s s a r y: , , , " ロ ア 日 F ' O l l fS i nt h eu p p e rp . a r tc ft h e Fonnationa r egroupedi n t o 7 4 K .ARAIe ta l . t h r e et y p e s, withr e s p e c tt os t r a t i g r a p h i c a ls u c c e s s i o no ft h ef a c i e s( F i g .1 1 ) .F i g .1 5shows p a l e o e n v i r o n m e n t a li n t e r p r e t a t i o no feachf a c i e sformingt h r e et y p e so ft h eupperpar t . F a c i e sA t h o r o u g h l yd e s c r i b e daboves u g g e s t st h a ti ti saccumulatedunderas t r o n gwave a c t i o nabovef a i r w e a t h e rwavebasesucha slowert ouppers h o r e f a c e . Type1 Type2 Type3 i n n e r s h e l f B r y o z o a d o m i n a t e d o u t e r s h e l f E J ¥ i n n e r 5 h e l f o u t e r 5 h e l f I n f e r r e de n v i r o n m e n t sa tmaximum t r a n s g r e s s i o n w e l l5 0 r t e df i n es a n d s t o n e dv e η f i n e s a n d s t o n e C ;c a l c a r e o u sm e d i u m .? a n d s t o n e O: c a l c a r e o u sf i n es a n d s t o n e E; c a l c a r e o u sc o a r s es a n d s t o n e A; B :p o o r l y5 0由 tt r a n s g r e s s i o n ~ 権 r e g r e s s l o n m a x i m u mt r a n s g r e s s i o n F i g .1 5 .E n v i r o n m e n t so fE a c hTypeo fS e d i m e n t a r yC y c l e si n f e r r e db yl i t h o -a n db i o f a c i e s . a c ksedimentarys t r u c t u r e so fwavea c t i o ni no r i g i n,ands u g g e s t Bothf a c i e sB andC l as i m i l a rwaterdeptho faccumulation, deeperthanf a i r w e a t h e rwavebase, a se v i d e n c e dby molluscana s s e m b l a g e s .Theprominentchangei nwaterdepthfromf a c i e sA t of a c i e sB andCi saUributedt oar a p i dr e l a t i v er i s eo fs e a l e v e . lL i t h o s k e l sabundanti nf a c i e sCa r e r e f e r r e dt ot h ereworkedo r i g i nwhichhavebeenerodedfrom o l d e ru n c o n s o l i d a t e do r weaklyc o n s o l i d a t e dd e p o s i t sfromane a r l i e rsedimentaryc y c l eandhavebeeni n c o r p o r a t e di n t oyoungers e d i m e n t s .Therefore, f a c i e sB andC seemt oformd i f f e r e n tp a r t so fa t r a n s g r e s s i v esands h e e t(SWIFTe ta l .,1 9 7 1 ) .A modernanalogueo fs u c hat r a n s g r e s s i v e sands h e e thasbeendocumentedi nd e t a i lfromt h es h e l fandt h euppers l o p eo f fSendai, No r t h e a s tHonshu,J apan(SAITOe ta l .,1 9 8 9 ) . F a c i e sD y i e l d sA c i l a nak α z i m a i assemblage,whichdwelled i n froms u b n e r i t i ct o 0 6 0t o2 0 0 2 5 0m i nd e p t h ;F i g .6 ), andi sa s s i g n e dt obea c c u m u l a t b a t h y n e r i t i czone(from5 eda to u t e rs h e l f . . MizuPlanarc r o s ss t r a t i f i c a t i o n sa r eobservedi nt h ebryozoa-dominatedf a c i e sE i v i n gfrome u n e r i t i ct om e s o n e r i t i czone(fromlowt i d e h o p e c t e ny e s s o e n s i sassemblagel markt o5 0 6 0m i nd e p t h ;F i g .6 )hasbeenobservedi nt h esamef a c i e sa tnearbyo u t c r o p s S巴d i m e n t a r yC y c l i c i t i ε sa n dt h e i rl m p l i c a t i o n so It h ε J u n i c h oF o r m a t i o n 7 5 Hence‘ t h ef a c i e sE wasaccumulatedu n d e rh i g he n e r g yregimes u c ha si n n e rs h e l f a c h i nt h eu p p e rp a r tc h a n g e st h ee n v i r ol1m e n t a lspectrum Thus,e froms h o r e f a c e( f a c i e s [0i n n e ro ro u t e rs h e l f( f a c i e sB,D andE ) .T h i sc y c l i cchangeo f 口a l s obεbeste x p l a i n e dbyr e l a t i v es e al e v e lc h a n g e . ca 1t ot h ε f o l l o w i n gc o n c l u s i o n s : Ther e l e v a n tf a c t sd ε s c r i b ε dabovεmayl e ac e q u e n c et h a ti sacon TheJ u n i c h oFormationr e p r e s e n t sanu n c o n f o r m i t . ' }boundeds f o r m a b l es u c c e s s i o no fg e n e t i c a l l yr e l a t e ds t r a t a . Thεlowerp a r to ft h ef o r m a t i o n formedu n d e rt h er a p i d duet or e l a t i v es e a l e v e lr i s e .A f t e rt h et r a n s g r e s s i o n 1t or ε g r ε臼 i o n .( 3 )The1'e l a t l v ε s e a I e v e l waso ft h et h i rc 1 i s i tt u r n ec ( 0. 11 anc 1e vens m a l l e ro r d e r,andhac 1a l 1a mplitudεofa tl e a s t1 0 0m.( 4 )Ther e l a t i v e e v e lchangei s c a u s e dby a f f e c t e dw i t ht h e t e c t o n i c s e al s u b s i d e n c e . 1m i d d l ep a r t so ft h eJ u n i c h oFormationi s Eachs ε d i m e n t a r yc y c l eo ft h eu p p e ranc e q u i v a l e n tt oap a r a s e q u e n c e,whichi sar e l a t i v e l yc o n f o1'mal コ l es u c c e s s i o no f 1s01 'b e d s e t sbounded m a r i n e f l o o d i n gs u r f a c e sandt h e i rc o r r e l a t i v es u r f a c e s r e l a t e db ec 九 T AGONERet a l1 9 8 8 ) . The o ft h es e d i m e n t a r y i nt h eu p p e randm i d d l ep a r t so ft h e se s ti J natedt obεint h eo r d e1' o ffewt e n st h o u s a n dyea1'sont h ea v e r a g eb a s ε d Fo1'mationi t i g1'a p h y .Theseh i g h f r e q u e n c y c y c l e sa r emostl i k e l ya s c r i b e d onmagnetost1'a u s t a t i cs e a I e v e . l Thea p p a r e n t t ohaveformedu n d e ramajorc o n t r o lo fg l a c i oe d i f f e r e n c ei nt h e f a c i e sbetweent h em i d d l eandu p p ε rp a r tappea1'st o e p t hd u r i n gt h ed e p o s i t i o n onw a t e rd Thed i f f e r e n c ei n s u c c e s s i o namongt h r e et y p e so ft h eu p p e rp a r ti sa l s o Environmentsa tmaximumt r a n s g r e s s i o nchangefromi n n e r d e p e n d e n tt owate1' s h e l ft oo u t e rs h e l f( f r o m 1t o3 ) andt h ε t h i c k n e s so ff a c i e sA whichi sc h a r a c t e r i z ε d s h o r e f a c e have t od e c r e a s efrom 1t o3 .Fromt h i sf a c ti ti s a r to ft h eJ u n i c h o Formation h a s been formed u n d e rt h e c o n c l u d e dt h a tt h e uppe1' p f 1u e n c eo f1'e lョt i v es e a I e v e lchangeo fas m a l l e ro1'd e1' ( F i g .1 6 ) . combinedi n r e l a t e c 1f a c i e smodelshavebeenc o n s t r u c t e dfoγmoc 1e r ns h a l l o wmarineno 日t 1 'o p i c a lc a r b o n a t es e d i m e n t s( e .g .SCOFFIN et NELSON and 1 9 8 3 ; Ther e l a t i v eabundanceo f f o r a m i n i f e r sh a s乳 c o r r e l a t i o n COLLINS, Ad e p o s i t i o n a l v v i t ho t h e rs k e l e t a lcomponentsandap o s i t i v ec o r r e l a t i o nw i t hw a t e r 下' o r m a t i ol1b a s ec 1011s u c hf a c i e smodels s e t t i n gi se n v i s a g e df o ra c c u m u l a t eo ft h e ( F i g1 7 ) . 仁 : l i m e n t son a modelo ft h en o n t r o p i c a lc a r b o n a t eand1 1 1 i x e ds e s h e l fi sp r e l i m i n a r i l yc o n s t r u c t e dw i t hr e s p e c tt ot h ee a r l yP l e i s t o c e n eg l a c i o e u s t a c y . 1i m e n t a r yc y c l e si nt h eu p p ε rp a r to ft h eJ u n i c h o Threet y p e s 1 3o fF i g .1 8 )o fs ec a r ea d o p t ec 1a st h ef u n d a m e n t a l Formationandt h a t(Type4onF i g .1 8 )i nt h em i d d l e 人 司 吋 司 局 フ 司 喝 som ・ c eo fi n f o r m a t i o n .B a s i ca s s u m p t i o n sa r et h a tb o t hp e r i oc 1i c i t yanda m p l i t u d eo ft h e 6 K .ARAIe ta . 1 ウ 円 いv s e m43 0 c a l c a r e o!Js b r}fGiZ08. s a n d s t o日8 1 do日1日記 ' l s d CCl8l(E>S . 1 t I / f f acoma 1 1 1口 s o r l e d ¥ : e r y iI円煙 Sl~L 百 a 呂 E s o r i ' 8 dl i i l己 E l 。 a l c a r e v u s 日現 D b r y o z o a 1 1! n o d l e r r n岱 cl f l d巴! o n e e I002'(58 I GaIG8<向。l1S 同 n2ι 円e s a n d s t o H日 o t l日 c a l c巴I"e m ' 9 r 1 [umS S o C a 月泊四 Ulh 口 ß~{日 Is p o o r l ys o r l e d 川口 η '1/ ' 7 10 'C沼 f o V' 2Ty f i n eS t Lt bisロ ヲf 剖 a s s o i 訪 r ; 日1 GOfÜ~~ i r A I w ,~11 s o r t e df i n恐 s a l n r h s l o n e 比Om 以 内 F i g .1 6 .Summary0 1c y c l i cc h a n g e so fI it h .andb i o . f a c i e si nt h巴 u p p e rp a r t s e a i e v e lfluctuationεresimi 1ar i n a successionamongthεfourtypes asenvisa日 dand Iromthe timeandthatthεdifference . 1t o4 )wascontrolled W3 , t ε r o fthehighs t i l l s t a n df a c i e si neach S ε d u n e r r t a r yC y c l i c i . t . i e sanc 1t h e i rl n l ] コ l i c z , t i o n so ft h eJ u n i c h oFurmation LOV'iJ' 門 戸y f{ '~HÌ!if:~rgy fac~es Fades E(B3G) 醐 bedclod F i g, 1 7, A modelf o ra c c u m u J a t i o no ft h es h a l l o wmarinen o n t r o p i c a lc a r b o n a t ea ts t uc 1i e da r e a . C h o r a c t e r i s t i cc 1i s t r i b u t i o no fb i o c l a s t i c si sb a s e1 c011 moderna n a l o g u e s ;t h eR o c k a l lBank ta l ., 1 9 8 0 ),t h eS c o t tS h ε l f(NELSONandBORNHOLD,1 9 8 3 )a n dt h eR o t t n e s tS h e l f ( S C O F F I Ne ( C O L L I N S,1 9 8 8 ) t y p e . Thus thεfour 有 are t o represent d i f f e r e n t watεr fromthemost"coastal" a l s oi n f e r r e d that eventhe s i t eo f on a s h e l fp r o f i l e, 1tothemost"basinal"Type4 1v ' l 1a s not I ti s the low s t i l l s t a n d Prior to i n i t i a t i o no fthe shal Jow marine n o n t r o p i c a l carbona : i e and 7 8 K .ARA!e taL I y p e3 Type2 「 一 Le日end 冨 田 ! 田r e o u s印 抗 告 出 回 b u r r o w s 斗" I o u 山 盟 国 ! 田 町u sn 耐 l um s s Zunar. 口 白l 白r e o u sf i n e ss 四 p陥 a r びoss s t r a t i iに主主1IOn 口 問 │ 国 「 巴ous v er . )i f 'i l e5 S 目 p岡 鉱 山 富 町 曲 目 m ロ回 W3 ! 1回 l e df i n e S5 i T 1e じ てI n l u m 今 剖 S Q f 8 剖 u n F i g .1 8 .A s c h e m3it i cd i3ig r a mo fn o n t r o p i c3i! c 3 i r b o n a t el i t h o f a c i e sd i s t r i b u t i o ni nap a r a s ε q u e n c e p e1 3 ;C y c l e so ft h eu p p e rp a r t,Typ 巴4 ;C yc !eo ft h er n i d d l ep a r t。 f r a r n e w o r k 寸y mixeds ε d i口n e n t sc h a r a c t e r i z e dt h es t i l l s t a n de n v i r o n m e n tf r o r nc o a s t a lf a c i e sA s o r t e df i n e t ob a s i n a lf a c i e sF f i n e w i t ht h ef a c i e sE e commenceei a s i nb e t v v e e n .As 十h ft I 1e t h ef a c i e s B コ 工1εdv e r yf i n e s o c i a t e dw i t hlandwardr e t r e3.to medium c o v e r e dt h ei n n e rs h e l fa sa f a c i e sC . ap ε r i o do ft h e a c t i v es h o r e f a c ee r o s i o n sands h e et 了et h es l i b s t r a t e swere c o l o n i z e d wavec o n t i n u e do v e rt h ei n n e r whe v v i t ht h econtemporaryb i o t a whichc o n t r i b u t e ds k e l e t a ld ε b r i st o Theo u t e rs h el Is u b s t r a t e sa r ec h e x a c t e r i z e dw i t h s e d i m e n t so fv e r ylowr a t eo fs e d i m e n t a t i o n . w h i c ha r e a s c o n d e n s ε ds e c t i o n . a sw e l la s a f t e rt h e maxi.mum h i g hs t a n d‘ a l i m i t e d t o o k and t h eb i o t i c t o g ε t h e rw i t h I i m i t e d seaward t r an .s p o r to ff i n es e d i m e n t V v h i c h formed consequεa s e q u e n c e f a c i e sD t of a c i e s ノ LML Cめnr . ;h l l Sh ms ( 1 ) t i o no fr n o l l u s c a n ( 2 ) O l~t r e l a t i u no f f a c l ε s and d i s t r i b u i n d i c a t et h a tt h e Formationwasformedu n d e ra h 色nt u r n e dt oa a s s o c i a t e dw i t hr e l a t i v es e a l e v e lr i s e‘ whicht t h e Formationi sd i v i d e di n t ot h r e ep a r t s,anddεmon- S ε c l i m e n t 3 T yC y c l i c i t i 色s a n dt h とi rl m p l i c a t i o n so ft h eJ u n i c h oF o r m a t i o n 7 9 s t r a t e sd i s t i n c t o fl i t h o -andb i o f a c i ε sb o t hi nt h em i d d l eandu p p ε rparL each ( ) fwhichピ l e m o n s t r a t e s ( 3 ) Then l Id d l己 p a r tc o n s i s t so fa tl e a s tt I 1r e e h estormwaveb a s e s h o a l i n g s e q u ε 九Cξacrosst i m i l a r ¥ y e t v日l r i e d d e f i n e c lw i t hw ε l l s o r t ε df i n ε I nt h eu p p e rp a r t,s s a n d s t o n ea t showt h a tI lu c t u a t i o n so fr e l a t i v es ε o I e v e l o c c u r r e da tl e a s tf o u r e n td i f f e r e n c ei nt h el i t h o f a c i e sbetweent h emi1 cd l e t i m e sc l u r i n gi t s Theapp乱r ondu p p e rp a r ta p p e a r st odepende s s e n t i a l l yont h eε d 寸h e o f出 eu p p e r a r e i n t ot h r 沼田 t y p e s,o fwhicht h ed i f f e r e n c己 i salsodε011wat日rc 1e p t h .Thεupper o ft h e FormationI 1a sformed u n d ε rt h ecombinedi n f l u c n c co fs e a l ε v e l o ftwod i f f e r e n to r d e r s o ft h eJ u n i c h oFormationc o n f i r m st h a tt h el o w e rp a r to ft h e C h r o n . Basedont h i s ,t h ea v ε r a g es e d i m e n t a t i o nr a t ε i sr e e s t i m a l e dt ob ea b o u t3 0 n d e rt h e o fi t sc o n s t a n c yf o rt h eF o r m c d i o n . 1 0 0 0yu The o ft h e c h a n g e si nt h em i d d l ean1 cu p p e rp a r t so ft h e Formationi se s t i m a t e dt ob eaf e v vt e nt h o u s a n c ly e a r s .The o ft h er e l a t i v e 0m.These c y c l e so ft h e Formationw i t h s e a I e v e lc h a n g e si supt o3 s u c h anda m p l i t u d ea r emost a t t r i b u t e 1 c: 1 0g l a c i o e u s t a t i cs e a l巴v e l change ( 8 )The measuredi ne a c h ε o f t h e m i d d l ep a r t whichi sc h a r a c t e r i z e d d o u b l e i swarranteda tp r e s e n t,t h i sf a c tmo.y s u g g e s ta 日 c o n c l u s i v e most c o r r e l a t i o n between t h ec o n c e n t r a t i o no f m i n e r a l sandt h er e l a t i v ε s e al e v e lf a l l . v V et h a n k Prof .K . HIROOKA o f a n d Dr .I ¥ ! I . TORII o I f o rt h e i rk i n d n e s swho gave a c c e s st o i n s t r u m e n t s .F r u i t f u l s p e c i a l l y f i e l d f r o r n Dr .A . d i s c u s s i o n s and c o n s t r u c t i v e comments,e KITAMURAandMr .K .FURUYAo fKanazawa andD r s .K .IKEHAR九 M.SAITO andH.YAMAMOTOo fThe o fJapana r e Prof .K . C I H N Z E l o f andDr .S .MATSUIo IUtsunomiya gavev a l u a b l e a d v i c e0 1 1 o fm o l l u s c a nf o s s i l s . o fr o c k sf o r measure ments was f a c i l i t a t e dw i t ht h e by M e s s r s .K . FURUYA and N. H A l ¥ I [A TANI o f Kanazawa anda l s obys t u d e n t so fToyamaU n i v e r s i t y . 司 R e f e r e n c e e AOKLN.and K . ,( 1 9 7 3 ) .C o m p i l a t i o no ft h e and1刀 o l l u s c a na sちe m 1 コ l a g e s 8 0 K ARAIe ta l o ft h eP l e i s t o c e n eShimosa G e o l .5 0 c .l a D a凡 4 5 3 4 6 4 e a s t e r np a r to IKanto w i t h Ce ロt r a l l 一一一一-and一一一←一一 P l e i s t o c e n em o l l u s c a n o ft h eBoso B),1 ,1 0 7 1 4 8 . 5 a . I n s t . Univ T s u k u b a・ Environmento ft h e V V e s to fHimi D G J X . E α γt h F ; α C .Sc i .Kanaza i s h w i t hEn交l ←一一一 o ft h eJ u n i c h o Southwesto fHimi C e n t r a l i .Kanazawa U n i v . E a r t h F a c .Sc D . J . J .a ロd J . ( 1 9 8 5 ) .C e n o z o i c 4 0 7 1 4 1 8 . GeoL5 0 c .A t n .BuU, 1 . ヨndEDWARDS A .R . , N e ' 0 TZ e a l a n dP ! e i s t o c e n ea n : }l a t e Pl i :o c e n e BELlpA G , . l 1 1 9 -1 4 2 . P a l e o c l i m a t o l .P a l a e o e c o E v i d e n c ef o rachangeI nt h e o f . 4 c l i m a t e a t2 fromw h o i e c o r e s u r e m e n t s . 8 9 1 9 0 0 . o ft h eR o t t n ε s t SouthwestA u s t r a l i a : c a r b 川 崎 t e 5 e d i m e n i a γGω . l , 1 5 4 9 . a R . P r o c .R .5 0 c .,2 J人 2 9 5 3 0 5 c f J e v e l s .U .,HARDENBOL l2nd HAQ,B s i n c et h eT r i a s s i c .S c i e刀 c e, 1 1 5 61 1 6 7 . F o r a n u n i f e rao ft h eH ; . r n i C e n t r a l Hokuriku 8 9 1 6 3。 i . 2ηds e r Tohoku Sc 一一一一一一, a n i I 日 づ ( 1 9 8 6 ) . o ft h e C e n o z o i ci nsouthemp a r to f Noto 二 (ε n t r a l c l 2 s s i f i c a t i o na n d P a r t 1 nHimiandi t se n v i r o n s .I nN A K . A c G A V v A ヲ ノ 同 】 f 皮 A C ommemor . μt i v e KAYANAGI e d s . i n Nobu K1TAM[ 1 1 1 1( i nJ ap a n e s ew i t hE n g l i s h Vo . l,9 HIGO, A o fm o l l u s c a nf a u n ao ft h e i o . lS o c a r e a oe d .HIGO, B P l e i s t o c e n e I a r m w a t e r moUuscan a s s o c i a t i o n s: nt h ε from i nc o l dandV o r t h e a s t P a l e o c l i m a t o. l ShimokitaP e n i n s u l a,N 2 6 3 2' 73 . o fs e d i m e n t san 1 cm o l l u s c a nf o s s i l Y ., KITANIURA,A and 臼 a s s o c i a t i o n sc a u s e d s e al e v e lc h a n g e s t h e P l e i s t o c e n e-ac a s es t u d vo ft h ε r n i d d l ep a r to fthεOmmaFormationa tt h et y p ε 6 w i t hE n g l i s h 1 93 Check l i s t andb i b l i o g r a p h yo ftheRecent marine 白 叫 S ec 1i m己主t 呂r yC y c l i c i t i 己s a n dt hで : irl m p l i c a t i o n so ft h eJ u n i c h oF o r m a t i o n U 一 日 ﹁ mD-hi γし 'k 。︹し a F AL ︺ SEPM ' J 7 1 しU ゐ 、ハ叫し T Q n ハ 仁 し 戸 し jFL . -0 c u 門、いレ U ハ ML a l o e d s .S e a L e v e l 叫川 同 iu ロ n o C 旬 ♂" 1 t 4 叫1 T.ond 大 仏 フ j LOUTIT τ 目 n / 母d s .L三O. W 、 l l o H u s c a 日 8 1 u b l . D . 1 司 18:~; 司 213 τ Late Cenozoic p l a n k t o n i cf o r a m i n i f e r a l け o fl10 r t h w e s tP a c i f i csεsequences.lnTAKAYANAGI, Y 目 e d s .1 1 2 S c l e c t c dρ a t e r si nh o勾 o r i n Aι ン 4NO‘3 9 5 4 2 2 . E . andCox,A . , 0 : 1S u T n ev o l c a r n cr o c l ¥ " . s 汀 d ov o l c a n i c A n t a r c t i c a .,l.うん: y s .l ? e s 1 1 5 9 9 1 1 6 1 2 fromt h eMdVh , . I The p r e s e n ts t a t u so ft l ほ p o l a r i t yt i m e s c a l e . M."N., 日d . TheEa バh :I i sO r i , c ! i n,E v o l u t i o nandS iη I c h t r e ' ,Londo ロ P 噌 吋 , ラ 】 ~)4 :3 ω566 加 T, Y .and Hokuriku P l a n k t o n i cforaminifεoft h eYabuta C e n t r a l e f e r e n c et oi t s 工 age a :ndi t s f o r m a t i o n s-.Bun O sakaMus l. J aLH i s .,3 51 . 1 3 w i t b c .S.and B .D s k e l e t a lc a r b o n a t es e d i m e n t son r 、 J ortheastemVancouver Canada Mar. G e o l 2 4 1 2 6 6 . S c o t t ODIN,C .S .andNIATTER, D ε g l a 1 1 C 0 1 l i a r u 1 1 1 o r i g i n e e S 正 6 1 1 6 4 1 孔1 1 i cs i g n i f i c a n t 氾 o ft h e faunao f t l 日 Sea' b o r d θ r l a n d ., S a i t oHoー 州 知 Mus.1Vat 田万i s t .・R e s .Bul 1 . , 1 :. 1 7 . し ( 1 9 5 2 ) . Ont h ev e r t i c a id i s t r i b u t i o no f marine mollmca. " { / e n u s びα βa n .j . Mala , ゥ01 . ) , 2 73 5 JapanesewithE n g l i s h 、 'YOKOYAMA'st y p emolluscafromt h e andQua : I e r n a r vo f: I h日 KantoA.r e a .Pal , α e o n i o. lSoc . λ1-148. V V .1 " , andcarbon o fh o l e 502B εvidεncef o rtwomodeso f ,6 84 5 5 4 6 4 . J .F ., Ca1 cr e t ε and E d e i ・ u V V e s t e l e d .E u o l u t i o nand W c s t e r n Aμs C a r b o n a t e i m l i a . Am. Assoc P e t r o . l Geo , . l Mern., 2 5 0 2 8 2 . sands h e e t y" ! A .and t h es h e l fandupper o f f 市 リ , 吋 戸 守 ッ , T . , KATO,I v 1 . and KUDO T 吋 C a l c a r e o u sm i c r o f o s s i l Cenozoicf o r m a t i o n sd i s t r i b u t e di nt h ec o a s to f S e a -Part3 :Akita a r e aand0前 ! Peninsala¥ . 1! a! Ja ni l s s oc .P e t r o l 1 . 1 4 v v i t h , 8 2 IζARAIe ta . l E .T ., G . J . G .E .and J .D . , ( 1 9 8 0 ) . t e m p e r a t e, c a r b o n a t es e d i m e n t a t i o n o r t h e a s tA t l a n t i c .] .S e d i m e n t .P e t r o l .,5 0,3 3 1 3 5 6 . R o c k a l lBank,n N .J . and N . ( 1 9 7 3 ) . i s o t o p e and F~"~V'HU.iSUL o f P a c i f i cc o r eV 2 8 2 3 8 : t e m p e r a t u r e sand 05 and1 06 y e a rscale.η R e s .,3,3 9 5 5 . i c evolumesona1 D .J .P ., D .J .and J . 1 9 71 .R e l i c ts e d i m e n t sonc o n t i n e n t a l s h ε l v e s :ar e c o n s i d e r a t i o n .] . 7 9,3 2 23 4 9 . T ., KUDO,T SATO,T and K . , ( 1 9 8 8 ) .C a l c a r e o u s m i c r o f o s s i l o ft h e C e n o z o i cf o r m a t i o n sd i s t r i b u t e di n t h ec o a s to ft h e S e a .-P a r t2 :Hokuriku b. o s i n-.].戸a n .A s s o c P e t r o l . T e c h ., ( 1 )9 2 7 i i Vi t h S .and ( 1 9 8 9 ) .Sedim色n t a r y and色n v i r o n m e n t si nt h em i d d l e -l a t eP l e i s t o c e n eShimosa Boso C e n t r a l ] .G e o l .S o c . α fp : an,9 5,9 3 3 9 5 1 ]ap a n e s ev v i t hE n g l i s h .R . , R . M フ., TODD,R . J .. M ., S . γAIL,P J .N .andHATFIELD,V I T .G ., S e i s m i c and lI n : C .E . ,e d .S e i s m i cs t 切 戸 戸l i c a t i o n st o o fs e al e v e. 1 4 9 2 1 2 . Am.f l s s o c .P e l r o l . Gω. VAN J . H.W., R . P . J .F LOUTIT,T .S .andHARDENBOL フ J . , Ano v e r v i e wo ft h ef u n d a m e n t a i l so f s e q u e n c e and d e f i n i t i o n s . C .K .e t e d s .S e aL e v e l 3 9 4 5 . SEPM l! .Ll t-'"Il.~1. D .F ., E v i d e n c ef o rand sea-levelεsfromt h ε s t a b l e I L G U S,C .K. e t d ,e d s .S e a L e v e l Cha幻ges-An r e c o r do ft h eC e n o z o i c .I n羽T 1 う e c .P ; 刈l ., 3 1 3 6 SEPMS ~HL'"~"L".. , T ., HIR 仁OKA ,} ι N La nd ( 1 9 8 3 ) . r e s u l t son s t 仕r 抗 a t i 泡 g r 印 ぱ oft h e m 山 江 n 凶 i 1 比 c カ オ hoFo 侃r -m抗 at i 白 on(Yab 叫 u 抗t I aF伐of l 百四 1 m 区 I I τ プ 口 n 1 a t i ω o n 叫 1 )d i s t r i b u t e d加 i nHimiC α i t 匂 y,ToyamaPr 町e f た ε c t t 町 1 fe .A,rよn .S c i .Ka幻azawaU n i v .,2 0, 2 94 2 ZUDERVELD,J .D . A,“ ( 1 9 6 7 ) .A .C . ε t i z a t i o no fr o c k s : o fr e s u l t s .I n D . CREER, K. f v I S . e d s . M e t h o d s i n T 司 ヲ ヲ 什 戸 。 守 ・ 叶