acta geologica polonica
Vol. 25, No. 2 Warszawa 197&
KRZYSZTOF BIRKENMAJER & JERZY TRAMMER
Lower Triassic conodonts from Hornsund, South Spitsbergen
ABSTRACT: Lower Triassic {Dienerian) oonodont fauna determined from the' Myalina marker horizon of the Vardebukta Formation at Horns'Uud, Spitsbergen, includes: Ellisonia triassica Muller, Neospathodus dieneri Sweet, N. peculiaris Sweet and N. svalbardensis Trammer, sp. n. This is the first record of the Triassic conodonts from Svalbard. The age of the Vardebukta Formation at Horns'Und is determined as the Grdesbachian and Dienerian.
INTRODUCTION
During the PrdliSh 19'6.0 SpitSbergen Expedition (leader ProOf. S. Sie dlecki) K. Birke:nmajer eoNooted on the soUithern SIlope of Hyrnefjellet,. inner HornsWld, nUlIlle:rous frish remains (Birkerumajer 1964a, p. 14) in a thin interea,lation of fine-grained conglomerate of Lower Triassic age .. The samples were sent to Docenrt; A. Jerzmaitska (Wroclaw University) for reexamlnati,oo of the fish f'aJuna km,own already to Stensi6 (1918). Whd'J.e separating fish :sca1es and te€lth from the rock, she has a1so found. some conodorrts. These were handed 'Over to J. Tramm·er 'Wh'O is respon sible f'Or their palae OUTLINE OF GEOLOGY The Tri'a'SSic S€iC'tion between Hyrnefjell€lt and Treskelodden, inner' Hornsrund (Figs 1, 2), wals :investigaited by Birkenmaj-er (19519) and Bu-chan. & al. (19i65, Figs 2'O~21), and reexamined in 1974 by Bitkenmajer. Its lowest · Hthostra1tigraphicurut is the Vardehukta FormatU'Dn (Table 1). :300 KR'ZY,SiZ'l'OiF B1RK'ENMAJER & JERZY TRAMMER TORELL LAND 10, 20, lJJ km Fi'g. 1. Location of the COIIlOOOlIlt fauna (tmok dot) at Hyrnefjellet, Hornsund, in the maps of Svalbard (A) ' and Spitsbergen (B) restiJng tpa~acdnfoQll'tnl;a!bily (hiatus) upon the Upper Permian. brachioapod cherty limestone (Rapp Srtarostin Fomnatdon) of !j;he Kungurian ,to Ka zanian a1ge (Birkenmajer & Czarnieaki 19160; Birkenmajer 1964b - cf. Fig. 3). The Vardebukta Formation, 12'0-130 m thick, may be subdivided at Hornsund into the lower and upper members (Fig. 3), about 30 and 90-100 ID thick respectively. The ~dwer member begilllS wi:th grey to greenrlsh shaile, 24-26 IlIl thiclr, IWIith thin iInlterealations of similarly coloured siltstone to fine-grained sandstone, sometimes also with clay -irronstOiI1e noduies. There follows ,the MyaUna marker horizon, 5-6 m thick, which lConsiS:Vs 'Of grey pyritic-sideritic limestone and fine-grained sandstone ~ayers im !j;he lower part, passing upwaTd into grey sideritic or marly shale, and finaa'ly imo whitish sandstone and quartzite with Bub- LOWER TRIASSICCONlODo,NT1S FROM HOIRNSUND 301 Table 1 Subdivision of the Tviassic succession in SvalbaTd SPITSBERGEN' BARENTS91YA & I ISFJORDEN & BELLSUND EDGE~YA (Buchan & al.,1965) (Flood & al.,1971) De Geerdalen Mb. De Geerdalen Fm. Kapp Toscana Kapp Toscana Fm Tschermakfjellet Group Tschermakfjellet Mb. Mb. e. ~ IBotnehelO Fm ]i IBotneheia :::J _ C! 0 .~ ·1 ~, Mb. ~ 11101 ~ Ill,~lt------~ -§I . Kaosfjellet Mb. Sassendalen c rnlfli Sticky ~ Sticky Keep (\) Group c § 'I Keep Mb. 0 Mb. Cl Iskletten ~ '0 ~ Fm. c Cl Siksaken Mb. III III Vardebukta Vardebukta Fm. Cl lfl Fm. Selmaneset Mb. ordinate grey sideritic-pyritk limestone, If weathered, the rocks of the Myalina marker hori'zon heicome distinctly brown-red. Numerous burrows occur in the horizon, especially within the sandstone bands. Pelecypod moulds Ooour abundantly, 'especially in the bottom and top pa'rts 'Of the ho:rizon, with Myalina degeeri L'llIIlclgreln and Anodontophora :Sp. de termined f!'lom the bottom P&"!t of the horiz'on. An interealation of f;ine -gra.ined qu:arl:z ·conglomerate or cooTse-grained sandstone, dark-grey if fresh and brownish if weathered, 5-10 cm thi-ck, appears in the upper pad of the M1/O{Zii71.A mar&er horizon on the southern slope of Hyrnefjellet. From this conglomerate came fish teeth and scales ·co'ilected 'by Ho,e'l and R0vtiJg's Spi1lsibergen Expedition in 1917, determined by Stensi6 (1918) as: Hybodus sp., Acrodus spitzbergensis? Hulke, Acro lepis arctica? A. S. WoodtwalI"d and Gyrolepis? sp. 'The conodonts from the ,same hOTi'zo!Il illllClude: Ellisania triassica Miiller, Neospathodus dieneri Sweet, N. peculiaris Sweet and N. svalbardensis Trammer, sp. n. The upper member of the Varo.€bukta FormationconsiJsts of light -gTey 'to b}tack shale, marly shale and arena'cecms mad, altertlla,ti'll,g ' rwith th'in silltstOlll,e ofrt;,en fShorwing 'stmall..,scale tCurr,ent lami.nation and ripples. The si1'tstones are mOISt frequent in the low€r part of this tmember. There 'is :a Itra!IlSi:tion fl'Olm the VaJ'debukta Formation ;to the o;verly ing Sticky Keep Formation, the latter characterized by ;:tlternating bands of haTdcalcareoUlS -siltston€ tto silty limest'One and softer 'black to green ar€na'ceous OT argiTI.a,ceous shale. 302 K1RZYlSZ'I1OF BlR'KENMAJER & JERZY TRAMMER CONODONT FAUNA AND ITS AGE The following 'oonodonts hav,e been determined from the fish -bearing ,eonglomerate of the Myalina marker horizon (lower member of the Vardebukta F'Ormati'On): EHisonia triassica Muller, 1956, sensu Sweet, 1970 (LB elements); 7 speci- mens - P1. 1, Figs 1-3; Neospathodus dieneri Sweet, 1970; 5 specimens - P1. 1, Fig. 4; Neospathodus pecuUaris Sweet, 1970; 1 specimen - P1. 1, FUg. 8; Neospathodus sva~bardensis Trammer, sp. n .; 12 specimens - PI. 1, Figs 5-7; P1. 2, Figs 1-7. The species Neospathodus dieneri is an index form for the Dienerian stage and lower part of the SmiIthian stage 'Of the Lower Triassic 1 (Sweet & al. 197.1; KozUIr & MostleT 1972; McTavish 1973; Sweet 1973). N eospathodus peculiaris i'S known from the Griesbarchian IOf British Columbia {Mosher 1973) and from the Upper Dienerian of West Pakistan (Sweet 1970). The common oocurrence 'Of these two f'Orms determines the age of the fo.'Sh-bearing 'congl'Qlmerate ,of !the Myalina marker horiZion as Dienerian. It has 1110t beenpOlSSible to decide whether we deal here with the Lower (Candidus Z'One) or !the Upper Dienerian (Sverdrupi Zone), as 'zona~ indkes 'Were missilIlg, b1l't a Lower Diener.ian age of the oonodont assemblalge s,eems most probable (see below). AGE OF THE VARDEBUKTA FORMATION AT HORNSUND Buchan & at (19,65) determined the age of the Vardebukta Format ion in Spitsbergen as Lower Scythian, and the Stkky Keep Formation as Upper Scythian. The formation was subdivided between Isfjorden and Bellsund il111'O ,the l'Ower Selmaneset Member and the upper Siksaken Member (Table 1), but n'O subdivisi'On 'Of the formation has so far been proposed for the Hom'S/Und area. P'Oody fossildferous shales of the lower part of the SeImaneset Member yielded Claraia cf. staehei Birttner, ?Ophiceras sp. and Propty chites d. rosenkrantzi Spath (Frebold, in Hoel & Orvin 1937; Frebold. 1929; Bue-han & al. 1~65). The sandstones and shaly limestones of the upper part of the SeImaneset Member alIlti the Siksaken Member con tained a better preserved 'bivalve tfauna with Myalina degeeri Lundgren and Anodontophora breviformis Spath (Freb'Old 1939; Buchan & al. 1965). 1 Subdivision of the Lower Triassic (Scythian) after Tozer (1967). HYRNEFJ ElLET NW SE :WNW ESE: WSW ENE ., ,j/!--' to ~/ " ~ : ~!Il ,.-"1 I I .I~ / I , I ~ / I ~..,. n i ~ lA "!I lI:I /- / I ' / ~ I / '.' I CD ,/ CD " / //", 1 " \ L/lf :lOOm I I I § Fdg. 2. Position of the ,CQ[],odont faullla (asterisk) in the ·geological section of HY'I'nefjellet, HomsiIlllld (after Bi~menmajer, 1975) 1 Lowm' a~rbcm!.ferous: 2 Md'llldleCao."boniiferous: 3 Upper Cao."·bondferous and Lawer Permian (TreSkelodden Formation): 4 UpperPermdialn (~ staros tLn FarlllaltiJOIl1); 5 VIII/l" This fauna 'Ocours ,espedally in the Myalina shale of Lundgren (1887) whi~h ,correSiplonds to our Myalina marker hori'Wn at Hornsllnd, and was regarded as being of Lower Scythialll aJg.e .(Fr,ebold 1935, 1939, 1951). To,zer & Parker (19'68) determined the age of the Vardebukta Forma,tiOlll in Spitsberg.en as GrieSbaochian and Dienerian (Table 2). Finds of ammon-aids of the genus Otoceras (cf. Petrenko 1963 - fide Tozer & Pa.rker 19168; P,cheilillla 196,5), 'anti especially of Otoceras boreale Spath (Tmer & Parker 1968) art; the bare of the VaTdebukta Formation in central Spitsbergen are illldicative of Lower G:rrl.:asbachialll age {Bo.realis Zone). The ISIpecies Claraia stachei Bittm.er js indicative of the Griesba,ehian, probably Upper Griesba'chian, while Proptychites cl. rosenkrantZi Spath determined by Buchan & al. (1965), a,C'06rding to TOiZer & Parker (1968), HYRNEFJELLc T TRESKELEN S slope Creek IV z SOm :::!; I ...... Sticky Keep' ,', .. ' ...... i Formation ...... - VI ...... '0 -- -- z I Z ~S VI<{ ~i i:r u <{ ~6 Fig. 3. Lithological columns of the Vardebukta Formation in inner fI()rIlsund, and the positioo. of the conodont fauna 1 conglomerate; 2 clay .ilroOlIlStxme; 3 shaile, siW1;y shale:, ,maIl"J; 4 snlotslxme; 5 S3iIlidstOllle, quartzite; 6 siKrea"Jtic or sio1ty MmemOllle; 7 che<:'ty Iime$OIIle LOWER TRIASSl is either a Proptychites or Paranorites, probably of Upper Griesbachian or Dieneriam a.ge. The Dienerian age 'Of a higher part of 'the Vardebukta Forma Table 2 Stratigrarphic position of the Vardebukta Formation ~PjTS! ERGEN Sub- BARENTS0VA Series Stage Zone BELLSUND & HORNSUND I stage ISFJORDEN & EDGE0VA Tozer & Park er. I9SS: (this paper) (Flood & 01.,1971) I Subrobustus [ SPATHIAN i Pilaticus Sticky . Sti!=ky t u i Keep Keep Tardus I & - Formation Formation Sticky .... ' (j) I SMITHIAN 1!! (j) Rorronderi Keep a; I ;p « Member - Sverdrupi "' 0:: ! "'~ DIENERIAN ~ .... I Candidus ~ Vardebukta Vardebukta 0:: Strig(ltus Formation Formation w i UPPER ?; Commune Vardebukta 0 IGRIESBACHIAN Formation , -' Boreale LOWER , t Con cavum of Freb'Old wa'Spla~ed by 'them in rthe Griesbachian or rthe Dieneri:an~ above the Griesbaehiarn Claraia bed. Flood & 'at (1971) restdcted the age of the Vardebuk'ta Formation in Barentsaya and Edgeeya to the Griesbachian, a's, ·in Barentseya,. Claraia stachei B'irttneroocurred in the uppermost part 'Of the formation, . togerther with Ophiceras(?) sp. The oonadont falUna deteIilIl:i.ned, from the Myalina marke'r horizon at HO!I'll:SIUnd indkates ,the age of i1Js upper part as the Dienerian. The Griesbachiam age is thus \Suggesrted f'or 'the lawermost part of the Varde bukta Formation at Hornsund, ;represented by unfossiliferous shale with. silt5tone inteI'calations, underlying the Myalina marke;r horizon. The upper memlber of the Vartiebukta Formatian at Hornsund, above this horizan, would nalturaUy fall in'to a higher part ·af the Dienerian, as there is faumal evidence foOr Ithe Smitman and Spathian ages of the Sticky Keep' Formation elsewhere in Spitsberg'en (cf. Tozer & Parker 1968). :306 KRZYSZTOF BliR'KENMAJER & JEiRZY TRAMMER SYSTEMATIC DESCRIPTION Genus NEOSPATHODUS Mosher, 1968 Neospathodus svaZbardensis Trammer, Sip. n. I(PL 1, Figs 5-7; PI. 2, Figs 1-7) Hototype: The spec.i.men (pl'esetnited ID Pt 2, Figs la, b. Type horizon: V,a!l"ide·bukitla Flo!l"matdion, [Lower TrILass1c (nl~nerii'aill). Type tocaUty: Hy.rnefjeilllet" S sl'O(PE!, HOII1IliSUnd, 8p!itSberge.n (Svalb8Jrd ,ar.ehipelago). Derivatton of the name: svatbardensis - after Sva.:~rurd, the NQI"'Wegian name of' the SpitSbeTgen iBliands. Diagnosis. - Species of the genus Neospathodus with high even crest, without :posterior process. Main tooth thickest of all teeth, vertical or slightly oblique. The .remaining teeth equal in size, only 2-3 anterior teeth disUnctly smaller. Material. - 12 specimens. Desc1·iption. - Large, thick form with a pwminent lateral rib and straight basal margin.' Basal cavity medium sized, rectangular, with rounded angles, or drop -like; 7-12 . teeth fused, only their apices are free. Height of teeth similar, only 2-3 anterior teeth distinctly smaller than the others. Teeth usually vertical, but .sometJmes those dose to the main tooth are slightly tilted posteI'iorly. Teeth roundish or slightly laterally flattened in cross-section. Main tooth vertical or slightly oblique, usually distinctly thiclker than the other teeth. Remarks. - The species described differs from Neospathodus pakistanensis Sweet, 1970, and from N. novaehoZZandiae McTavish, 1973, i'n the lack of posterior process, the mode of teeth development and the proportions between them. The species N. conservativus (Muller, 1956) lis devoid of straight basal margin. Occurrence. - The species is known from the type locality only. Polish Academy of Sciences Institute of Geology Institute at Geology of the Warsaw University Senacka 3, 31-002 Cracow, Poland 'Al. Zwirki i Wigury 93, 02-089 Warsaw, Poland (K. Birkenmajer) (J. Trammer) REFERENCES BIRKENMAJER K. 1959. Report on the geological investigations of the Hornsund area, Vestspitsbergen, in 1'9100. Pt. II: The post-Caledonian succ6&sion. - Bull. Acad. Polon. Sci., ser. Sci. Chim. Geol. Geogr., 7 (3), 191-196. Varsovie. 1964a. CoU!'se of the geological investigations of the Hornsund area, Vestspits bergen, in 1959 and 1960. - Stud.ia Geol. Polon;, 11, 7-21. Warszawa. 1964Jb. Devoni'aI!l, Carboniiferous aI!ld Partmian formations ,of Hornsund, Vest spits,bergen. - Studia Geol. Polon., 11, 47-123. Warszawa. 19715. J'Uras'sic and Lower Cretaceous semmentalt"y formations of SW TorelI Land, Spitsbergen. - Studia Geol. Polon., 44, 7-44. Warszawa. LOWER TRIASSI.C CONODONT,S FROM HORNSUND 307 . BIRKENMAJER K. & CZARNIECKI S. 1960. Strafiigraphy of mario:J.e Carl:xlniferous and Permiam. deposits in Hornsund (Vestsp;itsbergen), 'based on brachiopods. Bull. Acad.' P%n. Sci., SeT. Sd. Geol., .Geogr., 8 (3),203-209. Varsovie. BUCHAN S. H., CHALLINOR A.; HARLAND W. B. & PARKER J. R. 19'65. The ~ria&slc stratigraphy of Svalbarct ·...".. IVorsk Polarinst. Skr., 135, 1-93. Oslo. FLOOD B., NAGY J. & WINSNEST. S. 1971. The Triassic succession of Barents",y~, Edge0ya, .and. Hopen (Svalbard).· - Norsk Polarinst. Medd., 100, 1-.20. Oslo. F:REBOLD H. 1£2'1). Untersuchungen liber die Fauna, die StraJ;igraphie und Palao geograJPhie der Trias. Spitzioorgens. - Skr. Svalb. og Ishavet, 26, 1-66. Oslo. 1935. G:eologie von SpitZlbergen, der Bareninsel, des Konig Karl- und Frlmz ..' -,Joseph,.Lanp.es. - Geol. d. Erde (Herausg. van E. Krenkel). Borntraeger Verl. Berlin, 1-U'5 pp. . . 1939 .. Das Festungsprmil auf Spitzbergen. V: Stratigraphie und Invertebraten fauna.der alter en Eotrias. - Skr. Svalb. og Ishavet, 77, 1-58. Oslo . . . 1951. Geologie des .aarents~chelfes. - Abh. Akad. Wiss. Berlin, Jg. 1950, No; 5, 1-,.150. B.erlin .. HOEL A. & ORVIN A. K. 1937. Das FesJtungsp.!'ofil auf' Spitzbergm, .Karbon-Kw1de. I: Vermessungsresultate. - Skr. Svalb. og Ishavet, 18, 1-59. Oslo. KOZUR H. & MOSTLER H. 1972. Die Bedeutung . der Oonodonten filr stratigra .phische und palageographische Untersuchungen in der Trias. - Mitt. Ges. Geol. Bergbaustud., 21, 777-810:·'tooslbiuck. McTAVISH R. A. 1973. Triassk conodonrt; faunas from Western Australia. - N. Jb. Geol. Paliiont., Abh., 143 (3), 2715-303. Stuttgai"t. MOSHER L. C. 1973. Triass1-c conodonts from British Columbia and the Northern Arctic Islands. - Geol. Surv. Can. Bull., 222, 141--,192. Ottawa. PCHELINA T. M. H135. Mezorojske otlOlZhenija rajona Van-Keulenfjorda (Zapadnyj Shpitsbergen). - Mat. po Geol. Shpitsbergena (Red. V. N. Sokolov). Nauch. -Issled. Imst. Geol. Arktiki, 1~173. Leningrad. STENSI6 A. E. 1918. Notes 0tIl S>QIIIle msh remains collected at Hornsund by the Nor wegian Spitzbergoen Expedition in 1917. - Norsk Geol. Tidsskr., 5, 7'5-73. Kristiania. SWEET W. C. 1970. Uppermost Permian and Lower Triassic conodonts of the Salt Ran,ge and Trans-Indus Ranges, Wesrt; Paldstan. In: B. KUMMEL & C. TEI CHERT (Eds), Sllratigraphic boundary problems: Permian and Triassic of West Pakistan. - Univ. Kansas Dept. Geol. Spec. Pub I., 4, 207--.2715,. Lawrence. 1973. Late Permian and Early TlI"iassic ()OIIl()dont fau,nas. In: A. LOGAN & L. V. HILLS (Eds), The Permian and Triassic Systems and their mutual boun dary. - Can. Soc. Petrol. Geol., Spec. Publ., Vol. 2, 639-646. Ottawa. SWEET W. C., MOSHER L. C., CLARK D. L., COLLINSON J. W. & HASENMUEL LER W. A. 1971. Conodont biostratigraphy of the Triassic. In: W. C. SWEET & S. M. BERGSTR6M(Eds)., Symposium on condont biostratigraphy. - Geo/. Soc. Am., Mem., 127, 4141-400. Boulder. TOZER E. T. 1967. A standard fOIl" Triassic time. - Geol. Surv. Can. Bull., 156, 1---,103. Ottawa. TOZER E. T. & PARKER J. R. 1968. Notes on the Th:-iassic biostratiglI"aphy od' Sval· bard. - Geoi. Mag., 105 (6), 526--541. Hertford. 308 KRZYSZTOF BIRKENMAJER 8. JE·RZY TRAMMER K.BIRKENMAJER i J. TRAMMER DOLNOTRIASOWE KONODONTY Z FIORDU HORNSUND NA SPITSBERGENIE (Streszczenie) W drobnoziarnistym zlepiencu poziomu z MyaUna dolnotriasowej' formacji z Vardebukta we fiord:Die Horlllsund (poludniowy Spitsbergen), stwierdzono wyst'i powarnie na'St~pujqcych konodontow: Ellisonia triassica MUller, Neospathodus die neri Sweet, N. peculiaris Sweet oraz nowej formy oznac'zonej jako Neospathodus . svalbardensis Trammer, sp.. Ill. Jest to ptierwsze stwierdzen1ie wyst~powalIl!ia kiono dontow w triasowych utworach archipelagu Svalbard. W pracy 'l'ozwaumo takze pozycj~ stratygrafiCZlllq formacji z Vardebukta we fiordzie Hornsund i pr:reprowa drono dyskusj~ wieku tej fO!l."macji, ktory okreslono na Griesbachian i Dienerian, z tym ze poziom ' z Myalina zawierajqcy konodonty okrealono jako dolny Dien.erian, W cz~sci systematycznej opiosane nowy gatunek konodonta, Neospathodus svalba1' densis Trammer, sp, n·, ACTA GEOOLOGICA POLONiCA, VOL. 25 K . B.FRKElNMAJER & J . TRAMMER, PLo t Lower Triassic (Dienerian) conodonts from the Vardebukta Formation at Horn~ und . Spits'bergen 1,2, 3 - Eltisonta triasstca Mt1IJler, 1956, sensu.Sweet, 1970 (LB elemen~) 4 - Neospathodus dieneri Sweet, ~970 5,6,7 - NeospathodUB svalbardensis Tra.mmer, sp. n. 8 - Neospathodus pecultaris SWeet, 1970 All .photos X 100; taken by .L. Luszezew~ka, M. Se. AC'DA GEOILOGICA POLONICA, VOL. 25 Ko HIlRKIDNMAJER & J . TRAMMER, PLo 2 Lower Triass:ic (Dienerian) conodonts fT·om the Vardebukta Formation at Hormmnd, Spitsberg,en 1-7 - Neospathodus svatoardensis Tra'mmer, <.W. n.; la, b - presents the hOolatype (la side v.iew , 10 ,tqp Vliew) All photos X 100; taken by L. :t.usxczewska, M. Se.