Resultados de pesquisa

Micro-scale fcatures developed in coarse sand deposits present in the higher interfluves of the Serra do Gerês are studied. Two main types of features were identified: simple lag-surfaces and microaccumulations against obstacles. A morphological typology for the later is presented. The morphological study, grain-size analysis and comparison of the aspeet and location of the micro-accumulations against obstacles with shrub anemomorphisms allowed a first genetical interpretation for the studied features. This approach emphasises the importance of water and wind erosion in the Serra do Gerês higher areas. The role of water erosion in the genesis of simple lag-surfaces and micro-accumulations against obstac1es is mainly by washing of the fines. Wind erosion acts twofolds through accumulation and deflation of fines.

The detailed geomorphological mapping of landforms and deposits is widespread in Quaternary geomorphology studies. It consists on the precise representation of the spatial position of geomorphological information and their characterization (e.g. topography, hydrology, morphometry, morphography, morphogenesis,morphochronology and morphodynamics) in large-scale maps (usually 1:5,000 to 1:25,000).The data is collectcd using both remote sensing (aerial photo interpretation, satellite images, etc.) and detailed field surveys. However, in areas without topographic maps, or where the scale of the existing is too small, it becomes very difficult, or even impossible to make a detailed geomorphological survey. But even in areas with good topographic data, the precise location of small or very irregular landforms and deposits is frequently diffic...

O presente trabalho reúne algumas observações recentes relativas aos vestígios da glaciação da Serra da Estrela, nomeadamente no que se refere a depósitos glaciários, que não foram objecto das investigações clássicas. Essencialmente, dá-se conta da descoberta de tills subglaciários, os quais, no vale do Zêzere, se encontram até uma posição bastante alta, revelando a existência de uma glaciação mais importante do que era antes assumido. No vale do Conde foi encontrado um corte mais complexo, com diferentes tipos de till e que testemunham o limite nordeste da calote de planalto. Refere-se também a existência de acumulações arenosas na margem esquerda do vale do Zêzere, de origem ainda duvidosa, mas que deverão ser depósitos de tipo "grèze com estratificação irregular", acumuladas numa fase de recessão glaciária. Por último, chama-se a at...