Recursos de colección

Estudo Geral - Universidade de Coimbra (19.630 recursos)

ESTUDO GERAL é a designação do repositório digital da produção científica da Universidade de Coimbra, com o objectivo de divulgar conteúdos digitais de natureza científica de autores ligados à Universidade de Coimbra. A sua criação insere-se no movimento de Acesso Livre à Literatura científica (Open Access), ao qual o Conselho de Reitores das Universidades Portuguesas aderiu em 2006 e que a Universidade de Coimbra subscreveu. À semelhança de outras grandes universidades nacionais e internacionais, a UC tem o maior interesse em aumentar a sua presença na rede informática mundial, sendo cada vez mais - e também por essa via - um emissor de conhecimento e cultura.

FCTUC Ciências da Terra - Artigos em Revistas Internacionais

Mostrando recursos 1 - 20 de 55

  1. La Sedimentation cyclique marno-calcaire dans le Toarcien du Bassin Lusitanien (Portugal)

    Duarte, Luís V.
    Dans le secteur nord du Bassin lusitanien, les sédiments toarciens montrent une alternance marne-calcaire monotoneet une organisation en séquences de díverses échelles, dont les calcaires occupent le sommet. La cyclicité de ces unités marne-calcaire est l'objet de discussions, compte-tenu de l'absence d'une échelle de temps fiable et du problème de la signification génétique des couples élémentaires marne-calcaire (séquences élémentaires). Cette étude est basée sur quelques traitements mathématiques communément utilisés dans l'analyse de séquences temporelles : l'autocorrélation et l'analyse spectrale des pourcentages de calcaire déterminés selon des intervalles régulièrement espacés ; l'analyse spectrale de l'épaisseur et du pourcentage de calcaire par...

  2. Definition of the Portuguese frameworks with international relevance as an input for the European geological heritage characterisation

    Bilha, J.; Andrade, C.; Azerêdo, Ana C.; Barriga, F.; Cachão, M.; Cunha, P. P.; Crispim, J. A.; Dantas, P.; Duarte, L. V.; Freitas, M.C.; Granja, M. H.; Henriques, M. H.; Lopes, L.; Madeira, J.; Matos, J. M. X.; Noronha, F.; Pais, J.; Piçarra, J.; Ramalho, M. M.; Relvas, J. M. R.; Ribeiro, A.; Santos, A.; Santos, V.; Terrinha, P.
    This work constitutes the first contribution for the systematisation of the geological heritage knowledge in Portugal, following the international recomendations for the characterisation of geological heritage (IUGS, ProGEO). The application of the ProGEO methodology has resulted on the creation of fourteen frameworks with international relevance, established by consensus among the Portuguese geological community. The description of each category in this paper is not exhaustive and just the most relevant scientific settings are presented. The following are the three key outcomes of this work: i) At a national level, the most important geosites are identified, indicating where geoconservation efforts should be...

  3. Toarcian nannobiohorizons from the Lusitanian Basin (Portugal) and their calibration against ammonite zones.

    Perilli, N.; Duarte, Luis V.
    The Lower Jurassic is well represented in west-central Portugal (Lusitanian Basin), where several outcrops with exceptional exposures exist. Among these, three sites have a major interest for Geological Heritage: S. Pedro de Moel, Rabaçal and Peniche. These localities display important sections for the study of the Liassic carbonate successions, whose scientific and educational value, for the domains of Palaeontology, Stratigraphy, Sedimentology and Geomorphology is widely known. The aim of this work is to enumerate the main scientific arguments for considering these Portuguese Liassic localities as national and international relevance and as an important heritage value (Geosite).

  4. The geological heritage of the Lower Jurassic of Central Portugal: selected sites, inventory and main scientific arguments

    Duarte, Luís
    The Lower Jurassic is well represented in west-central Portugal (Lusitanian Basin), where several outcrops with exceptional exposures exist. Among these, three sites have a major interest for Geological Heritage: S. Pedro de Moel, Rabaçal and Peniche. These localities display important sections for the study of the Liassic carbonate successions, whose scientific and educational value, for the domains of Palaeontology, Stratigraphy, Sedimentology and Geomorphology is widely known. The aim of this work is to enumerate the main scientific arguments for considering these Portuguese Liassic localities as national and international relevance and as an important heritage value (Geosite).

  5. Lower to Middle Toarcian from the Coimbra region (Lusitanian Basin, Portugal): sequence stratigraphy, calcareous nannofossils and stable-isotope evolution

    Duarte, Luís; Perilli, Nicola; Dino, Rodolfo; Rodrigues, René; Paredes, Ricardo

  6. The North-Lusitanian Subbasin (Portugal) from the Triassic to the Middle Jurassic: a model of an “aborted rift”

    Soares, António F.; Rocha, Rogério B.; Elmi, Serge; Henriques, Maria Helena; Mouterde, René; Almeras, Yves; Ruget, Christiane; Marques, Júlio; Duarte, Luis; Carapito, Maria Cristina; Kullberg, José Carlos
    The North-Lusitanian Subbasin has sustained a complex evolution whichcart be divided into five main stages: 1. Liassic Distension leading to the differentiation of the Arunca-Montemor lineament; 2. Lower Liassic Rifting with development of endemic ammonites-faunas (Upper Sinemurian); 3. Differential Subsidence (Middle Liassic to Lower Aalenian): eustatic changes were complicated by a strong acceleration of the differential subsidence; 4. Progradation of a carbonate platform (Middle Aalenian to Lower Callovian); 5. The closure of the subbasin began during the Middle Callovian and was followed by emersions.

  7. Pliensbachian (Early Jurassic) calcareous nannofossils from the Peniche section (Lusitanian Basin, Portugal): A clue for palaeoenvironmental reconstructions

    Reggiani, L.; Mattioli, E.; Pittet, B.; Duarte, L. V.; Oliveira, L. C. Veiga de; Comas-Rengifo, M. J.
    Quantitative analysis of Early Jurassic calcareous nannofossil assemblages from the Peniche section in Portugal have been performed in order to interpret palaeoenvironmental changes occurring in the Lusitanian Basin during the Late Pliensbachian Davoei, Margaritatus and Spinatum Ammonite Zones. Nannofossil data are compared to already published carbon and oxygen stable isotope data, organic matter content (wt.%Total Organic Carbon, TOC), and biomarker analysis. A signi!cant change in calcareous nannofossil assemblages and species diversity at the transition between the Margaritatus and Spinatum Ammonite Zones matches with the pattern shown by geochemical data. This suggests that a profound change in environmental conditions occurred at that time. In the Davoei and Margaritatus...

  8. Can biogeochemistry aid in the palaeoenvironmental/early diagenesis reconstruction of the ˜187 Ma (Pliensbachian) organic-rich hemipelagic series of the Lusitanian Basin (Portugal)?

    Silva, Ricardo L.; Mendonça Filho, João G.; Silva, Frederico S. da; Duarte, Luís V.; Silva, Taís F.; Ferreira, Rui; Azerêdo, Ana C.

  9. Micropropagation of Melissa officinalis L. through proliferation of axillary shoots

    Tavares, A. C.; Pimenta, M. C.; Gonçalves, M. T.
    Multiple shoots were differentiated in cotyledonary nodes of 10 d old seedlings of Melissa officinalis, cultured on MS medium supplemented with BAP (0-4 mg/l). The production of shoots was further induced in subcultures of the original explant, after the first harvest of shoots (stumps), using similar conditions. The highest average number of shoots in the two inoculations was obtained with 2 mg/l of BAP: 24 axillary shoots per explant, 7 in the first inoculation and 17 in the second one. The maximum elongation of shoots was achieved with BAP at 0.2 mg/l, and higher concentrations of the hormone induced a...

  10. An attempt to correct for the fading in million year old basaltic rocks

    Morthekai, P.; Jain, Mayank; Cunha, Pedro P.; Azevedo, José M.; Singhvi, Ashok K.

  11. Cretaceous sedimentary and tectonic evolution of the northern sector of the Lusitanian Basin

    Cunha, Pedro P.; Pena dos Reis, P.

  12. Tectonic control of the Tejo river fluvial incision during the late Cenozoic, in Rodão - central Portugal (Atlantic Iberian border)

    Cunha, Pedro P.; Martins, A.A.; Daveau, S.; Friend, P.F.

  13. Definition of the Portuguese frameworks with international relevance as an input for the European geological heritage characterisation

    Brilha, J.; Cunha, Pedro P.; Azerêdo, A.; Barriga, F. J. A. S.; Azeredo, A.; Cachão, M.; Couto, H.; Andrade, C.; Crispim, J. A.; Dantas, P.; Duarte, L. V.; Freitas, M. C.; Granja, M. H.; Henriques, M. H.; Lopes, L.; Madeira, J.; Matos, J. M. X.; Noronha, F.; Pais, J.; Piçarra, J.; Ramalho, M. M.; Relvas, J. M. R. S.; Ribeiro, A.; Santos, A.; Santos, V. F.; Terrinha, P.
    This work constitutes the first contribution for the systematisation of the geological heritage knowledge in Portugal, following the international recomendations for the characterisation of geological heritage (IUGS, ProGEO). The application of the ProGEO methodology has resulted on the creation of fourteen frameworks with international relevance, established by consensus among the Portuguese geological community. The description of each category in this paper is not exhaustive and just the most relevant scientific settings are presented. The following are the three key outcomes of this work: i) At a national level, the most important geosites are identified, indicating where geoconservation efforts should be...

  14. Cenozoic seismic stratigraphy and tectonic evolution of the Algarve margin (offshore Portugal, southwestern Iberian Peninsula)

    Lopes, F.C.; Cunha, Pedro P.; Le Gall, B.

  15. The Paleogene of the Algarve margin: evidence from multichannel seismic data

    Lopes, F.C.; Cunha, Pedro P.; Bernard, Le Gal

  16. Stratigraphy and allogenic controls of the western Portugal Cretaceous: an updated synthesis

    Dinis, J.; Cunha, Pedro P.; Rey, J.; Callapez, P.; Pena dos Reis, P.

  17. Dating the Tejo River lower terraces in the Ródão area (Portugal) to assess the role of tectonics and uplift

    Cunha, Pedro P.; Martins, A.A.; Huot, S.; Murray, A.; Raposo, L.

  18. Geomorphological correlation of the tectonically displaced Tejo river terraces (Gavião-Chamusca area, central Portugal) supported by luminescence dating

    Martins, A.A.; Cunha, Pedro P.; Huot, S.; Murray, A.S.; Buylaert, J.P.

  19. Geoarcheology of Pleistocene open-air sites in the Vila Nova da Barquinha - Santa Cita area (Lower Tejo River basin, central Portugal)

    Martins, A.A.; Cunha, Pedro P.; Rosina, P.; Oosterbeck, L.; Cura, S.; Grimaldi, S.; Gomes, J.; Murray, A.S.; Matos, J.

  20. Optical dating of clastic deposits generated by an extreme marine coastal flood: the 1755 tsunami deposits in the Algarve (Portugal)

    Cunha, Pedro P.; Buylaert, J.P.; Murray, A.S.; Andrade, C.; Freitas, M.C.; Fatela, F.; Munhá, J.M.; Martins, A.A.; Sugisaki, S.

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