Browsing by Author "Albardeiro, L."
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- A avaliação de risco sísmico no Algarve: efeito de sítioPublication . Albardeiro, L.; Moura, DelmindaAs características físicas locais traduzem no seu todo, aquilo a que se designa por efeito de sítio, ou seja, a resposta do substrato geológico a um determinado estímulo como é, neste caso, a propagação de uma onda sísmica. Face a este estímulo, a conjugação dos vários atributos físicos locais, pode resultar na amplificação do movimento do substrato, no aumento do tempo do movimento e na geração de movimentos diferenciais. Este tipo de efeito designa-se por agravamento.
- Consequências da alteração climática do Holocénico Médio nas zonas costeiras: Algarve, PortugalPublication . Moura, Delminda; Albardeiro, L.; Boski, T.; Veiga-Pires, C.; Rodrigues, A. L.Na costa Sul do Algarve, estão expostos aeolianitos correspondentes a duas fases morfogenéticas do Holocénico Médio, correlativas em parte, da alteração climática generalizada que ocorreu no hemisfério norte, cerca dos 8000 anos.
- Evolução da linha de costa durante a transgressão holocénica: Baía de Armação de Pêra (Sul de Portugal)Publication . Moura, Delminda; Albardeiro, L.; Veiga-Pires, C.; Boski, T.As zona costeiras são importantes zona húmidas, suporte de ecossistemas cuja conservação depende da estabilidade dos ambientes geológicos litorais. Estes respondem a numerosos factores, entre os quais a variação do nível médio do mar (nmm).(...)
- Holocene sea level fluctuations and coastal evolution in the central Algarve (southern Portugal)Publication . Moura, Delminda; Veiga-Pires, C.; Albardeiro, L.; Boski, T.; Rodrigues, Ana; Tareco, HelderIn Armação de Pêra Bay, southern Portugal, environmental changes during the Holocene can be interpreted based on the morphological and sedimentological similarities between older geomorphic features (cemented beach and dune rocks) and present coastal features. Using knowledge of the present beach and dune processes, we propose a two-step model for the evolution of Armação de Pêra Bay. First, during the rapid sea level rise between about 8800 and 6600 yr cal BP, the bay changed from a positive to a negative budget littoral cell and transgressive dunes formed, favoured by drought conditions. At about 5000 yr cal BP, during a sea level maximum, beach width was less than the critical fetch and dunes stabilized and underwent cementation during the wetter Atlantic climatic event. The second phase of dune accumulation started at about 3200 yr cal BP, due to a regression of sea level during which the bay changed back to a positive budget littoral cell in which beach width was greater than the critical fetch. Currently, the beach width is less than the critical fetch, dunes are inactive, and the sedimentary budget is negative due to sediment storage in local river systems.
- Morphological features and processes in the central Algarve rocky coast (South Portugal)Publication . Moura, Delminda; Albardeiro, L.; Veiga-Pires, C.; Boski, T.; Tigano, EsterMorphological features along the Algarve rocky coast, South Portugal, are identified and described, with an emphasis on shore platforms and notches. The contributions of processes, such as wave attack, chemical weathering and bioerosion, to sculpting the shore platforms are discussed. The preferential localization of shore platforms on sites exposed to waves, and the lack of significant chemical weathering, point to wave erosion as the first-order factor in platform formation, whilst bioerosion/bioprotection, lithology and geological structure determine platform morphological variations. In addition, platforms above the present intertidal zone appear to have a polygenetic evolution, being inherited from former sea-level highstands and currently undergoing chemical weathering. The occurrence of notch features is independent of the degree of exposure to waves, but they mostly occur where the substratum is sand. Hydrostatic pressure appears to be an important factor in the formation of marine caves in the more sheltered sites.
- Palaeosurface reconstruction based on sedimentary record and in sea level evolution in the Guadiana Estuary (Southern Iberia)Publication . Loureiro, C.; Boski, T.; Albardeiro, L.; Moura, Delminda; Terefenko, P.; Camacho, Sarita; Veiga-Pires, C.The sedimentary infilling of the Guadiana estuary, in the Southern Iberian Peninsula, has been extensively studied using a variety of laboratory methods, namely geochemical and sedimentological analyses, foraminifera assemblages and palynological profiles, supported by 14C dating [1-3](...)
- Plataformas litorais no sul de Portugal: uma tentativa de datação com U/Th em cracasPublication . Veiga-Pires, C.; Ghaleb, Bassam; Campo, Leif; Albardeiro, L.; Moura, Delminda; Machado, NunoNa costa sul portuguesa, mais especificamente na zona central algarvia, foram identificadas várias plataformas litorais situadas acima da presente faixa intermareal.
- Post last glacial maximum (LGM) shoreline evolution in the Algarve (south Portugal)Publication . Moura, Delminda; Albardeiro, L.; Veiga-Pires, C.; Boski, T.Aeolianites spanning the last 20 ka, are outcropping in a different geomorphological context along the Algarve coast, South Portugal. Here we use the term aeolianite as defined by Fairbidge and Johnson (1978), being a wind-blown sediment originating from the beach with a high carbonate content. The therefore it is related with sea-level fluctuations. However, other factors like coastal plain slope, marine environment, and coastal morphology, influence the morphogenetic processes.
- Quaternary sea level highstands in the Algarve (South Portugal)Publication . Moura, Delminda; Albardeiro, L.; Veiga-Pires, C.; Boski, T.Algarve is the Portuguese southernmost region in which we can distinguish three main domains in the coastal zone. In the west coast, abrupt cliffs are cutting mainly Paleozoic schists and graywackes, prevailing small enclosed beaches with the largest sandy beaches being developed adjacently to the river mouths. In the windward side (west) of the south coast, cliffs were formed essentially into the Mesozoic and Miocene limestones.
- Shore Platforms in the Algarve (South Portugal) Rocky Coast, an Inheritance of the Last Interglacial Stage?Publication . Moura, Delminda; Veiga-Pires, C.; Albardeiro, L.; Boski, T.Shore platforms, notches, and marine caves are common yet distinctive morphological features along the southern coast of Portugal. The central Algarve rocky coast has provided a favorable setting in which to understand the processes contributing to shore platform development. This is because the morphology and characteristics of the features vary along the coast, as do several factors implicated in their development such as wave climate (including wave direction and frequency), seabed morphology and depth, bedrock lithology, karstification and geological structure.