Ne\T Hettangian Ammonite Faunas and a Triassic Jurassic Boundary Succession, Fernie Formation, \Nlliston Lake

Rivista Italiana di Paleonrologia e Srrarigrafia volume I l0 no. I 2 pls. pp. 53-60 April 2004

NE\T HETTANGIAN AMMONITE FAUNAS AND A TRIASSIC JURASSIC BOUNDARY SUCCESSION, FERNIE FORMATION, \NLLISTON LAKE. BRITISH COLUMBIA

RUSSELL HALL & SIMONA PITARU

Receioed September 19, 2002: accepted September 30,2003

Key uords: Ammonites, Biostratigraphy, British Columbia, z.ioni contenenti la maggior parte delle ammoniti. Le faune nnvenure Fernie Formation, Hettanqian, Pardonet Formation, Rhaeti;rn, Trias- sono riferibili all'Hettangiano e le associazioni differiscono un poco da sic-Jur;rssic boundary. quelle delle Queen Charlorte Islands e del Nevada. Si rratta della pri- ma documentazione, nella Fernie Formation, di una estesa successione Abstract. A relatively new shoreline section on Peirce Reach, Hettangian.r contenente .rmmoniti. Villiston I-ake, north-eastern British Columbia, provides conrinuous lJ Hettangiano inferiore è rappresentato da esemplari scarsamen- exposure through a Triassic-Jurassic boundary succession, with apparent te preservati di Psilocerus majus, P. plicatun, P. cf. rectocostatum, P cf. srratisraphic conrinuir)' from the Pardonet Fornrrtion (Upper Norian) Pl,lnocost.ttum che sono presenti in rutta la parte inferiore della sez-io- into the ovcrlying Fernie Formation (Hettangian and younger). These ne. Successivamente si registra la conrparsa diWaehnerocerai seguito da rocks are part of autochthonous North America, deposited along the Sunrisites sunrisense e le prrme Scblotheima che documentano I'Hettan- giano queste western nrargin of the Jurassrc craton. medio. Con faune è associato un solo individuo di grandi The section at Black Bear Ridge consists of 22 m of flaggy-bed- dimensioni di Alsatites liasicus. Al di sopra compaiono diverse specie ded, brown-weathering siltstones :rnd several thick, resistant siltstones, di Schlotheimia (5. angulata, S. angulata densicostata, S. cf. oxl,gonia), and contains calcareous concrerions which have yielded most of the Kamnerkarites friga and Laqueocerds sp. che indicano la parte inferiore thrce-dimensicnal anrmonites. V/hile it is clear these anrmonites rep- dell'Hettangiano superiore. La parte superiore dell'Hettangiano è docu- resent parts of the lower, middle and upper Hettangian, rhe sequence of mentata rl tetto della sezione dalla presenz a di Badouxia ( B. canadensis, B. striata, B. oregonensis) e Pseudaetontoceras doetzkirchneri. faunas differs somewhat from those reported fronr the Queen Charlotte Islands and Nevada. This is the first record of an exrensive sequence of Hettan{Ìian strata and :rnrmonite faunas in the Fernie Formatron. Lower Hettangian faun,rs include poorly presen ed, laterally flat- Introduction rened Psiloceras (P ntajus, P plicatum, P. cf. rectocost.ttunt, P. cf. plano- costatunt), occurring throughout the lower part of the section fronr The in the outcrop the Foothills 3.0 to 8.3 nr. At 9.5 nt Waehnerocerar Jppeîrs, represenring the middle Jurassic belt of Hettangian, followed by Sunrisites sunrisense at 10.8 m. and the first and Front Ranges, Canadian Rocky Mountains, of west- Schlotheinia at 13.3 m. A single large specimen of Akatites liasicus is ern Alberta and north-eastern and south-eastern British associated with these faunas. Beds above 13.3 m yield several species Columbia (B.C.) is largely represented by the Fernie For- of Schlotheimia (5. angulata, S. angulata densicostata, S. c[. ol,gonia), mation. The lower contact is an unconformity of regional Kanmerbarìtes friga and Laqueoccras sp., indicatine the lower parts of extent: it overlies upper Palaeozoic the upper Hettangian. Uppernrost Hettangian faunas occur îr rhr' îop or Triassic strata with of the exposed section in beds from 21.0 ro 21.7 m, and include Ba- a considerable hiatus, the lowermost Jurassic strata being douxia (8. canadensis, B. striata, B. oregonensis) and Pseudaetonoceras Sinemurian, but more commonly Pliensbachian or even doetzkirclneri. Toarcian, in age (Hall 1984, 1987, Poulton er al. 1994). Hettangian ammonites were first reporred from outcrop Riassunto. Unir sezione rel;rtivamente nuor':r lunto la linea di costr di Peace Re;rch, Lago di Villiston, British Columbir nordorien- by Tozer (1982) at Black Bear Ridge in north-eastern tale, fornisce unl esposizione continua di una successione che contie- B.C., a relatively neq/ exposure produced by shoreline ne il limite Triassico-Giurassico con evidente conrinuità strîrigr:rfica erosion along Villiston Lake (Fig. t). This body of wa- dalla Pardonet Forrlttion del Norico Superiore alla sovr;rstante Iie rnie teq formed behind the !(A.C. Bennett dam when it was Fornration dell' Hettangiano. Queste roccc fanno parte dell'autocto- Peace no nordanrericano che si è depositato lungo il margine occidentale del completed on the River tn 1967, submerged previ- cratone Giurassico. L;r sezione di Black Bear Ridge è costiruita d;i una ously-known river level outcrops of Jurassic strata at Ne- Dotente succcssione di siltiti anche debolnrcnte stratificate con concrc- parle-pas rapids to depths of nearly 100 m.

Geology & Geophysics, U n iversity of Calgarl', Calg:rr1', Alberta, Canada T2N I N4. E-nrail: hallr(ii ucalg1ry,.6x )4 R. Hall Et S. Pítaru

oreo of mop obove

mop loken from Holfwoy River V Voncouver 'l:250 000 topogrophic mopsheet C Colgory

Fio I Map showinu location of Black Bear Ridgc section orr the north shorc'of Villiston l.;rke (Peace Reach) in north-castern British Colunr- bir, rpproxim;rtel1, 50 knr l'est of the \XlA.C. Bennett dr:r,.rt *rid reiercnce 975 155 on Mount Brervster l:50 OOO topogrephic m,rp- sheet (123' 2'23" \( 56'5'49" N). Other e\posurcs of a Triassìc-Jurassic bounderv succcssion llso occur;rt P;rrdonet Creek ;rnd Ne- parle-pas Point.

At Black Bear Ridge Tozer (1,982) reported Juras- Geological setting sic ammonites from three levels in the lower Fernie For- The lower and middle parts of the Fernie Forma- mation, 7.5 to 9 m above the Monotis Beds which con-r- tion consist lareely dark prise the top of the Upper Norian Pardonet Forn.ration. of shales, with minor sandstones, siltstones, and black linrestones, and represenr the upper- He described and illustrated a single, large specin-ren of most (Hettangian Psiloceras (Parapbylloceras) calliphyllum, but the addi- part to Callovian) of a passive nrargin sequence which had been accumulatins alone the western tional material was not studied. That material has been margin the An.rerican generously rnade available to us and is included in this of North craton since Proterozo- ic time. The source clastic study. Tozer also briefly discussed several other locali- of sediments comprising the lower and middle Fernie was ties along the shores of Viiliston Lake, and to the north Formation to the east on the craton, but by the Late (represented and south of the lake, at which Triassic-Jurassic bound- Jurassic in the Passage Beds the upper Fernie ary sequences are exposed; faunas from these localities of Formation) this direc- tion had been reversed. Accretion rer- are not discussed further in this paper. Our collections of ;rllochthonous ranes along the western margin the craton resulted in from the section at Black Bear Ridge, made in the spring of magmatic activit,v, thrusting, and st;rcking overthrust field seasons of 1999,2000, and 2001, now number ap- of belts to produce crustal loading zrnd initi;rtion of rr fore- proximately 300 an-rmonite specimens, and another 150 deep east of the deformed belt. in the ammonite fragments. In this paper we summarize the Uplift Cordilleran regions to the west provided 11 new sedir.r-rent taxonomy and stratigraphic distributions of these am- source of (Poulton et al. 1994). monites, comment on their ages and likely correlation with already-established Hettangian zonations, and il- lustr;1te selected key taxa. Detailed descrip- taxonomic Triassic-Jurassic boundary succession tions and illustrations will appear elsewhere; once this study is completed the permanent reposrrory for this The uppermost 30 m of the Pardonet Formation material will be the Geoloeical Survev of Canada col- consist of distinctive, crenulated beds produced by dense lections in Ottawa. coquinas of Monotis subcircularis,with rare limestone con- Artnorttte faunas from Britisb Colunbia 55

ffi ltbrouscillcltcbcd J__ ! ! .,..J.,. L^ SlCAreoUS 5lllSlr)lìe ! ., ! € =--....-... Jnal)'slltslonc^. E È : ! I ! Pd. - Pardonct Fornration ì v p È No. - Norian ì ! c S I v I ! { s 1 p q 3 a s s s ì È { à à È q 4 v) ,à q .t a ...J....J....J. I ttl 2l rn I I I I

20 nr

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16m

15 rn .._1....J....J 14 nr

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o 5nr T .J....J....J :l ttl nr

3nr 2m- ---+ Conodonts è. lml

Our - Z - + Monoti.s beds

lr;,, Measured section of the Los e r l;e rnie Fornt;rtion .rt Bhck Beer Ridge, r'ith strrìtigrrphic r,rnscs of all identified Hcrrirngjxn amnronite spccics. l)rtunl (0 nr) is the topnrost surf,rce ol tlrc '1loriotis bc'ds.

cretions containinc the ammonords Paraguembelites and by 3 rn of poorly fossiliferous, brown-weathering, flaggy- Lissonites (Cordilleranus Zone) and the conodonts Epi- bedded, fine siltstones below the first identifiable Hettan- go n do I e I la b i d en t ata an d lr,[ or i go n tl o le I la s t e i n b erge n s i s (Bi - eian (LowerJurassic) ammonites (Fig. 2). The topmost dentata Zone) (Orchard et al. 2OO1a, b). bed of the Monotìs beds is verv resistant and provides a The so-called Monotis beds are conformablv overlain distinctive marker bed used as the drtum in this study; 56 R. Hall k S. Pitaru

above this level Monotis is almost completely absent, ex- Psiloceras plicatum (Quenstedt) (Pl. 1, fig. 2) occurs between cept for an impression in a concrerion 1.5 m above datum. 6.5 and 7 .3 m, associated with numerous ? Kammerharites sp.; this fauna is correlated with the lower part of the Polymorphum Zone of Norrh Orchard et al. (2001a, p. 7) reported a few large conodont America. elements resembling Epigondolella mosheri and also E. ex At 8.3 m Psiloceras cf. rectocostlrtum Hillebrandt occurs with 2 gr. bidentata from a limestone concrerion "sitting direct- (Paraphylloceras) calliphyllum (Neumayr), which was described and il- ly above the last bedding surface of Monotis". They sug- lustrated by Tozer (1982), and this level is correlated wirh the upper gested this association might indicate the presence of the part of the Polymorphum Zone of North America and the Rectocos- tatum Zone of South America. Several species of Neoadapbyllites (N. Rhaetian Amoenum Zone. The extent of Rhaetian strata compressus, N. cf. microumbilicatus) occur ar this level. preserved in the Triassic-Jurassic boundary succession exposed at Black Bear Ridge has recently become an issue Middle Hettangian faunas in precisely dating and interpreting the significance of Taylor et al. (2001) reported occurrences of 6oth Waehnerocer- as carbon- and nitrogen-isotopic excursions measured there and Caloceras in the uppermost part of their Polymorphum Zone, though it was noted that the upper parr of the range of C. crassicos- (Sephton et aL.2002; Hall & Pitaru 2003). tdtum Guex mav have been removed at an erosional unconformity. At Interbedded with the ilaggy siltstones at 0.8 m and Black Bear Ridge the first occurrence of Waehnerocera,s is at 9.5 m, 0.9 m above datum are rwo fibrous, crystalline calcite well above the lasr Psiloceras (at 8.3 m). The middle part of our sec- beds ("beef") which Tozer (1982) and Stott (1998) ten- tion, corresponding broadly to the srandard Liasicus Zone, is dominated by schlotheimiids. tatively suggested marked the base of the Fernie Forma- Beds fron, 9.5-1A.7 m contain Waehneroceras bircìnun (Quen- tion; however, there are no significant lithological differ- stedt), with highly compressed whorls ornamented by heavy, strongly ences in the bedded siltstones below and above these two sinuous, unbranching ribs which increase in height approaching the beds which would warranr formational differentiarion. venter, where they reach maximum height, and are projected forward At 1.5 m and 1..7 m above datum are rwo thin calcareous over the venter (forming an angle of 150") but are not interrupted; this gives the venter a crenulated appearance in lateral view (Pl. l, figs.3 beds from which fragmented conodonr elemenrs of Epi- 4b). Nevadaphyllites cf. microumbilicatus Taylor and one small speci- gondolella sp. have been recovered (C. Henderson pers. men of Togaticeras togatum (Neumayr) are associated with W. hircinum comm.). The first identifiable LowerJurassic ammonites at 9.5 m, andW cf. portlocÈi (Vright) appears near the top of the range occur 3.0 m above datum, but again there is no lithologi- of the latter raxon, xr i0.7 m. This species has very srrong, sharp ribs cal change warranting recognition of a new formarion at which are only slightly sigmoidal, attain maximum heighr on the ventral margins, but are then abruptly interrupted to leave a this level. Placement of the Pardonet/Fernie formation smooth band along the venter, at least on juvenile whorls (Pl. 1, figs. Z a,b). boundary in this section remains unresolved. At lO.8 m Waehneroceras cf.ponlocki and other specifically inde- terminate specimens belonging to this genus are associated with numerous small specimens of Sunrisites sunrìsense Guex, and at 10.9 m, a sin- Hettangian strata and ammonite faunas gle, large specim en o[ Akatites liasiczs (d'Orbigny). Sunrisites sunrisense, which ranges up to 11.8 m, is evolute, with round to slightly depressed Above the top of the Monotis beds are just over whorl cross-sections, and blunt, heary', evenly-spaced and slightly con- 22 m of flaggy- to massively-bedded, brown and yellow- cave ribs which fade near mid-flank leaving a smooth, broadly-rounded venter crossed only by abundant fine striae which occur on and between ish-weathering, fine-grained siltstones containing cal- the ribs on the flanks and then project forward over the venter (Pl. 1, careous concretions up 0.8 m diamerer. to in The am- figs. 6 a,b). The many-whorled, serpenticone specimen of A. Iiasicushas monites found in this sequence indicate the presence of a relative umbilical diameter of 70"/o, and dense (36-44 per half-whorl), lower, middle and upper Hettangian strata (Fig. 2); most strong, concave, and evenly-spaced ribs (Pl. t, fig. 5). of the three-dimensional ammonites are found in concretions, with lateral impressions occurring less frequently on bedding plane surfaces of the siltstones. \lhile most specimens throughout this section are of very small size, usually less than 6 cm in diameter, one complete ammonite and several body chamber fragments indicate that some shells exceeded 30 cm in diameter. Where possi- ble, in the following faunal descriptions our ammonire associations are correlated wirh the zonal scheme for the Hettansian of the western Cordilleran regions of Nonh

America proposed by Taylor et al. (2001 ) . PLATE 1 Lower and middle Hettangian ammonites from Black Bear Ridge. Lower Hettangian faunas All specimens reproduced at natural size except where otherwise in- The first Psiloceras, strongly rrbbed Psiloceras zaTzs (Neumayr), dicated. was found at 3.0 m, just 1.3 m above rhe uppermosr conodont-bear- lie. 1 - Psiloceras cf . planocostatzm Hillebrandt from 4.05 m; Fig. 2 - ing bed (Fig. 2). At 4.5 m this species is associated wirh c[. plano- P Psìloceras plicatzz (Quenstedt) Írom 7.3 m; Fig. 3a,b - Waehneroceras costatum Hillebrandt (Pl. 1, fig. 1) and these beds are correlated with hircinum (Quenstedt) from lO.O m; Fis.4a,b -Waehneroceras subangu- the Planocostatum Subzone of South America 2OOO); (Hillebrandt the lare (Oppel), x 2, from 13.3 m; Fig. 5 - Akatites liasicus (d'Orbrgny),x first costate species in the zonal scheme proposed for North America 0.8 fronr 10.9 m; Fie. 6a,b - Sunrisites sunrisense Guex, x 2, from 11.8 occur in the PolymorphumZone (Taylor et al. 2001). m.; Fig. Za,b - l(/aebneroceras cf. portlochi $fright), x 2, from 10.5 m.

58 K. Hall (l 5. l'ttaru

Schlotheimia angulata (Schlotheim), S. angulata densicostata as, and Franziceras. These absences may reflect the more Lange, and S. cf. oxVgonia Lange occurwithWaehneroceras subangulare northerly location of the Black Bear Ridge section com- (Oppel) (Pl. 1, figs. 4 a,b) and a single, small specimen of Kammerkar- pared to Nevada, which was some 2000 km farther south ites friga (\Waehner) at 13.3 m. ScbLotheimia angulata (Pl. 2, figs. 5 a,b) has strong, unbranched, proverse ribs which reach maximum heighr on along the Jurassic cratonic margin, and the Queen Char- the ventral margins, and form an angle of 90" on the venter rvhere they lotte Islands (Tipper tr Guex 1994) which, as part of the flatten or fade to produce a pseudo-groove along the venter. Scblothe- accreted $frangellia Terrane, were also at least that far imia angulata densicostata differs in having slightly more numerous ribs south in EarlyJurassic time (Smith & Tipper 1986). (19-20 vs. 15-16 per half-whorl at the same diameter) u.hich meet in a slightly larger angle on the venter (Pl. 2, figs. 4 4b).'ilaehneroceras swbangulare has evenly-spaced, unbranched ribs, mostly concave, with Acknozoledgemenrs. 'il/e thank Drs. John-Paul Zonneveld (Geo- only the slightest sinuosity and arching forward on the venter where logical Survey of Canada) and Charles Henderson (University of Cal- they are flattened and broaden, but are not interrupted (Pl. I, figs. 4 gary) for suggesting we investigate the exposures of the Fernie For- a,b). The highest schlotheimiids occur at 14.5 m. mation at Black Bear Ridge, and for their assistance, along with Dr. M. Orchard (Geological Survey of Canada), in arranging field parties and Upper Hettangian faunas transportation during three visits to the locality. Dr. E.Tozer (Geologi- Above an unfossiliferous interval between 14.5 and I 8.0 m, up- cal Survey of Canada) very generously provided information on field per Hettangian ammonites appear in abundance: firsr Laqueoceras (Pl. localities and made available his earlier collections for inclusion in this 2,fig.3), then ar 21.0 nt Badouxia and Pseudaetomoceras,tnd these beds study. Helpful comments from G. Warrington and J. Pólfy enabled us are correlated with the Peruvianus through lower Canadensis zones of to clarify and improve this contribution. South America and the Oregonensis to Canadensis zones of North America (generally equivalent to the standard Angulata Zone of north- west Europe). Associations at this level offer the firmest correlations, both with other North American successions as well as those in South America. The inner whorls of Badouxia striata Guex (Pl. 2, fig. 1) have blunt ribs which fade on the flanks and, during ontoseny, are replaced by sinuous striae; specimens of B. canadensis (Frebold), which appears a littfe higher, a,nd B. oregonensls Taylor are all very small and with their outer preserved whorls crushed. The associated Pseudaetomoceras doetzkirchneri (Guembel) is an evolute, highly compressed form with strong, heavy ribs which are straight on the lower flanks, then become sickle- shaped, with marked forward projection on the upper two-thirds of the flanks; a sharp, narrow keel is present (PI.2, fig.2).

Comparisons with other Hettangian ammonite sequences from western North America

So far at this locality, no specimens have been found of smooth species of Psiloceras, such as P tilman- ni and P pacificwm, which characrerrze lowermost Het- tangian strata in Nevada (Taylor et al. 2001) and South America (Hillebrandt 2000). While the schlotheimiid-bearing beds 6.3 m to 14.5 m above datum are correlated with the interval represented by the Polymorphum, Mulleri, Occidentalis, Coro- noides and lower Pleuroacanthitoides zones of Taylor et al.'s (2001) zonal scheme, more detailed correlations are

difficult. The occurren ce of ? Kammerbarites sp. with psi- loceratids would represent a lower occurrence than eise- where in North America (generaily lower middle Het- tangian) if our generic assignment ìs confirmed. The association of ?Kammerkarites with Discamphiceras at7.2 m suggests a correlation of this part of the succession with the lowest interval faunas recorded by Pilfy er al. (1999) in the Alaska Peninsula (Ewphyllites-Franziceras beds). PLATE 2 Hettangian faunas are dominated by Our middle Upper Hettangian ammonites from Black Bear Ridge. All specimens 'Waehneroceras species of and Schlotbeimia which are less reproduced at natural size except where otherwise indicated. common in some other western North American faunas. Fig,. 1 - Badouxia oregonensis Taylor, x 2, from 2l .0 m; Fig. 2 - Pseuda- Conversely, some genera which occur elsewhere are ab- etomoceras doetzhirchnerì (Guembel), x 2, from 21.7 m; Fig. 3 - Laque- ocerds sp., from 18.0 m; Fig. 4a,b - Schlotheimia angukta densicostata sent at Black Bear Ridge, specifically Pleuroacanthites, Eu- Lange, x 2, from 13.3 m; Fig. 5a,b - Schlotheimia angulata (Schlothe- p u F s o n s, An lati c era s, E o ly t o c hy llite s, M ll erite s, ergu ite gu er- rm), x J, trom lJ.J nl.

60 R. Hall 8t S. Pitaru

REFERENCES

Hall R.L. (1984) - Lithostratigraphy and biostratigraphy of the Poulton T.P, ChristopherJ.E., Hayes BJ.R., LosertJ., Tittemore Fernie Formation, Canadian Rocky Mountains. In: Stott J., Er Gilchrist R.D. (1994) -Jurassic and lowermost Cre- D.F. t{ Glass D. (eds.). The Mesozoic of Middle North taceous strata of the Western Canada Sedimentary Basin. America. Can. Soc. Petr. Geol., Memoir 9,233-248, Calgary. In: Mossop G. & Shetsen I. (compilers). Geological Atias Hall R.L. (1987) - New LowerJurassic ammonite faunas from of the'ùlestern Canada Sedimentary Basin. Canc. Soc. Petr. the Fernie Formation, southern Canadian Rocky Moun- GeoL. & Alberta Res, Cownc.,297-316, Calgary. tains. Can. Journ. Eartb Sci.,24:1688-1704, Ottawa. Sephton M.A., Amor K., Franchi LA., Vignall PB., Newton R., Hall R.L. & Pitaru S. (2003) - Carbon and nitrogen isotope dis- & Zonneveld J . P. (2002) - Carbon and nitrogen isotope turbances and an end-Norian (Late Triassic) extinction disturbances and an end-Norian (Late Triassic) extinc- event. CommenÍ. Geolog) Forunt, c 24-25 Boulder. tion event. Geologt,30: lllg-l122, Boulder. Hillebrandt A. von. (2000) - Die Ammoniten-Fauna des Smith PL. Ec Tipper H.\( (1986) - Plate tectonics and paleo- sùdamerikanischen Hettangian (basalerJura). Teil I, II, biogeography. Early Jurassic (Pliensbachian) endemism IIl. Palaeontograpbica Abt. A, 258: l-116, Stuttgart. and diversity. Palaios, l: 399 -412, Tulsa. Orchard M.J., McRoberts C.A., Tozer E.T., Johns M.J., Stott D.F. (1998) - Fernie Formation and Minnes Group (Juras- Sandy M.R., & ShanerJ.S. (2001a) - An intercalibrated sic and lowermost Cretaceous), northern Rocky Moun- biostratigraphy of the Upper Triassic of Black Bear Ridge, tain Foothills, Alberta and British Columbia. Geol, Suru. Villiston Lake, northeast British Columbia. Geol. Sut'u. Canada BuLl., 516:1-516, Ottawa. Can., Current Àes., 4,6: 1-21, Ottawa. Taylor, D.G., Guex, J., & Rakus, M. (2001) - Hettangian and Orchard M.J., Zonneveld J.-P, Johns M.J., McRoberts C.A., Sinemurian ammonoid zonation for the western Cordil- Sandy M.R., Tozer E.T., & Carrelli, G. G. (2001b) - Fos- lera of North America. Bull. Soc. Vawd. Sc. Nat., 87 (4): sil succession and sequence stratigraphy of the Upper 381 -421 , Lausanne. Triassic of Black Bear Ridge, northeast British Colum- Tipper, H.\W & Guex,J. (1994) - Preliminary remarks on the Het- bia, a GSSP prospect for the Carnian-Norian boundary. tangian ammonite succession in the Queen Charlotte Is- Albertiana, 25: 10-22, Utrecht. lands, British Columbia. Geobios, 17 485-492,Yilleurbanne. PillyJ., Smith PL., MortensenJ.K., Er Friedman R.M. (1999) - Tozer E.T. (1982) - Late Triassic (Upper Norian) and earliest Integrated ammonite biochronology and U-Pb geochro- Jurassic (Hettangian) rocks and ammonoid faunas, Half- nometry from a basal Jurassic section in Alaska. Geo/. way River area and Pine Pass map areas, British Columbia. Soc. Amer. Bull.,l11: 1537-1549, Boulder. Geol. Swru. Canada Pap.,82 (1A): 385-391, Ottawa.