The Iberian Pyrite Belt (IPB) hosts one of the largest concentrations of massive sulfides in the ... more The Iberian Pyrite Belt (IPB) hosts one of the largest concentrations of massive sulfides in the Earth's crust. This highly productive VMS belt contains more than 85 massive sulfide deposits, totalling an estimate of 1600 Mt of massive ore and about 250 Mt of stockwork ore (Leistel et al., 1998; Oliveira et al., 2005; Tornos, 2006). Included in the South Portuguese Zone the IPB is represented by the Phyllite-Quartzite Group (PQG) composed of shales and quartzites of late Devonian age followed by the Volcanic-Sedimentary Complex (VSC) a submarine succession of sediments and felsic and basic volcanic rocks (late Famennian-late Viséan age). Above the IPB a turbidite sedimentary unit occurs being represented by the Baixo Alentejo Flysch Group (BAFG). The ore deposits are hosted by felsic volcanic rocks and sediments that are dominant in the lower part of the VSC succession. The Neves Corvo (ProMine, EU FP7) project area is focused on the Neves Corvo deposit, an active copper mine. T...
Page 1. e-Terra http://e-terra.geopor.pt ISSN 1645-0388 Volume 10 nº 5 2010 Revista Electrónica... more Page 1. e-Terra http://e-terra.geopor.pt ISSN 1645-0388 Volume 10 nº 5 2010 Revista Electrónica de Ciências da Terra Geosciences On-line Journal GEOTIC Sociedade Geológica de Portugal VIII Congresso Nacional de Geologia ...
... Elevation differences along each profile are minimal except at Escanxinhas and Trafal 4, wher... more ... Elevation differences along each profile are minimal except at Escanxinhas and Trafal 4, where they do not exceed 3 m. A fixed spread with 48 channels, 50 Hz vertical receivers and a 250kg accelerated weight-drop seismic source were used in the acquisition of the seismic ...
Studies performed on the Carcavai fault zone, Eastern Algarve, revealed several deformational fea... more Studies performed on the Carcavai fault zone, Eastern Algarve, revealed several deformational features in Plio-Quaternary sediments with potential neotectonic implications. These features include fracturing (faults and joints) and clastic dikes, located along the Carcavai fault. Most of the fractures appear to be the expression of the fault activity affecting the Plio-Quaternary sediments. This is suggested by a consistent strike, subparallel to the major tectonic structure, and by the location pattern. Evidences of the fault activity were also identified in the Mesozoic and Paleozoic rocks, though the age of that deformation is poorly constrained. It consists in the presence of zones of intensely brecciated rock and of adjoining coarse sedimentary deposits probably related to the dismantling of a fault scarp. The acquired data point to a late hercynian structure, reactivated as a left-lateral strike-slip fault with a thrust component during the Plio-Quaternary.
The development of seismogenic source models is one of the first steps in seismic hazard assessme... more The development of seismogenic source models is one of the first steps in seismic hazard assessment. In seismic hazard terminology, seismic source zones (SSZ) are polygons that delineate areas with homogeneous characteristics of seismicity. The importance of using knowledge on geology, seismicity and tectonics in the definition of source zones has been recognized for a long time. However, the definition of SSZ tends to be subjective and controversial. In the SHARE (Seismic Hazard Harmonization in Europe) FP7 project, seismic hazard will be assessed with a logic tree approach that allows for three types of branches for seismicity models: a) smoothed seismicity, b) SSZ, c) SSZ and faults. In this context, a large-scale zonation model for use in the smoothed seismicity branch, and a new consensus SSZ model for Portugal and Azores have been developed. The new models are being achieved with the participation of regional experts and external experts, according the SSHAC (1997) level-3 met...
The Algarve province of Portugal is located near the E-W Eurasia-Africa plate boundary. It is cha... more The Algarve province of Portugal is located near the E-W Eurasia-Africa plate boundary. It is characterized by a moderate seismicity, with some important historical earthquakes causing important damage and economical losses. Not only has it suffered the effects of large plate boundary events but also the impact of local onshore moderate-sized earthquake sources. The seismic hazard evaluation and mitigation of the area is therefore of great importance to the local populations and the large number of tourists that frequent the region. This paper focuses the evaluation of the most interesting and useful geotechnical near-surface parameters and a soil classification. The classification based upon the European Code 8 for civil engineering and SPT bedrock data, was carried out for land use planning and design of critical facilities. P-wave and S-wave seismic velocities were obtained through the acquisition, processing and interpretation refraction profiles. Hundreds of SPT parameters from...
The Iberian Pyrite Belt (IPB) hosts one of the largest concentrations of massive sulfides in the ... more The Iberian Pyrite Belt (IPB) hosts one of the largest concentrations of massive sulfides in the Earth's crust. This highly productive VMS belt contains more than 85 massive sulfide deposits, totalling an estimate of 1600 Mt of massive ore and about 250 Mt of stockwork ore (Leistel et al., 1998; Oliveira et al., 2005; Tornos, 2006). Included in the South Portuguese Zone the IPB is represented by the Phyllite-Quartzite Group (PQG) composed of shales and quartzites of late Devonian age followed by the Volcanic-Sedimentary Complex (VSC) a submarine succession of sediments and felsic and basic volcanic rocks (late Famennian-late Viséan age). Above the IPB a turbidite sedimentary unit occurs being represented by the Baixo Alentejo Flysch Group (BAFG). The ore deposits are hosted by felsic volcanic rocks and sediments that are dominant in the lower part of the VSC succession. The Neves Corvo (ProMine, EU FP7) project area is focused on the Neves Corvo deposit, an active copper mine. T...
Page 1. e-Terra http://e-terra.geopor.pt ISSN 1645-0388 Volume 10 nº 5 2010 Revista Electrónica... more Page 1. e-Terra http://e-terra.geopor.pt ISSN 1645-0388 Volume 10 nº 5 2010 Revista Electrónica de Ciências da Terra Geosciences On-line Journal GEOTIC Sociedade Geológica de Portugal VIII Congresso Nacional de Geologia ...
... Elevation differences along each profile are minimal except at Escanxinhas and Trafal 4, wher... more ... Elevation differences along each profile are minimal except at Escanxinhas and Trafal 4, where they do not exceed 3 m. A fixed spread with 48 channels, 50 Hz vertical receivers and a 250kg accelerated weight-drop seismic source were used in the acquisition of the seismic ...
Studies performed on the Carcavai fault zone, Eastern Algarve, revealed several deformational fea... more Studies performed on the Carcavai fault zone, Eastern Algarve, revealed several deformational features in Plio-Quaternary sediments with potential neotectonic implications. These features include fracturing (faults and joints) and clastic dikes, located along the Carcavai fault. Most of the fractures appear to be the expression of the fault activity affecting the Plio-Quaternary sediments. This is suggested by a consistent strike, subparallel to the major tectonic structure, and by the location pattern. Evidences of the fault activity were also identified in the Mesozoic and Paleozoic rocks, though the age of that deformation is poorly constrained. It consists in the presence of zones of intensely brecciated rock and of adjoining coarse sedimentary deposits probably related to the dismantling of a fault scarp. The acquired data point to a late hercynian structure, reactivated as a left-lateral strike-slip fault with a thrust component during the Plio-Quaternary.
The development of seismogenic source models is one of the first steps in seismic hazard assessme... more The development of seismogenic source models is one of the first steps in seismic hazard assessment. In seismic hazard terminology, seismic source zones (SSZ) are polygons that delineate areas with homogeneous characteristics of seismicity. The importance of using knowledge on geology, seismicity and tectonics in the definition of source zones has been recognized for a long time. However, the definition of SSZ tends to be subjective and controversial. In the SHARE (Seismic Hazard Harmonization in Europe) FP7 project, seismic hazard will be assessed with a logic tree approach that allows for three types of branches for seismicity models: a) smoothed seismicity, b) SSZ, c) SSZ and faults. In this context, a large-scale zonation model for use in the smoothed seismicity branch, and a new consensus SSZ model for Portugal and Azores have been developed. The new models are being achieved with the participation of regional experts and external experts, according the SSHAC (1997) level-3 met...
The Algarve province of Portugal is located near the E-W Eurasia-Africa plate boundary. It is cha... more The Algarve province of Portugal is located near the E-W Eurasia-Africa plate boundary. It is characterized by a moderate seismicity, with some important historical earthquakes causing important damage and economical losses. Not only has it suffered the effects of large plate boundary events but also the impact of local onshore moderate-sized earthquake sources. The seismic hazard evaluation and mitigation of the area is therefore of great importance to the local populations and the large number of tourists that frequent the region. This paper focuses the evaluation of the most interesting and useful geotechnical near-surface parameters and a soil classification. The classification based upon the European Code 8 for civil engineering and SPT bedrock data, was carried out for land use planning and design of critical facilities. P-wave and S-wave seismic velocities were obtained through the acquisition, processing and interpretation refraction profiles. Hundreds of SPT parameters from...
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