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Extensive bulk-sampling of the continuous Cretaceous-Paleogene boundary section at Gams (Styria, Austria) allows for the first time the description of the elasmobranch communities inhabiting the bathyal environment of this well-known section. The sampled succession comprises six horizons from the uppermost Maastrichtian (upper part of <italic>Nephrolites frequens</italic> Zone CC26) and five horizons from the lowermost Danian (Zone NP1), which yielded a total of 1852 elasmobranch teeth. Although the majority of the teeth are not well preserved, this study enabled the description of at least 16 taxa of the orders Hexanchiformes, Squaliformes, Orectolobiformes, Lamniformes and Carcharhiniformes, providing a rare snapshot of elasmobranch diversity of this specific environmental setting. Beside minor diversity fluctuations between the assemblages, the extensive bulk-sampling of this section did not reveal a marked diversity decline related to the end-Cretaceous mass extinction event. However, a noteworthy correlation between the deepening upward trend of the section with the appearance of frilled and goblin sharks points to changes in palaeobathymetry, which is also reflected in the increase of the total proportion of squaliform teeth in the uppermost sampled horizon. Furthermore, teeth of the extinct triakid <italic>Palaeogaleus</italic> were recovered exclusively from the Danian deeper deposits, expanding the palaeoecological range of the genus down to fairly deep marine environments. In addition, this study provides the first record of the lamniform <italic>Cretolamna</italic> ex gr. <italic>borealis</italic> from the Danian of the Tethyan Realm expanding the palaeogeographic distribution of this group.
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Department of Earth Sciences, NAWI Geocenter

Elasmobranch assemblages from a bathyal environment spanning the Cretaceous-Paleogene boundary in Austria

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Ophiolites are remnants of oceanic crust and mantle, now typically found within continental mountain ranges like the Alps. Particularly in areas once part of the Tethys Ocean, ophiolites are often accompanied by narrow stripes of metamorphic rocks, commonly referred to as metamorphic soles. These metamorphic soles typically exhibit peak metamorphic conditions characteristic of either granulite or amphibolite facies. Geochronological studies of Tethyan ophiolites indicate that the development of these metamorphic soles occurred almost simultaneously with the crystallization of the ophiolite’s crustal sequence. Geological evidence also suggests that the metamorphism of the sole rocks took place concurrently with deformation, likely at the same time as the ophiolite’s obduction. In our research, we explore the metamorphic effects of shearing in an ophiolite sequence overlying a crustal sequence. Our findings reveal that strong lithologies like ophiolites can produce additional heat through the dissipation of mechanical energy, which can potentially explain the high temperatures found in metamorphic-sole rocks. In addition, heating-driven softening of the footwall rocks eventually leads to the migration of the active shear zone from the mantle sequence into the upper crustal domain. This migration may be responsible for the metamorphic sole incorporation at the base of the ophiolite. Finally, we demonstrate that stopping the shearing process rapidly cools these rocks, corresponding with the findings from thermochronological studies from Oman ophiolite.
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A thermo-mechanical model of the thermal evolution and incorporation of metamorphic soles in Tethyan ophiolites: a case study from Oman

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In the 1980s, large parts of the Bohemian Massif in Austria were explored for the occurrence of raw materials (Göd, 1988), and a trace content of topaz was discovered in channels draining the eastern slope of the Ostrong (Lower Austria). Orthogneiss bodies in the Ostrong Nappe System are shown to be the source of these topaz occurrences, and Raman spectroscopy indicates that topaz is fluorine rich. So far, this is the only occurrence of topaz-bearing orthogneiss within the entire Moldanubian Superunit. The orthogneiss shows a tectonic overprint and exhibits a weak to well-developed foliation, as well as local folding. Samples taken near the tectonic boundary of the Ostrong to the Drosendorf Nappe Systems show stronger shear deformation with a pronounced mylonitic foliation and stretching lineation. Detailed geo-chemical investigations of the major and trace elements indicate a classification as S-type granite with a high degree of differentiation and a peraluminous character. The orthogneiss has a high SiO2 content of 72.8–77.3 wt%, as well as a noteworthy high fluorine content of up to 2760 ppm. Mineral compositions show zoned plagioclase with an albite component of about 87–99 mol%, increasing towards the grain margin. Garnet occurs rarely, but consistently in those samples near the tectonic boundary of the Ostrong- to the Drosendorf Nappe Systems. Garnet is almandine-dominated, shows no zoning and is single-phased. Sillimanite is common and samples near the tectonic boundary also contain kyanite. To determine the previously unknown protolith age of the orthogneiss, U-Pb zircon dating was applied. Three zircon fractions from two samples yield concordia ages of 475.3 ± 1.0 Ma, 474.8 ± 2.9 Ma, and 473.5 ± 1.5 Ma, identical in assigned uncertainties, reflecting magmatic zircon growth. Furthermore, the short prismatic habit of zircon grains indicates a plutonic rather than volcanic origin of the protolith. Dating results also provide a minimum sedimentation age for the rocks of the Ostrong Nappe System within Austria. In comparison with other metagranitoids and orthogneisses of the Moldanubian Nappes, the investigated orthogneiss shows strong similarities with the Gföhl Gneiss and the Moldanubian Granulite. The orthogneiss therefore is considered as a more fractionated equivalent of the Gföhl Gneiss. In conclusion we suggest to name the studied orthogneiss <italic>Laimbach Orthogneiss</italic> in the rank of a lithodeme (NACSN, 2005), after the locality Laimbach am Ostrong (48°19′01″N; 15°07′19″E), which is located centrally with respect to the occurrences of this gneiss.
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Topaz-bearing Lower Ordovician orthogneiss within the Ostrong Nappe System – The Laimbach Orthogneiss (Bohemian Massif, Lower Austria)

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Recently, samples of natrochalcite, NaCu2(SO4)2∙H3O2, were discovered from the Esperanza Mine, Lavrion Mining District, Greece. In the present study this material is characterized by single crystal X-ray diffraction at ambient and LT conditions. Natrochalcite is monoclinic, space group <italic>C</italic>2/<italic>m</italic>, with <italic>a</italic> = 8.809(2), <italic>b</italic> = 6.196(1), <italic>c</italic> = 7.504(2) Å, <italic>β</italic> = 118.56(3)°, <italic>V</italic> = 359.7(1) Å3, <italic>Z</italic> = 2, <italic>R</italic>1 = 0.0195 at room temperature. No symmetry change was observed down to 100K.
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Natrochalcite NaCu2(SO4)2∙H3O2 from the Lavrion Mining District – a brief characterisation

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Low-relief surfaces at high elevations are peculiar features of the Eastern Alps that are best explained as relicts of morphological base levels that escaped erosive decay during uplift. To expand our knowledge of such surfaces in the Eastern Alps, the Fischbach Alps at the eastern end of the range are investigated. There, a large number of these elevated low-relief surfaces have been known for some time, but modern mapping is absent and their genesis is not well understood. A combined approach of field mapping, morphometric analysis of a digital elevation model and downstream projection of geomorphic equilibrium sections in river profiles was employed to: (i) create a geomorphological map of the region and (ii) to extract quantitative data from river profiles to infer the amount of uplift and incision. Six discrete levels of low-relief surfaces and relict landscapes are recognized at elevations between ~500 m and ~1600 m. Some of the lower levels are interpreted to relate to the well-known <italic>Trahutten, Landscha</italic> and <italic>Stadelberg</italic> levels, known from other parts of Styria, respectively. Mapped low-relief surface levels follow the northward directed topographic gradient in the mountainous region of the Fischbach Alps. The formation of elevated low-relief surfaces is consistent with a Piedmonttreppen model, where successive phases of tectonic uplift and tectonic quiescence led to a succession of incised landscapes and low-relief surfaces. However, the entire region south of the Murztal was also then tilted towards the Styrian Basin by about ~1–2°. Swath profile analysis for the Raab and Weizbach Klamm suggests a minimum of ~400–450 m incision since the formation of the so called <italic>Hubenhalt</italic> level. This implies that the geomorphic response to tectonic uplift after the formation of the higher <italic>Wolscheneck</italic> and <italic>Koralm</italic> relict landscapes led to an estimated incision of up to 1000 m (868±101 m), relative to the base level of today’s Styrian Basin at ~380 m. By comparing published age data to the presented mapping results, the onset for much of the uplift at the eastern end of the Alps is suggested to lie between ~4–7 Ma, before the formation of the <italic>Hubenhalt</italic> and <italic>Trahutten</italic> levels. Because the mapped levels correlate well with those in many other regions at similar elevations, a growing body of work now suggests that the underlying uplift event has a large wavelength.
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The Fischbach Alps: A Geomorphological Record of late Neogene Uplift at the Eastern Margin of the European Alps

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The Carnic Alps (eastern Southern Alps) provide a classical area to study polyphase very-low- to low-grade metamorphism within the Variscan belt of Europe. Temperature indicators collected during the past three decades map the general metamorphic structure of a mountain chain affected by three major tectonic events (Variscan and Alpine thrusting, Oligocene transpression). Thermometric data obtained by Raman Spectroscopy of carbonaceous material (RSCM) described in this study extend the already published database, provide a map of metamorphic isotherms, and are interpreted in the view of current tectonic concepts. The RSCM temperatures of this study describe a gradient between ca. 460 °C in the tectonically deepest segments, bordered by the Periadriatic Fault System, and temperatures of ca. 200 °C in Permian- Triassic boundary strata of the Gartnerkofel-1 core. Mapped isotherms indicate three domains with different thermal histories, characterized by Variscan imbrication of an accretionary wedge, Permo-Mesozoic burial, and Oligocene contact metamorphism.
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Raman Spectroscopy of carbonaceous material thermometry in the Carnic Alps (Austria, Italy)

AHEAD OF PRINT

Volume 117 (2024): Issue 1 (January 2024)

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Austrian Journal of Earth Sciences

 AUSTRIAN JOURNAL OF EARTH SCIENCES is the official journal of the Austrian Geological (ÖGG), Mineralogical (ÖMG), Palaeontological (ÖPG) and Hydrogeological (ÖVH) Societies, hosted by a country that is famous for its spectacular mountains, sedimentary basins and classical fossil sites that were and are the birthplace for many geoscientific concepts in modern Earth science. Further information on the journal may also be obtained from the local website at: www.ajes.at     AUSTRIAN JOURNAL OF EARTH SCIENCE focuses on all aspects relevant to the geosciences of the Alpine realm including the Bohemian Massif, the surrounding sedimentary basins and related regions in Central Europe, for example the Tethyan and Paratethyan realms. As such, we invite contributions from the fields of mineralogy, geology, geophysics, petrology or hydrogeology, as well as all aspects of palaeontology, palaeobiogeography and biostratigraphy that are of relevance to the greater Alpine orogen and its surrounding oceans. Contributions on other regions are welcome if they embed their findings into a conceptual framework that relates the contribution to Alpine-type orogens and Alpine regions in general and are thus relevant to an international audience. Contributions are subject to peer review and editorial control according to SCI guidelines to ensure that the required standard of scientific excellence is maintained.     AUSTRIAN JOURNAL OF EARTH SCIENCES is a peer reviewed journal.   Why subscribe and read   The journal of the Austrian Geological Society is published for more than 100 years, starting in 1908 as ‘Mitteilungen der Geologischen Gesellschaft in Wien’. Traditionally, the main focus of the journal is on Alpine and Austrian geology and applied geosciences but contributions to all aspects of Earth Sciences are welcome. Austrian Journal of Earth Sciences is an Open Access Journal hosted as of 2018 by SCIENDO. For earlier back issues go to the Archive section at: ajes.at/index.php/archive   Why submit   The journal of the Austrian Geological Society is published for more than 100 years, starting in 1908 as ‘Mitteilungen der Geologischen Gesellschaft in Wien’. Traditionally, the main focus of the journal is on Alpine and Austrian geology and applied geosciences but contributions to all aspects of Earth Sciences are welcome. Austrian Journal of Earth Sciences is an Open Access Journal hosted as of 2018 by SCIENDO. As of 2021, AJES represents all Austrian Earth Science societies. For earlier back issues go to the Archive section at: ajes.at/index.php/archive     Archiving   Sciendo archives the contents of this journal in Portico - digital long-term preservation service of scholarly books, journals and collections.   Plagiarism Policy   The editorial board is participating in a growing community of Similarity Check System's users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process. 