99 Stop A 3 / 3 PICHLER SECTION ( GAMS )

Austrian Journal of Earth Sciences, 2009

In the Styrian Basin, early Miocene marine sedimentation of the Karpatian (upper Burdigalian) ended with basin shallowing, marrd ked regression and tectonic movements. The Karpatian sedimentation cycle corresponds to the global 3 order cycle TB 2.2, followed by the Bur5/Lan1 sea-level fall. This regression was combined with tectonic movements (the Styrian Tectonic Phase), seen in the Styrian Unconformity by an angular discordance at the Wagna and Katzengraben outcrops and also in deep wells. Sediments of the first middle Miocene (Badenian/Langhian) transgression are commonly eroded or reduced in thickness at the basin borders. In the basin center, the bathyal environment continues from the Karpatian to the Badenian. Sediments of the first Badenian transgression have been dated by calcareous nannoplankton as NN4 and correlated by the occurrence of Praeorbulina sicana with the basal rd Langhian. The 3 order sequence corresponds to TB 2.3. The erosional phase of the sea-level fall Lan2/Ser1 can only be observed in near-shore facies, followed by transgressive beds within Zone NN5, which represents the second, main Badenian transgression in the Central Paratethys and corresponds to the long global cycle TB 2. The highstand system tract of this cycle is expressed in rd carbonate build-ups of the Weissenegg Formation. According to the global 3 order sequences, the youngest sediments of the Retznei section (< 14.39 Ma) overlying the carbonate buildups belong to the falling-stage system tract of TB2, but did not record regression, but instead continuous deepening of the Styrian Basin, indicating strong subsidence during the early middle Miocene. Die marine Sedimentation während des älteren Miozäns (Karpatium / Oberes Burdigalium) endete im Steirischen Becken mit einer starken, durch tektonische Bewegungen verstärkten Regression. Der Sedimentationszyklus im Karpatium entspricht der globalen Sequenz TB 2.2 und wird durch das Absinken des Meeresspiegels (Bur5/Lan1) begrenzt. Die Kombination der Regression mit den tektonischen Bewegungen ("Steirische Tektonische Phase") ist als Winkeldiskordanz und Sedimentationsunterbrechung ("Styrian

Minerals

This study investigates the Paleogene deep-water depositional system of the Gosau Group at Gams, Styria (Austria). The examined sections of the Danian to the Ypresian age (NP1–NP12) comprise sediments of the Nierental and Zwieselalm Formations. Four deep-water clastic facies assemblages were encountered: (1) pelagic marls with thin turbidites, (2) carbonate-rich turbidites, (3) carbonate-poor turbidites, and (4) marl-bearing turbidites; slump beds and mass flow deposits are common features in all facies assemblages. Based on heavy mineral, thin section, microprobe, and paleoflow analyses, provenance was from the surrounding Northern Calcareous Alps (NCA) rocks and exhuming metamorphic Upper Austroalpine units to the south. In addition, biogenic calcareous material was delivered by adjacent contemporaneous shelf zones. The sedimentary depocenter was situated at the slope of the incipient Alpine orogenic wedge, in frontal parts of the NCA, facing the subducting Penninic Ocean/Alpine T...

Palaeogeography, Palaeoclimatology, Palaeoecology, 2005

The 40 m thick Untersberg section (Salzburg, Austria) of the Northern Calcareous Alps comprises the Palaeocene-Eocene transition and spans the upper part of calcareous nannoplankton zone NP9 and the lower part of zone NP10 (subzone NP10a). These zones are equivalent to planktonic foraminifera zone P5 and the lower part of zone P6 (sub-zone P6a). The succession was deposited in a lower bathyal slope environment at a palaeodepth of about 2000 m. Within the dominantly marlstone succession, a 5.5-m-thick intercalation of red and green claystone and marly claystone represents the global negative carbon isotope excursion (CIE) which is used to recognize the Palaeocene-Eocene boundary. The CIE was associated with a shallowing of the calcite compensation depth by at least 1 km. Throughout the section, clay mineral assemblages are dominated by smectite, indicating a seasonal climate with alternating wet and dry conditions. A 49% increase in detrital quartz and feldspar within the CIE-interval suggests enhanced continental runoff. This was probably the result of the establishment of a monsoonal setting, in which vegetation was sparse, while periodic high rainfall caused pronounced sediment transport. The increased terrestrially derived input is associated with abundant radiolarian casts indicating high primary productivity. This suggests that seasonal nutrient pulses resulting from intensified precipitation during the wet season have caused high surface-water fertility. The benthic foraminifera faunas of the samples rich in siliceous plankton are strongly dominated by Glomospira spp., Nuttalides truempyii, Abyssamina poagi, Anomalinoides praeacutus, Anomalinoides nobilis, and Oridorsalis spp. We assume that the Glomospira-Nuttalides fauna consists of opportunistic species which quickly react to seasonally varying amounts of food. The calcareous nannoplankton assemblage of the CIE-interval is characterized by the first occurrences of the genus Rhomboaster and of Discoaster araneus and Discoaster mahmoudii, whereas Scapholithus apertus become extinct at the Palaeocene-Eocene boundary. Within nannoplankton sub-zone NP10a, a series of primarily basaltic ashes give evidence for a major episode of explosive volcanism which can be correlated with the positive ash-series of the Fur-Formation in northern Denmark.

2013

The northern Tethyan margin is a key region for determining environmental changes associated with the collision of continental and oceanic tectonic plates and Alpine orogeny. Herein we investigated Middle to Late Eocene neritic to bathyal sediments deposited during an interval of unstable climatic conditions. In order to quantify paleoenvironmental changes, we developed a detailed age model based on biozonations of planktic foraminifera, calcareous nannoplankton, and larger benthic foraminifera. The section at Adelholzen covers the almost complete Lutetian Stage (calcareous nannoplankton zones NP15a-16, planktic foraminifera zones E8-11, shallow benthic (foraminifera) zones SBZ13-15) and large parts of the Priabonian Stage (NP18-20, E14/15), while the intermediate Bartonian Stage (NP17) is completely missing. Foraminiferal, calcareous nannoplankton, and macrofossil assemblages were analyzed for changes in paleo-water depth, mixing and stratification, paleo-primary productivity (pPP), food supply, and bottom water oxygenation. Paleo-water depth estimates range from 50 m (middle neritic, early Lutetian) to nearly 500 m (upper bathyal, late Priabonian). The combination of assemblage composition, planktic and benthic foraminiferal accumulation rates, and derived parameters (carbon-flux to sea floor, pPP) enabled us to identify a series of distinct paleoceanographic events of at least regional significance. Such events are characterized by considerable changes in primary productivity or reduced bottom water ventilation. Calculated pPP-values indicate oligotrophic conditions throughout. Der nördliche Tethysrand ist von besonderer Bedeutung für die Ermittlung von Umweltveränderungen verbunden mit der Kollision kontinentaler und ozeanischer Platten, sowie der alpinen Orogenese. In diesem Beitrag untersuchen wir neritische bis bathyale Ablagerungen des mittleren bis späten Eozäns, einer Periode instabiler Klimabedingungen. Um die Umweltveränderungen quantifizieren zu können, wurde auf der Basis von Biozonen planktischer Foraminiferen, kalkigem Nannoplankton, und Großforaminiferen ein genaues Altersmodell entwickelt. Das Profil von Adelholzen umfasst fast das gesamte Lutetium (kalkige Nannoplankton Zonen NP15a-16, planktische Foraminiferen Zonen E8-11, "shallow benthic (foraminifera) zones" SBZ13-15) und weite Teile des Priaboniums (NP18-20, E14/15). Das dazwischenliegende Bartonium (NP 17) fehlt vollständig. Foraminiferen, kalkiges Nannoplankton und Makrofossilassoziationen wurden auf Veränderungen der Paläowassertiefe, Durchmischung und Schichtung, Paläoprimärproduktivität (pPP), Nahrungszufluß und Bodenwasserbelüftung hin analysiert. Die Paläowassertiefen reichen von 50 m (mittleres Neritikum, frühes Lutetium) bis nahezu 500 m (oberes Bathyal, spätes Priabonium). Die Verbindung aller Fossilassoziationen mit planktischen und benthischen Foraminiferenakkumulationsraten sowie abgeleiteten Parametern (Kohlenstoff-Fluß zum Meeresboden, pPP) erlaubte die Identifizierung mehrerer unterschiedlicher paläoozeanographischer Ereignisse von mindestens regionaler Bedeutung. Diese Ereignisse zeichnen sich durch deutliche Änderungen der Primärproduktivität und Sauerstoffversorgung im Bodenwasser aus. Die errechneten pPP-Werte deuten auf durchgehend oligotrophe Bedingungen hin. ____________________________________________________ _________________________ KEYWORDS planktic and benthic foraminifera deepening upward sequence calcareous nannoplankton paleo-primary productivity northern Tethyan margin paleo-water depth Eocene

Stratigraphy, Composition, Origins, and Paleoceanographic and Paleoclimatic Significance, 2009

Austrian Journal of Earth Sciences

Abstract The northern Tethyan margin is a key region for determining environmental changes associated with the collision of continental and oceanic tectonic plates and Alpine orogeny. Herein we investigated Middle to Late Eocene neritic to bathyal sediments depo- sited during an interval of unstable climatic conditions. In order to quantify paleoenvironmental changes, we developed a detailed age model based on biozonations of planktic foraminifera, calcareous nannoplankton, and larger benthic foraminifera. The section at Adelholzen covers the almost complete Lutetian Stage (calcareous nannoplankton zones NP15a-16, planktic foraminifera zones E8-11, shallow benthic (foraminifera) zones SBZ13-15) and large parts of the Priabonian Stage (NP18-20, E14/15), while the inter- mediate Bartonian Stage (NP17) is completely missing. Foraminiferal, calcareous nannoplankton, and macrofossil assemblages were analyzed for changes in paleo-water depth, mixing and stratification, paleo-primary produ...

2013

aBhandlungen der geologischen BundesansTalT, Band 66 issn 0378-0864 isBn 978-3-85316-071-8 alle rechte für in-und ausland vorbehalten. Verlag: geologische Bundesanstalt, neulinggasse 38, a 1030 Wien. Technische redaktion: christoph Janda (geologische Bundesanstalt). lektorat: christian cermak (geologische Bundesanstalt). cover: monika Brüggemann-ledolter (geologische Bundesanstalt). Verlagsort: Wien. Ziel der "abhandlungen der geologischen Bundesanstalt" ist die dokumentation und Verbreitung erdwissenschaftlicher forschungsergebnisse. satz, gestaltung und druckvorbereitung: peter ableidinger im auftrag der geologischen Bundesanstalt. druck: grasl druck & neue medien gmbh, Bad Vöslau. franz neubauer university of salzburg department of geography and geology hellbrunnerstraße 34, a-5020 salzburg, austria

Austrian Journal of Earth Sciences, 2022

The Gosau Group (Turonian to Ypresian) of the Eastern Alps is a synorogenic wedge-top succession that accumulated in active depocenters in an oblique-convergent plate tectonic setting. Due to high morphological differentiation of depocenters by tectonism, the Gosau Group displays a wide range of facies as well as marked facies heteropy and thickness variations over short lateral distances. In the area of the locations Gosau and Russbach, the Hochmoos Formation along the SE basin margin near Gosauschmied comprises coastal to shallow-marine deposits and small rudist bioconstructions and was investigated by way of field mapping, profile descriptions, microfacies analysis, isotope measurements and assessment of fossil content. Strontium isotope ratios ( 87 Sr/ 86 Sr) from 0.707485 (oldest) to 0.707549 (youngest) indicate a latest Santonian age, with the youngest parts of the Hochmoos Formation possibly extending into the Campanian. On the west side of the study area, the succession of lithologies and fossil content record transgression of a fan-delta to marginal-marine environment (lowstand to transgressive systems tract), followed by shallow neritic deposition (part of the transgressive systems tract) and, finally, by progradational stacking of limestone beds in the highstand systems tract, culminating in growth of rudist thickets in an inner shelf and partially protected 'lagoonal' milieu. Eventually, at the inception of the following falling stage systems tract, input of large clasts of Dachstein Limestone, quartz and chert record a recurrence of the subaqueous part of a fan-delta. On the east side of the study area, a preponderance of rudist-clastic limestones over a few rudist biostromes preserved in situ indicate a normal-marine environment punctuated by high-energy events, such as storms or tsunami. The scarcity of benthic foraminifera and the presence of only isolated specimens of colonial corals underscore a habitat with a calcarenitic substrate frequently shifted by currents. Several lines of evidence indicate that the western part of the study area was more proximal relative to the eastern one. With a maximum thickness of 68 m, the Hochmoos Formation at Gosauschmied is slightly thicker and more distal than outcrops located nearer to the basin margin and farther towards the SE (Schmiedsippl, Katzhofgraben), but significantly thinner than the nearly 300 m at Gosau Pass-Gschütt, or the thickness of 170 m observed in the area of Rigaus-Abtenau farther in the West. These thickness variations are interpreted as a result of extensional syndepositional tectonism. At Gosauschmied, the vertical arrangement of facies records a cycle of relative sea-level change that may have been tectonically enhanced.

2012

Austrian Journal of Earth Sciences