Austrian Journal of Earth Sciences最新文献

{"title":"The Alland earthquake sequence in Eastern Austria: Shedding light on tectonic stress geometry in a key area of seismic hazard","authors":"S. Schippkus, H. Hausmann, Z. Duputel, G. Bokelmann","doi":"10.17738/ajes.2019.0010","DOIUrl":"https://doi.org/10.17738/ajes.2019.0010","url":null,"abstract":"Abstract We present our results on the fault geometry of the Alland earthquake sequence in eastern Austria (Eastern Alps) and discuss its implications for the regional stress regime and active tectonics. The series contains 71 known events with local magnitudes 0.1 ≤ ML ≤ 4.2 that occurred in between 2016 and 2017. We locate the earthquakes in a regional 3D velocity model to find absolute locations. These locations are then refined by relocating all events relative to each other using a double-difference approach, based on relative travel times measured from waveform cross-correlation and catalogue data. We also invert for the moment tensor of the ML = 4.2 mainshock by fitting synthetic waveforms to the recorded seismo-grams using a combination of the L1- and L2-norms of the waveform differences. Direct comparison of waveforms of the largest events in the sequence suggests that all of them ruptured with very similar mechanisms. We find that the sequence ruptured a reverse fault, that is dipping with ~30° towards ~north-northeast (NNE) at 6–7 km depth. This is supported by both the hypocentres and the mainshock source mechanism. The fault is most likely located in the buried basement of the Bohemian massif, the “Bohemian Spur”. This (reverse) fault has a nearly perpendicular orientation to the normal-fault structures of the Vienna Basin Transfer Fault System further east at a shallower depth, indicating a lateral stress decoupling that can also act as a vertical stress decoupling in some places. In the west, earthquakes (at a larger depth within the upper crust) show compressive stresses, whereas the Vienna Basin to the east shows extensional (normal-faulting) stress. This provides insight into the regional stress field and its spatial variation, and it helps to better understand earthquakes in the area, including the “1590 Ried am Riederberg” earthquake.","PeriodicalId":49319,"journal":{"name":"Austrian Journal of Earth Sciences","volume":"112 1","pages":"182 - 194"},"PeriodicalIF":1.7,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47176280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The benthic foraminifer Stomatorbina binkhorsti (Reuss, 1862): Taxonomic review and ecological insights","authors":"F. Schlagintweit, S. Rigaud","doi":"10.17738/ajes.2019.0011","DOIUrl":"https://doi.org/10.17738/ajes.2019.0011","url":null,"abstract":"Abstract The benthic foraminifer Rosalina binkhorsti Reuss, 1862, was cosmopolitan in Late Cretaceous to early Paleogene shallow-water seas. It possesses a distinctive composite wall made of a continuous, agglutinated layer discontinuously covered by secondary hyaline outer deposits. Its taxonomic position, phylogeny, morphology, wall structure, and composition have been debated for a long time. Based on abundant, well-preserved material from the Danian of the Kambühel Formation in the Northern Calcareous Alps, Austria, we identify elements in the here emended species Stomatorbina binkhorsti which support a strong affinity to the order Textulariida, within the genus Stomatorbina Dorreen, 1948. Usually regarded as free (non-fixing), S. binkhorsti is here illustrated attached to small bioclasts in high-energy carbonate settings. The attached specimens are juvenile forms with a wall covered by massive hyaline deposits. This observation suggests that secondary lamellar parts added to the wall may have served for stabilisation or fixation to the substrate. Rosalina binkhorsti Reuss, 1862, war eine in den Flachwassermeeren der Oberkreide und des frühen Paläogens kosmopolitische benthonische Foraminifere. Sie besitzt eine zusammengesetzte Wand, bestehend aus einer kontinuierlichen agglutinierten Lage welche diskontinuierlich von äusseren sekundär-hyalinen Abschnitten bedeckt ist. Ihre taxonomische Position, Phylogenie, Morphologie, Wandstruktur und –zusammensetzung ist seit langem umstritten. Basierend auf gut erhaltenem und reichhaltigem Material aus dem Danium der Kambühel Formation in den Nördlichen Kalkalpen von Österreich, werden Charakteristika identifiziert, welche nachhaltig eine Affinität zur Gattung Stomatorbina Dorreen, 1948 innerhalb der Ordnung Textulariida belegen. Diese Foraminiferenart, gewöhnlich als frei lebend (nicht fixiert) angesehen, wird illustriert fixiert an kleine Bioklasten in einem hochenergetischen karbonatischen Ablagerungsmilieu. Die fixierten Formen sind gewöhnlich juvenile Exemplare deren Wand mehr oder weniger massiv von hyalinen Ablagerungen bedeckt ist. Dies lässt vermuten, dass sekundäre lamellare Ablagerung, die der Wand hinzugefügt werden, eine Rolle in der Stabilisierung oder der Fixierung auf dem Substrat spielten.","PeriodicalId":49319,"journal":{"name":"Austrian Journal of Earth Sciences","volume":"112 1","pages":"195 - 206"},"PeriodicalIF":1.7,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.17738/ajes.2019.0011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46989429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evidence for pre-Pleistocene landforms in the Eastern Alps: Geomorphological constraints from the Gurktal Alps","authors":"T. Bartosch, K. Stüwe","doi":"10.17738/ajes.2019.0006","DOIUrl":"https://doi.org/10.17738/ajes.2019.0006","url":null,"abstract":"Abstract We present evidence for a series of pre-Pleistocene landforms on hand of a new geomorphological map for the Gurktal region of the Eastern Alps. The Gurktal Alps region is the westernmost region of the Eastern Alps that escaped the glacial reshaping in the Pleistocene. Its morphology therefore preserves evidence of older landforms in closer proximity to the central part of the range than any other region in the Alps. The region is therefore useful to document aspects of the geomorphological evolution for the Eastern Alps during both, the Pleistocene glaciations and the earlier uplift history. Our mapping approach is twofold. We applied stream-power analysis outside the glacially overprinted areas to detect and classify spatially distinct quasi-stable stream segments, which we expanded to planar objects using slope analysis combined with field mapping. Our mapping results document four palaeo-surfaces located roughly at about 1500 m, 1200 m, 900 m and about 800 m above sea level. We correlate these levels with well-known palaeo-surfaces from the eastern end of the Alps and suggest that they can be interpreted in terms of more than 1000 m of surface uplift in the last six million years. Channel analysis and the distribution of Pleistocene gravel terraces suggest that the main trunk of the river Gurk was diverted from the Wimitz valley in the Rissian. Furthermore, steam-power analysis documents an ongoing activity of the Görschitztal fault and some inferred Pleistocene activity of a north-west trending fault close to the township of Gurk.","PeriodicalId":49319,"journal":{"name":"Austrian Journal of Earth Sciences","volume":"112 1","pages":"84 - 102"},"PeriodicalIF":1.7,"publicationDate":"2019-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43074942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Norian fish deposits of Wiestal („Seefeld Member“, Northern Calcareous Alps, Salzburg, Austria) – taxonomy and palaeoenvironmental implications","authors":"T. Hornung, Ilja Kogan, Gero Moosleitner, G. Wolf, J. G. van der Wielen","doi":"10.17738/ajes.2019.0008","DOIUrl":"https://doi.org/10.17738/ajes.2019.0008","url":null,"abstract":"Abstract The Alaunian Seefeld Member of the Upper Triassic, a dark grey laminated and bituminous dolomitic limestone succession outcropping near the Wiestal-reservoir lake northeast of Hallein (Salzburg, Austria) is known for its extremely rich ‘ganoid’ fish fauna since more than a century. A privately initiated excavation that took place from 2012 to 2014 yielded far more than a thousand well-preserved fish fossils recovered largely from five mm-thin fossil horizons. The actinopterygian assemblage is dominated by several growth stages of the highly variable ginglymodian Paralepidotus ornatus, allowing for a documentation of ontogenetic transformations in cranial and postcranial morphology, dentition and squamation patterns, associated with habitat and dietary shifts. Small-sized swarm-fishes such as the macrosemiid Legnonotus and the teleost Pholidophorus are rather common members of the assemblage, while the occurrence of the ginglymodian Semiolepis, the dapediid Dandya, the dwarfish pycnodont Eomesodon and the large predatory ‘palaeopterygian’ Saurichthys is restricted to rare individuals. A single scale of a large-sized coelacanth, a well-preserved, small lobster-like decapod, plant remains and coaly gagate derived from disarticulated driftwood belong to rare associated finds. Both the perfect preservation of all fossils and the bituminous laminated dolomitic limestones barren of microfossils argue for a deposition under anoxic conditions, most probably due to salinity stratification. The occurrence of complete swarms, partly showing isoorientation of fish carcasses in distinct layers, speaks in favour of recurrent and rapid mortality events triggered by upwelling anoxic bottom water, most likely released by severe tropical storms.","PeriodicalId":49319,"journal":{"name":"Austrian Journal of Earth Sciences","volume":"112 1","pages":"125 - 165"},"PeriodicalIF":1.7,"publicationDate":"2019-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45101140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Palynology, microfacies and ostracods of the Permian–Triassic boundary interval in the Rosengarten/Catinaccio Massif (Southern Alps, Italy)","authors":"H. Nowak, W. Mette, F. M. Petti, G. Roghi, E. Kustatscher","doi":"10.17738/ajes.2019.0007","DOIUrl":"https://doi.org/10.17738/ajes.2019.0007","url":null,"abstract":"Abstract The Laurinswand section in the Rosengarten/Catinaccio Massif (Dolomites, Southern Alps, Italy) covers the Permian–Triassic boundary in a proximal marine setting. The section has been studied for palynology, ostracods and carbonate microfacies. Five microfacies types are defined for the carbonates of the Bellerophon Formation (Changhsingian) in this section. Ostracod assemblages from the upper Bellerophon Formation show a moderate to high diversity and mostly indicate normal marine conditions, with some samples from the upper Casera Razzo Member being dominated by eurytopic forms. The ostracod fauna follows transgressive-regressive trends with low diverse assemblages occurring in the regressive parts. These trends are also reflected in the microfacies and can be assigned to three sequences. Palynological assemblages are dominated by phytoclasts, which is typical for proximal marine environments. Sporomorphs are represented predominantly by bisaccate and asaccate pollen grains and are mostly minor components of the palynofacies. Other minor, but consistent components in the Bellerophon Formation are acritarchs, Reduviasporonites and unidentified possible algae or fungi. The latter are particularly abundant in samples with ostracod faunas indicating restricted conditions. The Werfen Formation (uppermost Permian to Lower Triassic) yielded quantitatively poor palynological assemblages, with one sample from the Tesero Member showing a notable increase in spores and spore tetrads. This is indicative of the so-called “spore spike”, a well-known signal from this interval. One sample from the overlying Mazzin Member demonstrated a high relative abundance of Reduviasporonites, which may be related to mass occurrences of this taxon in the Tesero Member at Tesero and at other localities near the Permian–Triassic boundary. Such a mass occurrence normally pre-dates the spore spike, whereas at the Laurinswand, the former post-dates the latter considerably. Das Profil an der Laurinswand im Rosengarten/Catinaccio-Massif (Dolomiten, Südalpen, Italien) umfasst die Perm-Trias-Grenze in einem proximalen, marinen Milieu. Das Profil wurde auf Palynologie, Ostrakodenfaunen und Karbonat-Mikrofazies untersucht. Fünf Mikrofaziestypen wurden für die Karbonate der Bellerophon-Formation (Changhsingium) definiert. Ostrakodenvergesellschaftungen aus der oberen Bellerophon-Formation weisen eine mittlere bis hohe Diver-sität auf und deuten überwiegend auf normalmarine Bedingungen hin, allerdings werden einige Proben aus dem oberen Casera-Razzo-Member von eurytopen Formen dominiert. Die Ostrakodenfauna folgt transgressiv-regressiven Trends, wobei weniger diverse Faunen in den regressiven Teilen auftreten. Diese Trends sind auch in der Mikrofazies reflektiert und können drei Sequenzen zugeordnet werden. Palynologische Rückstände werden von Phytoklasten dominiert, was typisch für ein proximales, marines Ablagerungsmilieu ist. Sporomorphe sind vor allem durch bisaccate und as","PeriodicalId":49319,"journal":{"name":"Austrian Journal of Earth Sciences","volume":"112 1","pages":"103 - 124"},"PeriodicalIF":1.7,"publicationDate":"2019-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42531823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sandstone petrography and geochemistry of the Nayband Formation (Upper Triassic, Central Iran): Implications for sediment provenance and tectonic setting","authors":"Asghar Etesampour, A. Mahboubi, R. Moussavi-Harami, N. Arzani, M. Salehi","doi":"10.17738/ajes.2019.0002","DOIUrl":"https://doi.org/10.17738/ajes.2019.0002","url":null,"abstract":"Abstract The Upper Triassic (Norian–Rhaetian) Nayband Formation is situated at the southwestern margin of Central East Iranian Microcontinent and records Eo-Cimmerian events. The formation is composed of mixed carbonate-siliciclastic deposits. This study presents information on the tectonic reconstruction and palaeoclimate of the southwestern margin of Central East Iranian Microcontinent during the Late Triassic. Petrography and modal analyses of sandstones show a variety of quartz-rich petrofacies including subarkose, lithic arkose, sublitharenite, feldspathic litharenite and litharenite. The combined modal analysis and geochemical results of major and trace elements of the sandstone samples represents mixed sedimentary, intermediate, felsic igneous rocks and moderate- to high-grade metamorphic provenance areas. The major elements and modal analyses of the Nayband Formation sandstone samples suggest an active continental margin tec-tonic settings. The palaeoclimatic conditions were sub-humid to humid with relatively low to moderate weathering in the source area which is in agreement with the palaeogeography and palaeotectonic history of southwestern margin of Central East Iranian Microcontinent during the Late Triassic.","PeriodicalId":49319,"journal":{"name":"Austrian Journal of Earth Sciences","volume":"112 1","pages":"20 - 41"},"PeriodicalIF":1.7,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47509384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Karst hydrogeology of Lamprechtsofen (Leoganger Steinberge, Salzburg)","authors":"Katharina Gröbner, Wolfgang Gadermayr, Giorgio Höfer-Öllinger, H. Huemer, Ch . Spötl","doi":"10.17738/ajes.2019.0004","DOIUrl":"https://doi.org/10.17738/ajes.2019.0004","url":null,"abstract":"Abstract The Leoganger Steinberge are a heavily karstified massif largely composed of Dachstein dolomite and limestone hosting the deepest through-trip cave in the world, Lamprechtsofen, whose frontal parts are developed as a show cave. Many parts of this 60 km-long and 1724 m-deep system are hydrologically active. 1.5 km behind the lower cave entrance Grüntopf stream and Kneippklamm stream merge to form the main cave stream. Another underground stream, Stainerhallen stream, flows through the eponymous hall of the show cave. Since 2007 water temperature, electrical conductivity and water level have been monitored in the Grüntopf and Kneippklamm stream. Water temperature and water level in the Stainerhallen and main cave stream have been measured since 2016. The long-term dataset (2013–2017) shows that the water temperature of the cave streams (Grüntopf stream: 3.7–5.2°C; Kneippklamm stream: 5.1–5.9°C) is largely invariant, but the electrical conductivity varies strongly (Grüntopf stream: 107–210 µS/cm; Kneippklamm stream: 131–248 µS/cm) in response to snowmelt and precipitation events. The event water of the Kneippklamm stream is characterized by a low electrical conductivity and is then followed by slightly warmer and higher mineralized water derived from the phreatic zone. This dual flow pattern also explains the asymmetrical changes of the water level during snowmelt: the fast event water flows directly through vadose pathways to the measurement site, whereas the hydraulic (phreatic) response is delayed. The Grüntopf stream reacts to precipitation and snowmelt events by changes in the karst-water table, which can be explained by a piston flow-model. The Kneippklamm stream reveals evidence of a lifter system. The altitude of the catchments was calculated using δ18O values of water samples from the underground streams and from surface precipitation. The Grüntopf stream shows the highest mean catchment (2280 m a.s.l.), which is in agreement with its daily fluctuations of the water level until August caused by long-lasting snowmelt. The Stainerhallen stream has the lowest catchment (average 1400 m a.s.l.). The catchments of the other two streams are at intermediate elevations (1770–1920 m a.s.l.). The integration of the catchment analyses and observations from tracer tests conducted in the 1970s showed that the latter reflected only one aspect of the karst water regime in this massif. During times of high recharge the water level rises, new flow paths are activated and the karst watershed shifts.","PeriodicalId":49319,"journal":{"name":"Austrian Journal of Earth Sciences","volume":"112 1","pages":"50 - 61"},"PeriodicalIF":1.7,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43267594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recharge and dynamics of a karst groundwater system in Kakheti (Eastern Georgia)","authors":"Sopio Vepkhvadze, G. Melikadze, M. Todadze, P. Malík, A. Gventsadze","doi":"10.17738/ajes.2019.0003","DOIUrl":"https://doi.org/10.17738/ajes.2019.0003","url":null,"abstract":"Abstract Monitoring temporal variations of 18O and 2H isotopes in precipitation, groundwater and surface water was performed in the region of Kakheti (East Georgia). Data were collected from three meteorological stations at altitudes between 400 - 1,100 m a.s.l., from two shallow and one deep hydrogeological boreholes, and from two surface water monitoring stations (Alazani River and Patmasuri karstic stream). 18O values in precipitation show an annual variation between -22 ‰ and +1 ‰ and a distinct altitude effect. A clear correlation exists between the seasonal isotope composition of precipitation, shallow groundwater and surface water. A five-fold amplitude dampening and a delay of 10-15 days was observed. The data show that precipitation in the Caucasus Mountains to the North infiltrates into the Upper Jurassic - Lower Cretaceous karstic aquifer and travels to the Alazani valley towards south-east. The isotopic signature of winter precipitation is reflected in stream water as well as in shallow groundwater isotope data of groundwater in a 2,000-m-deep hydrogeological borehole at Heretiskari show a distinctly different character with δ18O ranging between -2.8 ‰ to -2.2 ‰ and a deuterium excess of -25 ‰.","PeriodicalId":49319,"journal":{"name":"Austrian Journal of Earth Sciences","volume":"112 1","pages":"42 - 49"},"PeriodicalIF":1.7,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42331555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geoarchaeological evaluation of the Roman topography and accessibility by sea of ancient Osor (Cres Island, Croatia)","authors":"E. Draganits, S. Gier, Nives Doneus, M. Doneus","doi":"10.17738/ajes.2019.0001","DOIUrl":"https://doi.org/10.17738/ajes.2019.0001","url":null,"abstract":"Abstract We combine geoarchaeological investigations with high-resolution airborne laser scanning (ALS) topographic and airborne laser bathymetric (ALB) measurements to reassess the topography of the Roman city of Apsorus (modern Osor, northeastern Adriatic Sea, Croatia), which has generally been interpreted as important nodal point of Roman maritime traffic. Apsorus is located at the isthmus connecting Cres and Lošinj islands, which is 90 m wide at the narrowest part and dissected by a canal of supposed Roman age. A conspicuous low-lying wetland north of the city has been suggested to be a former sea passage and harbour area. Geoarchaeological coring, sedimentological analysis and radiocarbon dating suggest that this depression was already silted up with terrestrial sediments some 6,000 years ago and, especially in combination with the lower sea-level at that time, could not have been a Roman harbour. The combination of the ALS/ALB topographic data with lower sea-levels reconstructed for the Roman period challenges the traditional view which places ancient Osor on a small island and allows for new interpretations of the accessibility of Osor by sea.","PeriodicalId":49319,"journal":{"name":"Austrian Journal of Earth Sciences","volume":"112 1","pages":"1 - 19"},"PeriodicalIF":1.7,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46603730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural evidence of in-sequence and out-of-sequence thrusting in the Karwendel mountains and the tectonic subdivision of the western Northern Calcareous Alps","authors":"Sinah Kilian, H. Ortner","doi":"10.17738/ajes.2019.0005","DOIUrl":"https://doi.org/10.17738/ajes.2019.0005","url":null,"abstract":"Abstract We present the results of a field study in the Karwendel mountains in the western Northern Calcareous Alps, where we analysed the boundary between two major thrust sheets in detail in a key outcrop where nappe tectonics had been recognized already at the beginning of the 20th century. We use the macroscopic structural record of thrust sheet transport in the footwall and hanging wall of this boundary, such as folds, foliation and faults. In the footwall, competent stratigraphic units tend to preserve a full record of deformation while incompetent units get pervasively overprinted and only document the youngest deformation. Transport across the thrust persisted throughout the deformation history of the Northern Calcareous Alps from the late Early Cretaceous to the Miocene. As a consequence of transtensive, S-block down strike-slip tectonics, postdating folding of the major thrust, new out-of-sequence thrusts formed that climbed across the step, and ultimately placed units belonging to the footwall of the initial thrust onto its hanging wall. One of these out-of-sequence thrusts had been used to delimit the uppermost large thrust sheet (Inntal thrust sheet) of the western Northern Calcareous against the next, tectonically deeper, (Lechtal) thrust sheet. Based on the structural geometry of the folded thrust and the age of the youngest sediments below the thrust, we redefine the thrust sheets, and name the combined former Inntal- and part of the Lechtal thrust sheet as the new Karwendel thrust sheet and the former Allgäu- and part of the Lechtal thrust sheet as the new Tannheim thrust sheet.","PeriodicalId":49319,"journal":{"name":"Austrian Journal of Earth Sciences","volume":"112 1","pages":"62 - 83"},"PeriodicalIF":1.7,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42219952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}