Littérature scientifique sur le sujet « Hattfjelldal »

The nappe stack in the Røssvatnet–Hattfjelldal region in the Central Norwegian Caledonides consists of seven nappes formed at the boundary between tectonostratigraphically upper and uppermost Caledonian levels. The rocks of all nappes share a polyphase tectonometamorphic evolution that is younger than the 491 ± 10 Ma depositional (volcanic) age of parts of the succession. Early stages of deformation characterized by centimetre- to kilometre-scale folding and intense shearing accompanied by greenschist to amphibolite facies peak metamorphism are correlated with the Early Ordovician Taconian accretionary orogeny along the Laurentian margin. The Taconian structures are cut by the Krutfjellet gabbro and diorite, which yield U–Pb zircon ages of 446 ± 5 and 444 ± 4 Ma, respectively. Large-scale nappe stacking and folding post-dating the emplacement of the gabbro is related to the collision of Laurentia with Baltica (Scandian orogeny) and was followed by late- to post-orogenic extension. The revised tectonostratigraphy assigns the structurally higher nappes to the Uppermost Allochthon, whereas the lower nappes are correlated with the Middle Köli Nappe Complex (Upper Allochthon). The boundary between these nappes is marked by an imbricate zone. Taconian deformation was probably much more penetrative and widespread than hitherto thought and therefore parts of the nappe stack were probably assembled before Scandian collision.Supplementary material: Electronic Supplement 1: U–Pb zircon data and Electronic Supplement 2: Methods (laser ablation inductively coupled plasma mass spectrometry U–Pb zircon geochronology) are available at https://doi.org/10.6084/m9.figshare.c.5357255

Background: Previous serological screenings have indicated that Eurasian semi-domesticated tundra reindeer (Rangifer tarandus tarandus) in Finnmark, Northern Norway, are exposed to alphaherpesvirus, gammaherpesvirus and pestivirus. Alphaherpesvirus (i.e., Cervid herpesvirus 2; CvHV2) has been identified as the transmissible component of infectious keratoconjunctivitis (IKC). Limited knowledge exists on the presence and prevalence of virus infections in other herding regions in Norway, which are hosting ~67,000 semi-domesticated reindeer and have contact with other species and populations of wildlife and livestock than those present in Finnmark.Methods: Blood samples (n = 618) were obtained over five winter seasons (2013–2018), from eight different herds representing summer pasture districts in Tana, Lakselv, Tromsø, Lødingen, Hattfjelldal, Fosen, Røros, and Filefjell, distributed from North to South of the reindeer herding regions in Norway. Blood samples were investigated for specific antibodies against five viral pathogen groups, alphaherpesvirus, gammaherpesvirus (viruses in the malignant catarrhal fever group; MCFV), pestivirus, bluetongue virus (BTV), and Schmallenberg virus (SBV), by using commercial multispecies serological tests (ELISA). In addition, swab samples obtained from the nasal mucosal membrane from 486 reindeer were investigated by PCR for parapoxvirus-specific DNA.Results: Antibodies against aphaherpesvirus and MCFV were found in all eight herds, with a total prevalence of 42% (range 21–62%) and 11% (range 2–15%), respectively. Anti-Pestivirus antibodies were detected in five of eight herds, with a total prevalence of 19% (range 0–52%), with two of the herds having a particularly high seroprevalence. Antibodies against BTV or SBV were not detected in any of the animals. Parapoxvirus-specific DNA was detected in two animals representing two different herds in Finnmark.Conclusions: This study confirmed that alphaherpesvirus and MCFV are enzootic throughout the geographical reindeer herding regions in Norway, and that pestivirus is present in most of the herds, with varying seroprevalence. No exposure to BTV and SBV was evident. This study also indicated that semi-domesticated reindeer in Finnmark are exposed to parapoxvirus without disease outbreaks being reported from this region.