- Arqueologia Mineira – Notícia Sobre um Pilão de Minérios Pré-histórico.
O. da Veiga Ferreira ; L. de Albuquerque e Castro (8 pages)
- Breve Notícia Sobre a Aplicação do Processo Magnético de Prospecção em Alguns dos Jazigos de Magnetite do Alentejo.
A. A. Soares de Andrade (22 pages)
Abstract: The Portuguese Government, represented by Direcção Geral de Minas e Serviços Geológicos, wishing to inventory the reserves of magnetic iron ores existing on the Portuguese continental territory, have signed agreements with the Swedish enterprise, Aktiebolaget Elektrisk Malmletning of Stockolm (The Electrical Prospecting C.º) to carrying out the geomagnetic survey of given regions where the geognostic conditions were favourable to the appearance of magnetite.The Serviço de Fomento Mineiro, of that Direcção Geral, was the entity appointed to organize and co-operate in that work. (…)
This notice merely refers to the magnetic survey effected at the Montemor-o-Novo and Alvito ore deposits, because only at these places the research works and mining studies are considered as finished or at such a state of progress that they allow some conclusions about their behavior as far as deepness is concerned.
(…) Parcial abstract
- Considerações Sobre as Formações Cupríferas da Região de Barrancos.
João Martins da Silva (21 pages)
Abstract: There are several copper deposits in region of Barrancos. The sedimentary strata containing the ores belong to Dilurian period and they are formed by brownish and dark gray clay slates, grauwacks, quartzites, and limestones. They are very folded. A diabasic rock breaks through these silurian sediments. The copper veins occur near the limestones or in the schists. The adjoining-rock shows silicification. In limestones, near the veins, we did not observe Ca-Mg-Fe silicates, but we meet a little metasomatic pyrite. The mettalic minerals develop in the filling. The predominating gangue mineral is quartz, but carbonates are also common, such as siderite and a little calcite; barite occurs sometimes. The principal ore mineral is chalcopyrite; bornite and native copper are ocasionally of importance; sometimes, chrysocolla, tetrahedrite, and gold appear.Owing to processes of superficial alteration, we find also the following minerals: chalcosite, covellite, melaconite, cuprite, malachite, azurite, and limonite. Some of these supergene minerals contributed to increase the teor of the ore. The filling structure is brecciated, seldom banded, and the ore concentration is generally irregular or in «pockets». High-temperature minerals, such as garnet, piroxene, tourmaline, amphibole, olivina, ilmenite, or magnetite, are absent. We think these metalliferous deposits were formed by ascending thermal waters in connection with intrusive diabases.
- Resumo da Actividade do Serviço de Fomento Mineiro Durante o Primeiro Semestre de 1949
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