13 research outputs found

    U–Pb Zircon geochronology of the Cambro-Ordovician metagranites and metavolcanic rocks of central and NW Iberia

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    New U–Pb zircon data from metagranites and metavolcanic rocks of the Schist-Graywacke Complex Domain and the Schistose Domain of Galicia Tras-os-Montes Zone from central and NW Iberia contribute to constrain the timing of the Cambro-Ordovician magmatism from Central Iberian and Galicia Tras-os-Montes Zones which occurred between 498 and 462 Ma. The crystallization ages of the metagranites and metavolcanic rocks from the northern Schist-Graywacke Complex Domain are as follows: (a) in west Salamanca, 489 ± 5 Ma for Vitigudino, 486 ± 6 Ma for Fermoselle and 471 ± 7 Ma for Ledesma; (b) in northern Gredos, 498 ± 4 Ma for Castellanos, 492 ± 4 Ma for San Pelayo and 488 ± 3 Ma for Bercimuelle; (c) in Guadarrama, 490 ± 5 Ma for La Estacion I, 489 ± 9 Ma for La Canada, 484 ± 6 Ma for Vegas de Matute (leucocratic), 483 ± 6 Ma for El Cardoso, 482 ± 8 Ma for La Morcuera, 481 ± 9 Ma for Buitrago de Lozoya, 478 ± 7 Ma for La Hoya, 476 ± 5 Ma for Vegas de Matute (melanocratic), 475 ± 5 Ma for Riaza, 473 ± 8 Ma for La Estacion II and 462 ± 11 Ma for La Berzosa; and (d) in Toledo, 489 ± 7 Ma for Mohares and 480 ± 8 Ma for Polan. The crystallization ages of the metagranites from the Schistose Domain of Galicia Tras-os-Montes Zone are 497 ± 6 Ma for Laxe, 486 ± 8 Ma for San Mamede, 482 ± 7 Ma for Bangueses, 481 ± 5 Ma for Noia, 480 ± 10 for Rial de Sabucedo, 476 ± 9 Ma for Vilanova, 475 ± 6 Ma for Pontevedra, 470 ± 6 Ma for Cherpa and 462 ± 8 Ma for Bande.This magmatism is characterized by an average isotopic composition of (87Sr/86Sr)485Ma ≈ 0.712, (eNd)485Ma ≈ -4.1 and (TDM) ≈ 1.62 Ga, and a high zircon inheritance, composed of Ediacaran–Early Cambrian (65 %) and, to a lesser extent, Cryogenian, Tonian, Mesoproterozoic, Orosirian and Archean pre-magmatic cores. Combining our geochronological and isotopic data with others of similar rocks from the European Variscan Belt, it may be deduced that Cambro-Ordovician magmas from this belt were mainly generated by partial melting of Ediacaran–Early Cambrian igneous rocks

    Serological and molecular detection of Toscana and other Phleboviruses in patients and sandflies in Tunisia.

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    Background: Our aim is to detect the infection by Toscana virus (TOSV) and other Phleboviruses in the sera and cerebro-spinal fluid (CSF) of patients with meningitis in Tunisia. We examined various species of phlebotomus present in Tunisia to determine whether or not a direct relationship exists between cases of meningitis and the viruses circulating in the insect vectors. Methods: Patients with the meningeal syndrome were tested for anti-TOSV IgM and IgG using an indirect Enzyme-Linked Immunosorbent Assay (ELISA) and for the presence of TOSV and other Phleboviruses using a RT-PCR test. An entomological study was carried out using CDC light traps to trap sandflies in different bioclimatic zones of Tunisia. Collected sandflies were tested by RT-PCR for the presence of TOSV and other Phleboviruses and subsequently by viral isolation on Vero cells. Results: Of 263 patients were tested using ELISA of which 12.16% (n = 32/263) were IgM positive for anti TOSV. Of these 32 patients, 78% (n = 25/32) were IgG positive. 12.86% (n = 18/140) of the CSF samples tested by RT-PCR were positive for the Toscana virus. One CSF sample tested by RT-PCR revealed the presence of Sandfly Fever Sicilian Virus (SFSV). The Punique virus was identified in one sandfly pool. Conclusions: This study confirms, for the first time, that TOSV is involved in a neurological disorder in North Africa. The incidence of this involvement in Tunisia conforms with observations made in other Mediterranean countries. Moreover, for the first time, a molecular approach was used to detect SFSV in a Tunisian patient displaying neurological symptoms. Keywords: Toscana virus, ELISA, Nested RT-PCR, Viral isolation, Sandfly Fever Sicilian virus, Punique virus, Phlebovirus, Sandflies, Phlebotomus, Tunisi

    The 600 Ma-Old Pan-African Magmatism in the In Ouzzal Terrane (Tuareg Shield, Algeria): Witness of the Metacratonisation of a Rigid Block

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    The high-level sub-circular North Tihimatine granitic pluton, intrusive in the In Ouzzal terrane, has been dated at 600 ± 5 Ma (LA-ICP-MS U–Pb zircon) and at 602 ± 4 Ma (SHRIMP U–Pb zircon). At this time, while Tihimatine intruded a brittle In Ouzzal without major metamorphism, large high-K calc-alkaline granitoid batholiths emplaced in the adjacent terranes under ductile conditions and regional amphibolite facies metamorphism. Outside In Ouzzal, high-level plutons emplaced under brittle conditions are known only at c. 580 Ma. The In Ouzzal terrane (500 km × 80 to 5 km), made of c. 2 Ga very high-temperature granulitic lithologies with Archean protoliths, is the sole terrane within the Tuareg Shield to have been largely unaffected by the Pan-African orogeny. The field, petrographic, geochemical and isotopic characteristics of the In Ouzzal granitic plutons studied herein, give keys for the understanding of the atypical behavior of the In Ouzzal terrane. The In Ouzzal Pan-African granitoids present chemical compositions varying from medium-K to high-K calc-alkaline to alkaline compositions. This is recorded by the Sr and Nd radiogenic isotopes (−4 < ɛNd < −30; 0.704 < ISr < 0.713), pointing to a mixing between a heterogeneous and old Rb-depleted source, the Eburnean granulitic In Ouzzal crust, and a Pan-African mantle. The latter is represented by the nearby bimodal Tin Zebane dyke swarm (ɛNd = +6.2, ISr = 0.7028; Hadj Kaddour et al. in Lithos 45:223–243, 1998), emplaced along the mega-shear zone bounding the In Ouzzal terrane to the west. Trace element composition and Sr–Nd isotope modeling indicate that 20–40% of different crustal lithologies outcropping in the In Ouzzal terrane mixed with mantle melts. At least two, most probably three, Eburnean granulitic reservoirs with Archean protoliths are needed to explain the chemical variability of the In Ouzzal plutons. The Pan-African post-collisional period is related to a northward tectonic escape of the Tuareg terranes, including the rigid In Ouzzal terrane, bounded by major shear zones. Blocking of the movement of the In Ouzzal terrane, which occurred 20 Ma earlier (at 600 Ma) on the western side than on the eastern side, induced its fracturing along oblique faults inside the terrane. This process allowed asthenosphere to rise and to locally melt the In Ouzzal crust, giving rise to the studied plutons. This corresponds to a metacratonization process. The In Ouzzal terrane demonstrates that a relatively small rigid block can survive within a major orogen affected by a post-collisional tectonic escape at the cost of a metacratonization, particularly at depth along faults

    Sandfly-Borne Phlebovirus Isolations From Turkey: New Insight Into the Sandfly Fever Sicilian and Sandfly Fever Naples Species

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    Southern Anatolia in Turkey at the border with Syria, where many refugee camps are settled, is endemic for sandfly-borne leishmaniasis. Sandfly-borne phleboviruses are also known to circulate in this region, although their relevance in terms of medical implications is virtually unknown. Therefore, the specific objectives of our study were firstly to identify isolate and characterise potentially pathogenic phleboviruses in sandflies; secondly to determine the complete genomic sequence of any viruses that we were able to isolate; and thirdly, to further our understanding of the potential medical importance and epidemiological significance of these viruses. To achieve these objectives, we organised field campaigns in 2012 and 2013. Two new phleboviruses (Toros and Zerdali viruses) were isolated and characterized by complete genome sequencing and phylogenetic analyses. Toros virus was genetically most closely related to Corfou virus within the Sandfly fever Sicilian group. Zerdali virus was most closely related to Tehran virus within the Sandfly fever Naples species. Although these new viruses belong to genetic groups that include several human pathogens, it is not yet clear if Toros and Zerdali viruses can infect humans and cause disease such as sandfly fever. Consequently, the availability of these genetically characterized infectious viruses will enable seroprevalence studies to establish their medical importance in this region and to assist the health agencies to develop appropriate and effective disease control strategies., We provide evidence that sandfly-borne phleboviruses belonging to 3 distinct genetic and phylogenetic groups (Sandfly fever Naples virus [SFNV], Sandfly fever Sicilian virus [SFSV], and Salehabad virus [SALV]) co-circulate in Adana city, in Mediterranean Turkey. While Adana virus was recently described as a new member of the SALV species, Zerdali and Toros viruses are described here as new phleboviruses genetically closely related to SFNV and SFSV, respectively. In this study, isolated and characterised these two new viruses by determining their complete genome sequence and by phylogenetic analysis. This study demonstrates that 3 distinct viruses can co-circulate in the same geographic area and based on their phylogenetic relationships and association with sandflies are likely to be transmitted by these arthropod vectors. Our molecular and phylogenetic data are important for establishing group-specific molecular detection assays in order to further understand of the possible impact of these viruses in animal and human health in this region of Turkey.PubMedWoSScopu
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