Rivist;r It;rlian;r di Paleontologi;r e Str';.rtigrafia volLltìtr' I Iu no. I pp. 339-344 April 2004
THE BOREAL-TETHYAN BIOGEOGRAPHICAL MOLLUSC ECOTONE IN EUROPE DURING THE JURAS SIC-CRETACEOUS TRANSITION
VICTOR A. ZAKHAROV & MIKHAIL A. ROGOV'
Receit'ed October 9, 2002; Ltccepted October 7, 2003
Kel';'or,1t: nrollusc;.r, biogeographical ecotone, Jurassic/ ceous in the Boreal-Pacific Realm (Zakharov et aL. 1996). Cretlceous, Europe. The position of the Boreal-Tethyan ecotone in the Bo- real-Atlantic Realm from Late Volgian to Early Neoco- Abstr,tct. Llte Jur;rssic ;rrrd e;rrliest Crctaceous molluscs of the northern henrispherc s,ere clistinctly cìifferentiated geographicellv into mian is assumed on the basis of ammonites (Zakharov Bore,rl t,rr,r, usuallv north of 50' N, end Tethr.an trx;r, usuallv sourh of 8c Bosomolov 1998). It is very important to investigate -15'N. Betl,een these l;rtitudes certain lreas rvere displaced îronr tinre the Boreal-Tethyan migrations inside the ecotone at the to tinlc', ,rlthough the biogeographic;rl ecotonc was stable. The nrrsni- Jurassic/Cretzlceous transition to make a precise correia- tude of the ecotone and the migration of nrolluscs inside the ecotone tion between the Tithonian-Voleian and the Berriasian- variccl in tinrc lnd spacc, in direction (unidirectional and bìdirection- ,rl) ,rnd intcnsitr'(erp;rnsion;lnd "isoliìtc str;u'ing"). The frequencv of Boreal Berriasian. the Boreal-Tethvirn nrigriìtions of nrolluscs is explaincd b1. custacy and bl,geogr.rphicrl barriers existing betu.een the Northern C,ruclsus and Middle-Russìrn brsins. Material and methods
Riassurtto.l rrolluschi nr;rrìni del Giur;rssìco superiore e del pri- D;rta on anrnronite, belemnite and bivalve migrations across the rlo Cret,tcc'o dell'cnrislcro scttcntrion,rle creno nettalrellte diffc.renzi;rti south nrlrsin of the Boreal-Atlantic Realnr fronr Lare Jurassic (Kimmer- d;rl pr.rnto di vistr geografico in tara boreali, di solito r Nord dei 50'N, idgirn :rnd Vrlgian) to Earll' Neocomiirn (Boreal Berriasian -Valangin- e tetidei, Sud dei Tra queste Jatitr,rdini certe lree trrxl di solito;r 45'N. ian) rvere revicwed. The migrltions were considered at substage inter- venivano di voltl in volta sposriÌte, sebbene l'ccotono bioseosrafico vals. The latitudes of 45'and 50'N rvere accepted as the northern mar- fosse stabile. L;rnrpiezz;r dell'ecotono e h migr:rzione dei molluschi ll gìn of thc Tethls-Pantalassa Super-realm, and as the southern m.rrgin suo interno è r.ariatr nel tempo e nello spezio, in direz-ione (unidirezio- of the P;rnbore;rl Sr-rper-realnr, respectively. A taxon "advancing" from nale e bidirczìonale) ed ìntensità (espansione e "dìspersione isolat,r"). north to south lnd crossing 50" N was considered a boreal influence, La frequenz;r delle nrisr;rzioni borelli-tetidee deì molluschi è spiegat;r and the limit of Tethl'xn influence s.as ser ar the crossing of 45" N for dall'eustasil e dall'esistcnza un;r b;rrrier;r geografica bacinì del di tra i taxa "nroving" fronr south to north. C;ruc;rso setterrtrionale e della Russia centriÌle. Nes molluscan data collected over the last few decades, mainly from UpperJurassic lnd Lower Neocomian sequences of Europe, have irnproved our knon,ledge of the Boreal-Tethyan ecotone, of the posi- tion of the southern margin of the Boreal-Atlantic Realm (Sachs et al. lntroduction l9l1; Fis. l), and of the migr:rtìon of Tethyan mollusc associations and taxll into:rnd from the Boreal basins (Fig.2). Mìgrations with differ- The Boreal-Tethyan biogeographical ecotone exist- ent intensities ;rnd directìon from the Kimrneridsian ro the Valanginian, ed in Europe during the late Jurassic-earliest Cretaceous considered in thìs paper, rvere restricted to the Boreal-Atlantic Realm represented by a co-occurrence of Boreal and Tethyan (\ùí/est Europe;rn and East European Provinces). The nrolluscs, such as ;rnrnronoìcls, belenrnites lnd bìr,alves, were divided into 3 groups: Teth- forms. Durins the Mesozoic it was located in the North- y;rn, Boreal and Sub-boreal (nrostlv with Tethyan affinities typical for ern Hemisphere alons the Tethys-Pantalassa Panboreal / thc ccotones). It is impossible to attribute some ammonoids, such as Super-realms boundary. The ecotone was established by PhylJoceratide and Lytoceratìda, to either the Tethyan or Boreal Realm. the molluscs in the Triassic, Jurassic and Early Creta- Thcir clistribution n;rs probabll' controlled b1' u'atcr depth.
Geologicel Institute of RAS, Pvzhevskii Lirnc, Moscol,, 1O9O1Z, Russia. E-m;ril: nrzarctic(ri mtu-net.ru; rogor,_m(i.rambler.ru 340 V. A. Zakharov 8< M. A. Rogor.,
Fig. 1 - Boreal-Tethyan ecotone rn the Upper Kimmeridgian (Autissiodorensis Chron) o{ Europe. 1 - land; 2 - Teth- yanammonites,3-Sub- boreal ammonites, 4 - Bo- real ammonites; 5-10. Finds of the selected anrmonire genera: Sub-boreal: 5 - Graoesia, 6 - Aulacostepba- nus; Boreal: 7 - Suboxydis- cites, 8- Amoeboceras; Teth- yan: 9 - Metahaploceras/ Neochetoceras, 10 - Aspido- ceras.
-t3--'jr5 ffi 1i_--- I2l r6t7v 8n9 o 10
Results grations of the Mediterranean ammonoids into the East- European Province during the Latest Kimmeridgian and It is interesting to note that in Europe an ammonite Early Volgian), while influences refer to the moving ecotone was either absent for a rather long time (from the of separate taxa, usually with an insignificant number of Latest Volgian to the beginning of the Valanginian) or specimens (e.g., penetration of Aspidoceras îorrh:ward in- quite restricted (during the Late Boreal Berriasian). Sub- to West Siberia). Expansions quite often lead to the start- boreal ammonites are either unknown or they occupied ing of endemic clades (e.g. Riasanites in Central Russia, a small area (e.g. Garniericeras). At the beginning of the Late Valanginian Neocomitidae of '$festern Europe), but Valan ginian, P latylenticera.s appeared, presumably from they may be restricted to short intervals without new Boreal ancestors, but its geographical distribution was taxa. The most indicative example of such migrations typically Sub-boreal. During the Berriasian and Valangin- was the penetration of numerous Anaspidoceras neobur- ian, the bivalve Bwchia extended to the South, up to 48o gense into the East-European Province during the Early \West-European N in the Province of the Boreal-Atlan- Voigian (Pseudoscythica Chron, neoburgense hemera) tic Realm, and reached 42 - 40'N in the East-European (Rogov 2002). Buchia bivalves also illustrate the inten- Province (Zakharov 198 1 ; Kelly 1 990) . Tethyan trigoniid sity of migrations. The migration-influences in the Bo- bivalves penetrated up to 55o N into the East-European real-Atlantic Realm took place during the Late Jurassic Province during the Volgian (Gerasimov 1955). The most - Early Neocomian in the West-European Province (Fig. northern penetration of Tethyan ammonoids known was 2a), and during the Berriasian - Valanginian in the East- made by Aspidoceras (Late Kimmeridgian, East-European European Province (Fig. 2b). Province, 65" N; Bogomolov & Dzyuba 1998; Fig.1). Two kinds of migrations were determined based Based on intensity, migrations are subdivided into on the direction of penetration: bidirectional (e.g., Vol- expansions (mass migrations) and influences (isolated gian- Early Berriasian) and unidirectional (e.g., latest Va-
a ). Borcal-Atlantic Rcal nr ( Wcst-Europe'an Provincc ;
I 'iiiiii.iir.ril..rrlr Krrrr- l-.rtc K11- l:rrlr \lrtltllc I rrl.' l.rrlr l-.ttc . .l .rtlr l.ltu !, = i ;ì;i,.jr;:;; Titlrrrrìan Tithrrnrrrr Titlrrrnnrr l.lcnr.rirrn Llcnrr:rarr \.rl.lrì!lrìr.It \ililt)rtDt.ril i =:: : - /; f .,,1r fiin- f ,rr:Î;x-- l .rrlr \lrLlJlr I irtr lJ.,r..rl I .rII\ Lirl( /- 2 --= . ntcr'i,lgrrn nrerrrl_rr,rl \irllrin Yolgrirn \irlgtiu Bctttlstrn Vrlrnrrirrrn \:rhnginirn " t=t 80 80 o a c) .î\a- : :: o ì! (.) o= o ì> 70 hil .! iì ì>*:ì ,i E 0) :.! n I ^.-$ o (_) <{ :q -q: ìi: Ì E! I 60 t. I Èò s :-: c- Ò a< rrl a <() t ì{ -Y- rr 50i 50 c) ,--+.--, tha K S9 '._Ia I e8 l"l È at- 40 1 o E .)iì E* 40 -i UN -Y- í<{! g 6 E> =x o() o. : 30'E :s ì: ,;ó -àà 30 :l.i: On- .eó l.l I g t :< !^jìs ^z =è 20E !È 20 FT b). Bclrcal-Atlantic Rcalnr ( East-Europcan Provincc)
l:.rrlr \'lrdril.' l.rt.' |Jrl\ l..ltJ I trrll Lrrc . fitlrruirn-litltrnr.rtt IitìtLrnntt [Jcrn,titrn Ilct ri.r.r.ril \.tl.rtì!rDt.ttì \.rl.rrrLrilr.rrr =- - tn-l r:: \lrtitilc L.rlc ll.rrrrrl lrrlr l.îtc l- | \irlgrrn \irìgrrrn . llcrrnsrrrn Vilxn!rilnn Vrllrruinirrr lffi | \ Àa 80 f- | ar )rr.È + a \ = iì r.\ l/r lqqrr=-l ì ì=! ai o !!r 0) 70 trs: Q' h := N8 = 10 -:> < x ìì o)- E a! ì.F^l ! lc) x as o - v- È x .:ì ì .9 ÈV:?- o 60 60 È-j-._------=.: .B A.s _--. v E ilp î 91 50 ùÒ; 50 .sE _g_. Ar -_t OJ 9.9 40 .g ÉÉ z6 oP 40- t o= 'fr-;o o0 -oB riOE} !o r! Jfl l)o É, b 30 g9 àÉ .Í E€ .lo O 330 aa tìig. 2 - Setting of the Borell-Tethy:rn ecotone lnd bounclary benveen Boreal ;rnd Tethl's-Pantalass:r Super-realnrs from Kimnreridgian to Va- hnginian. l-2 - Bore;rl (A) and Tethvan (ll) expansions ( 1) and isoletecl strîving (2); 3 - finds of Rudistr together with Boreal amnro- nites; 4-findsofTethl,anbelenrnites (Hibolithes) torcthcrwithboreal anrmonites; 5-findsof hemratypiccoralstogetherwithboreal ;rrrnronires; 6-occ;rnic;rmÌìlonitcsinthchighlrtitudes(Ph-Phvlloceratid;r;I--Lytoceratìda; B-Ilocbíanites);7-ecotonebasedon lmnronoids; 8 - ecotone b;rsed on lnrnronites;rnd bir';rhcs or onlv on bir':rlves. Alfiliations of ;rmnronites and bivalves noted by clifferent fonts. Anrmonites: Tcthy;rn Glochicer,ts. Bore,rl u'ith Tethyln aflinities Suhoxvtliscites. Sub-borerrl Zaraiskites, Boreal Surites. Bivalves: Bo- rerl Buchia, Teth.van Trigoniidoe. the tenrperirture gradient between zoochorems (the influ- barriers. Thus, a significant northward displacement of ence of this factor is felt if geographical barriers imped- the Tethys-Panthalassa/Panboreal Super-realms bound- ins n.ìisrations are absent) . As a rule, at this time the eco- ary developed in the latest Valanginian of the West-Eu- tone widens. Quite often unidirectional micrations are .ìc- ropean Province. Nevertheless, only Boreal amn'ronoids companied bv displacement of the high-rank zoochorenls occur in the East-European Province during this interval. boundaries. They are ch:rracterized by a sharp cl.rance of The Boreal-Tethyan ecotone in Europe was not always amnlonoid associations. In the West-European and East- delineated clearly. The increasing Boreal influence can be European Provinces of the Boreal-Atlantic Realm, despite seen in the Northern Hemisphere at the beginning of the their proxirnity, n.rollusc n-rigrations are not always nlutu- Cretaceous: the Super-realms boundary, in particular in ally correl;rted (Fig.2,3). This may be explained by the the tarly Valanginian, is displaced to the south (Fig. 2). influence of currents and the presence of geouraphic:rl This obviously indicates the development of the Boreal 342 V. A. Zaleharoo k M. A. Rogoa NOI{1}ll.RN L,\'il]ljDFtS NORTIìtrlìN LATITUDIS 36 40 44 48 14 48 52 _L 1.. \ eÒ) t-\ at)v TETH\AN TAXA \ Q' Molluscs migration restricted by the ecotone in the Boreal-Atlantic Realnr from Kimr.neridgian to Valanginiln. a) \fest-European Prov- ince; b) East-European Provrnce. transgression. The Terhyan influence in the Kimmeridgian During the pwschi hemera in the Central Rus- and earliest Volgian is appreciable only within the limits sian Sea the ammonoids were essentially comparable ro of the Boreal-Atlantic Realm, q/hs1s .migrarion waves, those in Poland. Only Tethyan Danwbisphinctes are rarer are observed (Fig. 3b). in Russia. Associations of Bivalves (largely Bwchia) and The examples considered and illusrrated above eive belemnites (only Cylindroteutbis) became extreme Bo- the average patrern of migrations (for the substage lev- real, which indicates a srrengrhening of the influence of el) and positions of the ecotone. However, in reality the the Arctic Basin. Sub-boreal influences were n.rarked also character and direction of migrations might strongly vary in Western Europe. Rare Sub-boreal Pseudoairgatites (?) during this insignificant time interval. The change of the tenuicostatum was presenr in Austria (Zeiss 1977).In the Boreal-Tethyan migrations during the latest Early Vol- Panderi Chron all migrations of molluscs were characrer- gian to the earliest Middle Volgian (in the Tethyan scale ized by individual penerrations (isolated straying), but this time spans the interval from the base of the Middle were variable in direction. Connections between Cen- Tithonian up to the Calpionella Zone A of the Upper Ti- tral Russian and North Caucasian Seas were somewhat thonian) is discussed as an example. amplified. Sutneria, Lingulaticeras, and Pseudolissoceras In the neoburgense hemera (corresponding approxi- penetrated into the Volga region from the sourh, and rare mately to the Semiforme Chron) mass penerration of the Dorsoplanites extended into Caucasus from the north Tethyan molluscs into the Central Russia was observed. (Douvillé 1910; Khimshiashvili 1989). At the same tirne, The ammonites Anaspidoceras and Sutneria were more individual Zaraiskites regularis penetrated into the Balkan- common, the Tethyan Hibolithes superseded the Boreal Carpathian resion through the Polish Basin. Cylindroteuthinae in the Volga region, and among bi- valves both Tethyan (Myopborella) and Boreal (Bucbia) taxa rÀ/ere present (Rogov 2004). Apparently, this was Discussion a mass unilateral misration from the North Caucasian Sea. However, this event is unknown in the Timan-Pe- What factors influenced mollusc Boreal-Tethyan chora Province and in Sub-polar Ural. At the same time, migrations and the adjustment of the bio-geoeraphical it is possible that some Boreal ammonites penetrated in- ecotone? A primary facror, accepred by a majority of to Southern Germany (Scherzinger & Schweigert 1999) researchers, was cooler water temperature in the north. during the neoburgense hemera, though the identification However, only a few Boreal and Tethyan molluscs were of these ammonites is doubtful. involved. Some typical Tethyan molluscs reached 60" N IJorc,tl-TbtlD,an acotoile in Upper Jur,tssic of Europe J+J Fi.t. .+ - Tr-.tntqre ssite-reqressilc cun c (fronr S:rh:rgi;rn et al. 1996) and I cth) rn anrnronitc nrigrations .'! 2' i Ztltc ;rmrnonite nrigr:rtions via the Midclle Russian Sea during the Kirrmeridgien-Valangin- l). bidichotonrus J 'l ia n. [.Jrllgurcd Ncocorrititlrc ,'7 P.polvptr chus e.a ,\l N.ìil inror skcnsis "l Ioplitcs arnoltìi" (in tlo{oslo\sk\. Ifì97) l'. albidunt - v6 S. tzikl inirnus -frlnscaspi ^J= itcs tìj Iì. rjrsarrcnsis.t !3 << S. spasskùrsis ll. kochi v- (iarnierrccras & Iìirsîn itcs. Iì iasarrilcs I:Ltth\rric!-rr\ (. rocìigcr (. subditus K. lirlccns I:. nikitini \'. r irgalus [). pandcri l. pscudoscrthicr I. sokolor i AnrrsPttl,rcetus. I'scuthrlissrrccr y l. klinror i Lirrgulalice'ras. \cochcloccras ,,, , \' lìtlll\\lllu()ftn\15 - a j? ,\.cudoxus \lctahaploccras. ..\spirloccras. I À.nrutrhilis (ìhrclticcras s.l. = ;i^Z 7ll.onrorlocc r ? .-, , ffiEiit.ìi,tiu.",". ; I= ! tit)ll\tcl j \. rJ\trr N4clahrploccras. Lingulrticcrrs ^v .\.sfrnlufì and even 65"N, i.e. nloved aw:ìy fronl the Tethys-Pirn- Boreirl-Atlantic Reah.n lMiddle-Russian sea). As seen in thalassa nr:lrsin (45'N) to 2.000-2.500 krn to the north.-_+Fig. 4, thc coincidence of transsression peaks with epi- Anrong "Boreal wrnderers> are the cephalopods, rvhich sodes of aulmonoid nrisrations is observed only for the penerrared southwirrd beyond 38'N, but co\rered a lc'sser Kinrnreridqian -Middle Volgian interval, rvhile in the Ber- distance, since they nloved away fronl the margin of the riasi:rn :Ì correlation is absent. Obviously, the nricration- Panboreirl Super-reirln.r no nlore than 700 km. It is likely expansion of berriasellids durine the Boreal Berriasian that only er few Tethy;rn molluscs h:rd ter.nperature roler- is not connected with a eustatic rise (Fig.4). This event ances wider than the Boreal forr.r.rs. This could be consid- nrav be related to the destruction of a geographical bar- ered as a possible explanation for tl.re nlxinl,v southern rier bctrveen the Northern Caucasus ;rnd Middle-Russian origin of the rrajority of Boreirl taxr. The hieh frequencv basins. Apparently, the influence of Tethyan over Boreal of the Boreal-Tethyan ulisrations is explirined bv eustacy: water nlasses prevailed, when connections between the durirrg a rise of seiì-level nligration prlthways were operìed, Middlc-Rr-rssian Sea and the Arctic basin were restricred and durins sea-level firlls nrigration pirthwavs were closed to the r.rorth. (Kenrper er al. 198 l). In addition, it is supposed thirt rises of se;'r-level eliminated tenlperature b,'rrriers between wrrer tltknor;'ledgcnelts. This project h;rs becn supported bv RFBR masses. A n.rost suitirblc rrea to cl.reck these hypotheses Gr;rnts No. 0l-05-6.+6+2 antì 0-3-05-6.{292. We .rlso thirnk our ro'ir.rvcrs is tl.re central part of the East-Europcan Province oî the G.\ù/cstcrnrrrnn ancl A.C. lìiccarclì for their r',rh-rrrblc coÌlulenrs. 344 V A. Zakharoa &. M. A. Rogoa REFERENCES Bogomolov Yu.I. & Dzyuba O.S. (1998) - Cephalopoda from ranean faunal elements and ammonire biosrratigraphy of the Kimmeridgian section of Lopsia river (Subarctic Ural). the Volgian staue Stratigraphy and correlation with Ti- In: Vyltzan I.A. (Ed.): Urgent questions of geology and thonian of the Lower Volgian of Russian platform. Àjz. geography of Siberia: 180-182, Tomsk. fin Russian] It. Paleont. Strat., 1,10:321-328, Milano. Bogoslovsky (1897) N.A. - Der Rjasan-Horizonr, seine Sahagirn D., Pinous O.V, Olfcriev A.G. & Z:rkharov V.A. Fauna, seine srratigraphischen Beziehungen und sein (1996) - Eustatic curve for rhe Middle Jurassic - Cre- wahrscheinliches Alter. Mater. Geol. Rzss. 1g: 1-15g., taceous based on Russian Platform and Siberian stratig- Sai nt-Petersbu rg. raphy: zonal resolution. AApG Bull., gO/9: 1433-145g, Douvillé R. (1 910) - lJn Virgatites du Caucase occidental; ori- New-York. gine méditerranéenne pseudo- de ce genre; Ataxioceras, Sachs VN., Basov VA., Dagys A.A., Dagys A.S., Zakharov VA., oirgatites erVirgatospbinctes. Bull. Soc. géol. France. Sér.4. et al. (t971) - Paleozoogeography of the seas of Boreal l8:730-739, Paris. Belt in theJurassic and Neocomian. In: Bogolepov K.V Gerasimov PA. (1955) Index - fossils of the Mesozoic of the (Ed.): Problenrs of general and regional geology: 179- central province of the European part of the USSR. 211, Novosibirsk. Iin Russian] Part 1. Y. oî zl+ pp., Gosroprekhizdat, Moscow. [in Scherzinger A. & Schweigert C. liefl; - Die Ammoniten- Russian] Faunenhorizonte der Neubure-Formation (Oberjura, Kelly S.R.A. (1990) Biostratigraphy - of the UpperJurassic and Sùdliche Frankenalb) and ihre Beziehungen zum Lower Cretaceous deposits of Europe on Buchias. In: Volgiunr. Mitt. Ba1,sr. Staatsslg. Palaont. hist. Geol., 39: Menner VV (Ed.): Jurassic-Cretaceous boundary: 129- 3-12, Mùnchen. 151, Moscow. Russian] [in Zakharov VA. ( 198 I ) - Buchiids and biostrarigraphv of the bo- Kemper E., Rawson PF. & ThieuloyJ.-P (1981) - Ammonites of real Upper Jurassic and Neocomian. Trans. Inst. Geol. Tethyan ancesrry in the early Lower Cretaceous of norrh- Geopbl's., 458 271, pp., Moscorv. [in Russian] west Europe. Palaeontologt, 24/2: 251-311, London. Zakharov VA. S{ Bosomolov YL (1998) - Climatic and facial Khimshiashvili N.G. (1989) - Berriasellids of the Caucasus. Ti- control in Late Volgian - Boreal Valanginian amnronires thonian fauna of the Lakorizi-Tau Mt. (Bsyb g6 basin). distriburion in rhe Northern Hemisphere. In: Olóriz F. pp., Tbilisi. Russian] [in (ed.): Cephalopods - present .nd p.rì, IV Intern. Symp., Rawson P.F. (1973) - Lower Cretaceous (Riasanian-Barremian) Granada, Júy l5-17, 1996. Abstracrs volume: 175-177, marine connections and cephalopod migrations between Granad:r. the Tethyan and Boreal realms. In: Casey pF. R., Rawson Zakharov VA., Kurushin N.I., Er Pokhialainen Vp (1996) - (Eds.): The Boreal Lower Creraceous. Geot. J. Spec, Is_ Paleobioeeographic criteria of terrane geodynamics of sue, 5: 13 1-1 44, London. Northeastern Asia in Mesozoic. Russian Geolog and Rogov M.A. (2002) Stratigraphy and correlation - wirh Titho- G eopbysics. 37 / 1 1: 1 -22, N.-Y. nian of the Lower Volgian plarform. of Russian Stratigra- Zeiss A. (1977) - Sonre ammonires of rhe Kletnice Beds (Up- Geol. Conelation, Pb,. lO/ 4: 348-364, Birmingham. per Tithonian) and remarks on correlation of the Up- Rogov M.A. (200a) The Russian Platform - as a key region for permosr Jurassic. Acta geol. Polonica., 27/3: j69-3g6, Volgian/Tithonian correlation: a review of the Mediter_ \larszawa.