Anthracoporella mounds in the Late Carboniferous Auernig Group,Carnic Alps (Austria)

Summary A heretofore undocumented example of skeletal mounds formed by the dasycladacean algaAnthracoporella spectabilis is described from mixed carbonate-clastic cycles (Auernig cyclothems) of the Late Carboniferous (Gzhelian) Auernig Group of the central Carnic Alps in southern Austria. The massive mound facies forms biostromal reef mounds that are up to several m thick and extend laterally over more than 100 m. The mound facies is developed in the middle of bedded limestones, which are up to 16 m thick. These limestones formed during relative sea-level highstands when clastic influx was near zero. The mound facies is characterized by well developed baffler and binder guilds and does not show any horizontal or vertical zonation. Within the massive mound faciesAnthracoporella is frequently found in growth position forming bafflestones and wackestones composed of abundantAnthracoporella skeletons which toppled in situ or drifted slightly.Anthracoporella grew in such profusion that it dominated the available sea bottom living space, forming ‘algal meadows’ which acted as efficient sediment producers and bafflers. BecauseAnthracoporella could not provide a substantial reef framework, and could not withstand high water turbulence, the biostromal skeletal mounds accumulated in shallow, quiet water below the active wave base in water depths less than 30 m. The massive mound facies is under- and overlain by, and laterally grades into bedded, fossiliferous limestones of the intermound facies, composed mainly of different types of wackestones and packstones. Individual beds containAnthracoporella andArchaeolithophyllum missouriense in growth position, forming “micromounds’. Two stages of mound formation are recognized: (1) the stabilization stage when bioclastic wackestones accumulated, and (2) the skeletal mound stage when the sea-bottom was colonized byAnthracoporella and other members of the baffler and binder guilds, formingAnthracoporella bafflestones and wackestones of the mound facies. A slight drop in sea-level led to the termination of the mound growth and accumulation of organic debris, particularly calcareous algae, fusulinids, crinoids and bryozoans, forming well bedded limestones, which overlie the mound facies     

The schulterkofel section in the Carnic Alps,Austria: Implications for the carboniferous-permian boundary

Summary The upper part of the LowerPseudoschwagerina Limestone (Rattendorf Group), outcropping on the northwestern flank of Schulterkofel Mountain, Carnic Alps (Austria) is described with special emphasis on fusulinid microfossils and facies. This fusulinid-rich section offers an ideal opportunity for biostratigraphy in defining the Permo-Carboniferous boundary in this region. The LowerPseudoschwagerina Limestone is composed of shallow-marine limestones with intercalated thin siltstone and sandstone beds. Fusulinid limestones are represented by two types of wackestones, both containing large quantities of smaller foraminifers. Fusulinid grainstones are rare. Limestones rich in fusulinids were found only within the bedded limestone facies in beds both below and especially above siliciclastic intercalations. This may indicate that the best living conditions for fusulinids existed immediately before and especially after the climax of a regressive phase (sea-level lowstand). The fusulinid limestones were deposited within a protected, shallow-marine shelf environment with normal salinity. Pseudoschwagerinid fusulinids appear in the upper part of the LowerPseudoschwagerina Limestone, in samples SK 107d (undeterminable species) and SK 108, i.e. between 92 m and 93 m above the base of the section within a bedded limestone immediately above the uppermost clastic intercalation. The fusulinid fauna is represented by about 30 species belonging to only a few genera. Species ofTriticites andRugosofusulina dominate, whereas those ofDaixina, Rugosochusenella andPseudofusulina are rare. A characteristic feature of the fauna is the strong similarity with fusulinid faunas described from Russia as well as from Middle and East Asia. Some of the described fusulinids are new for the Carnic Alps. The first appearance ofPseudoschwagerina andOccidentoschwagerina (Occidentoschwagerina alpina Zone) in the upper part of the LowerPseudoschwagerina Limestone in the Schulterkofel section defines the position of the Carboniferous-Permian boundary.     

Non-marine biota from the Lower Permian of the central Southern Alps (Orobic and Collio basins, N Italy): a key to the paleoenvironment

The Lower Permian in the central Southern Alps yields an important low-diversity fossil assemblage which was deposited in a varied continental setting, showing mainly alluvial fan to lacustrine and, locally, playa-like floodplain environments. The present study is not taxonomical and its objective is to make a first report of new invertebrate organisms and trackways discovered in the Orobic and Collio basins. Such a fossil record, which comprises freshwater jellyfishes, arthropod tracks, stromatolites, algae and other organisms, will further our knowledge about the local and regional geological history of the central-western Southern Alps and improve our understanding of Early Permian palaeoenvironments. On the whole, in both intramontane basins the ichnodiversity and fossil content decreases from a stratigraphic lower portion, mainly lacustrine and alluvial, towards an upper one, characterised by coarse alluvial deposits to floodplain fines. On the basis of both the already known palaeontological data from the two basins, mainly macroflora and tetrapod footprint associations, and the recently discovered taxa, we tried to make reliable palaeoenvironmental inferences and, possibly, hypothesise on a climatic change, which could have occurred during the Early Permian.     

Funsulinid assemblages and facies of the Bombaso Fm. and basal meledis Fm. (Moscovian-Kasimovian) in the central Carnic Alps (Austria/Italy)

Summary The Bombaso Formation and basal Meledis Formation in the central Carnic Alps near Straniger Alm and Zollnersee (Austria/Italy) unconformably overlie the folded Variscan basement and consist of shallow marine clastic and carbonate sediments which are arranged to form two fining and deepening upward sequences. Particularly limestones and even breccias of the Bombaso Formation yielded a rich fusulinid fauna composed of 34 species which are attributed to the following zones:Quasifusulinoides quasifusulinoides-Protriticites ovatus; Protriticites pseudomontiparus, andMontiparus montiparus. Breccias of the Bombaso Formation west of Straniger Alm contain the oldest fusulinid fauna of the Carnic Alps, belonging to theQuasifusulinoides quasifusulinoides —Protriticites ovatus zone. The fauna is composed ofQuasifusulinoides quasifusulinoides, Q. fallax, Q. intermedius, Protriticites cf.ovoides, andPr. ovatus. This assemblage is most similar to that of the Peskovskaya Formation of the Myachkovian Horizon in the Moscow Basin indicating uppermost Moscovian age. Limestones from depositional sequence 1 at Zollnersee also contain fusulinids of the uppermost Moscovian which are characterized by a more diverse assemblage:Schubertella donetzica, Fusiella lancetiformis, Beedeina ulitinensis, B. consobrina, B. nytvica, B. siviniensis, Quasifusulinoides pakhrensis, Q. fallax, Q. kljasmicus, Q. quasifusulinoides, Fusulinella rara, andProtriticites ovatus. Limestones and calcareous sandstones-siltstones of the basal Meledis Formation of depositional sequence 2 near Zollnersee and at Cima Val di Puartis are characterized by fusulinids of theProtriticites pseudomontiparus zone (Protriticites globulus, Pr. pseudomontiparus, Pr. sphaericus, Pr. rotundatus, Pr. ovoides, Pr. lamellosus, andPraeobsoletes burkemensis) and byMontiparus paramontiparus zone (Praeobsoletes pauper, P. burkemensis, Obsoletes timanicus, O. obsoletes, Montiparus paramontiparus, M. umbonoplicatus, M. montiparus, M. likharevi, M. rhombiformis andM. priscus) indicating lower to middle Kasimovian age (Krevyakinskian and Khamovnicheskian Horizons of the Russian Platform). In memoriam FranzKahler (1900–1995)     

Jurassic neptunian dikes at Mt Mangart (Julian Alps,NW Slovenia)

Jurassic neptunian dikes are common within Upper Triassic to Lower Jurassic platform limestone of the Julian Alps. At Mt Mangart, the following geometries were observed: irregular dissolution cavities, thin penetrative fractures, larger fractures with sharp sidewalls, and laterally confined breccia bodies. Inside a complex neptunian dike system two main generations of infillings were differentiated. The first generation is heterogeneous and consists of bioclastic limestones, representing uniquely preserved sediments subdivided into five different microfacies. The second generation is more common and typically consists of coarse-grained breccias with host-rock clasts and marly limestone matrix containing echinoderms. Fracture formation and void filling of the first generation of neptunian dikes is dated as Pliensbachian and is interpreted to be caused by the Julian carbonate platform dissection due to widely recognized Lower Jurassic Tethyan rifting. The timing of formation for the second generation is only broadly constrained, ranging from the Pliensbachian to the Late Cretaceous.     

Facies and biota of Anisian to Carnian carbonate platforms in the Northern Calcareous Alps (Tyrol and Bavaria)

Summary During the Middle and early Late Triassic carbonate ramps and rimmed platforms developed at the northwestern margin of the Tethys ocean. In the Northern Calcareous Alps, Anisian stacked homoclinal ramps evolved through a transitional stage with distally steepened ramps to huge rimmed platforms of Late Ladinian to Early Carnian age. Middle Triassic to early Late Triassic facies and biota of basin, slope and platform depositional systems are described. Special emphasis is given to foraminifers, sponges, microproblematic organisms and algae. The Ladinian to early Carnian reef associations are characterized by the abundance of segmented sponges, microproblematica, biogenic crusts and synsedimentary cements. Among the foraminifers, recifal forms likeHydrania dulloi andCucurbita infundibuliformis (Carnian in age) are reported from the Northern Calcareous Alps for the first time. Some sphinctozoid sponges likeParavesicocaulis concentricus were known until now only from the Hungarian and Russian Triassic.     

An upper Tuvalian (Triassic) platform-basin system in the Julian Alps: the start-up of the Dolomia Principale (Southern Alps,Italy)

Summary East of Cave del Predil (formerly Raibl), a platform-basin transition of the Dolomia Principale (Hauptdolomit) is spectacularly exposed at a seismic scale. Therefore, the eastern margin of the vast domain of the Dolomia Principale, facing the Slovenian Basin, is documented. Despite of strong dolomitization of the massive margin, some sedimentary structures and fossils have been recognized. Corals seem to be very rare and sponges to be absent, whereas serpulids and marine phreatic cements seem to have been the main components of the framework. Interior platform bedded dolomites lap off the massive margin. Clinoforms interfinger with upper Tuvalian basinal deposits (Carnitza Formation). This setting documents the start-up of the Dolomia Principale during late Tuvalian time. Moreover, this margin of the Dolomia Principale is the more ancient so far pointed out. It testifies to the recovery of a rimmed platform after the late Julian-early Tuvalian crisis.     

Coralline-algal assemblages of a Burdigalian platform slope: implications for carbonate platform reconstruction (northern Sardinia,western Mediterranean Sea)

The rhodolithic slope deposits of a Burdigalian carbonate platform in Sardinia near Sedini were analyzed to reconstruct facies and palaeobathymetry. There is a distinct red-algal growth zonation along the platform slope. The clinoform rollover area consists of coralline-algal bindstones, which downslope change into a zone where rhodoliths are locally fused by progressive encrustation. Mid-slope rhodoliths are moderately branched, and downslope rhodoliths have fruticose protuberances, resulting in branching rhodolith growth patterns. There is a sharp change from the rhodolitic rudstones to the basinal, bivalve-dominated rudstones at the clinoform bottomsets. Red-algal genera identified include Sporolithon, Lithophyllum, Spongites, Hydrolithon, Mesophyllum, Lithoporella, Neogoniolithon, and other mastophoroids and melobesioids. Genera and subfamilies show a zonation along the clinoforms, allowing palaeobathymetric estimates. The clinoform rollovers formed at a water depth of around 40 m and the bottomsets around 60 m. Results from geometrical reconstruction show that coral reefs in the inner platform formed at water depths of around 20 m. Therefore, the Sedini carbonate platform is an example of a reef-bearing platform in which the edge or the platform-interior reefs do not build up to sea level.     

Norian serpulid and microbial bioconstructions: Implication for the platform evolution in the Lombardy Basin (Southern Alps,Italy)

Summary The development of peculiar margin facies and abundant talus breccias within the Dolomia Principale inner platform is commonly observed in the Lombardy Basin during the Norian. The organisms building these margins are mainly serpulids, benthic microbes, subordinate porostomata and other encrusting forms; typical margin organisms, as sponges or corals, are extremely rare or absent. The build-ups form narrow rims along the borders of tectonic-controlled intraplatform basins. Regional back-stepping and progradation of the margin facies on the talus breccias produced by the erosion of the reef is commonly observed in the uppermost Dolomia Principale depositional system. Widespread occurrence of serpulids and microbial margins in middle-late Norian times is indicative of stressed environmental conditions—fluctuation of salinity and temperature on the inner platform and in the intraplatform basins—controlled by palaeogeographic setting. Physical characteristics allowed the bloom of forms able to develop in a wide range of environmental conditions, such as serpulids. In the Late Norian, major input of fine-grained clastics is recorded; close to the Norian-Rhaetian boundary, carbonate ramps were regionally restored. Locally, small serpulid and microbial bioconstructions still persist in the lowermost part of the shaly succession, even if they are less abundant with respect to the Dolomia Principale. Patch-reefs generally do not build a platform margin, but represent isolated mounds within shaly deposits. These build-ups occur on the edge of former structural highs; the communities survived the environmental change responsible for the siliciclastic input and locally managed to produce mounds during the deposition of the lower part of the upper depositional system (Riva di Solto Shale).     

An Alpine immigrant: Phragmoceras Broderip, 1839 from the Silurian of the Carnic Alps (Austria)

A rare occurrence of Phragmoceras imbricatum Barrande is recorded from moderately shallow marine Silurian sequences in the Carnic Alps (Austria). The specimen was collected from a condensed series of nautiloid-bearing wackestones/packstones which are documented as being one of the earliest levels of the Silurian Cephalopod Limestone Biofacies deposited along the North Gondwana margin. The presence of this genus and particular species in the Alpine area, whether as an in situ fauna or as a “stray immigrant”, during a period of global eustatic lowstand, adds new data with regard to the mechanisms of faunal exchange of nectobenthic nautiloid taxa between the Carnic Alps, the Prague Basin, SW Sardinia, Avalonia and Baltica which must have been made possible by currents connecting all five areas. It seems likely that some of the nautiloid taxa appearing in the Prague Basin during the Ludlow may have already been present in the Carnic Alps much earlier in the Silurian; these document early faunal affinities with Baltica. As well as confirming the existence of open migrational seaways between these terranes at a precise stratigraphic interval during the Silurian (lower Homerian: Wenlock), the presence of this species also indicates a prevailing more temperate paleoenvironment in these areas which this element of a usually tropical fauna could tolerate, and provides significant evidence that warm water currents reached the Carnic Alps at this time. In addition due to the bathymetric restrictions of the shells of these particular faunas, exchange by currents could not have taken place over great distances, even considering drifted individuals, and therefore indicates the relatively close positions/connections of various peri-Gondwana Terranes such as the Carnic Alps, SW Sardinia and the Prague Basin to Avalonia and Baltica during this time slice.     

Analysis of Late Jurassic to Early Cretaceous algal debris-facies of the Plassen carbonate platform in the Northern Calcareous Alps (Germany,Austria) and in the Kurbnesh area of the Mirdita zone (Albania): a tool to reconstruct tectonics and palaeogeography of eroded platforms

A characteristic microfacies of the Late Jurassic to Early Cretaceous allodapic Barmstein Limestone of the Northern Calcareous Alps are clasts of wackestones with numerous fragments of calcareous algae (“algal debris-facies”). According to dasycladale palaeocoenoses, several subtypes comprising different associations can be distinguished. One association is characterized by the debris of an unknown large dasycladalean alga reported as dasycladalean alga indet. sp. 1 from different localities in the Northern Calcareous Alps, typically forming a monospecific assemblage. Another microfacies type contains star-like calcitic bodies tentatively referred to the morphospecies Coptocampylodon pantici Ljubović-Obradović and Radoičić, originally described as being from the Turonian of NW-Serbia. Other Coptocampylodon-like bodies represent the calcified tufts of the laterals of Selliporella neocomiensis (Radoičić). The occurrence of Coptocampylodon pantici-like microfossils in the Late Tithonian to Early Berriasian, shows that obviously different species of dasycladaleans display identical to similar shaped tufts of laterals in transverse sections when becoming fragmented. Coptocampylodon pantici Ljubović-Obradović and Radoičić was observed only from different occurrences of Barmstein Limestone, but not from the autochthonous platform carbonates of the Plassen carbonate platform. The Coptocampylodon algal debris-facies is also reported from the Late Jurassic of Albania, Mirdita zone. Occurrences of different types of algal debris-facies in components of mass-flow deposits can be used as a tool to reconstruct eroded carbonate platforms and tectonics, as demonstrated in the Northern Calcareous Alps and the Albanides. Finally, the general occurrences of algal debris-facies in both settings—intra-Tethyan mostly isolated platforms (Alps, Albanides) vs. extended epeiric platforms (Middle East)—are compared and discussed.     

Hyloidichnus bifurcatus Gilmore, 1927 and Limnopus heterodactylus (King, 1845) from the Early Permian of Southern Alps (N Italy): A New Equilibrium in the Ichnofauna

Studies on Early Permian tetrapod ichnofauna emphasized the scarcity of forms from Italian sites. A revision work on the entire collections revealed the presence of Hyloidichnus bifurcatus Gilmore, 1927 and Limnopus heterodactylus (King, 1845). The ichnoassociation now lists seven ichnogenera: Amphisauropus, Batrachichnus, Dromopus, Erpetopus, Hyloidichnus, Limnopus, Varanopus. These new data enlarge the ichnoceonosis, adding tracks of medium-size captorhinomorphs (Hyloidichnus) and temnospondyls (Limnopus) to the Italian ichnofauna, previously characterized by scarcity of predators and amphibians. Radiometric ages give a strong age constraint to the ichnoassociation (Early Kungurian), allowing useful correlations to contemporary successions all over the world. The main difference is the absence of Ichniotherium and Dimetropus, and this could have a stratigraphic or paleoenvironmental significance. The fauna is similar in two main basins, Collio and Orobic. It differs solely in the proportions between ichnotaxa, with a predominance of areoscelid traces (Dromopus) in the Collio Basin and of captorhinomorph traces (Erpetopus, Varanopus, Hyloidichnus) in the Orobic Basin. This datum could reflect slightly different environments, seasonal in the Collio Basin (alluvial plain) and more arid in the Orobic Basin (playa-like). The lack of some forms in smaller basins of the Athesian Volcanic Complex is probably due to a bias.     

Quaternary carbonate-rocky talus slope successions (Eastern Alps, Austria): sedimentary facies and facies architecture

Quaternary carbonate-lithic talus slope successions of the Eastern Alps record an overall correlation between prevalent sedimentary facies, depositional geometry, and geomorphic maturity of the slope. After exposure of high cliffs by deglaciation or rocksliding, a low-dipping immature talus dominated by unsorted rockfalls initially accumulates. With progressive talus buildup, slope segments of different dips develop. Concomitantly, prevalent depositional processes change to grain flows and sorted rockfalls in the proximal, steep-dipping (35°–30°) slope segment, while deposits of cohesive debris-flows, ephemeral fluid flows and larger rockfalls prevail in the distal, lower-dipping slope segment. In mature talus deposystems, the proximal slope succession overlies the lower-dipping package of the distal slope along a thin ‘downlap interval’. Immediately after cliff exposure by deglaciation or rocksliding, talus may aggrade at rates of up to a few tens of meters per 1,000 years, but the accumulation rate slows strongly with progressive maturity of slopes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Robust sequential Factor Analysis of geochemical data from the Permian-Triassic Gartnerkofel-1 core (Southern Alps): the geochemical response to changing paleo-oceanographic conditions in shallow-marine carbonate platforms

The Gartnerkofel-1 core provides a high-quality multi-element dataset that characterizes an Upper Permian to Lower Triassic shallow-marine carbonate sequence (Bellerophon and Werfen Formations) of the Carnic Alps (Southern Alps). Based on the well-known sedimentological evolution, robust sequential Factor Analysis is explored as a multivariate statistical technique to understand geochemical processes in carbonate platforms. The results demonstrate that 93% of the whole-rock compositional variability of the Gartnerkofel-1 core can be explained by the detrital input that is diluted by the carbonate production and the early diagenetic redox state. Two stages of anoxia, one at the Permian/Triassic boundary and one in the Mazzin Member of the Werfen Formation, are related to indicative factor scores. The factor scores within this interval suggest an enhanced dolomitization of shales and marls, a mobilization of manganese, and an accumulation of syndiagenetically precipitated pyrite.     

Linking taphonomy to community-level abundance: Insights into compositional fidelity of the Upper Triassic shell concentrations (Eastern Alps)

Although actualistic live/dead comparisons lead to robust estimates of fidelity of modern death assemblages, quantitative evaluation of fidelity of fossil assemblage remains uncertain. In this paper, effects of storm reworking on compositional fidelity of the Upper Triassic shell concentrations (Eastern Alps, Austria) are evaluated. An exploratory approach is based on comparison of reworked and non-reworked assemblages in ordination analyses. Non-reworked assemblages of one or more communities provide a baseline for evaluation of fidelity of reworked assemblages. In siliciclastic-rich intervals of the Kössen Formation, shell concentrations are represented by (1) packstones with small, shallow infaunal bivalves, (2) floatstones and pavements with large semi-infaunal bivalves, and (3) bioclastic marlstones. In carbonate-rich intervals, bioclastic floatstones with bivalves and brachiopods occur. Analyzing all shell concentrations, eight sample groups sharing similar species composition are discriminated. Limited effect of storm reworking on composition of shell concentrations is indicated by (1) a general persistence of six sample groups when only non-reworked assemblages are analyzed, (2) similarity in composition between reworked and non-reworked assemblages within sample groups, and (3) compositional segregation between non-reworked assemblages of distinctive sample groups, mostly without any reworked assemblages of intermediate composition.Depth-related variations in dead-shell production, shell destruction and body size governed preservation and distribution of the shell concentrations along onshore-offshore gradient in the Kössen Basin. First, at times when environmental conditions were unfavorable for shell producers, coupled with high background shell destruction rates, limestone beds formed during storm events were shell-poor. Second, less common shell concentrations in upper than in lower parts of siliciclastic intervals can be related to higher environmental stress in shallower habitats. Third, the difference between shell concentrations dominated by small and large bivalves is driven by between-habitat differences in body size and is not due to a differential sorting of small and large shells. Combining community analysis based on species abundances with taphonomic analysis can thus be helpful in tracking fidelity of fossil assemblages.     

A three- and two-dimensional documentation of structural elements in schwagerinids (superfamily Fusulinoidea) exemplified by silicified material from the Upper Carboniferous of the Carnic Alps (Austria/Italy): a comparison with verbeekinoideans and alveolinids

Silicified schwagerinids (superfamily Fusulinoidea v. Moeller 1878) from the Upper Carboniferous (Carnic Alps, Austria and Italy) were isolated from cemented carbonate rocks using hydrochloric acid. The shells show details of the wall texture and of internal structures in three dimensions which are illustrated with SEM pictures. Thin sections from hand specimens provided two-dimensional sections of the shell for comparison. The functional significance of fusulinoidean internal structures is discussed and compared with verbeekinoideans and alveolinids. Particular attention is paid on the disposition of the different openings within the shell and from the chamber lumen to the outside which reflects the direction of protoplasmic flow. Based on the knowledge of the nature of protoplasm ultrastructure in Recent foraminifera and its biological significance we draw some conclusions about the nature of protoplasm in fusulinoideans and its change within the Permian verbeekinoideans.     

Characteristics of the Lofer cyclicity in the type locality of the Dachstein Limestone (Dachstein Plateau,Austria)

In the present paper, the results of our studies in the type locality of the Dachstein Limestone are summarised in order to contribute to the correct interpretation of the Lofer cycles. In the sections studied on the Dachstein Plateau, the boundaries of the Lofer cycles are usually erosional disconformities showing karstification features. Penetration by karstic solution was not more than a few decimetres, since during the recurrent sea-level drops the platform only slightly emerged above sea level. The reddish or greenish argillaceous carbonate interlayers (facies A) cannot be interpreted as in situ palaeosol horizons. They are tidal flat deposits consisting predominantly of subtidal carbonate mud redeposited by storms that was mixed with reworked airborne fine carbonate particles and argillite and/or reworked lateritic soil, which were accumulated on the subaerially exposed platform. Rip-ups from consolidated sediment, blackened intraclasts and skeletons of tidal flat biota may have also contributed to the sediment of facies A. Erosional boundaries of most of the investigated cycles, and definite features of karstic solution beneath the disconformities, suggest periodical drops of sea level followed by a renewed transgression. This appears to confirm the allocyclic model for the explanation of the origin of the Lofer cycles.     

Biostratigraphical correlation of late carboniferous (Kasimovian) sections in the Carnic Alps (Austria/Italy): Integrated paleontological data, facies, and discussion

Summary The fusulinacean faunal content of the Bombaso Fm. and lower part of the Auernig Group (Carnic Alps, Austria/Italy) is reviewed and completed by data on conodonts and algae. Four different faunal associations can be distinguished within this stratigraphic interval. The beginning of the postvariscan sedimentation in the investigated sections is diachronous, shifting in age from early Kasimovian (Krevyakinian) at Zollner Lake and Mt. Auernig, early to middle Kasimovian at Cima Val di Puartis to late Kasimovian (Dorogomilovian) at Mt. Ro?kofel. The sections analyzed consist of shallow-marine sediments, which differ in microfacies of limestones and partly in biotic assemblages. They are geographically isolated and could not be traced laterally for lithologic correlation in the field. The biostratigraphic correlation with the faunas of the stratotype sections in the Moscow Basin is hindered by the searceness of fusulinaceans in the critical levels, especially in the lowermost Kasimovian, and differences in the species composition. A biostratigraphic correlation of the Bombaso Fm. and basal part of the Auernig Group with the Peski Fm. (Myachkovian) of the Moscow Basin, as suggested byDavydov & Krainer (1999), is not confirmed by our results. Due to our taxonomic reinterpretation of the oldest fauna (Protriticites aff.permirus with distinct mural pores and largeBeedeina (Pseudotriticites) asiaticus) a lowermost Kasimovian (Lower Krevyakinian) age is more probable. This correlation is supported by the co-occurring conodont fauna, which is suggested to belong to the zone of “Streptognathodus subexcelsus”. This biozone reaches from the topmost Peski Fm. to the Suvorovo Fm. (Lower Krevyakinian) in the Moscow Basin, and may be correlated with the uppermost Desmoinesian of the Midcontinent North America. Fusulinaceans and conodonts of the overlying strata at Zollner Lake and from the sections at Cima Val di Puartis and Mt. Auernig most probably correspond to the upper Krevyakinian/lowermost Khamovnikian of the Russian platform (Lower Missourian of the Midcontinent North America). The algal associations (Dvinella, Beresella, Herakella) from these lowermost strata are unique for the Carnic Alps. Their stratigraphic range points to Moscovian-Kasimovian as well, and fits with the fusulinacean and conodont data. Sediments of the N?lbling Group (=“untere kalkreiche Schichtgruppe”) have their correlative levels in the upper Khamovnikian, but reach higher into the Dorogomilovian. More reliable correlations are possible with the fusulinacean faunas of the Cantabrian Mts. and Central Asia, based on the coincidence of several species. A revised biostratigraphic correlation with the different remote basins of the Paleotethyan realm and the Russian Platform is given, based on own data and recent results by the members of the SCCS Working group to define a GSSP close to the Moscovian/Kasimovian boundary. The sequence-stratigraphic scheme, the systematics, and the biostratigraphic correlation ofDavydov & Krainer (1999) are discussed.     

Taphonomy of fossil macro-invertebrate assemblages as a tool for ecostratigraphic interpretation in Upper Jurassic shelf deposits (Prebetic Zone, southern Spain)

Composition and taphonomy of macro-invertebrate fossil assemblages, together with facies analysis, have been approached in order to interpret shifting paleoenvironmental conditions in the External Prebetic (S-SE Spain) during the early Late Jurassic (Middle Oxfordian). In oolitic and spongiolitic limestones, the size of fossil remains, mode of preservation, within-bed position, corrasion, fragmentation, epibiont and biogenic encrustation, disarticulation and uncoupling, allow recognition of two taphofacies, respectively. Identified ecostratigraphic events and trends accord with rapid flooding under high-energy conditions related to ecospace enlargement for cephalopods and then the persistence of lower energy, long-lasting exposure of skeletals and higher sedimentary rates. The paleoenvironmental interpretation is consistent with neritic environments shifting from shallow carbonate to hemipelagic sedimentation and enlarging of shelf ecospace for marine invertebrates.