Advertisement

STRATI 2013 pp 759-762 | Cite as

Provenance of Late Triassic Basins During the First Stages of Rifting in Pangaea (SW Iberia)

  • F. Vilallonga
  • M. F. PereiraEmail author
  • C. Ribeiro
  • M. Chichorro
  • M. Hofmann
  • K. Drost
  • U. Linnemann
Conference paper
Part of the Springer Geology book series (SPRINGERGEOL)

Abstract

The Late Triassic basins of SW Portugal were filled with continental detrital deposits dominated by sandstones and some interbedded conglomerates and mudstones. In this study, detrital zircons were separated from samples of the Upper Triassic sandstones of the Silves Formation collected in the Alentejo and Algarve basins. Conventional methods of separation of heavy minerals by sizing, magnetism, and gravity were used, and the zircon grains were dated by U–Pb geochronology using laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS). The analysis of detrital zircon populations using the Kolmogorov–Smirnov statistical test highlights the similarities and differences between samples within the same basin and between the two basins. Samples of both basins have significant similarities with respect to the populations of detrital zircons with ages older than ca. 515 Ma, reflecting their association with the northern Gondwana basement. A comparison of the populations of detrital zircon ages younger than ca. 515 Ma for the two basins shows that: (1) in the Alentejo Basin, Palaeozoic grains reflect the influence of sources related to the upper Palaeozoic formations of the South Portuguese Zone, or the Ossa Morena Zone basement with Variscan (late Palaeozoic) zircon-forming events; and (2) in the Algarve Basin, grains of Palaeozoic age are insignificant, which suggests the Upper Devonian formations of the South Portuguese Zone, or the Ossa Morena Zone basement without Variscan zircon-forming events, as the potential sources.

Keywords

Detrital zircon U–Pb geochronology Provenance analysis Silves Formation 

Notes

Acknowledgments

This paper is a contribution to research projects GONDWANA-PTDC/CTE-GIX/110426/2009 and GOLD- PTDC/GEO–GEO/2446/2012 funded by Fundação para a Ciência e Tecnologia (Portugal) and IGCP project 574 and IGCP 597 (UNESCO-IUGS). F. Vilallonga acknowledges a FCT PhD grant, SFRH/BD/45694/2008. C. Ribeiro acknowledges the funding provided by the Évora Geophysics Centre, Portugal, under the contract with FCT, PEst-OE/CTE/UI0078/2011. It is a contribution to project PEst-OE/CTE/UI4073/2014.

References

  1. Azerêdo, A. C., Duarte, L. V., Henriques, M. H., & Manuppella, G. (2003). Da dinâmica continental no Triásico aos Mares do Jurássico Inferior e Médio. Cadernos de Geologia de Portugal. Instituto Geológico e Mineiro, Lisboa, 43 p.Google Scholar
  2. Choffat, P. (1887). Recherches sur les terrains secondaires au Sud du Sado. Comissão dos TrabalhosGeológicos dePortugal I(II), 222–312.Google Scholar
  3. Inverno, C. M. C., Manuppella, G., Zbyszewski, G., Pais, J., & Ribeiro, M. L. (1993). Carta Geológica de Portugal na Escala 1/50 000. Notícia Explicativa da Folha 42-C Santiago do Cacém. S.G.P., Lisboa, 75 p.Google Scholar
  4. Oliveira, J. T. (1990). Stratigraphy and synsedimentary tectonism in the South Portuguese Zone. In R. D. Dallmeyer & E. Martínez (Eds.), Pre-Mesozoic geology of Iberia (pp. 334–347). Springer: New York.Google Scholar
  5. Palain, C. (1976). Une série détritique terrigène. Les “Grès de Silves”: Trias et Lias inférieur du Portugal. Memórias dos Serviços Geológicos de Portugal, N. S. 25, 377 p.Google Scholar
  6. Palain, C. (1979). Connaissances stratigraphiques sur la base du Mésozoique portugais. Ciências da Terra,5, 11–28.Google Scholar
  7. Pereira, M. F., Chichorro, M., Solá, A. R., Silva, J. B., Sanchez-Garcia, T., & Bellido, F. (2011). Tracing the Cadomian magmatism with detrital/inherited zircon ages by in situ U-Pb SHRIMP geochronology (Ossa-Morena Zone, SW Iberian Massif). Lithos,123, 204–217.CrossRefGoogle Scholar
  8. Pereira, M. F., Chichorro, M., Johnston, S. T., Gutierrez-Alonso, G., Silva, J. B., Linnemann, U., et al. (2012). The missing Rheic Ocean magmatic arcs: provenance analysis of Late Paleozoic sedimentary clastic rocks of SW Iberia. Gondwana Research,22(3–4), 882–891.CrossRefGoogle Scholar
  9. Rocha, R. B. (1976). Estudo estratigrafico e paleontològico do Jurassico do Algarve Occidental. Ciências da Terra 2, 178 p.Google Scholar
  10. Vilallonga, F. (2013). Análise de proveniência sedimentar das bacias do Carbónico e do Triásico do SW de Portugal (Alentejo e Algarve): contributo para o conhecimento dos processos de formação e fragmentação da Pangeia. Ph.D., ECT, Universidade de Évora, 333p.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • F. Vilallonga
    • 1
  • M. F. Pereira
    • 1
    Email author
  • C. Ribeiro
    • 2
  • M. Chichorro
    • 3
  • M. Hofmann
    • 4
  • K. Drost
    • 5
  • U. Linnemann
    • 4
  1. 1.IDL, Departamento de GeociênciasEscola de Ciencias e Tecnologia, Universidade de ÉvoraEvoraPortugal
  2. 2.CGE, Departamento de GeociênciasEscola de Ciencias e Tecnologia, Universidade de ÉvoraEvoraPortugal
  3. 3.CICEGe, Departamento de Ciências da Terra, Faculdade de Ciências e TecnologiaUniversidade Nova de LisboaCaparicaPortugal
  4. 4.Senckenberg Naturhistorische Sammlungen DresdenDresdenGermany
  5. 5.Department of GeosciencesUniversity of TubingenTubingenGermany

Personalised recommendations