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Manganese pebbles from Hochschartehöhlesystem (the Hoher Göll Massif, Austria) : insight into potential genesis and provenance

Kicińska Ditta, Michniewicz Jacek, Kubiak Michał

Annales Societatis Geologorum Poloniae

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2023

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Vol. 93, No. 2

211--223

EN

Heavy, black manganese pebbles have been found in the clastic sediments of the Hochschartehöhlensystem (the Northern Calcareous Alps). Six selected pebbles were subjected to X-ray diffraction, optical microscopy and optical and electron microscopy analysis. The results reveal that the main component of the pebbles is manganese silicate, braunite, Mn2+Mn3+6(SiO4)O8. Braunite is a mineral formed at elevated temperatures, mainly through hydrothermal, metamorphic or diagenetic processes. This means that the manganese pebbles were formed outside the caves. However, manganese rock was not found in situ on the surface of the Hoher Göll Massif. This probably indicates that their origin is from eroded parts of Mesozoic rocks. The first studies of pebbles and their mineralogy, by analogy with contemporary marine sediments, indicate that their genesis is related to spreading zones and accompanies hydrothermal vents. The analysed material highlights two important issues: (1) the manganese pebbles are significant arguments for the occurrence of hydrothermal vents in the Northern Calcareous Alps; and (2) the importance of cave sediments studies, which provide relevant evidence for palaeogeographic reconstruction.

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Origin of fine-grained clastic sediments in caves of the Hoher Göll massif (the Northern Calcareous Alps, Austria)

Kicińska Ditta

Annales Societatis Geologorum Poloniae

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2021

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Vol. 91, No. 4

363--373

EN

The Hoher Göll Massif is situated 20 km south of Salzburg and belongs to the Northern Calcareous Alps (Austria). It is a ridge ca. 11 km long and 3 km wide with the highest summit Hoher Göll (2522 m a.s.l.), encircled by deeply incised valleys with bottoms ca. 2,000 m below it. Cave clastic deposits were studied in the Hochschartehöhlensystem, Dämchenhöhle and Hintere caves. The caves belong to the Giant Cave Level, with the exception of part of the Hochschartehöhlensystem, that is Der Sprechender Steine Cave, the highest parts of which belong to the Ruin Cave Level. The sources of the cave sediments have been identified from the composition of the heavy fractions. Preliminary studies of the Hoher Göll caves reveal that the cave fills were derived from the Oligocene to earliest Miocene Augenstein Formation, the deposits of the Palaeo-Inn River and the siliciclastic basal strata of the Northern Calcareous Alps. The clastic material deposited as the Augenstein Formation was transported from southern parts of the Eastern Alps and by the Palaeo-Inn river from their western part. According to heavy minerals, the sources of the clastic material were on the Palaeozoic terrains, the post-Palaeozoic sequence, and the Middle Austroalpine Unit. Later, during or after the mountain uplift, weathered materials from the Augenstein and Palaeo-Inn deposits were eroded and transported from the surface into caves by allogenic streams. Some of the sediments were likely to have been transported later to the Giant Cave Level from the southern part of the Northern Calcareous Alps.

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The Steinplatte complex (Late Triassic, Northern Calcareous Alps, Austria) - subsidence-controlled development of a carbonate-platform-to-intrashelfbasin-transition

Kaufmann B.

Acta Geologica Polonica

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2009

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Vol. 59, no. 3

341-357

EN

In Rhaetian (Late Triassic) times, the Hauptdolomit/Dachstein carbonate shelf situated at the passive continental margin of the northwestern Tethys was characterized by an extensional tectonic regime. Rifting and spreading movements fragmented this shelf into a loosely fitted mosaic of fault-bounded blocks characterized by a differential subsidence pattern. This is expressed in significant thickness variations of platform carbonates and in the formation of the intrashelf Kossen Basin. In this study, it can be demonstrated that tectonic subsidence triggered the development of a carbonate platform margin and that the influence of eustatic sea-level changes was negligible. The Steinplatte complex developed at the transition of the Kossen Basin to the Dachstein Carbonate Platform. Small-scale isolated carbonate mounds situated on a smoothly inclined homoclinal ramp characterized the initial phase and acted as nuclei of further carbonate buildup growth. However, only the ideal palaeogeographic position far enough away from the carbonate-suppressive terrigenous influence of the Kossen Beds, combined with vigorous carbonate production stimulated by rapid subsidence-caused sea-level rise, favoured continuous mound growth. Once established, the carbonate buildup was characterized by rapid aggradational growth, developing a palaeogeographic high with a steep slope and a depression with decreased sedimentation behind, several kilometres distant from the Dachstein Carbonate Platform. Contemporaneously, isostatic adjustment caused an accommodation minimum on the nearby margin of the Dachstein Carbonate Platform leading to its westward progradation. Fading out of subsidence caused filling of the former depression in the back of the buildup by prograding shallow-water Dachstein Limestones. Thus, a new platform margin was established in the Steinplatte area, elevated almost 200 m above the adjacent Kossen Basin. At the Triassic-Jurassic boundary, the Steinplatte complex was subjected to subaerial exposure by a sudden tectonic uplift followed by a rapid isostatic drop. Emergence is indicated by levels of karstified limestones directly underlying supposed exposure surfaces. Final drowning of the Steinplatte complex as well as of the whole Dachstein Carbonate Platform is indicated by the cover of Early Jurassic (Sinemurian) deeper water, ammonitebearing limestones (Adnet Formation).

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Chronostratigraphic significance of an early Valanginian (Cretaceous) calpionellid association (Hochkogel section, Upper Austria, Northern Calcareous Alps)

Lukeneder A., Reháková D.

Geological Quarterly

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2007

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Vol. 51, No 1

27-38

EN

Early Cretaceous calpionellid samples were collected at the ammonoid-bearing Hochkogellocality in the southern most part of the Reichraming Nappe (Ebenforst Syncline, Northern Calcareous Alps). The microfossil fauna sampled from limestone parts of the Rossfeld Formation indicates an early Valanginian age. The standard Calpionellites Zone (with darderi and major subzones) coincides with the early Valanginian ammonoid zones of Busnardoites campylotoxus and Tirnovella pertransiens. The deposition of the limestones in this area occurred in an unstable environment disturbed by gravitational transport which accounts for the different sedimen tary components and accompanying fossils in the accumulated layers, transported from a source area situated to the south.

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Upper Jurassic - Lower Cretaceous platform to basin transition of the Northern Calcareous Alps

Fenninger A., Rasser M.

Volumina Jurassica

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2006

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Vol. 4, no. 1

87-87

EN

Tectonic events in the Upper Triassic caused the break of carbonate platforms in the Northern Calcareous Alps (NCA). Drawning and synsedimentary faulting stipulated a highly structured seaflor topography with sedimentation of crinoidal limestones, cherty limestones as well as cephalopod limestones on top of the Triassic platforms. This mainly pelagic development lasted until the Oxfordian with deposition of radiolarites and siliceous limestones. The Upper Jurassic to Lower Cretaceous development is linked to the opening of the Northern Atlantic and the Penninic Ocean and led to the break up of Pangea and the Austroalpine units. They became independent from the European Plate and are considered as microplate north of the Apulian Plate. Basin sediments of the central part of the NCA are represented by radiolarites and cherty limestones overlain by Tithonian to Valangian micritic sediments with intercalations of allodapic limestones. Carbonate breccias together with variagated nodular limestones and periplatform ooze are interpreted as slope deposits. Platform environments are represented by large carbonate mud areas with local patch reefs. Other reefal areas of the platform are dominated by "stromatoporids", "chaetedids", scleractinians and microincrusters binding reef rubble. Inner platform environments are dominated by "stromatoporids" while corals are subordinate. In open platform environments secondary framework builders can bind reef rubble. The Jurassic Alpine reefs reflect trends to coral adapted oligotrophic high-energy conditions, representing ancestors of modern reefs. Beside the typical reef guild organisms, gastropods (nerineids) and patches of dasycladales are typical for low energy environments.

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The Triassic/Jurassic boundary beds of the Karwendel Syncline (Austria) - initial report of a new GSSP candidate for the base of the Jurassic

von Hillebrandt A., Krystyn L., Kuerschner W.

Volumina Jurassica

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2006

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Vol. 4, no. 1

287-288

EN

The northwestern part of the Northern Calcareous Alps (NCA) is famous for its fully marine and complete Triassic/Jurassic transition beds formed in an intraplatform through of the western Tethys called as Eiberg Basin (Krystyn et al. 2005). A classic boundary section (Kendlbachgraben) with a relatively rich Rhaetian invertebrate fauna is known since 150 years but with the handicap of a 15 m gap between the last Triassic (Choristoceras marshi) and the first Jurassic ammonite (Psiloceras calliphyllum). A wealth of macro- and microfaunistic information has since been added (Golebiowski 1990) favouring a TJB directly on top of the Koessen Formation (Eiberg Member), just above the disappearance of many Triassic fossil groups (ammonoids, conodonts, brachiopods). New palynological and isotopic research in the area (Kuerschner et al. in press) now points to a boundary located 6 m higher within the Tiefengraben Member (or Grenzmergel) of the lower Kendlbach Formation where along with a distinct δ ¹ ³C shift the appearance of Cerebropollenites thiergatii marks the onset of Jurassic palynomorphs (Fig. 1). Another drastic negative C isotope excursion occurs at the top of the Koessen Formation concomitant with the disappearance of Triassic macrofauna, and both isotopic events can be recognized in boundary sections in England, Greenland and Nevada. The Triassic/Jurassic boundary (TJB) beds of the Karwendel Syncline (northern Tyrol) are well exposed at many places, easily correlatable by palynology (Fig. 1) and show a thicker (about 20 m), lithologically different, marl-dominated Tiefengraben Member with reddish clays ("Schattwald beds" auct.) at the base. They are richer and more diverse in micro- and macrofauna, and they contain an ammonite horizon around 7 m above the Koessen top with a new psiloceratid ammonite unknown from Europe and the Tethys realm. Based on its less intended suture line, the involute conch (umbilical width 40%) and juvenile tubercles (Knötchenstadium) the species is close to the South American earliest psiloceratid P. tilmanni but differs in a subtriangular cross-section. The new "Liassic" ammonite layer corresponds closely to the turnover in the Forminifera and to the onset of "Jurassic" ostracods (e.g. Cytherelloidea pulchella) as well as palynomorphs, with C. thiergatii as a first order correlation tool to marginal marine and continental basins. Bivalves in the basal Grenzmergel may bridge the present macrofaunal gap down to the Koessen Formation top but have still to be evaluated; a nannoplankton analysis is already under way. The investigated sections provide an important new insight in the nature of the physical and biological changes occurring around the boundary with rapidly changing palynomorph associations that point to several short-termed climatic oscillations. In which way they have affected the environmental conditions across the TJB and have controlled the stratigraphic ranges of biomarkers will be an important issue of the ongoing studies. Irrespective of any extinction scenario we see the fossil and geochemical record of the Karwendel Syncline as a major improvement of our knowledge of this time interval and as justified reason to introduce there a section as GSSP candidate for the Triassic/Jurassic boundary.

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First nearly complete skeleton of the Cretaceous duvaliid belemnite Conobelus

Lukeneder A.

Acta Geologica Polonica

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2005

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Vol. 55, no. 2

147-162

EN

The first Cretaceous belemnite preserved with the rostrum, slightly compressed phragmocone and part of the proostracum is described from the Early Cretaceous (Late Valanginian) Rossfeld Formation (Eibeck, Reichraming Nappe of the Northern Calcareous Alps). The rostrum has dorsal groove (alveolar furrow) typical of duvaliids, and its conical shape (round in transverse section outline), and the rounded apex allow its attribution to Conobelus Stolley, 1919. The new species C. pseudoheres sp. nov. is proposed based on the unique features of the specimen, i.e. persistently parallel lateral sides throughout the rostrum and the conical, blunt outline at the apex. The ration between rostrum and phragmocone is 0.78; the distances between the calcitic septa of the anterior end of the phragmocone range from 3 to 5 mm. The proostracum is 0.02 mm thick. The apical angle is 32° and the alveolar angle (posterior end of the phragmocone) is 24°.The alveolus is 40 mm long, yielding a ratio between rostrum and alveolus of 1.86. The depositional history with its fast sedimentation along with absent/limited post-mortem transportation led to extraordinarily good preservation of the examined specimen.

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The Olcostephanus Level : an Upper Valanginian ammonoid mass-occurrence (Lowel Cretaceous, Northern Calcareous Alps, Austria)

Lukeneder A.

Acta Geologica Polonica

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2004

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Vol. 54, no. 1

23-33

EN

The Early Cretaceous mass-occurrence of Olcostephanus (Olcostephanus) guebhardi morph. querolensis BULOT from the Late Valanginian Saynoceras verrucosum Zone of the KB1-A section, Ternberg Nappe, the Northern Calcareous Alps (Upper Austria) is described. This horizon, spanning an interval of almost 3 metres, is interpreted as a long-term accumulation from the water column combined with temporary redeposition from local submarine highs. The fauna of the Olcostephanus horizon is composed of nine genera and ten species. The Olcostephanus mass-occurrence represents a widespread phenomenon. It appears most commonly at oceanographic elevations where olcostephanid shells accumulated on the sea-floor during see-level highs.