ABSTRACT Although tectonically dislocated at present, the paleogeographic zones of the northern Eastern Alps formed an interconnected paleobathymetric setting during the Upper Cretaceous (Coniacian to Maastrichtian). By comparing the paleoenvironments of the five sedimentary regions, paleo-oceanographic and paleobathymetric models are presented for the northern part of the Alps. These results are in agreement with recent oceanographic findings. The sediments of the Helvetikum Zone represent continental shelf facies in the north, whereas the Ultrahelvetikum and Marginal Flysch Zone facies indicate upper to lower areas of the continental slope in the northern Tethys. The Flysch Zone exhibits a large scale subduction of the Penninic oceanic-basin. Litho- and biofacies data suggest that the Flysch basin corresponds to an abyssal-trench environment, while wildflysch and conglomeratic turbidite sediments of the Marginal Flysch Zone indicate tectonic fragmentation of the northern slope areas of the Flysch-trench. The Gosau Zone, on the other hand, represents an arctrench gap environment in the south. The Gosau basins were developed on a tectonically mobile Triassic to Jurassic calcareous platform that advanced to the north since the Lower Cretaceous and evolved into a submarine plateau with trench-like basins during the Upper Cretaceous. These basins then received turbidite sediments during the Campanian and Maastrichtian. The record of the Gosau sediments reveals an intra-Gosau synsedimentary tectogenesis of the Austro-Alpine units. Compared to recent bathymetric data (DSDP), it is suggested the Flysch basin was located below the calcite compensation depth (CCD) in a depth range of about 3,000–5,000 m. The neighboring basins, i.e., the depositional sites of the Ultrahelvetikum and Marginal Flysch in the north, were situated above the CCD, although the mid-slope basin (Marginal Flysch) studied was located below the foraminiferal lysocline. The three Gosau basins studied represent various depth levels, relative to the calcite compensation zone, suggesting a differential subsidence of the calcareous platform during the Coniacian to Maastrichtian tectogenesis. The Reichenhall and Gosau Basins subsided to middle and upper bathyal depths and were above the CCD, the Kössen Basin subsided below a local CCD indicating a strong vertical motion related to isostatic adjustment of the basement rock. ZUSAMMENFASSUNG Die Zonen des nördlichen Teils der Ostalpen, heute tektonisch disloziert, standen in der Oberkreide in einem kontinuierlichen paläobathymetrischen Zusammenhang. Durch einen Vergleich der Ablagerungsräume der fünf wichtigsten Zonen kann ein paläoozeanographisches Bild für einen Teil der nördlichen Ostalpen entworfen werden. Die Ergebnisse wurden mit den rezenten ozeanographischen Konstellationen verglichen. Die Sedimente der Helvetischen Zone im Norden stellen Schelfablagerungen dar, während die Ultrahelvetische Zone und die “Randflysch-Zone” Sedimentationsgebiete vom höheren zum tieferen “Continental-slope” repräsentieren. Die Flysch-zone weist auf eine großräumliche “Subduction zone” im Penninischen Trog hin. Litho- und biofazielle Ergebnisse lassen annehmen, daß das Flyschbecken einem abyssalen Trog entsprach, während die “Randflysch-Zone” (mit Wildflysch und konglomeratischer Turbidit-Fazies) auf den unmittelbar nördlich anschließenden Kontinental-Abhang hinweist, der unter starker tektonischer Zerstückelung stand. Die Gosau-Becken entwickelten sich auf einer mobilen triadischen-jurassischen Plattform (Nördliche Kalkalpen), die seit der Unterkreide nordwärts wanderte. Auf dieser submarinen Plattform bildeten sich während der Oberkreide durch Zerbrechung grabenähnliche Becken. Die sehr unterschliedlichen Sediment-Abfolgen der Gosau zeigen diese starke, synsedimentäre intra-gosauische Tektogenese der kalkalpinen Plattform. Im Vergleich mit Rezentdaten wird auf eine Bildungstiefe des Flysch unter der CCD geschlossen. Die “Randflysch-Zone” reichte unter die Foraminiferen-Lysokline, während der Ablagerungsbereich des Ultrahelvetikums über der CCD und Lysokline lag. Die untersuchten Gosau-Becken zeigen Ablagerungsserien aus sehr unterschiedlichen Tiefenbereichen; dies zwingt zu der Annahme einer sehr differenzierten Absenkung der kalkalpinen Plattform während der Oberkreide. Die Becken von Reichenhall und dem Gosautal erreichten das mittlere Bathyal oberhalb der CCD, während das Becken von Kössen unter die CCD abgesenkt wurde.

Abstract The interplay of Late Cretaceous basin subsidence and oscillations in sea level produced a mixed freshwater–marine succession within the Upper Cretaceous Gosau Group of the Northern Calcareous Alps. Cored sections from wells of the Glinzendorf and Gießhübl Syncline, as well as sediments from the outcrop area of Grünbach–Neue Welt and Slovakian equivalents have been investigated for their stable isotopic composition. Bulk carbonate δ 13 C and δ 18 O values of 116 fine-grained samples (shales, siltstones, marls) and 87 Sr/ 86 Sr values of 10 samples from the borehole Markgrafneusiedl T1 were analysed in order to distinguish between non-marine and marine deposits and to compare and correlate isotope characteristics of the different Gosau synclines and basins. Non-marine samples have significantly lower mean δ 13 C values compared to the mean of marine samples. The discrimination between a marine and non-marine group using δ 18 O is also highly significant statistically, even though the difference between the average non-marine and marine values is small. Strontium isotope values of marine intervals are near the range of values of normal Upper Cretaceous sea water but show a trend towards higher ratios in marginal marine and non-marine deposits. Although diagenesis and the detrital carbonate admixture partly influence the isotopic composition, the original environmental signal can still be reliably identified.

Abstract This field trip leads from Munich through the nappe stack of the Northern Alps. The folded Molasse zone, which clearly reacted to the tectonic events in the alpine collision zone. The Flysch zone covers the underfilled deep sea basin along the Cretaceous pre-collisional active margin. The Helvetic nappes carry Cretaceous to Paleogene sediments that show strong facies differentiation due to an increasingly unstable European platform. These will be visited in two isolated windows. A cross section through a good part of the Northern Calcareous Alps along the Valepp Valley will give insight into the structure of the fold-and-thrust belt and the pre- and post-Gosau phase deformation. Sedimentological response to Late Cretaceous geodynamic processes will, finally, be studied in the famous Muttekopf area and its spectacular outcrops

ABSTRACT An Upper Cretaceous biolithitic complex exposed at Donje Orešje on Mt. Medvednica, Yugoslavia (northern Croatia), is composed of a central portion designated as a barrier-reef made up of rudistid and coral bioherms. Associated with the barrier-reef are fore-reef and peri-reefal breccias (reef talus) that originated from destruction of the reef-front. This breccia is unsorted, and contains the rubble of reef building organisms and biocalcarenite fragments. The breccia grades into detrital limestones, and more distally, the sediments are basinal hemipelagic and pelagic limestones with conspicuous turbidity features (“Scaglia”-beds). The backreef area contains nerineid (gastropod) biostromes and detrital limestone. The lagoon is mainly represented by clastic terrigenous deposits, through some rudist patch-reefs (“Gösau”-beds) occur rarely. Sporadically, the lagoon also exhibits fresh water characteristics. The reef-flat was successively contaminated by terrigenous clastic material transported from the lagoon, e.g., material derived from erosion on an island arc. The porous reef-frame acted as a barrier, preventing transport of clastic material toward the open sea, but trapping it in the lagoon. Areas with no barrier-reefs, or the areas where the reef was breached or destroyed, turbidity currents could and did deposit flysch-type sediments into the basin. Numerous fossils (rudists, corals, benthic and pelagic foraminifers, and nannoplankton) indicate that the Donje Orešje biolithitic complex is Upper Cretaceous in age (Santonian to lower Campanian). Barrier-reefs of the Donje Orešje type developed in the Upper Cretaceous and lower Paleogene of the Inner Dinarides on the slopes of island arcs. These island arcs and correlative trenches, as well as the inter-arc basins, were formed in a subduction zone of Tethyan oceanic crust beneath the Panonian, e.g., Rhodope Plate. The subduction zone is characterized by the occurrence of ophiolites and mélanges. The Adriatic Plate (the Outer Dinarides) is marked by uniform shallow water carbonate sedimentation (“Carbonate platform”). During its east-ward motion this plate was uplifted at the end of Cretaceous time (“Laramian Orogeny”), and accordingly sedi-mentation reflects regression and bauxite deposition. However, a continuous depositional sequence between Cre-taceous and Paleogene time has been determined for the Inner Dinarides. Apparently, there was not one simple slope between the Outer and Inner Dinarides, with transition from shallow water to basin sediments in the sense of a “classical géosynclinal concept,” but shallow water and basinal facies were successively reestablished due to the influence of island arcs. Distribution of the biolithitic complexes and other Upper Cretaceous facies in regular bands demonstrates that since Cretaceous time there has not been any regionally extended nappes. Such overthrustings would certainly have dislocated the original paleogeographical distribution of Upper Cretaceous facies belts. The main Dinarides “orogenic phase” occurred by the end of the Eocene, when intensive northward and northeastward movement of the African Craton caused a maximal compression and junction of the Adriatic and Panonian Plates. As a consequence, tectonic movements on the plates, as well as in the area of the “oceanic suture” of the Inner Dinarides, brought about the uplift of the Dinarides.

Abstract The classical Alpine folded belt of the Northern Calcareous Alps (NCA) of Austria is correlated with the Transdanubian Central Range (TCR) of Hungary using structural and stratigraphic relationships to restore the system. The semiquantitative map-view restoration of several consecutive Alpine deformational periods reveals unexpected similarities between the NCA and TCR. In fact, some west–northwest-trending right lateral strike-slip faults in the TCR (e.g., Telegdi-Roth, Padrag, and Vargesztes faults) are interpreted here for the first time to be analogous to those described from the NCA (e.g., Lammertal, Wolfgangsee-Windischgarsten, and Hochwart faults). These middle to late Miocene transpressional faults are reactivated in the Late Cretaceous tear faults, as can be documented by reflection seismic data in the subsurface of the southeastern Danube Basin. The structural correlation between the NCA and TCR provides further evidence for the much debated interpretation of the TCR in terms of a large Eo-Alpine (Cretaceous) nappe-system in an Uppermost Austroalpine structural position. Furthermore, recognition of a once continuous, regional-scale, right lateral strike-slip fault system in the NCA-TCR areas has a significant impact on the pre-Tertiary kinematic reconstructions of the broader Eastern Alps and Pannonian Basin region.