Michael W. Rasser

Application of neontological taxonomic concepts to Late Eocene coralline algae (Rhodophyta) of the Austrian Molasse Zone

Traditionally, different diagnostic characters have been used in the identification of fossil and Recent coralline algal genera. The taxonomy of fossil coralline algae has focused on well calcified features such as basal filaments and conceptacle perforation. In contrast, the taxonomy of Recent material uses a combination of several features with a low fossilization potential, such as epithallial cells and structures of sexual reproductive organs. In the studied material of the Late Eocene Austrian Molasse Zone Lithoporella, Neogoniolithon, Spongites, Phymatolithon and Sporolithon are identified and described applying features of neontological taxonomic concepts. These features are: (1) the arrangement of basal filaments; (2) the occurrence of cell fusions; (3) the relative length of subepithellial initials; (4) the conceptacle perforation; (5) the orientation of filaments around the conceptacle pore; and (6) the type of conceptacle roof formation. Some of these features were thought to be unpresentable in fossil material until recently. The fossilization potential of diagnostic features and the identification of the documented genera and species are discussed in detail. Moreover, a checklist for the description of fossil taxa is provided.

Coralline red algal limestones of the late Eocene alpine Foreland Basin in Upper Austria: Component analysis, facies and palecology

SummaryLate Eocene sediments of the Upper Austrian Alpine Foreland Basin discordantly overlie Mesozoic and crystalline rocks, which are deeply eroded and form a distinct pre-Eocene relief. Late Eocene deposits contain red algal limestones with a remarkable lateral extent and a high diversity of sedimentary facies. Towards the south the algal limestones change into more clastic sediments, which are characterized by larger foraminifera and bryozoans. Main components are coralline algal branches and detritus, coralline crusts, rhodoliths, peyssonneliacean aggregates and crusts, nummulitid and orthophragminid foraminifera, corals, bryozoans, as well as terrigenous components.Rank correlation and factor analysis were calculated in order to obtain informations about relations between components. Hierarchical cluster analysis allowed the designation of 17 facies, most of them are dominated by coralline algae. Actualistic comparisons and correlations obtained from statistical analyses allowed the reconstruction of the depositional environments.Main features of the northern area are huge accumulations of unattached coralline algae (branches, rhodoliths, detritus), which are comparable to the present-day “Maerl”-facies. They formed loose frameworks cut by sand channels. The frequency of coralline detritus decreases upsection. Peyssonneliacean algae in higher parts of the profiles show growth-forms that are comparable to peyssonneliaceans of the Mediterranean circalittoral soft bottoms. This succession can be interpreted by an increasing relative sea level. Besides, crustose coralline algal frameworks were growing on morphological highs which are partially comparable to the present-day “Coralligéne de Plateau” of the Mediterranean Sea.In contrast to the northern area, sedimentation rate of the southern area is too low to keep up with rising sea level. The typical succession from nummulitid- to orthophragminid-and bryozoan-dominated facies can be interpreted by an increasing water depth from shallowest subtidal to the deeper photic zone and finally to the aphotic zone.

Provenance analysis of Oligocene autochthonous and allochthonous coralline algae: a quantitative approach towards reconstructing transported assemblages

Abstract The Oligocene shallow-water carbonates of the Lower Inn Valley (Tyrol, Northern Calcareous Alps) contain a rich coralline algal flora. These carbonates are known from two distinct settings: (1) autochthonous limestones and (2) debris flows intercalated with deeper water marls. The carbonate facies are dominated not only by crustose coralline algae (Corallinaceae, Rhodophyta), but also by smaller and larger benthic foraminifers, bryozoans, corals as well as lithoclasts of Triassic origin. Five species of coralline algae are identified and described in detail: Lithoporella melobesioides , Lithothamnion sp. A, Lithothamnion sp. B, Mesophyllum sp., and Sporolithon sp. The distribution of algal taxa shows distinct relationships to non-algal biota and substrates: L. melobesioides preferably encrusts other coralline algae, Lithothamnion sp. A is found encrusting bryozoans, Lithothamnion sp. B encrusts corals, while Mesophyllum sp. grows directly on fine-grained, soft substrates. Besides the fact that algal taxa reveal close relationships to other components, it can also be shown that algal assemblages are highly correlated to carbonate facies types. Hierarchical cluster analysis based on the relative abundance of taxa reveals five coralline algal assemblages showing distinct distribution patterns among carbonate facies. While two of the assemblages are restricted to the debris flows, the other three were found in both debris flows and autochthonous occurrences. A correlation between algal assemblages and carbonate facies allows the following conclusions to be made: (1) Both coralline algal taxa in particular and algal assemblages as a whole show distinct relations to water depth (herein referred to as a summary of light conditions and hydrodynamic energy) and substrate relationships. This makes them potentially valuable indicators for palaeoecological reconstructions. (2) Most of the coralline algal assemblages in allochthonous occurrences (i.e. debris flow) can be traced back to facies patterns in autochthonous occurrences. This indicates that a thorough microfacies analysis combined with a systematic study of specific components can be very useful in the reconstruction of palaeoenvironments, even if these are not preserved in their original context. (3) Some of the coralline algal assemblages within debris flows cannot be traced to autochthonous facies and do not seem to reflect primary facies compositions as they contain an atypical mixture of algal taxa and other components. These are characterised by a relatively high abundance of lithoclasts (usually >20% of the components) and a high degree of fragmentation of coralline algae thalli.

Autochthonous facies and allochthonous debris flows compared: Early oligocene carbonate facies patterns of the Lower Inn Valley (Tyrol, Austria)

SummaryThis study presents a microfacies analysis and palaco-environmental interpretations of Early Oligocene carbon ates from the Lower Inn Valley Tertiary (“Unterinntal-Tertiär”) of Austria. The well preserved biogenic components allow detailed investigations of component relationships and controlling ecological parameters. The carbonates are dominated by coralline algae, corals, small and large benthic foraminifers, bryozoans and lithoclasts. Bivalves, gastropods, echinoderms, brachiopods and serpulids are subordinate. The limestones are present as A) autochthonous carbonates transgressing directly above the Triassic basement and B) allochthonous debris flows within deeper-water marls. These carbonates are found within the Paisslberg Formation. The Werlberg Member within this formation, pertains to the autochthonous carbonates and larger debris flows.Five facies types are separated following fabric analysis and statistical treatment (correlation, cluster analysis, principal components analysis) of semi-quantitative data consisting of component frequencies of thin sections. Facies distribution patterns are principally controlled by variations in substrate characteristics, turbulence and light along a depth gradient. Reconstruction of facies pattern distribution reveal both lateral and proximal-distal facies trends: coral-coralline algal facies, coralline algal facies as well as foraminiferal facies were situated in shallower environments, laterally adjacent to each other. These grade distally into coralline algal-bryozoan facies, bryozoan facies and finally into mollusc rich marls. Debris flows consisting of reworked material from all of the known facies (bioclastic packstone facies) is restricted to the debris flow and possible represents transport induced differentiation of components and grain size within distal debris flows.

Paleoecology and Taphonomy of Polystrata alba (Red Alga) from the Late Eocene Alpine Foreland: A New Tool for the Reconstruction of Sedimentary Environments

Abstract Polystrata alba (Pfender) Denizot, 1968 (Peyssonneliaceae, Rhodophyta) in Late Eocene algal limestones of the Upper Austrian Alpine Foreland Basin forms (1) horizontal crusts, (2) subspherical and irregular, unilayered rhodoliths with sediment-filled inner cavities, and (3) rhodoliths. Most of the described growth forms are unique and previously have not been described from fossil material. Comparisons with present-day analogues, however, reveal that most growth features can be explained by the interplay between sediment input and bottom stability. This actualistic approach allows the reconstruction of paleoecologic and taphonomic processes that influenced both growth forms of P. alba and the resulting sedimentary facies. The model described in this study provides a useful tool for the reconstruction of paleoenvironmental conditions.

Microtaphofacies: Exploring the Potential for Taphonomic Analysis in Carbonates

The microtaphofacies of Paleogene carbonates from three time units (Middle Eocene, Late Eocene and Early Oligocene) from the circumalpine area are described and compared. These carbonates are dominated by various larger foraminiferal and coralline red algal facies with subordinate coral and bryozoan facies.

Biostratigraphy and palaeoecology of a Middle Miocene (Karpathian, MN 5) fauna from the northern margin of the North Alpine Foreland Basin (Oggenhausen 2, SW' Germany)

The Oggenhausen fauna from the northern margin of the North Alpine Foreland Basin includes eight gastropod species, various crustacean claws, four fish species, twelve amphibian species, eight reptile species, a few indeterminate bird remains and 23 mammal species. The rodent fauna, especially the coexistence of the hamsters Megacricetodon aff. bavaricus and Megacricetodon aff. minor, allow for the most precise stratigraphic correlation within the MN 5 unit. It is younger than the faunas of Puttenhausen classic, Engelswies and Schellenfeld, but older than Ebershausen, Mohrenhausen, Furth and Frohberg. The vertebrate assemblage indicates a mixed environment with a shallow lake, ample vegetation nearby and an open hinterland. According to the aquatic inverte brates there were also ephemeral waters or marginal lakes portions that periodically dried out. The terrestrial gastropods suggest the co-existence of both wet, woody habitats, and more open environments.

The chondrinid land snail Granaria (Stylommatophora: Chondrinidae) in the Miocene of the Alpine Foreland: State of the art and taxonomic reassessment

Chondrinid snails are common in Middle to Late Miocene freshwater sediments of the North Alpine Foreland Basin (Molasse Zone) and the deposits of adjacent, time-equivalent fossil lakes, but their taxonomic status is unclear in most cases. This paper provides a taxonomic reassessment of this group. Granaria is the only genus of chondrinid snails identified in fossil material thus far. A neotype for Granaria schuebleri (Klein, 1847) is defined, while G. antiqua (Schubler in von Zieten, 1832) is considered a synonym of G. schuebleri (Klein, 1847). It is suggested that G. grossecostata (GottSchicK & WenZ, 1919) be accepted as a separate species instead of a subspecies of G. schuebleri (Klein, 1847). The taxonomic status of G. noerdlingensis (Klein, 1853) seems very doubtful, because the original description is based on incomplete casts and steinkerns. In Steinheim am Albuch, the type locality of the common species Granaria schuebleri (Klein, 1847), two further species could be confirmed, namely G. grossecostata (GottSchicK & WenZ, 1919) and G. pachygastra (FraaS in Miller, 1900). The original specimen of Pupa n. sp. (Klein 1853) was located, but a species designation is impossible due to its poor preservation.

Paleoenvironmental and diagenetic implications of δ18O and δ13C isotope ratios from the Upper Jurassic Plassen limestone (northern Calcareous Alps, Austria)

Abstract The first δ 18 O and δ 13 C data from the Upper Jurassic of the Northern Calcareous Alps are presented. The interpretation of stable isotope ratios serves as an approach for paleoenvironmental and diagenetic studies of the Plassen carbonate platform, which cannot be obtained by paleontological methods and microfacies analyses alone. The studied part of the Plassen limestone is characterized by (1) lithoclast facies, also called ‘intraformational breccia’; the origin of lithoclasts was formerly unknown; (2) peloid facies; (3) bioclastic facies, composed of peloids, porostromate algae, green algae and red algae; and (4) oncoid facies. Two types of fracturing and four cement generations can be distinguished. Isotope ratios of the matrix, oncoids, three cement generations and whole rock samples revealed that (1) the studied section represents an open marine carbonate platform with high water circulation and high input of cool oceanic waters; (2) the platform was not affected by emersion and fresh water influence; normal marine conditions prevailed; (3) carbonate cements were precipitated in a closed diagenetic system, but burial diagenesis was absent; (4) both fabric-selective and non-fabric-selective fracturing occurred in a normal marine environment, affecting the formation of ‘intraformational breccias’.

Miocene continental gastropods from the southern margin of the Swabian Alb (Baden-Württemberg, SW Germany)

The Middle Miocene silvana-beds outcropping at the southern margin of the Swabian Alb bear a wide array of terrestrial and freshwater gastropods. Especially in the surroundings of the Emerberg and Tautschbuch hills, there are records of several collection sites. In the present work, we investigated material from the historical localities from these two regions, housed in museum collections, in order to provide an updated check list, synthesizing the knowledge of the region in the hopes to spur renewed interest. In total, we report 14 freshwater and 50 land snail species from the area, but not all species reported in the literature could be confirmed.