132 research outputs found
El silĂșrico de Galicia Media (central): su importancia en la paleogrĂĄfica varisca
[Resumen] La sucesiĂłn silĂșrica es estudiada en el flanco Oeste y Sud-Oeste del anticlinal del (Ollo de Sapo» (Este de Cabo Ortegal y regiĂłn de VerĂn). Estas observaciones y los datos exIstentes permiten discutir ciertos problemas estratigrĂĄficos y paleogeogrĂĄficos. Se señala la originalidad de la zona de Galicia Media-"Tras"'os"Montesâ en el marco de la paleogeografĂa del SilĂșrico de la PenĂnsula IbĂ©rica[Abstract] The Silurian succession is described in the region located to the Westand the Southwest of the ((0llo de Sapo» anticline (East of Cabo ,Ortegal and Verinarea). Stratigraphical and palaeogeographical problems are discussed on the basis of this study and of previous data. The originality of the ((Middle-Galicia-Tras-os-Montes zone» in the Iherian Silurian palaeogeography is pointed out
Provenance analysis of Lower Palaeozoic siliciclastic rocks of the Southwestern Iberia (Ossa-Morena Zone) : distal shelf deposition on the North Gondwana passive margin
Revision of the age of magnetization of the Montmartin red beds, Normandy, France
A new roadcut has enabled us to sample the south-dipping limb of the Montmartin syncline for a palaeomagnetic reevaluation of an earlier result published by Jones, Van der Voo & Bonhommet. In combination with the results previously published in 1979 for the north-dipping beds of the syncline, a conclusively negative fold test is obtained. The resulting magnetization (declination/inclination =206°/-3°, Π95 = 12°, palaeopole at 38°S, 325°E) is interpreted to be of Late Carboniferous age, not Late Devonian as thought earlier. Simultaneously, we have re-evaluated the age of the rocks, previously thought to be Late Devonian on the basis of Acritarchs, Chitinozoans and spores. It has not been possible to reconfirm these fossils, not even in the same samples as studied originally; in contrast, the regional presence of Early Palaeozoic fossils suggests to us an age similar to that of other red beds in the Arrnorican Massif, which have been dated as Early Ordovician. The geodynamic implications of our finding that the Montmartin rocks are completely remagnetized, however, are of no great consequence for the geodynamics of the Hercynian belt. Pre-folding magnetization obtained from Silurian and Devonian rocks in Spain and Germany argue for the same conclusion as reached erroneously in our earlier study, namely that the Armorican Massif and adjacent parts of Hercynian Europe were adjointed to North America, Great Britain, the Baltic Shield and the Russian Platform since at least Late Devonian time. If a Medio-European ocean existed during the Palaeozoic, it was virtually closed before the mid-Devonian and of insignificant width during Culm deposition in Early Carboniferoirs time.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74719/1/j.1365-246X.1985.tb05108.x.pd
Graptolite faunas of the Llandovery âphtanitesâ at Les Fresnaies (Chalonnes-sur-Loire, southeastern Armorican Massif): Palaeontology and biostratigraphy
Palaeomagnetism of the Ordovician dolerites of the Crozon Peninsula (France)
In order to obtain a Lower Palaeozoic pole for the Armorican Massif and to test the origin of the Ibero-Armorican arc, the Ordovician dolerites of the Crozon peninsula have been palaeomagnetically studied. The samples show a multicomponent magnetization which has been revealed by AF and thermal demagnetization and thoroughly investigated with rock magnetic experiments, polished section examinations and K/Ar dating. Four groups of directions have been recognized, often superimposed on each other in an individual sample. One component (D) has always the lowest blocking temperatures and coercivities and is considered to be of viscous origin, acquired recently in situ or in the laboratory during storage. Two components (A and B) are interpreted to be of secondary origin and to correspond to the observed K/Ar age distribution between 300 and 190 Myr. These ages represent the time interval between two regional thermo-tectonic events, associated with the Hercynian orogeny and the intrusion of dykes related to the early opening of the Central Atlantic Ocean and the Bay of Biscay. A fourth component (C) could be of Ordovician or younger Palaeozoic age; it is not clear whether the age of the magnetization is pre- or post-folding, but a pre-folding age would yield a direction of magnetization similar to Ordovician results from the Iberian peninsula. The latter interpretation suggests a fairly high palaeolatitude, which is in agreement with a glacio-marine postulated for sediments overlying the dolerite sills.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73214/1/j.1365-246X.1983.tb03785.x.pd
Active surveillance of bat rabies in France: A 5-year study (2004â2009)
Active surveillance of bats in France started in 2004 with an analysis of 18 of the 45 bat species reported in Europe. Rabies antibodies were detected in six indigenous species, mainly in Eptesicus serotinus and Myotis myotis, suggesting previous contact with the EBLV-1 rabies virus. Nineteen of the 177 tested bats were shown serologically positive in seven sites, particularly in central and south-western France. Neither infectious viral particles nor viral genomes were detected in 173 and 308 tested oral swabs, respectively. The presence of neutralising antibodies in female bats (18.6%) was significantly higher than in males (5.6%)
In Vitro and In Vivo Isolation and Characterization of Duvenhage Virus
A fatal human case of Duvenhage virus (DUVV) infection in a Dutch traveller who had returned from Kenya was reported in 2007. She exhibited classical symptoms of rabies encephalitis with distinct pathological findings. In the present study we describe the isolation and characterization of DUVV in vitro and its passage in BALB/c mice. The virus proved to be neuroinvasive in both juvenile and adult mice, resulting in about 50% lethality upon peripheral infection. Clinical signs in infected mice were those of classical rabies. However, the distribution of viral antigen expression in the brain differed from that of classical rabies virus infection and neither inclusion bodies nor neuronal necrosis were observed. This is the first study to describe the in vitro and in vivo isolation and characterization of DUVV
The stratigraphy, correlation, provenance and palaeogeography of the Skiddaw Group (Ordovician) in the English Lake District
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