Swiss Journal of Geosciences最新文献

{"title":"Structural and metamorphic evolution of a subducted passive margin: insights from the Briançonnais nappes of the Western Alps (Ubaye–Maira valleys, France–Italy)","authors":"Davide Dana, Salvatore Iaccarino, Stefan M. Schmid, Alessandro Petroccia, André Michard","doi":"10.1186/s00015-023-00445-0","DOIUrl":"https://doi.org/10.1186/s00015-023-00445-0","url":null,"abstract":"This contribution analyses the structural architecture and tectono-metamorphic evolution of Briançonnais units in the southern French-Italian Western Alps. The studied area extends from a virtually non-metamorphic area adjacent to the Helvetic-Dauphinois External Domain in the west to the Monviso-Queyras ocean-derived units in the east, where metamorphism increases up to eclogite-facies. Mapping at the scale 1:10.000 of a mountainous part of the Ubaye-Maira transect was performed, which portrays in detail the Briançonnais units over ~ 100 km2. The lithologies include meta-andesite, meta-siliciclastics, marbles, turbiditic calcschists and flysch whose age spans from Late Carboniferous to Eocene. Metamorphism is low-grade greenschist-facies in the west but reaches the blueschist-facies to the east. Structures related to four phases of deformation are identified. The first two generations of structures (D1–D2), related to the original top-to-the-west nappe stacking, are associated with conditions close to the peak of Alpine metamorphism. Previous tectonic surfaces are transposed by the dominant deformation structures (D3), developed under retrograde/decompression conditions. This D3 corresponds to a backfolding and back-thrusting event with a top-to-the-E transport. A fourth phase (D4) developed during late low-grade metamorphic conditions and deforms the previous surfaces by locally developing a crenulation cleavage, followed by brittle tectonics. An updated metamorphic map is presented, backed on published estimates and new thermometric data obtained by Raman Spectroscopy of Carbonaceous Material (RSCM). The TRSCM values range from ~ 295 °C to > 350 °C, moving from the most external Briançonnais unit to the internal Queyras “Schistes Lustrés” units. Suspected Upper Cretaceous palaeofaults have been documented, allowing us to group the classic Aiguille de Mary and Ceillac (sub-) units into a single tectonic unit, here referred to as Maurin unit. The palaeogeographical reconstruction of the evolution of the studied transect highlights the importance of the Marinet and Maurin axial units in the feeding of the Late Cretaceous-Eocene breccias deposited on the more internal Acceglio-type units.","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138518791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 a pre-Himalayan metamorphism in the High Himalayan Crystalline of the Miyar Valley (NW India)","authors":"Martin Robyr","doi":"10.1186/s00015-023-00446-z","DOIUrl":"https://doi.org/10.1186/s00015-023-00446-z","url":null,"abstract":"Abstract Most of the tectonic, metamorphic and geochronological data suggest that the Himalaya is essentially the consequence of a single orogenic cycle associated with the India-Asia collision during the Cenozoic era. Therefore, metamorphic assemblages and tectonic structures across the Himalayan range are systematically considered as post-collisional geological records. However, over the last decades, several observations arguing for geological events predating the continental collision have become increasingly recurrent in the literature. Nevertheless, although some of these arguments are thoroughly documented, they are unduly ignored in the construction of models drawing the tectono-metamorphic evolution of the Himalayan range. Yet, the occurrence of a pre-Himalayan history would have considerable consequences on the classical models for the building of the Himalaya. The recent discovery of inclusions of staurolite crystals in greenschist facies garnets from the Miyar Valley in Upper Lahul region (Himachal Pradesh; NW India) revives the debate on the existence of a pre-Himalayan metamorphism. Indeed, the occurrence of high-temperature staurolites included in greenschist facies garnets suggests that the High Himalayan Crystalline rocks experienced an amphibolite facies metamorphism prior the predominant Himalayan greenschist facies metamorphism observed in this part of the range. In this study, phase petrology, microtectonic investigations combined with preexisting geochronological data infer that the crystallization of the included staurolite predates the growth of Himalayan garnets. These original data bring new arguments to bear on the long lasting debate of the existence of a Pre-Himalayan orogenic cycle. They lead to the conclusion that the growth of staurolite predates the continental collision between India and Asia and reflects a metamorphic event that belongs to a pre-Himalaya orogenic cycle.","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135933381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lithofacies, stratigraphy and depositional history of Middle Muschelkalk evaporites (Zeglingen Formation) in northern Switzerland","authors":"Johannes S. Pietsch, Andreas Wetzel, Gaudenz Deplazes, Marco Filipponi","doi":"10.1186/s00015-023-00441-4","DOIUrl":"https://doi.org/10.1186/s00015-023-00441-4","url":null,"abstract":"Abstract In northern Switzerland, Middle Muschelkalk evaporites (Zeglingen Formation) were deposited under arid conditions in the southernmost part of the epicontinental Central European Basin during times of reduced inflow of sea water from the Tethyan realm. Because of their marginal position in the basin, direct and detailed correlation of Muschelkalk sediments of northern Switzerland with equivalent strata in interior parts of the basin is not straightforward. Based on detailed sedimentological logging of 640 m of drill cores from ten wells in northern Switzerland, 22 lithofacies and 10 lithofacies associations were distinguished for the Middle Muschelkalk evaporites. High-resolution regional correlations of gamma-ray logs record substantial thickness variation of the evaporites. Locally, dissolution was recognized by visual core examination that could be dated to Middle Triassic times and that was likely related to subsurface fluid flow along deeper seated faults. In combination with the regional thickness variation, the dissolution phenomena suggest a tectonically active depositional setting in the Middle Triassic. Middle Muschelkalk evaporites consist of nine types of mainly auto-cyclic shallowing- or brining-upward mini-cycles which form a correlatable succession of five distinct 4th order cycle-sets. Despite the tectonically active depositional environment, most lithofacies encountered appear to have nearly flat bounding surfaces. Thus, marine transgressions flooded wide areas nearly simultaneously. The corresponding deposits serve as reference levels to tie the peripheral facies of northern Switzerland into the supra-regional context.","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135570610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anatomy of a km-scale fault zone controlling the Oligo-Miocene bending of the Ligurian Alps (NW Italy): integration of field and 3D high-resolution digital outcrop model data","authors":"Ludovico Manna, Michele Perozzo, Niccolò Menegoni, Silvia Tamburelli, Laura Crispini, Laura Federico, Silvio Seno, Matteo Maino","doi":"10.1186/s00015-023-00444-1","DOIUrl":"https://doi.org/10.1186/s00015-023-00444-1","url":null,"abstract":"Abstract We report the first description of a ~ 15 km long NE-SW-striking transtensive fault network crosscutting the metamorphic units of the Ligurian Alps. The main fault zone, hereby named Horse Head Fault Zone , is up to 250 m thick, involves quarzite, metarhyolite, marble and alternation of dolostone and limestone and minor pelite. Relatively narrow (~ 1–3 m-thick) fault cores are characterized by gouge and cataclasites, surrounded by brecciated damage zones as thick as tens to hundreds of meters. Damage zones show widespread evidence for dilation in the form of dilation breccia, large calcite crystals and aggregates, and centimeter- to meter-thick veins. Moreover, the fault zone contains a multitude of polished slip surfaces with multiple sets of slickensides and slickenfibers. Oblique to strike-slip kinematics dominates over the large part of the fault mirrors and both overprint and are overprinted by down-dip slip surfaces. The fault network includes dominant NE-SW right-lateral faults with a minor normal component and NW–SE left-lateral steep faults with a negligible reverse component, consistent with a km-size dextral NE-SW-striking Riedel shear zone, in turn representing an antithetic R’ of the regional sinistral shear zone constituted by the Ligurian Alps after the nappe stacking. The Horse Head Fault Zone accommodated km-scale displacement before the Early Miocene, as it is sealed by the sedimentary deposits of the Finale Ligure Basin, thus predating the Corsica-Sardinia drifting. Results of this work constraint the bending of the Ligurian Alps as part of the Western Alpine arc as accomplished through two consecutive, late Oligocene and Early Miocene, stages driven by the combination of Adria rotation and the rollback of the Apennine subduction.","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135597605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mid-Cretaceous extensional magmatism in the Alborz Mountains, north Iran; geochemistry and geochronology of Gasht-Masuleh gabbros","authors":"Leila Rezaei, Martin J. Timmerman, Mohssen Moazzen, Uwe Altenberger, Jiří Sláma, Masafumi Sudo, Christina Günter, Franziska D. H. Wilke, Anja M. Schleicher","doi":"10.1186/s00015-023-00443-2","DOIUrl":"https://doi.org/10.1186/s00015-023-00443-2","url":null,"abstract":"Abstract In the Gasht-Masuleh area in the Alborz Mountains, gabbroic magma intruded Palaeozoic metasediments and Mesozoic sediments and crystallised as isotropic and cumulate gabbros. LREE enrichment points to relatively low degrees of mantle melting and depletion of Ti, Nb and Ta relative to primitive mantle points to an arc related component in the magma. Clinopyroxene compositions indicate MORB to arc signatures. U–Pb zircon crystallisation ages of 99.5 ± 0.6 Ma and 99.4 ± 0.6 Ma and phlogopite 40 Ar/ 39 Ar ages of 97.1 ± 0.4 Ma, 97.5 ± 0.4 Ma, 97.1 ± 0.1 Ma, within 2σ error, indicate that gabbro intrusion occurred in the (Albian-)Cenomanian (mid-Cretaceous). As active subduction did not take place in the Cretaceous in North Iran, the small volume mafic magmatism in the Gasht-Masuleh area must be due to local, extension-related mantle melting. Melting was most likely caused by far field effects triggered by roll-back of the Neo-Tethys subducting slab. As subduction took place at a distance of ~ 400 km (present distance) from the Alborz Mountains, the observed arc geochemical signatures must be inherited from a previous subduction event and concomitant mantle metasomatism, possibly in combination with contamination of the magma by crustal material.","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136059962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 Twannberg iron meteorite strewn field in the Swiss Jura mountains: insights for Quaternary environmental conditions","authors":"B. Hofmann, N. Akçar, S. Szidat, Pierre G. Valla, M. Christl, Christoph Vockenhuber, Gökay Gino Priska Thomas Sandro Margrit Anna Daniel Urs Abay Bernasconi Berther Burri Cavegn Christen Comi, Gökay Abay, Gino Bernasconi, Priska Berther, T. Burri, Sandro Cavegn, Margrit Christen, Anna Comiotto, Daniel Ducrest, U. Eggenberger, Manuel Eggimann, Martin Gasser, E. Gnos, Andreas Gren, Adrian Stuart Grond, Rudolf Guhl, Martin Hänni, Marcel Häuselmann, Karin Heinritzi, B. Hofmann, M. Jost, Andreas Koppelt, A. Korochantsev, Shijie Li, Katarina Litwin, Nola Magri, Peter Marmet, Marianna Mészáros, Rico Mettler, Abdelaziz Mouadine, Roger Perrinjacquet, Raeto Raselli, Å. Rosén, Antoine S. G. Roth, Hans-Rudolf Rüegg, D. Sadilenko, Thomas Schüpbach, Thomas Smith, Beat Spahni, Christoph Spinnler, Thomas Spörri, T. Stalder, P. Stephenson, H. Strahm, Madeleine Sturny, Igor Talyukin, Sergey Vasiliev, M. Wälti, Fritz Weber, Johannes Weiss, F. Wildi, Elise Wimmer, K. Wimmer, Ernst Wyler, Reto Zünd","doi":"10.1186/s00015-023-00442-3","DOIUrl":"https://doi.org/10.1186/s00015-023-00442-3","url":null,"abstract":"","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43567751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Palaeomagnetic and mineral magnetic analyses of the Deckenschotter of northern Switzerland and southern Germany","authors":"S. Scheidt, Marius W. Buechi, R. Egli, A. Biedermann, G. Deplazes","doi":"10.1186/s00015-023-00439-y","DOIUrl":"https://doi.org/10.1186/s00015-023-00439-y","url":null,"abstract":"","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2023-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44258909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sedimentology of the Jura Molasse: Miocene tidal clastics and freshwater carbonates from the Tramelan-2 Borehole, NW Switzerland","authors":"N. H. Platt, A. Matter","doi":"10.1186/s00015-023-00436-1","DOIUrl":"https://doi.org/10.1186/s00015-023-00436-1","url":null,"abstract":"","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2023-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42152646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tectonics of the Western Internal Jura fold-and-thrust belt: 2D kinematic forward modelling","authors":"Adeline Marro, Louis Hauvette, Sandra Borderie, J. Mosar","doi":"10.1186/s00015-023-00435-2","DOIUrl":"https://doi.org/10.1186/s00015-023-00435-2","url":null,"abstract":"","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47590146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First fossil record of Varanus (Reptilia, Squamata) from Switzerland and the earliest occurrences of the genus in Europe","authors":"G. Georgalis, B. Mennecart, Krister T. Smith","doi":"10.1186/s00015-023-00440-5","DOIUrl":"https://doi.org/10.1186/s00015-023-00440-5","url":null,"abstract":"","PeriodicalId":49456,"journal":{"name":"Swiss Journal of Geosciences","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2023-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48466696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}