ZOBODAT - www.zobodat.at

Zoologisch-Botanische Datenbank/Zoological-Botanical Database

Digitale Literatur/Digital Literature

Zeitschrift/Journal: Beiträge zur Paläontologie

Jahr/Year: 2005

Band/Volume: 29

Autor(en)/Author(s): Lukeneder Alexander

Artikel/Article: An Early Cretaceous Ammonoid Association from Upper Austria (Late Valanginian, Northern Calcareous Alps) 1-13 ©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien Beitr. Paläont., 29:1-13, Wien 2005

An Early Cretaceous Ammonoid Association from Upper Austria (Late Valanginian, Northern Calcareous Alps)

by

Alexander L ukeneder * **

Lukeneder , A., 2005. An Early Cretaceous Ammonoid Association from Upper Austria (Late Valanginian, Northern Calcareous Alps). — Beitr. Palaont., 29:1-13, Wien.

Abstract Die Ammonoideen Fauna beinhaltet 7 verschiedene Gat­ tungen, von welchen jede durch mindestens 1-2 Arten Early Cretaceous ammonoids were collected at the repräsentiert wird. Das Vorkommen der Lokalität Hoch­ Hochkogel locality in the southernmost part of the Rei- kogel wird durch Bochianites (49 %), Ptychophylloceras chraming Nappe (Ebenforst Syncline, Northern Calcareous (18%) und Haploceras (18%) dominiert. Ancyloceratidae Alps). The cephalopod fauna sampled from marly parts of (durch Bochianites representiert) sind die häufigste Kom­ the Rossfeld Formation indicates Late Valanginian age. ponente. Ammonitidae und Phylloceratidae sind nahezu The ammonoid fauna comprises 7 different genera, each ausgeglichen (bei ca. 20 %). Lytoceratidae sind mit 7 % apparently represented by 1-2 species. The occurrence at unterdurchschnittlich vertreten. Ein einziger Tiefwasser the Hochkogel section is dominated by Bochianites (49 Nautilide und 2 Belemniten Rostren vervollständigen das %), Ptychophylloceras (18 %) and Haploceras (18 %). Bild der Cephalopoden Fauna. Brachiopoden, Muscheln Ancyloceratids (represented only by bochianitids) are the und Schnecken stellen die Hauptkomponenten der ben- most frequent component. Ammonitids and phylloceratids thischen Makro-Fauna dar. are roughly balanced (each about 20 %). Lytoceratids are In einem instabilen Umfeld kam es im Ober Valanginium represented with below average values (7 %). A single zur Ablagerung der Kalksteine, Mergel und Sandsteine deepwater nautiloid and 2 belemnite guards complete dieses Gebietes. Gravitativer Transport vom Herkunfts­ the cephalopod fauna. Brachiopods, bivalves and gas­ ort (im Süden gelegen) der verschiedenen Sedimente tropods make up the main components of the benthic und der fragmentierter Ammonoideen Exemplare wird macrofauna. angenommen. Die Cephalopoden Fauna zeigt einen rein The deposition of the limestones in this area occurred in Mediterranen Charakter. an unstable environment. Gravitational transport of dif­ Schlüsselwörter:Ammonoideen, Biostratigraphie, Unter- ferent sediments and fragmented cephalopod specimens Kreide (Valangin), Oberösterreich, Nördliche Kalkalpen is assumed for the accumulated layers from the source area (situated to the south). The cephalopod fauna consists solely of Mediterranean elements. 1. Introduction Keywords:Ammonoids, Biostratigraphy, Early Cretaceous (Valanginian), Upper Austria, Northern Calcareous Alps In the Reichraming Nappe (Bajuvaric Unit, Northern Cal­ careous Alps), Valanginian cephalopod-bearing deposits are recorded in two different facies, the Schrambach and Zusammenfassung the Rossfeld Formation. Upper Valanginian sediments of the Rossfeld Formation comprise turbiditic marls Unterkreide Ammonoideen wurden an der Fundstelle and sandstones, whereas the Schrambach Formation is Hochkogel im südlichsten Teil der Reichraming Decke built by limestones with turbiditic sandstone intercala­ (Ebenforst Mulde, Nördliche Kalkalpen) gesammelt. tions (V a i'cek & F aupl , 1996). The source area for the Die Cephalopoden Fauna aus den besammelten merge­ Rossfeld Formation and the sandstone intercalations of ligen Schichten der Rossfeld Formation, deutet auf Ober the Schrambach Formation was situated to the south of Valanginium hin. the basin (Faupl & W agreich , 1992; V asicek & Faupl 1996, 1998). The Rossfeld Formation is restricted to southern parts of *) Dr. Alexander L ukeneder , Department of Geology and the Reichraming Nappe. It is interpreted as a synorogenic Palaeontology, Natural History Muesum, Burgring 7, succession deposited at the beginning of the compressional A-1010 Wien, Austria, e-mail:alexander.lukeneder@ deformation within the Austroalpine unit (Faupl , 1979; nhm-wien.ac.at D ecker et al., 1987). The palaeogeographical reconstruc- ©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien

2 Beitr. Paläont., 29, Wien, 2005

Gosau Rossteld Jurassic sediments 1 Upper Triassic f Frankenfels - Lunz Group Formation L..Al including Schrambach Formation fcËÎj Formations l Nappe System

river fault forest road thrust 1 0 Km © sample location alpine pasture <8> mountains

Figure 1: Fig. la. Locality map of Upper Austria showing tectonic situation (Reichraming Nappe, Frankenfels Nappe) around the section investigated within the Northern Calcareous Alps. Fig. lb. Position of the Hochkogel locality and lithological formations of the Ebenforst Syncline. tion of the investigated area through the Lower Cretaceous 2. Geographical setting shows that the sedimentation of the Rossfeld Formation (sandstone intercalations within the lower part of the The outcrop is situated in the Reichraming Nappe in Upper section), in the internal and eastern parts of the Northern Austria. The exact position is about 5 km south of Brun- Calcareous Alps (southern parts of the ‘Bajuvarikum’) is nbach (652 m, OK 1:50,000, sheet 69 GroBraming, Fig. apparently connected with an uplift of the southernmost 1). The outcrop is located in the southernmost part of the parts. This reflects either beginning subduction of the east-west striking Ebenforst Syncline along a forest road, Penninic Ocean in the North or the obduction of oce­ running between the Sulzkogel (840 m) to the north and anic crust of the former Vardar Ocean at the boundary the Hochkogel (1157 m) to the south at the topmost part Austroalpine/Southern Alps (S chlagintweit , 1991). The of the Reixengraben at 885 m. stratigraphy of the Lower Cretaceous sediments around The grey sandstone succession comprising the marly the investigated area is based on ammonoids. A new ammonoid-bearing beds (dipping 225/60°) is located on cephalopod fauna was collected in limestone interbeds of the nothern side of the Hochkogel, on a nearly vertical the Rossfeld Formation. wall of the outcrop, which was exposed by road-cutting. During the 1990s, a rich cephalopod fauna was collected The occurrence is exposed in 3 distinct beds of 10-40 cm from Lower Cretaceous sediments from the surrounding thickness (fig. 2). The exact position of the ammonoid-oc- area of the herein presented locality (V asi'cek & Faupl , currence is fixed by GPS data (global positioning system): 1996, 1998, 1999; V asi'cek et al., 1994; see also Immel, N 47°47’ 15” and E 14°30’00” (fig. 2). 1987). The present contribution provides a detailed study of the rich and extraordinarily well-preserved Upper Valangin- 3. Geological setting and lithology ian ammonoid fauna from the Hochkogel section, which yields new and important biostratigraphical data, and The Upper Valanginian cephalopods described here were presents new facts on the correlations within the Northern collected from a little outcrop containing sandstones and Calcareous Alps. The Hochkogel fauna is also correlated marly limestones, located at the southern margin of the with the comparable faunas from the most recent papers Ebenforst Syncline. The Ebenforst Syncline is situated in on Lower Cretaceous faunas of Lukeneder (1997, 1998, the southernmost part of the Reichraming Nappe of the 2001a, b, 2003, 2004), L ukeneder & H arzhauser (2003) Northern Calcareous Alps. This region is part of the Baju and V asi'cek & F aupl (1996, 1998, 1999). varic Unit, which is neighboured and overlain in the sou ©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien

Lukeneder , A., An Early Cretaceous Ammonoid Association... 3

c

B

-1 Marly limestone with sandstone intercalations

flank of the Hochk eX*3ans'0n t*le ammonoid beds within the log of the investigated outcrop at the road-cut on the northern ©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien

4 Beitr. Palaont., 29, Wien, 2005

by the Tyrolian Nappes (Staufen-Hollengebirgs Nappe). however, even extraordinarily well-preserved individu­ The Ebenforst Syncline is followed directly to the north by als (e.g. lappets of microconchs) could be collected. The three additional synclines - the Anzenbach Syncline, the casts show perfectly preserved sculpture on the preserved Schneeberg Syncline of the Reichraming Nappe and the shell. Losenstein Syncline of the Temberg Nappe - all of which In most cases the specimens are fragmented and show are constituted by Lower Cretaceous sediments. considerable tectonic deformation, which hampers precise The locality is situated 500 m north of the border to the determination to species level. The ammonoid fragments southern Tyrolian Units and is tectonically shifted into the show original body-shape preservation and are not flat­ Weyer Arc Structure. The Ebenforst Syncline is formed tened as is usually the case in Lower Cretaceous sediments of a Jurassic sequence (Oberalm Formation, Scheiblberg- in most Austrian localities. They are orientated in various Kirchstein Formation, Hierlatzkalk). The core of the Eben­ directions within the limestone beds, and are horizontally forst Syncline consists of the Lower Cretaceous Rossfeld orientated in only few ‘abundance beds’ The latter beds Formation. The investigated ammonoid ‘mass-occurrence’ are assumed to be autochthonous. is situated in marly limestones of the Rossfeld Formation Bed-by-bed collecting and a systematic-taxonomic study (Late Valanginian). provide the basic data for the statistical analysis of the The terrigenous, proximal, deep-water turbiditic Rossfeld ammonite fauna. Palaeontological, palaeoecological and Formation of the Reichraming Nappe represents a syno- sedimentological investigations, combined with studies rogenic development. The Rossfeld Formation is mainly of lithofacies in thin sections, peels from polished rock composed of grey silty marls accompanied by conglomer­ surfaces and geochemical investigations, yielded infor­ ates and sandstones. mation about the environmental conditions in the area of The sandstones are fine, grey calcareous with slump struc­ deposition. tures. The intercalated marly bioturbated limestones are Calcium carbonate contents (CaC03) were determined light-coloured and are associated with a relatively monoto­ using the carbonate bomb technique. Total carbon content nous benthic macrofauna (brachiopods and bivalves). The was determined using a LECO WR-12 analyser. Total fabric is burrow-mottled to completely homogenised due organic carbon (TOC) contents were calculated as the to bioturbation and indicates rich benthic colonization. difference between total carbon and carbonate carbon, The sedimentological situation at the Hochkogel outcrop assuming that all carbonate is pure calcite. All the chemi­ differs somewhat from that of other ‘Rossfeld Formation’ cal analyses were carried out in the laboratories of the localities. In most cases we find marls or marlstones with Department of Geology and the Department of Forest intercalated sandstone layers. In contrast to the latter situ­ Ecology at the University of Vienna. ation, the Rossfeld Formation at the Hochkogel section The material examined is deposited in the palaeontological shows approx. 30 m of fine, grey calcareous sandstones collection of the Natural History Museum, Vienna, Austria (5-50 cm beds) with mass-plant debris on their upper side. (NHMW). All specimens in Plate 1 and 2 were coated with Three intercalated limestone beds of 10 to 40 cm thick­ ammonium chloride before photographing. ness (rich in ammonoids) can be distinguished. These limestone beds are in turn marked by ‘small’ rhythmically intercalated turbiditic sandstone layers of about 2-3 cm. A 5. Fauna of the Hochkogel section short-term sedimentation is proposed for the sandstone lay­ ers, whereas the limestone- and marl-beds reflect ‘normal’ The Hochkogel section yielded an extraordinarily rich sedimentation rates. invertebrate fauna consisting of ammonoids (800), nauti- The CaC03 (calcium carbonate contents, equivalents loids (1), lamellaptychi (3), echinoderms ( Phyllocrinus , calculated from total inorganic carbon) display values 1), brachiopods ( Triangope sp., 1) and bivalves (e.g. of about 64 %. The weight % TOC values (total organic inoceramids and others, 9). Some parts of these layers carbon) are about 2.7 % within the marls of the outcrop. contain at least 30 ammonoid specimens (fragments) per The maximum amount of 3.1 mg/g sulphur stems from 1 dm2. The fossiliferous part of the section shows remark­ the middle of limestone bed 2. ably abundant bochianitids. The abundant and generally well-preserved cephalopods (except fragmentation) are: Phylloceras thetys, Ptychophylloceras ptychoicum, Pty- 4. Material and methods chophylloceras semisulcatum, Lytoceras subfimbratum, Lytoceras lepidum, Lytoceras sutile, Lytoceras sp., Lep- During the course of this study, 155 determinable ammo­ totetragonites honnoratianus , Haploceras grasianum, noids, 640 undeterminable ammonoid fragments, 1 nau- Haploceras extracornutum, Neocomites sp., Bochianites tiloid, 2 belemnoids and 2 lamellaptychi were examined. neocomiensis, a single nautiloid and 2 lamellaptychi (Fig. Nearly every preservational stage was observed. Most 3). The author generally follows the classification of Cre­ of the specimens were crushed by sediment compaction. taceous Ammonoidea by W right et al. (1996). The suture Some of the ammonoids show remnants of the aragonitic lines are visible on only few specimens (e.g. Ptychophyl­ shell (still aragonitic). Most specimens show fragmen­ loceras ptychoicum), which also show shell preservation tation. Juvenile stages were represented by only a few (aragonitic). The cephalopod fauna consists of numerous specimens. Due to the overall high number of specimens, Mediterranean elements (dominated by Bochianites) (Fig. ©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien

Lukeneder , A., An Early Cretaceous Ammonoid Association... 5

3). No Boreal ammonoids were observed (for comparison comparable with the French localities. The only benthic see also H oedemaeker , 2002; R awson , 1995; V asicek & macrofossils observed in the ammonite beds are bivalves Faupl , 1996, 1998). and brachiopods. Carefully selected and washed samples The assumed ‘allochthonous’, fragmented cephalopod of the limestones contain primarily fine silt-sized, angular fauna at the Hochkogel section is composed of specimens quartz grains, some pyrite and phosphatic material (fish which were transported from other habitats into the pe­ scales and teeth). The rare, generally poorly preserved lagic basin of the Rossfeld Formation. These fragmented micro-invertebrate fauna consists of a few foraminifera specimens are accompanied by layers showing orientated (planktonic), radiolarians, ostracods, and sponge spicules ammonoid shells (e.g. Bochianites) on bedding planes. (investigated in thin sections). Thus, a reorientation through bottom currents is assumed for the specimens concentrated in such thin layers. Additional taphonomic processes which occurred within 6. Biostratigraphy sediments at the Hochkogel section are under investigation by the author (Lukeneder , in prep.) and will be presented The association indicates that the cephalopod-bearing in a separate paper. These include biostratinomy, which beds in the Rossfeld Formation belong to the Saynoceras involves preservational processes occurring between the verrucosum ammonite Zone of the early Late Valanginian death of the organism and its final emplacement within (according to the results of the Lyon meeting of the Lower the sediment (mechanical), and fossil diagenesis, which Cretaceous Ammonite Working Group of the IUGS; ‘Kil- involves fossilization processes occurring after burial ian Group’; H oedemaeker et al., 2003). (chemical). Biostratinomic processes can be subdivided into four categories: 1) reorientation and transport, 2) disarticulation, 3) fragmentation and 4) corrasion. S ta g e s Z o n e s S u b z o n e s One remarkable aspect is the absence of olcostephanids at P. picteti V asicek & F aupl the Hochkogel section. (1998) assumed P. o hm i P. catulloi that the most apparent difference between the investigated P ohmi localities of the Reichraming Nappe and localities in the Upper B. balearis Vocontian basin was the abundance of olcostephanids P. ligatus within sediments of the Vocontian basin and adjacent shelf versus their only sporadic occurrence in the Reichraming S. sa yn i Nappe. Lukeneder (2004), however, points out the impor­ tance of determining where the assemblage was deposited L. nodosoplicatum palaeogeographically and/or straitigrapically within this HAUTERIVIAN Lower 0 . (J.) je a n n o ti unstable region. Accordingly, different localities of the C. loryi same syncline (e.g. Ebenforst Syncline), located only 200 C. lo ryi m apart, show differences in the frequency of the same A. radiatus genus (e.g. Olcostephanus ) ranging from approx. 0 % - 50 T. callidiscus %. Recent contributions show that olcostephanids form a C. furcillata C. furcillata major and important group (46 %) in the investigated area, O. (O.) nickle si Lytoceratina N. peregrinus Upper N. peregrinus

K. pronecostatum S. verrucosum S. verrucosum VALANGINIAN K. biassalense B. cam pylotoxus Lower B. cam pylotoxus Ancyloceratina 50% T. pertransiens T. otopeta T. alpillensis Upper S. b o issieri B. picteti M. paramimounum D. d alm asi Middle S. occitanica B. p rivasensis BERRIASIAN T. subalpina Lower B. ja c o b i

Figure 4: The stratigraphic position within the Late Valanginian Figure 3: Ammonoid assemblage from the Hochkogel locality. (S. verrucosum Zone) of the Hochkogel fauna (in grey) in the Note the dominance of the Ancyloceratina and its abundant Ebenforst Syncline. Table after H oedemaeker et al. (2003, with genus Bochianites. modifications). ©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien

Beitr. Paläont., 29, Wien, 2005 6

The biostratigraphically indicative cephalopods are: Phyl- fragmentation and the diverse orientations of the ammo­ loceras thetys, Ptychophylloceras ptychoicum, Ptychophyl- noid specimens within the sediment furnish evidence for loceras semisulcatum, Lytoceras subfimbratum, Lytoceras a post-mortem turbidity-flow transport of the shells. lepidum, Lytoceras sutile, Lytoceras sp., Leptotetragonites The ammonoid beds are accompanied by layers showing honnoratianus, Haploceras grasianum, Haploceras extra- orientated ‘autochthonous’ straight ammonoid shells (e.g. cornutum and Bochianites neocomiensis. Bochianites) on bedding planes. Thus, for the specimens Although Saynoceras verrucosum is missing, the am- concentrated in such thin layers, a reorientation due to monoid assemblage, the abundance of Bochianites bottom currents is probable. Note that caution should be neocomiensis (see for example L ukeneder , 2004) and the exercised when applying the terms autochthonous and occurrence of Haploceras extracornutum hint at the early allochthonous in cephalopods. Late Valanginian Saynoceras verrucosum Zone. The main investigation topics of future work on the ammo­ noids from the remarkable Hochkogel section will be the taphonomy and microstructure of the ammonoid shells. 7. Results and Conclusions This will be accompanied by research on the original po­ sition and environmental conditions of the sedimentation The tectonically strongly deformed Lower Cretaceous area. This ultimately leads to the question whether the am­ sediments of the Ebenforst Syncline do not necessarily monoid assamblage is ‘autochthonous’ or ‘allochthonous’ create the perfect conditions for excellent preservation The expected answers are essential for geodynamic and of ammonoids. The macrofauna, as already stated, is palaeooceanographic conclusions. represented especially by ammonoids. The whole section yielded about 800 ammonoids (includes fragments). The ammonoid moulds are restricted to the limestone beds. 8. Acknowledgements No ammonoids were found within the encompassing sandstone layers. The latter were formed by turbidity Thanks are due to the Austrian Science Fund (FWF) for currents, show gradation and, on their top, plant debris. financial support (project P16100-N06). Sincere thanks are Some specimens (e.g. Ptychophylloceras) described extended to Herbert Summesberger (Vienna) for his valuable from the Hochkogel show exceptional shell preservation and constructive comments on the manuscript. Photographs (L ukeneder , in prep.). The accompanying invertebrate were taken by Rudolf Gold (Vienna). fauna consists of nautiloids, lamellaptychi, echinoderms (Phyllocrinus), brachiopods ( Triangope) and bivalves (e.g. inoceramids and others). 9. References The stratigraphic investigation of the ammonoid fauna re­ vealed that the Hochkogel section comprises lower Upper D ecker , K., Faupl , P. & M üller , A., 1987. Synorogenetic Valanginian sediments of the Saynoceras verrucosum Zone Sedimentation on the Northern Calcareous Alps Dur­ and belongs exclusively to the Mediterranean Province. ing the Early Cretaceous. — [in:] F lügel, H. W. & No descendants of the Boreal Province are observed at the Faupl , P. (eds.). Geodynamics of the eastern Alps, Hochkogel section. 126-141, Vienna. The following Mediterranean genera are observed: Phyl- F aupl , P. 1979. Turbidite series within the Cretaceous loceras, Ptychophylloceras, Ptychophylloceras, Lytoceras, sequence of the Austroalpine unit and their paleo- Leptotetragonites, Haploceras and Bochianites. The geographical significance. - [in:] W iedmann , J. ammonoid assemblage, the abundance of Bochianites (ed.). Aspekte der Kreide Europas. IUGS, Series A, neocomiensis, and the occurrence of Haploceras extracor­ 6:403^111, Stuttgart. nutum hint at the S. verrucosum ammonoid Zone. Faupl , P. & W agreich , M., 1992. Cretaceous flysch and Sorting, packing due to sedimentological or biological pelagic sequences of the Eastern Alps: correlations, effects, and alignments or concentration due to transport heavy minerals and palaeogeographic implications. or bottom currents can be observed. Thus, the analysis — Cretac. Research, 13:387^403, London. of the macrofauna and the sedimentological data support H oedemaeker , P.J. 2002. Correlating the uncorrelatables: a the interpretation of a highly dynamic palaeoenvironment Tethyan-Boreal correlation of Pre-Aptian Cretaceous on the slope to basin. The suggested palaeogeographic strata. — [in:] M ichalik , J. (ed.). Tethyan/Boreal position of the studied section indicates an influence of Cretaceous correlation. Mediterranean and Boreal turbiditic redeposition (‘debris flow’) and an allochthonous Cretaceous paleogeographic areas in central and East­ origin of the fragmented ammonoids collected. The shell ern Europe. Publishing House of the Slovak Academy transport took place via ‘mudflows’ after the embedding of Sciences, 235-284, Bratislava. in the sediment, as is reflected in the different alignments H oedemaeker , P.J., R eboulet , St., A guirre -U rreta , M., of the ammonoid shells and fragments within the sedi­ A lsen , R, Aoutem , M. A trops , F., B arrangua R., ment. The badly preserved, fragmented specimens within C ompany , M., G onzales , C , K lein , J., L ukeneder , the marly limestone layers were apparently transported A ., Ploch , I., R aisossadat , N ., R awson , R, R opolo, from a nearby, more shallow area such as that situated to R, V asicek , Z., V ermeulen , J. & W ippich , M., 2003. the south, where they had been deposited primarily. The Report on the 1st International Workshop of the IUGS ©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien

Lukeneder , A., An Early Cretaceous Ammonoid Association... 7

Lower Cretaceous Ammonite Working Group, the Aptian) ammonite sequences of NW-Europe and their ‘Kilian Group’(Lyon, 11 September 2002). — Cretac. correlation with the western Mediterranean faunas. Research, 24:89-94, London. — Mem. Descr. della Carta Geo. d’ltalia, 51:121-130, Immel, H., 1987. Die Kreideammoniten der Nördlichen Rome. Kalkalpen. — Zitteliana, 15:3-163, Munich. Schl AGiNTWEiT, E, 1991. Allochthone Urgonkalke im Mit­ Lukeneder , A., 1997. Zur Unterkreide Stratigraphie der tleren Abschnitt der Nördlichen Kalkalpen: Fazies, Schrambachschichten auf Blatt 69 Großraming. — Jb. Paläontologie und Paläogeographie. — Münchner Geol. B.-A., 140/3:370-372, Vienna. Geowiss. Abh., 20 (A): 1-120, Munich. L ukeneder , A., 1998. Zur Biostratigraphie der Schrambach V asi'cek , Z. & F aupl , R, 1996. Die Cephalopoden aus den Formation in der Temberger Decke (O.-Valanginium Rossfeldschichten der Reichraminger Decke (Ober- bis Aptium des Tiefbajuvarikums-Oberösterreich). valanginium; oberösterreichische Kalkalpen). — Jb. — Geol. Paläont. Mitteil. Innsbruck, 23:127-128, Geol. B.-A., 139:101-125, Vienna. Innsbruck. V asi'cek Z. & Faupl R, 1998. Late Valanginian cepha- Lukeneder . A., 2001a. Palaeoecological and palaeoocea- lopods in relation to the palaeogeographic position nographical significance of two ammonite mass-oc­ of the Rossfeld and Schrambach Formation of the currences in the Alpine Lower Cretaceous. — PhD- Reichraming Nappe (Northern Calcareous Alps, Thesis, University of Vienna, 316 pp., Vienna. Upper Austria). — Zbl. Geol. Paläont., part 1, H L ukeneder . A., 2001b. Die Unterkreide und ihre Fos­ 11/12:1421-1432, Stuttgart. silien am Fusse des Schobersteins (Oberösterreich; V asi'cek , Z. & Faupl , P, 1999. Zur Biostratigraphie der Ternberger Decke; Losensteiner Mulde). — Oö. Schrambachschichten in der Reichraminger Decke Geonachrichten, 16:13-28, Linz. (Unterkreide, oberösterreichische Kalkalpen). — Abh. Lukeneder , A., 2004. The Olcostephanus Level: An Upper Geol. B.-A., 56/2:593-624, Vienna. Valanginian ammonoid mass-occurrence (Lower Cre­ V asi'cek , Z., M ichali 'k, J., R ehäkovä , D. & F aupl , R, taceous, Northern Calcareous Alps, Austria). — Acta 1994. Stratigraphische Daten zur Unterkreide der Geol. Polonica, 54(l):23-33, Warszawa. Lunzer und reichraminger decke (Östliche Kalkalpen, Lukeneder , A. & H arzhauser , M., 2003. Olcostephanus Ober- und Niederösterreich). — Jb. Geol. B.-A., guebhardi as cryptic habitat for an Early Cretaceous 137/2:407^112, Vienna. coelobite community (Valanginian, Northern Calcare­ W right , C.W., C allamon , J.H. & Howarth , M.K., 1996. ous Alps, Austria). — Cretac. Research, 24:477^185, Cretaceous Ammonoidea. — [in:] Kaesler ,R .L. (ed.). London. Treatise on invertebrate paleontology. Part L. Mollusca R awson , P.F., 1995. The ‘Boreal’ Early Cretaceous (Pre- 4 Revised, 1-362, Kansas (Boulder and Lawrence). ©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien Beitr. Palaont., 29, Wien, 2005 8

PLATE 1

Exposures of the detailed Upper Valanginian logs with indicated ammonoid beds 1-3.

Fig. 1 Lower part of the Hochkogel section at the road cut. Author with left hand on bed 1.

Fig. 2 Detail of Fig. 1 showing section below bed 1.

Fig. 3 Lowermost part of the Hochkogel section showing slump structures (approx. 30 cm in diameter).

Fig. 4 Log with indicated position of ammonoid beds 1, 2 and 3.

Fig. 5 Detail of bed 1 with numbers on separated layers. a K W W L ukeneder , A., An Early Cretaceous Ammonoid Association... Ammonoid Cretaceous Early An A., ©Verein zurFörderungderPaläontologieamInstitutfürPaläontologie,GeozentrumWien PLATE 1 PLATE 9 ©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien Beitr. Palaont., 29, Wien, 2005 10

PLATE 2

Late Valanginian cephalopods from the Rossfeld Formation within the Ebenforst Syncline (Upper Austria). Typical representatives of the Hochkogel assemblage.

Fig. 1 Ptychophylloceras ptychoicum (Q uenstedt ), Hochkogel section - x 1, NHMW 2004 zO 116/0001.

Fig. 2 Ptychophylloceras ptychoicum (Q uenstedt ), Hochkogel section - x 1, NHMW 2004 zOl 16/0002.

Fig. 3 Ptychophylloceras semisulcatum (d ’O rbigny ), Hochkogel section - x 1, NHMW 2004 zOl 16/0003.

Fig. 4 Ptychophylloceras semisulcatum (d ’O rbigny ), Hochkogel section - x 1, NHMW 2004 zOl 16/0004.

Fig. 5 Phylloceras thetys (d ’O rbigny ), Hochkogel section - x 1, NHMW 2004 z0116/0005.

Fig. 6 Phylloceras thetys (d ’O rbigny ), Hochkogel section - x 1, NHMW 2004 z0116/0006.

Fig. 7 Lytoceras sutile Oppel, Hochkogel section - x 2, NHMW2004 zOl 16/0007.

Fig. 8 Lytoceras lepidum (d ’O rbigny ), Hochkogel section - x 2, NHMW 2004 zOl 16/0008.

Fig. 9 Leptotetragonites cf. honnoratianus (d ’O rbigny ), Hochkogel section - x 1, NHMW 2004 zO 116/0009.

Fig. 10 Haploceras grasianum (d ’O rbigny ), Hochkogel section - x 1, NHMW 2004 z0116/0010.

Fig. 11 Haploceras extracornutum C ecca , Hochkogel section - x 2, NHMW 2004 zOl 16/0011.

Fig. 12 INeocomites sp., Hochkogel section - x 1, NHMW 2004 zOl 16/0012.

Fig. 13 INeocomites sp., Hochkogel section - x 1, NHMW 2004 zO 116/0013.

Fig. 14 INeocomites sp., Hochkogel section - x 1, NHMW 2004 z0116/0014.

Fig. 15 INeocomites sp., Hochkogel section - x 1, NHMW 2004 zOl 16/0015.

All specimens in Plate 2 and 3 were coated with ammonium chloride before photographing. ©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien

Lukeneder , A., An Early Cretaceous Ammonoid Association... 11

PLATE 2

K r ^ j U Hr H<:3 JH ©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien

Beitr. Palaont., 29, Wien, 2005 12

PLATE 3

Late Valanginian cephalopods from the Rossfeld Formation within the Ebenforst Syncline (Upper Austria). Typical representatives of the Hochkogel assemblage.

Fig. 1 Fragment of a body chamber of an indet neocomitid ammonoid, Hochkogel section - x 1, NHMW2004 zO 116/0016.

Fig. 2 Microconch -lappet of Neocomites sp. (d ’O rbigny ), Hochkogel section - x 1, NHMW 2004z0116/0017.

Fig. 3 Fragment of a body chamber of an indet neocomitid ammonoid, Hochkogel section - x 1, NHMW 2004 zO 116/0018.

Fig. 4 Fragment of a body chamber of an indet neocomitid ammonoid, Hochkogel section - x 1, NHMW 2004 zO 116/0019.

Fig. 5 Bochianites neocomiensis (d ’O rbigny ), Hochkogel section - x 2, NHMW 2004 zOl 16/0020.

Fig. 6 Nautiloid, Hochkogel section - x 2, NHMW 2004 zO 116/0021.

Fig. 7 Accumulation of Bochianites neocomiensis (d ’Orbigny ) and Ptychophylloceras, Hochkogel section - x 1, NHMW 2004 zO 116/0022.

Fig. 8 Accumulation of Bochanites sp. and Ptychophylloceras semisulcatum (d ’Orbigny ), Hochkogel section - x 2, NHMW 2004 zO 116/0023.

Fig. 9 Accumulated fragments of Ptychophylloceras semisulcatum (d ’O rbigny ), Hochkogel section - x 1, NHMW 2004 zO 116/0024.

Fig. 10 Lamellaptychus sp., Hochkogel section - x 2, NHMW 2004 zO 116/0025.

Fig. 11 Belemnite rostrum, Hochkogel section - x 1, NHMW 2004 zOl 16/0026.

Fig. 12 Bivalve, Hochkogel section - x 1, NHMW 2004 zO 116/0027.

Fig. 13 Triangope sp., Hochkogel section - x 1, NHMW 2004 zO 116/0028.

Fig. 14 Phyllocrinus sp. , Hochkogel section - x 3, NHMW2004 zOl 16/0029. ©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien

Lukeneder , A., An Early Cretaceous Ammonoid Association... 13

PLATE 3