The Pl i ocene一Pl ei st ocene Boundar y 山 by E. Agui r r e and Q.Pas i ni The base of the Pleistocene Series is defined for- mally in a stratotype section at Vrica, Calabria, southern Italy. Biostratigraphic criteria for cor- relating the boundary level are well supported by magnetostratigraphic and geochronologic data. Introduction A pr e ci s e de f i n i t i on o f t he b ou nd a r y b et we en t he Pl i oc ene and the Pl ei st ocene became necessary i n or der t o resol ve several i nconsi st enci es of a recommendat i on pas sed at the 1 8t h I nt e r n at i on al Ge ol ogi c al Co ng r e s s i n Lo ndo n ( 1 9 48 ) c on ce r ni ng t er mi n ol o g y a nd r e c og ni t i o n of s t r at a of t h e se a ge s . Ac co r di ng l y, a t i t s 5t h Con g re s s i n Ma dr i d, 1 95 7, t he I nt er n at i on a l Un i o n of Qu at er n ar y Res e ar ch ( I NQUA) est abl i s hed a Subcommi ssi on I -D on t he Pl i ocene-Pl ei stocene Bo un dar y. La t e r , t hi s b ody b eg an t o f u nc t i on a l s o as t h e Worki ng Group on the Pl i ocene-P l ei st oee ne Boundary ( f o rmer l y t he " Ne og en e -Qua t e r n ar y Bou nd a r y " ) o f t h e I UGS Commi s s i on o n S t r a t i g r ap h y ( I CS) . Th e ai ms we r e t o p r o po s e cri teri a f or t he defi ni ti on of t he Pl i ocene-Pl ei st ocene Bo un da r y a nd t o p r o po s e a b ou nda r y s t r a t o t yp e l o ca t e d i n a sui tabl e sect i on. Resear ch and Proposal s At t he 8 t h I NQUA Co ngr e s s h el d i n Pa r i s , 19 69 , t he Le Castel l a s ect i on i n Cal abri a, I tal y was proposed as t ype number of quest i ons of cor rel ati on and defi ni ti on. ni zed, and t he present aut hors were el ect ed as Chai rman ( E. A. ) a nd S ec r et a r y ( G. P. ) o f b ot h b odi e s . Si n ce t he n t he wo r k of t h e Gr o up h a s c onc en t r a t e d on i d ent i f yi n g t he d i f f e r en t p r o bl ems i n vol ve d, o n e s t ab l i s hi ng t h e p er t i ne nt cr i t e r i a an d, n ot l ea s t , o n a r r i vi ng at a commo n t e rmi n ol o gy an d a c ommon un de r s t and i n g of t he who l e mat t er . Fo ur l i nke d qu e s t i o ns we r e d i s t i n gui s h e d: f i r s t , des i g nat i on of a t y pe ar ea; s ec on d, s e l e c t i o n o f a t y pe s ec t i o n; t hi r d, s e l ec t i o n of a p l an e i n t he t yp e s e ct i o n a s a b as i s f o r def i ni n g t he l owe r b ou n dar y of t he Pl e i s t oc e ne; an d f i n al l y, t he recogni ti on of the Pl i ocene-Pl ei stocene Boundary out si de the t yp e a r ea , or i n ot he r wor ds , t he me an s o f c or r el at i ng t he Bo un da r y o n a gl o ba l s c al e. Th e s ub j ec t of def i ni ng t he Boundary between t he Pl i ocene and Pl ei stocene was i s ol at ed f r om ot he r mo r e or l e s s r e l at e d pr ob l ems , s uc h a s t h e pe ndi ng def i n i t i on of t he Ca l a br i an, a nd t h e s t a t u s of t h e Qua t e r n ar y wi thi n t he chr onost rat i graphi c s cal e. At t he en d o f a Fi e l d Conf er e n ce o n t h e Bou nd ar y he l d i n t he P an j ab an d Kas hmi r i n 1 979 ( Sa s t r y e t a l . , 19 81 ) , a de ci s i on wa s a do pt ed t o mi n i mi ze cha n ge f r om t he g en er a l i nt ent i on o f t he 1 9 48 Co ng r e s s r e commen da t i on. Two de ci si on s of t hat Con gr e s s we r e emp hat i ca l l y c onf i r me d: t o e s t a bl i s h t he Bou nd ar y i n a cc or dan ce wi t h ge ne r a l l y a cc ep t e d p r i n ci pl es of s t r at i g r a ph y, an d t o s el e ct a t yp e s e ct i o n i n t h e Up pe r Ce n oz oi c mar i ne se q ue nce s of s o ut he r n I t al y. On t he o t he r 口 s e ct i o n f o r t he Ca l ab r i a n St ag e an d f or t h e Pl i oc e ne - Pl ei s t o ce ne Bou n dar y, b ut i t wa s s o on f ou n d t o b e i na de qu at e f o r t he pu r p os e. Dr . Ks e ni a V. Ni ki f o r o va ( U. S . S. R. ) wa s t hen as ke d t o r e or ga ni z e t he Wo r ki n g Gr ou p i n o r de r t o r e s ol ve a At t he 1 97 7 I NQUA Con gr e s s , t he memb e r s h i p of t he I CS Wo r ki n g Gr o up an d t h e I NQUA Su b commi s s i on was r e or ga - hand, two statement s of t he 1 8t h I GC Sessi on were def i ni tel y rej ect ed: t he equi val ence of the conti nent al "Vi l l af ranchi an' t wi t h t he mar i ne "Cal abri an, " and the accept ance of the f i r st 16'15} 17勺 no N介 日 Whe n t he I nt er nat i o nal Ge ol ogi ca l Cor r e l at i on Pr o gr amme ( I GCP) wa s l au nc he d by I UGS an d Un es c o i n 1 97 3, Dr . 17',, } Ni ki forova submi tt ed a project ent i t l ed " The Boundar y 吸 CATA NZA RO VRICA SECTI ON 兰夏薯舀 三李 匡z 6. z 参O ) ( } . ARINA C, CO LO NNE 小州 , Santa Mari a di Catanzaro and Le Cast el l a were vi si t ed and 3 D T o , CROTON E r弋 叭户 夕 扫 , 手 与〉才去支一 s i on i n Ca l ab r i a , du r i ng whi ch t he we l l - k nown s e ct i on s of 少界吠 and I GCP Pr oj ect 41 . al l t ook par t. Part i cipant s were conduct ed on a f i el d excur - 几 16'1} . Ma dr i d ( Al ber di and Ag ui r r e, 1 97 5) . Thi s wa s t he f i r s t of a s er i e s o f Fi e l d Co nf e r e nce s he l d j oi nt l y b y t he Wo r ki ng Gr o up I n 1 975 a s ympo s i um was he l d i n I t a l y on t he Neo g ene - Qu at e r na r y Bo un da r y i n wh i ch membe r s o f I GCP Pr oj e ct 41 , of t h e I CS Wo r ki ng Gr o up and of t he I NQUA Sub c ommi s s i o n September 1974, duri ng a Fi el d Conf erence on the Neogene- Quaternar y i n conti nental envi ronment s, and secti ons wer e st udi ed over a wi de area f rom Montpel l i er i n France t o 飞 L ' 朋}10 be t wee n t he Neog en e an d t h e Qua t er n a r y, " whi c h wa s a pp r ov e d as Pr o j ec t No. 41 , emb r a ci ng a s i mi l ar p r o j ect f r om I n di a. Pr o j ect 41 was l au nc he d i n Ba r ce l o na, S pai n, i n 飞 LE CASTELLA SECTIO N ) C} R- UTO di s cu s s ed ( Fi g. 1 ) . I n t he c ou r s e of t hi s e xc ur s i o n t he s e ct i on at Vr i ca n ea r Cr ot o ne was al s o vi s i t ed. Thi s ve r y i nt e r e s t i ng , } 一口 红一 」3 } = =月 ;卜 {5 Vll l } 6 L j 一州 7}}州 mar i ne Pl i o-P l ei st ocene secti on had then been recent l y di scovered by t he l ate Raimondo Sel l i and one of t he present Figure 1: Geological map of the Marchesato Penin一 sula (after Tortorici, 1982). I 一 Contine ntal sedi- ments (Pleistocene and Holocene), 2 一 Sediments of upper Pleistocene mari ne terraces, 3 一 middle to upper Pliocene and lower Pleistocene sediments, 4 一 au t h or s ( G. P. ) . So on af t er wa r d s , t he Vr i ca s e ct i o n ( Fi g. 2) was f u r t he r s t u di e d i n d et ai l b y nume r o us s pe ci a l i s t s ( e . g. Sel l i et al . , 1977; Col al onL y o et al . . 1981 . 1982, Nakaoawa. i n 6asi ry et ai . , i} 1 61 ; Uoraaovi cn el al . , 1} 0 62; Tauxe et aL, 1983; Pasi ni and Col al ont -o, and Nakavawa et al . . i n Van uouveri ng et ai . , i n press) . 116 Tortonian to lower Pliocene sediments, 5 一 Basement rocks, 6 一 Main faults (small triangles on downthrown sides), 7 一 Possible faults. Epi sodes, Vol. 8, No. 2, JUDe 1985 cl i mati c det er i orat i on i n t he I tal i an Pl i o-Pl ei st ocene 17. 凸内 s u c ce s s i on a s t he mai n cr i t er i on f or def i n i n g t h e b a se of t he Pl ei s t oc en e. The pa r t i ci p ant s of t he 1 97 9 Con f e r en ce i n I ndi a unani mous l y acknowl edged t hat the Vr i ca secti on was more sui tabl e than t hose of Sant a Mari a di Catanzar o and Le Ca s t el l a f o r def i ni n g a b as al b ou nd ar y s t r a t o t y pe f or t he Pl ei st ocene Seri es. 旦苦 W ork on the Vrica Section Ea r l y i n 1 98 0 , a p os t a l e n qui r y was c i r cul at ed t o a l l Vot i n g and Cor respondi ng Member s of the Wor ki ng Group i n or der t o det ermi ne whi ch of these t hree secti ons was consi dered as mo s t s u i t ab l e f or a bo un dar y s t r at ot ype , an d wh i c h cr i t er i a t he y p r ef e r r e d f o r c ho os i n g i t . The S ant a Ma r i a di Cat an za r o s e ct i o n was r e j e ct e d a s a t y pe s ec t i o n i n 40 of t he 4 6 answers, wi t h 6 undeci ded and not a si ngl e repl y i n f avour; the Le Cast el l a secti on was consi der ed unsui t abl e by 34 member s, approved by 1, wi t h 11 not answer i ng. The Vri ca sect i on was approved by 33 members and rej ected by 3, wi th 1 0 me mbe r s u nd ec i de d. The al l e g ed di s ad va nt ag es o f t he 诀 母 1 口刁 Z 『1{ 3 比 。 5 瓜卯习。 巨三{7 匡夏 圣B , / X 1 0刁 Santa Mar i a di Catanzaro secti on were: dubi ous or shal l ow- Figure 2: Geological map of the Vrica area ( modi一 wat er f aci es, parti al l y reworked f aunas, pr esence of several unexpos ed i nterval s, and a hi atus at t he bas e. The mai n reasons why t he Le Cast el l a secti on was rej ected wer e: rel ati ve l ack ot thi ckness of str at a, the presence of a hi at us fied from Selli et al., 1977). 1 一 Beach sa nd and du nes, 2 一 Calcarenites and sands of the - Milazzian' a pp r o xi ma t e l y at t he l e vel pr op os e d by Emi l i a ni et al . ( 1 961 ) a s t he Pl i oc en e - Pl ei s t oc en e Boun da r y, an d g en er al di f f i cu l t y mari ne terrace, 3 一 Grey silty and marly claystones with intercalated sapropelic lagers (lower Pleisto- cene), 4 一 First appearance of Hyalinea baltica, 35 m above the 里 volcanic ash layer (1. 99 Ma), 5 一 Grey i n access. silty and marly claystones with intercalated sapro- Subst anti al pr ogress was made on t he occasi on of t he 26th S e s s i on of t he I GC i n Pa r i s , 1 98 0 , i n a j o i n t mee t i n g of t he Boundary Wor ki ng Gr oup and I GCP Proj ect 41. The deci s i on was made t o pl ace the Pl i oc ene-P l ei st ocene Boundary s t r at ot yp e i n t h e Vr i c a S ect i on . The wo r d i n g o f t h e d ef i ni - t i o n was di s t i ng ui s he d e xpl i ci t l y f r om t h e c r i t er i a f or s e l ec t i ng t hat b ou n dar y p l an e. The f o r mer ha d t o be at a si ngl e beddi ng pl ane, whereas t he l at ter s houl d "be mul ti pl e; t h at i s a l l t he a va i l a bl e e vi d enc e, whi ch c an he l p wi de r a nge cor rel ati ons, shoul d be t aken i nt o account. " The f i r st occurr ence of the ost racode CvtherODteron testudo ( con- si aerec i to De a ' nortner n guest ") i n t r i e vr i ca sect i on, tr i e s a pr op e l i c l a y er e wi t hi n t h e s e ct i on an d i t s p r o xi mi t y t o a pal eomagnet i c r evers al were s i ngl ed out f or speci al at ten- t i on , a l t hou g h a f i na l de ci si o n o n t he b ou n da r y s t r a t ot ype wa s deferred. The ne e d f o r f ur t he r pa l e omagn et i c r e s ea r c h o n t h e Vr i c a secti on was st ressed at a j oi nt Fi el d Conference of I GCP Pr o j e ct s 41 a nd 1 28 , h el d i n Ar i z on a a nd Ca l i f or ni a ( U. S. A. ) i n 1981. Such work was soon carri ed out bot h by I t al i an- Ame r i ca n a nd J apa ne s e t e ams , wor ki ng i n de p en dent l y ( s ee Fi g. 3 , r i ght h an d c ol umns ) . pelic layers (lower Pleistocene, u pper and middle Pliocene), 6 一 Lower volcanic ash layer (l. a.; 2.22 Ma) , 7 一 Grey claystones ( middle Pliocene), 8 一 Faults, 9 一 Strike and dip, 10 一 Keg stratigraphic sections. t h e I CS Qu at er na r y Sub c or n mi s s i o n, whi ch al s o f u nc t i o ns a s t h e Commi s s i o n o n St r at i gr ap hy o f I NQUA; i t wa s app r o ve d b y an af f i r ma t i ve v ot e of 9 o f i t s Me mbe r s , wi t h n o ne gat i v e answer r ecei ved. Fi nal l y, the proposal was s ubmi t ted f or ma l l y t o t he I CS Meet i ng a t t he 2 7t h Se s s i on Geo l og i c al Congr es s,Moscow 1984. I n thi s sessi on i t was approved by the at tendi ng Members of t he I CS t o be forwarded i n a post al b al l ot t o Vot i n g Memb er s of t he Commi s s i o n. Rat i f i cat i on by I UGS i s r ep o r t e d b y M. G. Ba s s et t i n t h e a cc omp an yi n g p ap er . The submi ss i on compr i ses two separate but l i nked resol u- t i o ns : f i r s t l y , t he s e l ec t i on of t he Vr i ca s ec t i on as t he Pl i ocene-Pl ei st ocene Boundar y str at ot ype sect i on; and s e co nd l y, t he def i n i t i on of t h e Pl i o ce ne - Pl ei s t oc ene Bou nd ar y 一t ha t i s , t h e ba s e of t h e Pl ei s t oc ene s e r i e s一a t t he b as e of t h e mar i ne cl ay s t o ne s comf or mab l y o ve r l y i n g t h e ma r k er be d e i n the Vri ca sect i on. Fi na l l y , dur i n g a j oi n t me et i ng of t h e I NQUA S ub c ommi s s i on The St r at ot yp e S ec t i o n a nd Bo un da r y Cor r el at i on I-D and I GCP Proj ect 41 hel d i n Moscow i n 1982, a r ecom- mendati on was approved t o pl ace the Pl i ocene-Pl ei stocene Boundar y st ratotvpe at t he l evel of t he fi r st aDDearance of C. 上些1 旦旦2 i n t ne vr i ca secti on t consi aer ea pene -contempora- neous wi th the fi r st appear ance of t he mol l usc Arcti ca The Vri ca sect i on, l ocated 4 kni south of Crot one i n t he i s l a n d i c a i n I t a l i a n s h a l l o w wa t e r s e c t i o n s ) . E a r l y i n 1 9 8 3 t h i s r e c ommen da t i o n, an d t h e a l t e r n at i v e p r o p os a l of pl a ci n g t he Pl i o ce ne - Pl e i s t oc ene Bou nd ar y s t r at ot yp e s t r i ct l y i n r el at i on t o a p ar t i c ul ar mar k er b ed of t h e Vr i ca s e ct i o n, we r e s ub mi t t ed t o t he Vot i n g an d Ex - of f i c i o Memb er s of t he I CS Wo r ki n g Gr o up f o r a p os t al ba l l ot . Th e r e s ul t wa s a t i e , 8 t o 8 . The o f f i ce r s of t h e Wo r k i ng Gr ou p me e t i ng i n Madr i d i n Ma y 1 9 83 a g r ee d t o ma ke a new, j oi nt pr o po s a l , d es i gna t i ng t h e Pl i oce ne - Pl e i s t oc en e Bou n dar y s t r at ot ype at Vr i c a b ya l i t ho s t r at i gr ap hi cpl ane rel ated to t he sapr opel i c marker be K. V.Ni ki forova, as d e ( Fi g.3 Leader of I GCP Proj ect 41, and M. N . Al ekseev , Vice- Chai rman of the I CS Subcommi ssi on on Quat ernar y Strati- gr ap h y, a t t e nd ed t h at mee t i n g. A n ew ba l l o t i n J ul y of t h e same year favoured thi s pr oposal for defi ni t i on, wi t h 12 votes f o r , I ag ai ns t an d 2 a bs t ent i o ns ; o ne mor e v ot e i n f avo ur wa s recei ved l at er . The pr oposal was consequent l y submi tted t o Ep i s od es , Vol . 8, No. 2 , J u ne 1 98 5 Ma r ch es at o Pe ni n s u l a, Cal a br i a, I t al y ( Fi g. 1 ) , c on s i s t s o f o pe n s e a d ep os i t s pr e s er ve d i n t he eme r g en t po r t i o n of a l a t e Cen oz oi c s e di men t a r y b as i n. The r o c ks a r e ba t h ya l , ma r l y a nd s i l t y c l a y s t o ne s ( d a r k gr e y o r bl ue - g r e y i n co l ou r ) wi t h i nt e r b ed de d, f ai r l y con s pi cu ou s , p al e g r e y -p i n k s ap r o pe l i c marker beds. Some ver y t hi n sandy hori zons and a vol cani c a s h l a ye r a l s o o cc ur wi t hi n t he s e ct i on ( Fi g s . 2 a n d 3 ) . Th e Vr i ca s ec t i on ha s b ee n f av ou r e d b y t h e Wor k i n g Gr oup s i nce 1 97 5 a nd was gi ve n p r e f e r e nce i n 1 9 80 f or v ar i ou s r e as on s . Fi r s t , i t i s ea s i l y a cc es s i b l e, co nt i n uo us l y e xp o s ed, an d f r ee f r om bot h v e get at i on an d de br i s . I t s h ows a g oo d vert i cal devel opment of s trata, wi th some 306m of beds e xp os e d, an d t he r e i s s t r at i g r a phi c co nt i nu i t y t h r ou gh ou t. Se d i ment at i o n r at es t h r ou gh t h e s ec t i on r an g e f r om 31 0 mm to mor e than 750 mm per thousand year s. There ar e nei ther s t r u ct ur al comp l i c at i on s no r met amor ph i s m. Th e f ac i es a r e b at hya l an d t h er e a r e nume r o us f o s s i l s of di f f er e nt gr o u ps , s ev er al of wh i ch a r e s ui t ab l e f or wi de s p r ea d c or re l a t i ons ( Fi g. 3 ) . Co nd i t i on s r e c omme nde d f o r cu r r e n t g ui d el i ne s i n s t r at i gr ap hi c c l a s s i f i c at i on ( e. g. He d ber g, 1 9 76 ) r e l at i ng t o a t y pe s e ct i on a r e t h er e f o r e f ul l y s at i s f i ed i n t h eVr i c a s ect i o n. 117 M A G NETO ST RATIG R APH Y 118 !一 ! | ! 乏 二1哎}0哎 匡乏 山ld因的 ! lee | | 1 一 . 卜 乏 习1的的习芝yOO习囚的江 , 1 .月.................1 乏 D 卜吸OZ D 工己 匡 月. 二 习 1哎 1口 N 习几 es 牛 es .月 es 生 es 门J J J||1 N O江 囚卜几0 匡 山1卜卜口 十 ”月十 NO 匡 山』几0 匡山 HJ 卜口 ra IJ日||日J门1, ! 引川刽1 |引月引叫月训训训川川引 月 土 |到训副刽|到引副『 到刽刘门 土 .!1 引川引剥叫 月 别别川到让 |. | | | | 』 引酬 硕0二 吃口 戏 > n V A n 1 O o 曰 ee O O l es 出r一11山2 一 口 江n 卜 的一比 匡功 1 es 的工A山江山 哎曰山口O N乏J口 城习 口一一N O 曰 ............................Jl 的N山口山比011 氏 一 一~ 气 哎Zwe江山0-90)口 咬21 江0叹习O09O JOO口N 哎比国心奋峨口 哎 N l江 口 口 1 口 0 一0 哎Nl 庄山口1 山0 一口 别卫 别纠别 引引性 !川圳刘引叫川川引 引别引司引 土 引 引副 引 批 簇把 长非 群 } 副 | 1| 1|es.月 引川 引引酬 引1 !| 1| 的1叨N」0曰呀1 比喊曰 哎0.一 叮口 叭们 1山江卜庄山卜二0 卜U 丁|||||| 了D DO 工J口 0 峨 一2 一工 叭眺口- ‘2. 江曰刃 田OJ巴 ! 』... 川刽刁 引 ; 的习 口的 一 Cl 口曰< 曰 酬引引到叫于 J到 川 引刽纠月别 月 酬引引到 1 引 一山 匡卜卜 Nl口哎 乏 1一 司1山的 过江山吃H比的0口二 山 1 !. 一 一 哎口liN哎曰1< 哎N~匡0哎二0090 100山2 厂1 刃 2山峨卜少0 口 叹 咬 一 J 咬 卜 0 匡 0 图O JJ 沪 D万 因汪 卜只 田 l es l es lwe 的11N咬 1卜叹 砚21 匡山口f90曰巴 哎lyl-口一 0 哎1哎11 9一0 硬N}匡山口1 山OJO 。 U …。 、 。d6 U …0 。} 一 。 : 乏。山 0^ 1。 " 。.N . 。 0"n 歇引引引社 } 到} 别引引叫土 C Figure 3: Distribution in the Vrica section of the most sig nificant planktonic and benthic - organisms from blostrati graphic and blochronologic points of view. Ma卯 etostratig工aphy i刀 亡h, left-hand column is based on Tauxe and ot hers (1983) and in the r ight- hand column on Nakagawa (1983 personal communication,and in van Couvering et al., in press) E勺i sodes!V。州户 N。・护 Junel双 C L一 5 0 1 哎口一2哎 山口0 d 1 100 r 了 f尸 日} 习 州引 到川引引引 吐 e 2 O . | | 引割 引叫到川洲州 划训 到别叫土 n UJ ! -J P O cl ayst one 。 。 ! N1 I ntermedi at e h n - Si l t y ma r l y ! N2 土 M ILLO NORM AL SUBC H RO NS N3 I 妙u I n d a r y 一’ t r a t o t y p e AN D T日E JAR A- 5 r CT l ayer proposed Pl i oc ene IP } l el st oce ne EVENT BETW EEN 山 N 山 0 0 1 5 -山 -J d Reversed i Sa pr ope l一cl ay STRACODAI M OLLUSCA LITH O LO G Y 口口国曰口 l ayer s L i j 一! “ 。} I Undefi ned 2 5 0 ! Sa pr ope l i c 干 1HE O LDUVA I Sandy l ayer ' 1 0 1 Norm al { 2 0 PO LA R ITY SHO RT NOR MA L 3 0 0 { Vol cani c ash l ayer FO RA M FO RA M {N I F E R A NANNOPLANKTON SEC T I O N BEN T H I C P L A N K T I C CALCA REOUS VR ICA 参磷 二h u ,毛 f 沪诸 探 彝 德 巍 皱 ‘‘态、洲 吮劫黔一 飞 兹 1 蒸t‘ 外料哗 轰 身哭户' 毅 洲》蓬黔 . 一 耙敷1 粼麓簿哟 琴 瓤 参汤耀一 黔; 骼 澎 毅 粼嘱 滩矍彝壑 鬓 瓷声 A } 翼翼蕙霎 } 鬓鳌瓣 矍 黔 Section B of Figure 2, in foreground. Figure 4: On the ri叻 t' the uppermost part of Section A and the T he basal boundary Costa Tiziana Hotel are visible. Pleistocene Series is defined at stratotype for the the base of the bed immediately overlying marker bed e . ari ty Re co r d s o f c ha ng es i n ma gne t i c pol h 竺eal., als o been 1981) . t hese records was controvers i al i ni t i al ly, and i ndependent r esearch carr i ed out by r e po r t e d at Vr i ca ( Nak a gawa, 垫 S a s t r y eL Ta ux e a nd o t h er s ( 19 83 ) a nd f ur t he r wor k b y Nak ag awa and co-wor kers ( i n Van Couveri m- et al . , i n pr es s) , no doubt can remai n as t o the i denti f i cati on ol tr i e normal pol ari ty zone t he i mmedi ate f uture s houl d be the establ i shment of para- s t r at ot ype , o r h ypo s t r at ot ype s e ct i on s i n ot h e r a pp r op r i a t e mari ne bas i ns and i n cont i nent al s equences . We suggest that, a mon g ot he r s , t he Bo s o Peni ns ul a i n J ap a n an d o ne of t he goo d s e ct i o ns i n Eas t Af r i c a, s uch as Ol d uva i Go r ge i n Tan z ani a, Koo b i Fo r a . i n Ke ny a, o r t h e Shu n gur a f o rmat i on of t he l owe r Omo Bas i n, Et hi opi a, s h ou l d be c ons i de r e d f o r t h i s purpose. The s ec on d pa r t of t he s ubmi s s i o n r e f l e ct s t he a gr e emen t on t he def i ni t i o n of t he Pl i oc e ne - Pl e i s t oc en e Bo un da r y a nd i t s b ou n dar y s t r at ot yp e. The ba s e of t he be d of I s i l t y mar l y c l a ys t on e co nf or ma bl y ov er l yi ng t he s a pr o pe l i c b e d e at Vr i ca wa s s el ect ed a s t he pr ec i s e b oun da r y ma r k er poi nt f or ma ny reasons. The f act that s everal pal eontol ogi c events ( fi r st and l ast occurrences of mi crot os si l s ) str addl i ng tne proposed oounaary st r at ot ype occur i n It ali an shal l ow-water secti ons near the f i r s t a pp ea r an c e of t he mol l u s c Ar c t i c a i s l an di c a ( t h e mo s t r en owne d " no r t he r n g ue s t " ) i s f un da 布而谊呀万而石or t ant . I n f ac t , t he f i r s t ap pea r a nc e of色 些l an di ca i n t he Med i t e r - r anean area, and i n par ti cul ar i n t he I tal i an sequences , has b ee n f o r de cad e s o ne of t he ma i n c r i t er i a f o r def i ni n g t he bas e of the Pl ei st ocene Ser ies. Some of t he pa l e on t o l o gi c ev e nt s o cc ur r i n g c l o s el y a bo ve and bel ow the sel ected boundar y pl ane are, both i ndi vi dual ly and co l l e ct i ve l y , qu i t e r e l i a bl e f or wi d e s pr ea d c o r r e l at i o ns . The y i n cl ud e ( Fi g. 3 ) t h e l a s t o cc ur r e nce of t he ca l ca r ce ou s n an - no pl an kt o n卫竺c oa s 生 2 e - r - - b r o uwe 丝( b el ow) , t h e l a s t occ ur r enc e s of t he forami ni f er Gl obi L r eri noi des obl i quus ext remus and the na nn op l a nk t on Ca l c 主 d i s c u s mac i nt y旦 主( ab o ve) , a nd t he f i r s t app e a ra n ce of t he na nn op l an kt on Ge ph yr oca p s a oceanica ( a bo ve) . I n f ac t, t hes e p al e ont o l og i c al e ve nt s a r e found in t he same order and i n t he s ame pos i ti on wi th r espect to the Epi sodes, Vol . 8, No. 2, June 1985 s ec t i on i s al s o ve r y i mp or t ant b ec a us e r ef e re n ce t o t he ma g net os t r a t i gr a ph i c s c a l e an d t o r a di o met r i c a ge d et e r mi - nat i o ns a r e t he on l y cu r r e nt mea ns f or c or r el at i ng c o nt i - nen t al s e q uen ce s wi t h t he bo un da r y s t r a t o t y pe. Re l at i ve l y l i tt l e attent i on has so f ar been pai d to correl ati ons bet ween mari ne and non-mar i ne deposi t s. Nevert hel es s cont i nent al dep o s i t s a r e e xt en s i ve wo r l dwi de an d de s e r v e ca r ef ul co n- si der ati on i n veol ovi c resear ch and mappi ng, especi al l y as f ar as t he l at e Ce noz oi c i s co nc er ne d } Agu l r r e et al . ,里 v an Co uve r i ng et a l . , i n pr e s s ) . be l ow mar ke r be d e wi t h t he Ol d uva i s u bc hr o n ( s ee Fi g. 3 ) . We s t r on gl y r e co mme nd t h at a goa l of t h i s Wor ki n g Gr o up i n The i denti f i cati on of t he Ol duvai s ubchron i n t he Vr i ca Th e da t um s e l e ct ed a s t h e bo un da r y l e ve l i n t h e s t r a t o t y pe i s qui t e c on s p i cu o us an d i de nt i f i a bl e; be d e can be t r ac ed t hr ou gh ou t t he ou t cr op an d di s t i ng ui s he d f r om t he ot h er s ap r o pe l i c ma r k er bed s b y i t s t hi c kn es s ( ab ou t 1 90 cm) a nd r el at i ve po s i t i o n ( Fi gs . 3 an d 4 ) . Mor e o ve r , t hi s be d i n com- mo n wi t h t h e o t he r s a pr ope l i c be ds i n t h e s e ct i on i s cl e a r l y d i s t i n gu i s h ab l e f r om t he un der l yi ng an d ov er l yi ng cl a y s t r a t a bec au s e o f i t s f i ne l y l ami n at e d s t r uc t u r e a nd t he mar k ed l y di ff erent col ours i nvol ved. Th e a ge of t h e vo l ca ni c a s h l a ye r i n t he Vr i c a s e ct i on( 里i n Fi g. 3) h a s n ot ye t b een det e rmi ne d p r e ci s e l y. Ob r a dov i c h an d hi s co - wor k er s ( 1 98 2 ) co u l d o nl y de mon s t r at e t hat t hi s l a ye r i s ce r t ai n l y you ng er t ha n 1 . 99 1 0. 0 8 Ma. Howe ve r , a cce p t i n g t he a g e of 1 . 67 Ma f or t h e t o p o f t he Ol du va i s ubc h r on ( Man ki ne n an d Dal r ymp l e, 1 97 9 ) an d co ns i de r i n g t h at t h e se d i ment at 天 on r a t e i n t he i nt e r v al o f t he Vr i c a sect i on between t he top of t he Ol duvai and t he top of mar ker be d e i s 31 0 mm p er t hou s a nd y ea r s ( Taux e e t a l . , 1 983 ) , i t f o l l o ws t h at t he age o f t he def i n ed b as al Pl e i s t oc ene b oun da r y poi nt i s ab out 1 . 64 Ma. Th i s ag e i s co nf i r med b y i n de pe nd ent cal cu l at i on s b a se d on na nn of os s i l bi o ch r o nol og y ( Ri o a nd ot he r s , i n Va n Cou ve r i ng et al . , i n pr e s s ) . Co nc l u di ng St at eme nt The de f i ni t i on of. t he b eg i nn i ng of t he Pl ei s t o ce ne no l on ge r ha s a p r i ma r y c l i ma t i c i mp l i c at i on, wh i ch , b ec au s e of l at i t udi nal and al ti t udi nal eff ect s on wor l d cl i mate, woul d be di f f i cu l t t o pr ov i de . I n s ome a r e a t h e e ar l i e s t g l ac i a l pe r i od s wi l l be Pl i oc en e ag e, or ev en ol de r ; i n ot he r s t h ey wi l l be of mi d -Pl e i s t oc en e ag e. Pr e ci s e d ef i ni t i o n of t h e b as e of t he Pl e i s t o ce ne S e r i e s now p r o vi des a f i xe d r ef e r e nce p oi nt f o r s uc h ev en t s i n di f f e r e nt r eg i on s . 119 We b e l i e ve t h at t h e b a s al bo un da r y of t h e Pl ei s t o ce ne Ser i e s i s now concept ual l y cl ear and unambi guous i n i ts defi ni ti on. I t i s st abl e, cl ear l y i denti f i ed i n an appr oved str at otype, and Alberdi , M. T. and Agui rre, E,1975. Act as I Col oqui o L nt ernaci onai sobre Bi o. 5t rati - g N r e a 6 f g i a e n C o o - n C t u i a n e t e n r t i 慕老} 念C 6 g , e M n o a d S r u i d p e ) , r i v o . r ; 4 y , 沂u I a I 瓷 r n 1 a 3 r 9 i - o 1 4 I n 1 . f e r i o r , 1 9 7 4 . T r a b a j o s s o b r e ea s i l y co r r e l at e d wi t h a hi gh d eg r ee o f p r e ci s i o n t o o t he r Col a l o ng o , M. L. , Pa s i n i , G. , Pe l o s i o , G. , Raf f i , S . , Ri o , D. , Ru g gi er i , G. , S a r t o r i i , S . , ge o l og i ca l r e gi on s . Thi s def i n i t i o n i s mor e p r e ci s e t ha n a n y Sel li , R. and Spr ovi eri , R. , 1982. The Neogene-Quaternary boundar y def i ni t i on: a and pr oposal . Geografi a Fi si ca e Di nami ca Quat ernar i a, v. 5, no. 1, p. 59-68. at t emp t e d p r e vi ou s l y, b ut s u b s t a nt i al l y r e t ai ns t he con ce pt s review M. L. , Pasi ni , G. and Sartoni , S. , 198 1 . Remarks on t he Neogene Quaternary wi d el y a c cep t e d i n t h e pa s t f o r t he p os i t i on of t he ba s e of Colalongo, ou n da r y a nd t h e Vr i c a S e ct i on ( Ca l ab r i a , I t a l y) . B o l l e t t i n o So c i e t a Pa l e o n t o l o gi c a Pl ei s t o ce ne. Con s e que nt l y i t s ho u l d b e un d er s t an dab l e, b I tal i ans, v. 20, no. 2, p. 99-120. accept abl e and unequi vocal as a pract i cal st andar d by al l geol ogi st s. Acknowl edgeme nt s We are deepl y i ndebt ed t o R. Hey and R. P. Suggat e, who Emi l i ani , C. , Mayedso T. and Sel l i , R. , 1961. Pal eotemp er at ure anal ysi s of the Pl i o- - Pl ei stocene secti on at Le Castel l a, Calabri a, s outhern I tal y. Geol ogi cal Soci et y of Amer i ca Bul le ti n, v. 72, no. 5, p. 67}-688. c H l e a d s b s i e f r i g c , a 盆思, i n 1 o 9 l o 7 g 6 y . a I n d t e p r r n o a c t e i o d n u a r l e . S t J r o a h t n i g W r a i l p e h y i c a n G d u i S d o e n 扁e g u w i d Y e o t r o k , S 2 i r 0 黔a p h i c 劣架e i n , t 黑1 胃漂器橇u G r . n B a . l , 荞舔粼留撰默瓷黑 一 暇舞尹l e pa t i en t l y hel p ed u s by r ea di n g a n d c or r ec t i n g t h e l an gu age i n s u cc es s i v e ma nu s c r i p t s of t he Bou nd ar y Pr o po s al an d of t hi s s umma r y a cc ou nt , a s wel l a s t o t h e l at e A. Ma r t i ns s on , t o Ob r a d ov i c h , J . D. , Nae s e r , C. W. , I ze t t , G. A. , Pa s i n i , G. , Bi g az z i , G. , 1 98 2 . Ag e c o n - str ai nt s of the pr oposed Pl i o-Pl ei st ocene boundary strat ot ype at Vri ca, I tal y. Nature, v. 298, no. 58 69, p. 55-59. M. G. Bas set t and t o K. V. Ni ki f or ova and her t eam i n I GCP Pr oj ect 41 f or thei r most val uabl e advi ce. Fi nanci al ai d was Sast ry, M. V.A. , Kuri en, T. K. Dut ta, T. K. and Bi swas, S. ( eds. ) , 1981. Fiel d Conf erence: Neogene一 uaternary Boundary. I ndi a 1979. Pr oceedi ngs, Cal cutt a, Geol ogi cal Survey of I ndi a, 241p. f u r ni s h ed b y I UGS , I NQUA, t h e I t a l i a n CNR, t he Sp ani s h I GME and CAI CYT Proj ect 1849/82. Dr . Emi l i an o Ag ui r r e i s Di r e ct or o f t he Na t i ona l Mus e um of Na t u r a l S ci en ce s , J os 6 Gut i 6 r r ez Ab a sc a l 2, 2 8 006 Mad r i d, Sel l i , R. , Accorsi , C. A. , Bandi ni Mazzanti , M. , Bert ol ani Mar chett i , D. , Bi gazzi , G. , Bonadonna, F. P. , Bor setti , A.M. , Cat i, F. , Col al ongo, M. L. , D' Onof ri o, S. , Landi ni , W. , Mene si ni , E. , Mezzett i , R., Pas i ni , G. , Savel l i , C. and Tar npi e ri , R. , 1977. The Vri ca secti on (Cal abr i a, It al y). A potent i al Neogene-Quate rnar y Boundary St rat otype. Gi ornal e di Geol ogi a, 42 (l) , p. 181-204. Spai n. He i s Chai rman of t he I CS Pl i ocene-Pl ei stocene Tauxe, L. , Opdyke, N. D. , Pasi ni , G. and Elmi , C. , 1983. Age of the Pl i ocene- Pl ei s tocene Boundary i n the Vr i ca sect i on, southern I tal y. Natur e, v. 304, no. 5922, Bou n dar y Wor k i n g Gr ou p a nd Pr e s i de nt of I NQUA Subc om- p. 125-129. mi ssi on I - D. Tor tori ci , L. , 1 982. Anal i si del l e def ormazi oni f ragi t f dei sedi menti post orogeni del l a. Cal abri a. Bol l etti no Soci et a Geol ogi It al i a, v. 100, p. 291- 308. Dr . Gi a nc ar l o Pa s i ni i s Se cr e t a r y of I NQUA S ub c ommi s s i on Van Couveri ng, J. A. at al . , i n press . The Neogene-Quat ernary Boundar y, Fi nal report of I GCP Proj ect 41. I -D and has been res ponsi bl e f or much of the work and co- ordi nati on of res ul t s f rom the Vri ca st ratotype secti on. He wor ks at t he Nati onal Resear ch Counci l I nsti tut e of Mari ne 举 攀 毕 平 爷 毕 爷 Geol ogy i n Bol ogna, I t al y. Thl i n Sect i on Pr eparat i on *Rocks *Soi ls *Cerami cs *Refractori es *Concrete etc. We can pr ovi de a machi ne sys t em f or al l your t hi n sect i on pr epar at i ons , f e a t ur i ng a u t oma t i c p ar al l e l i s m and thi ckness cont rol . * Th, ? mo s t c ompr e he n s i v e, f ul l y i nt e gr at ed machi ne s ys t ems f or t he pr oduc t i on of FI NI SHED THI N SECTI ONS … PM 2 A F o r f u r t he r d e t a i l s wr i t e t o… AUTOMATED THI N SECTI ON 欢 120 Epi sodes, Vol . 8, No. 2, June 1985