One of the most remarkable features of the central Northern Calcareous Alps (Eastern Alps, Austria) is the widespread presence of Upper Triassic deep-water carbonates (the Hallstatt facies) and Permo-Triassic evaporites resting on deep-water Middle Jurassic strata and their underlying Upper Triassic shallow-water carbonate platform successions. The Hallstatt facies and accompanying evaporites have been classically interpreted to originate either from a location south of the time-equivalent carbonate platforms, or to have been deposited in deeper water seaways within the broad platform domain. To date, this dispute has been addressed mostly through the analysis of Triassic and Jurassic facies distribution in map view, which, however, is subject to some degree of ambiguity and subjectivity.
View Article and Find Full Text PDFWhereas deposits of extremely-rapid, 'catastrophic' mass wastings >10 m in volume (for example, the Marocche di Dro rock avalanche in the Southern Alps and the Flims rockslide in the Western Alps) are easily recognized by their sheer mass and blocky surface, the identification of catastrophic mass wastings partly removed by erosion must be based on deposit characteristics. Herein, a 'fossil' (pre-last glacial) rock avalanche, previously interpreted as either a till or debris flow, is described. The deposit, informally called 'Rubble Breccia', is located in the intramontane Campo Imperatore halfgraben that is bounded by a master fault with up to 900 m topographic throw.
View Article and Find Full Text PDFIt is often difficult to decide which cyanobacteria found in endolithic habitats of calcite spring-tufa deposits are present as ephemeral components of the biota or are persistent, structural elements. To answer this question, we repeatedly studied two microhabitats of contrasting calcareous tufa springs in the European Alps. Pigment extracts, fluorescence probe measurements of samples and traditional microscopy confirmed the dominance of cyanobacteria over eukaryotic algae and their viability in both microhabitats.
View Article and Find Full Text PDFSprings are biodiversity hotspots and unique habitats that are threatened, especially by water overdraft. Here we review knowledge on ambient-temperature (non-geothermal) freshwater springs that achieve sufficient oversaturation for CaCO3 -by physical CO2 degassing and activity of photoautotrophs- to deposit limestone, locally resulting in scenic carbonate structures: Limestone-Precipitating Springs (LPS). The most characteristic organisms in these springs are those that contribute to carbonate precipitation, e.
View Article and Find Full Text PDFIn the Obernberg valley, the Eastern Alps, landforms recently interpreted as moraines are re-interpreted as rock avalanche deposits. The catastrophic slope failure involved an initial rock volume of about 45 million m³, with a runout of 7.2 km over a total vertical distance of 1330 m (fahrböschung 10°).
View Article and Find Full Text PDF