Reconstructing the architectural evolution of volcanic islands from combined K/AR, morphologic, tectonic, and magnetic data. The Faial Island exemple (Azores)

The morpho-structural evolution of oceanic islands results from competition between volcano growth and partial destruction by mass-wasting processes. We present here a multi-disciplinary study of the successive stages of development of Faial (Azores) during the last 1 Myr. Using high-resolution digital elevation model (DEM), and new K/Ar, tectonic, and magnetic data, we reconstruct the rapidly evolving topography at successive stages, in response to complex interactions between volcanic construction and mass wasting, including the development of a graben. We show that: (1) sub-aerial evolution of the island first involved the rapid growth of a large elongated volcano at ca. 0.85 Ma, followed by its partial destruction over half a million years; (2) beginning about 360 ka a new small edifice grew on the NE of the island, and was subsequently cut by normal faults responsible for initiation of the graben; (3) after an apparent pause of ca. 250 kyr, the large Central Volcano (CV) developed on the western side of the island at ca 120 ka, accumulating a thick pile of lava flows in less than 20 kyr, which were partly channelized within the graben; (4) the period between 120 ka and 40 ka is marked by widespread deformation at the island scale, including westward propagation of faulting and associated erosion of the graben walls, which produced sedimentary deposits; subsequent growth of the CV at 40 ka was then constrained within the graben, with lava flowing onto the sediments up to the eastern shore; (5) the island evolution during the Holocene involves basaltic volcanic activity along the main southern faults and pyroclastic eruptions associated with the formation of a caldera volcano-tectonic depression. We conclude that the whole evolution of Faial Island has been characterized by successive short volcanic pulses probably controlled by brief episodes of regional deformation. Each pulse has been separated by considerable periods of volcanic inactivity during which the Faial graben gradually developed. We propose that the volume loss associated with sudden magma extraction from a shallow reservoir in different episodes triggered incremental downward graben movement, as observed historically, when immediate vertical collapse of up to 2 m was observed along the western segments of the graben at the end of the Capelinhos eruptive crises (1957-58).

Compreensão na leitura num manual de estudo do meio

A aquisição de competências ao nível da compreensão na leitura apresenta-se, cada vez mais, como o caminho para chegar ao conhecimento. O tipo de texto que se assume como o meio privilegiado de acesso ao conhecimento é o texto expositivo. Como tal, é importante que os textos a que os alunos têm acesso diariamente na sala de aula (nomeadamente, os textos dos manuais) sejam adequados ao desenvolvimento dessas competências. Neste estudo,analisaram-se os textos expositivos do manual de Estudo do Meio do 4.º ano mais adotado em Portugal no ano letivo 2010/2011. Em concreto, apurou-se a percentagem de textos expositivos existentes no manual, analisou-se a sua estrutura (Meyer, 1985), o tipo de questões que os acompanham, bem como as relações entre as perguntas e as respostas (Raphael, 1986, cit. em Giasson, 2000). O manual foi ainda analisado à luz do que é preconizado pelos documentos oficiais do Ministério da Educação.

Tradições orais como subsídio para escritas de cena: das tradições orais à artes performativas

Projeto para obtenção do Grau de Mestre em Teatro. Especialização em Artes Performativas — Escritas de Cena.