Encontrados 16 documentos, a visualizar página 1 de 2

Contribuição dos sistemas isotópicos Sm-Nd e Rb-Sr para o estudo petrogenético ...

O Granito do Porto corresponde a um granito hercínico, leucocrata, de duas micas, fortemente peraluminoso. No presente trabalho foram realizadas análises para os sistemas isotópicos Rb-Sr e Sm-Nd, em cinco amostras frescas do granito em estudo. Obteve-se uma isócrona Rb-Sr de 306±7 Ma (MSWD=0,71; 87Sr/86Sr inicial=0,7128), que dentro da margem de erro, deverá refletir a instalação magmática. Em termos de geoquí...

Discriminação de amostras de sedimentos para aplicação forense

Caracterização Geoquímica de Jazigos Filonianos de Pb-Zn-(Ag) através do Estudo...

Sulfides from Portuguese Vein-type Pb-Zn-(Ag) deposits were analysed with electronic microprobe. The results obtained for several minor elements present in galena and sphalerite were then statistically studied using principal components analysis (PCA). We intend to contribute to the geochemical characterization of these deposits through their contents in the minor elements. We hope to distinguish different subt...

Estudo de Inclusões Fluidas de Jazigos de Pb-Zn-(Ag) do Centro e Nordeste de Po...

Fluid Inclusion studies are being carried out in Pb-Zn-(Ag) deposits from NE and Central Portugal. In this brief abstract the preliminary results obtained for one of these deposits are presented: Ferronho deposit (Bragança district). Samples of quartz from the mineralized veins were petrographically studied and fluid inclusion assemblages defined in relation to different depositional events. Results from the mi...

Rochas xistentas de Trás-os-Montes como recurso

The abundance of schist outcrops in the Northeast and Centre regions of Portugal made schist, in the past, a common building material. A FCT R&D project is in course aiming the structural, mineralogical, petrographycal and technological characterization of the schist occurrences in NE Portugal and the promotion of those schistose rocks as a geological resource. In this contribution, we present three cases corre...

Sedimentologia e Estratigrafia –Estudo de um terraço de Lavadores. Contri...

Sedimentological studies of the terrace of the Pedras Amarelas in Lavaores (Vila Nova de Gaia) suggest, from the bottom up and to the migration of sedimentary environments to the west, the existence of coastal intertidal sedimentation, from the river sedimentation and culminating with swampy environments/lagoon in which there is evidence periglaciation. Geochronological studies conducted by OSL and 14C dating a...

Passeio Geológico da Foz do Douro: Consciencialização para a Geoconservação

The "Foz do Douro Geological Walk" has contributed to the public awareness of the Porto shoreline geoconservation. Considering the different school Knowledge, and in order promote significant practices in the aim of Geology, it was created in 2008 an Interpretative Centre and developed some science education materials. The investment in this project has proven to be fructiferous ; A criação do "Passeio Geológi...

Estudo da microfracturação do maciço granítico de Castelo Branco através dos Pl...

The main objective of this study was to determine the geometry of the FIP, in the Castelo Branco granite massif. This study showed that in addition to FIP in Mode I, are also present Mode II, suggesting that the directions found NE-SW to NNE-SSW and E-W to ESE-WNW can be interpreted as related to a maximum stress (σ1) oriented NE-SW. The NNW-SSE orientation corresponds to a late system

Geocronologia e petrogénese do plutonismo tardi-varisco (NW de Portugal): sínte...

No NW de Portugal ocorre um importante volume de granitóides, que correspondem a sucessivos pulsos magmáticos principalmente instalados na etapa pós-colisional da orogenia varisca (290-321 Ma). Trata-se de plutonismo com assinaturas químicas e isotópicas diversas e forte variabilidade composicional. No presente trabalho, apresenta-se uma síntese dos dados geocronológicos e petrogenéticos disponíveis e discute-s...

Cartografia Geológica à escala 1:10.000 da região SW da Folha Geológica 9C &#82...

The aim of this work was to conduct a geological survey and integrate the collected field data into a graphical environment for further processing and development of a geological map of an area belonging to the Vila Nova de Gaia municipality. The study included, therefore, the geological mapping, at a scale of 1:10,000 of the SW area of the 9C Geological Sheet, covering a total of about 18 km2. In the studied a...