Browsing by Author "Matos, João Xavier"
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- Carboniferous palynostratigraphy of the borehole SDJ1 from the Santa Susana region, Ossa Morena Zone, PortugalPublication . Pereira, Zélia; Lopes, Gilda; Fernandes, Paulo; Matos, João Xavier; Rosa, Diogo; Oliveira, José TomásThe borehole SDJ1, with a total depth of 404.5 meters, was drilled in 1991 by the Serviço de Fomento Mineiro to investigate an Electromagnetic TEM conductor (Oliveira & Matos 1991). This hole is located in the eastern sector of the Santa Susana/Moinho da Ordem coal mine (1927-1944), in the Jongeis mine sector. The borehole log indicates that it cuts lithologies of the Carboniferous Toca da Moura Complex (TMC) and the Santa Susana Formation (SSF).
- Contribuição para o estudo da estrutura da mina de Aljustrel (Faixa Piritosa Ibérica) com base em novos dados palinoestratigráficos do Complexo Vulcano-Sedimentar e da Fm. MértolaPublication . Matos, João Xavier; Pereira, Zélia; Fernandes, Paulo; Rosa, Diogo; Oliveira, José TomásA cartografia geológica de detalhe e a análise palinoestratigráfica de sedimentos do Complexo Vulcano-Sedimentar da Faixa Piritosa e da Fm. Mértola, na região da mina de Aljustrel, permite uma melhor compreensão da estrutura local. A Fm. Paraíso apresenta uma idade Tournaisiano sup. - Viseano inf. (biozonas CM e Pu). A Fm. Gavião tem uma idade semelhante, contendo associações de miosporos da biozona CM, do Tournaisiano sup. Propõe-se uma nova unidade sedimentar correspdente à base da Fm. Mértola, a Unidade Canal da BAI, de idade Viseano médio-sup. (biozona NM).
- Devonian and Carboniferous palynostratigraphy of the South Portuguese Zone - An overviewPublication . Pereira, Zélia; Matos, João Xavier; Fernandes, Paulo; Oliveira, José TomásA Zona Sul Portuguesa (ZSP) representa o ramo sul do Orógeno Varisco Ibérico e compreende os seguintes domínios, de norte para sul: o Antiforma do Pulo do Lobo, a Faixa Piritosa Ibérica, o Grupo do Flysch do Baixo Alentejo e o Sector Sudoeste (Anticlinais da Bordeira e Aljezur). No presente trabalho apresenta-se uma síntese dos conhecimentos palinoestratigráficos obtidos em secções seleccionadas dos vários domínios da ZSP. Os dados obtidos permitem estabelecer correlações cronoestratigráficas em toda a Zona Sul Portuguesa, contribuindo assim para o melhor conhecimento da sua evolução paleogeográfica e geodinâmica.
- Devonian and carboniferous palynostratigraphy of the South Portuguese zone, Portugal - an overviewPublication . Pereira, Zélia; Matos, João Xavier; Fernandes, Paulo; Oliveira, José TomásThe South Portuguese Zone (SPZ) represents the southern branch of the Iberian Variscides and comprehends the following geologic domains: the Pulo do Lobo Antiform, the Iberian Pyrite Belt, the Baixo Alentejo Flysch Group and the Southwest Portugal (Aljezur and Bordeira Anticlines). An overview of all the results recently achieved in palynostratigraphic research of selected sections all over the SPZ is presented. A chronostratigraphic correlation of the stratigraphic units recognized across the ZPZ and its geodynamic and palaeogeographic implications is attempted.
- A importância dos palinomorfos remobilizados no Complexo Vulcano-Sedimentar da Toca da Moura - Implicações para a evolução geodinâmica da Zona de Ossa Morena, PortugalPublication . Lopes, Gilda; Pereira, Zélia; Fernandes, Paulo; Wicander, Reed; Matos, João Xavier; Rosa, Diogo; Oliveira, José TomásO estudo palinostratigráfico da sondagem SDJ11 permitiu a recuperação de associações in situ de palinomorfos do Carbónico assim como associações de palinomorfos remobilizados do Câmbrico médio ao Devónico inferior e Câmbrico médio ao Tournaisiano.
- New data on the late Famennian miospore assemblage of the Cercal Anticline (westernmost Iberian Pyrite Belt area), PortugalPublication . Pereira, Zélia; Matos, João Xavier; Fernandes, Paulo; Oliveira, José TomásThe Cercal Anticline (CA) is located in the westernmost region of the Iberian Pyrite Belt (IPB). The exposed stratigraphic sequence includes, in ascending order, the Volcano-Sedimentary Complex (VSC) followed by the Xistos das Abertas Fm, which passes gradually to the flysch sequence of the Mira Formation (Carvalho, 1976).
- New lower Givetian age miospores of the Phyllite-Quartzite Group, São Francisco da Serra Anticline, Iberian Pyrite Belt - PortugalPublication . Pereira, Zélia; Matos, João Xavier; Fernandes, Paulo; Jorge, R. C. G. S.; Oliveira, José TomásPalynostratigraphical analysis of Phyllite Quartzite (PQ) Group shales recovered froma drill core and outcrops at the São Francisco da Serra anticline, in the westernmost area of the Iberian Pyrite Belt, yielded a moderately preserved miospore assemblage assigned to the upper part of AD miospore Biozone, subzone Lem, of lower Givetian age. This is the oldest age recognized, up to this date, for any rocks in the Iberian Pyrite Belt.
- A palinostratigrafia no contexto da interpretação estrutural da Faixa PiritosaPublication . Oliveira, José Tomás; Pereira, Zélia; Matos, João Xavier; Fernandes, PauloPalinostratigaphy has proved, during the last two decades, to be a powerful tool to date the lithostratigraphic units of the Pyrite Belt. This work presents the most recent palinostratigraphic research carried out in selected tectonic structures of the Pyrite Belt. The results obtained allow the clarification and precision of previous
- Palynostratigraphy study of the Caveira Mine (NW sector of the Iberian Pyrite Belt, Portugal)Publication . Pereira, Zélia; Fernandes, Paulo; Oliveira, José Tomás; Matos, João XavierIn the NW sector of Iberian Pyrite Belt, the geology is dominated by complex antiformal structures, as we can observe in the Lousal and Caveira old massive sulphide mines, both located at the Azinheira de Barros region. The age of the lithostratigraphic units of these structures is still poorly constrained and subsequently palynostratigraphy revisions are being undertaken.
- Provenance of the reworked Ordovician Palynomorphs in SDJ1 Borehole - Santa Susana Basin, Ossa Morena Zone, PortugalPublication . Lopes, Gilda; Pereira, Zélia; Fernandes, Paulo; Matos, João Xavier; Rosa, Diogo; Oliveira, José TomásThe detail palynological study of the exploration borehole SDJ1 located in the Santa Susana / Moinho da Ordem disused coal mine area (1927‐1944), western border of the Ossa Morena Zone (OMZ) in Portugal, is presented here. The borehole intersects lithologies of the Toca da Moura Complex (TMC) and the Santa Susana Formation (SSF), dated as mid late Viséan and Moscovian (Carboniferous), respectively, based on palynomorphs (Cunha in Andrade et al., 1991; Pereira et al., 2006; Machado, 2010; Pereira et al., 2011) and macroflora (Wagner & Sousa, 1983). Together with the miospore associations recovered, assemblages of exceptional well‐ preserved Lower Palaeozoic acritarchs, cryptospores and spores were identified, which are interpreted asreworked. From these, the major percentage is Ordovician acritarchs. The ages of the reworked palynomorphs suggest that considerable erosion of exposed Lower Palaeozoic OMZ basement occurred during early Carboniferous times. The exposure of these rocks may have occurred by the first phases of the Variscan Orogeny in the OMZ. In this work the acritarch assemblages recovered from the SDJ1 borehole are compared with the acritarch assemblage identified from the Phyllodocites Shales Formation (Cunha & Vanguestaine, 1988; Pereira et al, 2011) in Barrancos region. Due to the resemblance in the acritarchs assemblages of both places we suggest that the Early Ordovician Phyllodocites Shales and correlatives were one of the main sources of the reworked acritarchs (Piçarra et al., 2011).