Search

Located in the Iberian pyrite belt, the Neves-Corvo mine is a world-class massive sulfide deposit and the largest operating mine in Portugal with underground mining down to 1000 m depth focused on massive and stockwork Cu, Zn, Pb rich ores. Gravimetric data have had a leading role in the discovery of the seven known deposits, together with time-domain electromagnetic (TEM) ground data. In this work, we present the results of a 3D constrained gravity inversion carried out with legacy ground gravity data. The 3D gravity inversions were carried out using an updated density database containing approximately 142,000 measurements. A recently constructed 3D geological model based on reprocessed 2D seismic reflection, 3D seismic, TEM and updated geology from detailed surface mapping and drill-hole data, was used to constrain the inversions. The results show multiple high-density anomalies that may indicate the presence of mineralization at depth. These anomalies were therefore cross-checked with holes previously drilled. Approximately 97% of more than 1000 available surface drill-holes located on or at a distance of less than 200 m from the high-density anomalies intersected mineralization. However, gravity anomalies have been drilled in the past and particularly dense black shales or rhyolitic/gabbroic rocks have been intersected. To increase the success of future drilling, gravimetric anomalies have been correlated spatially with high-conductivity TEM zones and strong-amplitude seismic reflections, because igneous rocks usually present weak-to-moderate conductivity and a massive column of black shales presents a seismic signature quite different from that of mineralization. We concluded that some of these locations represent high-quality targets to consider following up with drilling and further exploration. info:eu-repo/semantics/publishedVersion

The Neves-Corvo world class Iberian Pyrite Belt volcanogenic massive sulphide (VMS) deposit located in southern Portugal, constitutes an important Cu–Zn–Pb active mine. Seven deposits are currently known, among which the Lombador deposit alone has estimated 150 Mt of massive sulphides. The life-time of the mine is dependent on the discovery of new exploration targets and it is vital to have accurate 3D geological models, not only to guide drilling campaigns but also to drive a winning/ new strategy, which in the past has led to Semblana and Monte Branco discoveries: geophysical inversion and modelling. Furthermore, 3D geological models can contribute to the understanding of the tectonic and stratigraphic evolution of the region. Therefore, the goal of this study is to produce a realistic 3D geological model of the Neves-Corvo region, as only one model is presently publicly available: the PROMINE model, which includes the study area of this work and extends from Aljustrel to the border with Spain. Lundin Mining has also produced two unpublished, confdential models in 2007 and 2017. The latest Lundin model incorporates the same geophysical data used in this work (2D and 3D seismic refection and time-domain electromagnetic (TEM) ground loop data) and approximately 7500 surface and underground drill-holes. The model presented in this research has much more detail than the 2012 PROMINE model in the Neves-Corvo region and uses an updated and revised drill-hole database with approximately 8000 drill-holes, revised geological cross-sections built from surface geology and drill-hole logs, new geological outcrop data, petrophysical and reprocessed geophysical data, and is therefore more detailed and accurate than any of the previous models, in particular the 2007 and PROMINE models. Land gravimetric and aeromagnetic data are also available in the study area but were not directly used to build the geological model but rather to investigate and check the model produced. Modelling was performed with industry standard software and the 3D curves resulting from the geological/geophysical interpretation were interpolated using diferent approaches to respect the hard data (interpretation lines and drill-holes). The resulting 3D stratigraphic surfaces required strong manual editing to respect the interpretation, due to the presence of folds, thrusts and tectonic nappes in the study area. The surfaces were afterwards tied to the drill-holes, resulting in a 3D model with great accuracy and detail in the near mining area and covering a larger area than previously available 3D geological models. The model has three major stratigraphic layers: the Mértola Flysch Formation and the Volcano-Sedimentary Complex (VSC), overlying the Phyllite-Quartzite Formation basement, and also the known VMS deposits (underlying the top of the Lower VSC) geometries according to drill-hole data. In the central part of the study area, where more drill-holes are available, the top of the Lower VSC sequence surface was also built. This approach will contribute to a better exploration drill-hole planning and the generation of new targets for exploration. info:eu-repo/semantics/publishedVersion

Submitted by CV Deposit (cvuser@cienciavitae.pt) on 2020-12-07T10:27:20Z No. of bitstreams: 2 Pereira_et_al.,_2019_reply_to_Pereira_F_et_al.pdf: 1256923 bytes, checksum: bdf7f3fa1bd9f4ded666862010280701 (MD5) package.zip: 1140324 bytes, checksum: e21f8c9e9cc52e3e4ba9974e490a9d6f (MD5) Approved for entry into archive by Paula Candeias (paula.candeias@lneg.pt) on 2020-12-15T14:39:13Z (GMT) No. of bitstreams: 2 package.zip: 1140324 bytes, checksum: e21f8c9e9cc52e3e4ba9974e490a9d6f (MD5) Pereira_et_al.,_2019_reply_to_Pereira_F_et_al.pdf: 1256923 bytes, checksum: bdf7f3fa1bd9f4ded666862010280701 (MD5) Made available in DSpace on 2020-12-15T14:39:13Z (GMT). No. of bitstreams: 2 package.zip: 1140324 bytes, checksum: e21f8c9e9cc52e3e4ba9974e490a9d6f (MD5) Pereira_et_al.,_2019_reply_to_Pereira_F_et_al.pdf: 1256923 bytes, checksum: bdf7f3fa1bd9f4ded666862010280701 (MD5) Previous issue date: 2019 info:eu-repo/semantics/publishedVersion

Several blind massive sulphide deposits associated with the Iberian Pyrite Belt (IPB) Volcano-Sedimentary Complex (VSC) (Figure 1) were discovered in SW Iberia using joint interpretation of geological and geophysical models, such as Neves-Corvo (Albouy et al., 1981; Leca et al., 1983) and Lagoa Salgada (Oliveira et al., 1998) in Portugal, and Valverde and Las Cruces in Spain. In the IPB Portuguese sector, the former government agencies Servico de Fomento Mineiro (SFM) and Instituto Geologico e Mineiro (IGM), as well as LNEG, fostered the acquisition of systematic geophysical surveys, in particular gravimetry, in the region during the second half of the 20th century.

Polycyclic aromatic hydrocarbons (PAHs) are a class of organic chemicals that are widely distributed in the atmosphere and well known for their adverse health effects. This study aims to describe, for the first time, the levels, sources and associated health risks of particulate PAHs in an urban background atmosphere of Lisbon, the capital and largest city in Portugal. PM10 aerosol samples were collected from early January to the end of December 2012 with a high-volume sampler and were later analyzed for 10 PAHs by high-performance liquid chromatography. The annual average of the sum of the concentrations of PAHs (ΣPAHs) was 1.64 ± 1.85 ng/m3. The dominant PAHs were pyrene, chrysene, benzo[b]fluoranthene, fluoranthene and benzo[g,h,i]perylene. Together these species accounted for approximately 70% of the ΣPAHs. A marked seasonal variation was observed for the investigated PAHs, with the highest values in winter and the lowest in spring and summer, reflecting the variation of emissions and meteorological conditions over time. The average concentration of benzo[a]pyrene was found to be 0.107 ± 0.152 ng/m3, not exceeding the target value of 1 ng/m3 established by European air quality legislation. Diagnostic ratios and principal component analysis were employed for the source apportionment of PAHs. Both tools indicated that vehicle exhaust was the main contributor to the atmospheric levels of PAHs in the study area.

The article is focused on the application of Energy dispersive micro X-ray fuorescence spectroscopy as a specifc method to determine the contents of potentially toxic elements and its spread in plant tissues. As a model species, Quercus spp. were selected. In order to compare the obtained results with previous research, four well-described abandoned Cu-deposits were selected for sampling: Ľubietová (Slovakia), Libiola and Caporciano (Italy), and São Domingos (Portugal). The results of micro X-ray fuorescence spectrometry confrm the irregular contamination of Quercus spp. by potentially toxic elements. The level of contamination is the highest predominantly in the root cortex, where is also the highest Ca contents (with exception of São Domingos). At Ľubietová and Caporciano, high Ni content was described in branches cortex, in branches mesoderm also Fe, Cu and Zn. At the same time, the inhibition infuence of Ca was also confrmed regarding the input of these elements into plants. info:eu-repo/semantics/publishedVersion

This article reports the results of a study concerning contamination of the dump-fields by potentially toxic elements at five abandoned copper mines: Ľubietová, Špania Dolina (Slovakia), Libiola, Caporciano (Italy) and São Domingos (Portugal). This paper offers an updated description of soil contamination at the individual deposits and indicates a possible solution of the derived environmental problems. Contamination of technosoils by PTEs at the dump-fields shows an irregular spatial distribution of Fe, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Sb and Pb. Contents of PTEs often exceed both national and EU law limits. Whereas at Ľubietová, Špania Dolina and Caporciano the environmental risk is limited, at Libiola and São Domingos it seems to be very heavy. The technosoil (slag) of the dump-fields is not well aerated and the soil colloids have (except for Špania Dolina) negative surface charge, so they are suitable for PTEs sorption. The main environmental risk in the mining area of Sao Domingos district is the long time formation of acid mine drainage water and the high Zn, As and Pb contents. The release of PTEs to the environmental components may be limited by phytostabilization and immobilization of metals, by suitable admixtures into the technosoil/slag. The environmental situation at Caporciano is not so compromised as at São Domingos mining area. Phytostabilization will be able to stop erosion, and installation of wetlands under the dump will stop the release of Cu to the environment. info:eu-repo/semantics/publishedVersion

The recently discovered massive and stockwork sulphide mineralization of Semblana-Rosa Magra and Monte Branco, situated ESE of the Neves–Corvo volcanogenic massive sulphide (VMS) deposit in the Iberian Pyrite Belt (IPB) is presented. Geological setting and tectonic model is discussed based on proxies such as palynostratigraphy and U–Pb zircon geochronology. The mineralization is found within the IPB Volcano-Sedimentary Complex (VSC) Lower sequence, which includes felsic volcanic rocks (rhyolites) with U–Pb ages in zircons of 359.6 ± 1.6 Ma, and black shales of the Neves Formation of late Strunian age. Massive sulphides are enveloped by these shales, implying that felsic volcanism, mineralization and shale sedimentation are essentially coeval. This circumstance is considered highly prospective, as it represents an important exploration vector to target VMS mineralization across the IPB, in areas where the Lower VSC sequence is present. The Upper VSC sequence, with siliciclastic and volcanogenic sedimentary rocks of middle–late Visean age, shows no massive mineralization but a late Tournaisian (350.9 ± 2.3 Ma) volcanism with disseminated sulphides was also identified. Nevertheless, stratigraphic palynological gaps were found within the Strunian and in the Tournaisian sediments, between the Lower and Upper VSC sequences, reflecting probable erosion and uplift mechanisms linked with extensional tectonics. The Semblana and Monte Branco deposits and the Rosa Magra stockwork are enclosed by tectonic sheets that dismembered the VSC sequence in a fold-and-thrust tectonic complex, characteristic of the NE Neves–Corvo region. The methodologies used allow a geological comparison between Neves–Corvo and other IPB mine regions such as Lousal–Caveira, Herrerias, Tharsis and Aznalcollar.

A detailed palynostratigraphic study of two Somincor/Lundin Mining exploration drill holes intercepting the Phyllite-Quartzite (PQ) Formation in the geological basement of the Neves-Corvo mine region (Portuguese sector of the Iberian Pyrite Belt – IPB) allowed to first recognise the oldest ages for this formation in this region, ranging from midGivetian/midFrasnian (base unknown) to late Famennian. The TA Miospore Biozone (Cristatisporites triangulatus-Ancyrospora ancyrea) of middle Givetian age (Middle Devonian) was identified in NK30B-1 drill hole (Lombador North mine sector), whereas the BM Miospore Biozone (Verrucosisporites bulliferus-Lophozonotriletes media) and IV Miospore Biozone (based in the first occurrence of Rugospora bricei and Diducites cf. poljessicus) of middle Frasnian (Late Devonian) age were both recognised in drill hole SJ32 (Corvo-Semblana mine sector). The common presence of Early-Middle Devonian reworked spores, as well as similar inherited zircon ages may suggest that the lower PQ Formation age is not yet known. At Neves-Corvo mine, the Volcano-Sedimentary Complex is deposited directly above the PQ basement, spanning different ages, pointing out two major unconformities, a VSC/upper and/or lower PQ sequences and an upper PQ/lower PQ sequences. A palynostratigraphic correlation of the lowermost Phyllite-Quartzite Formation across the IPB is established. Phyllite-Quartzite Formation palynoassemblage of Neves-Corvo region is compared with lowermost PQ assemblages recovered in the NW sector of IPB (S. Francisco da Serra and Lousal-Caveira mine structures, Portugal) and in E sectors of the IPB in Spain (Gerena-El Garrobo section). The similar palynological record (also including the same reworked taxa signature) and ages obtained, suggests identical sedimentary provenance, close paleogeographic domain and temporal affinity throughout the lowermost IPB Phyllite-Quartzite Formation. info:eu-repo/semantics/publishedVersion

Mining activity in Algares (Aljustrel Mine, Portuguese sector of the Iberian Pyrite Belt, IPB) stems prior to Roman times. As the orebody is vertical and relatively thin, mining was carried out mainly along underground adits (galleries). Nowadays, the deposit is considered exhausted and the area is being rehabilitated for a different use. The Algares +30 level adit intersects two volcanic units of the IPB Volcano-Sedimentary Complex. The massive sulphide and related stockwork zone are hosted by the Mine Tuff volcanic unit and are exposed in the walls of the gallery, showing intense hydrothermal alteration. Along the mine adit, the geological sequence is affected by strong oxidation and supergene alteration, giving rise to the formation of secondary minerals through the oxidation of the sulphides. The most common minerals found were melanterite (FeSO4&middot, 7H2O) and chalcanthite (CuSO4&middot, 5H2O), forming essentially massive or crystalline aggregates, ranging from greenish to bluish colours. Melanterite from the walls revealed to be Cu-rich by opposition to that from stalactites/stalagmites formed below the old ore storage silo revealing the low-copper-grade ores exploited underground. The mineralogy of the efflorescent salts was used to ascertain the processes involved in their formation, and moreover, the inventory of minerals is presented, as well as their principal characteristics.

We present palynological results from the northern sector of the Pulo do Lobo Domain, combining sections studied in Portugal and Spain. A total of 139 samples were studied, of which 56 are positive for palynology. The first age determination for the Pulo do Lobo Formation was achieved, indicating a mid-Frasnian age (Verrucosisporites bulliferus and Pustulatisporites rugulatus). The sediments of Peramora Melange (Spain) yielded the same palyno-assemblage as that of the Pulo do Lobo Fm. and are interpreted as a part of this formation. The Ribeira de Limas Fm. also yielded mid-Frasnian miospore assemblages, indicating the same age as the Pulo do Lobo Fm. The Santa Iria and Horta da Torre formations present spore assemblages assigned to the late Famennian in both Portugal and Spain. The phyllites interbedded with the quartzites of the Alajar Melange yielded a palyno-assemblage late Famennian in age that can be correlated to the Horta da Torre Fm. Therefore, the Alajar quartzites are interpreted as a lateral equivalent of the Horta da Torre Fm. in Spain. The palynological results obtained for the units of the northern sector of the Pulo do Lobo Domain are highly consistent and in agreement with stratigraphic mapping and structural interpretations. A detailed discussion of the palynological versus geochronological ages based on detrital zircons is included in this study. The palynological results and their comparison with the worldwide Upper Devonian palynological record suggest a close affinity with NW European palynofloras, placing the Pulo do Lobo Domain within the Avalonian paleobiogeographical province.

São Domingos belongs among the most important historic Iberian Pyrite Belt Cu mines. The anthrosoil is contaminated by a very high content of heavy metals and metalloids. The study was focused on evaluating the interaction of some chemical elements (Ca, Mg, Fe, Mn, Cu, Pb, Zn, Ag, Cd, Ni, Co, As, Sb) in the system soil vs. five autochthonous dominant plant species: Pinus pinaster Aiton, Quercus rotundifolia Lam., Agrostis sp., Juncus conglomeratus L. and Juncus effusus L. The plants are heavily contaminated by Cu, Pb, As and Zn. The bioconcentration factor proved that they exhibit features of metal tolerant excluders. The trees are accumulators of Ag, whereas the graminoids are hyper-accumulators of Ag and Juncus effusus of Co. The translocation factor confirmed that the selected elements are immobilised in the roots except for Mn and Zn in Pinus pinaster and Mn in Quercus rotundifolia and Juncus conglomeratus. The bioaccumulation of Mn, Zn and Cu at low pH increases. The increased content of Ca and Mg in the soil inhibits, in the case of some metals and metalloids, their intake to plants. Although the studied plants, despite their fitness and vitality at the contaminated sites, are not suitable for phytoextraction (except Co and Ag), they can be used for phytostabilisation at the mining habitats.

R 0052-GEO-FPI-5-E ALT20-03-0145-FEDER-000025 Project (PA 18111) The sheltered environment of the Algares +30 level adit (underground mine gallery) contributes to the preservation of secondary water-soluble minerals formed on the tunnel walls. The massive sulphide and related stockwork zone are hosted by the Mine Tuff volcanic unit and are exposed in the walls of the gallery, showing intense oxidation and hydrothermal alteration. Minerals from the halotrichite group were identified on the efflorescent salts, typically white fine-acicular crystals but also on aggregates with dark orange/brownish colour. Mineral characterization was performed using several methods and analytical techniques (XRD, XRF-WDS, SEM-EDS, DTA-TG), and the chemical formulas were calculated maintaining the ratio A:B∼= 1:2 in accordance with the general formula of the halotrichite group, AB2 (SO4 )4·22H2 O. This methodology allowed the assignment of the orange colour to the presence of trivalent iron on iron-rich pickeringite in partial substitution of aluminium. publishersversion published

Summary Three- and four-dimensional geological models provide important means for mineral exploration as they help to unravel the tectonic and depositional history of an area. They also serve to outline alteration zone patterns, establish ore-bearing fluid migration paths and identify potential areas for the deposition of minerals in economic concentrations. Geological models serve as constraints within the geophysical modelling process and contribute in the generation of new targets for exploration. In this work, we present a new 3D geological model of the Neves-Corvo mining area in the Iberian Pyrite Belt, Castro Verde, Portugal. The model provides higher resolution insight into a subsample of an area previously modelled using an updated (4D) geoscience data catalogue. The 3D model has been built using extensive ground-loop electromagnetic and seismic reflection data acquired by Lundin Mining, more than 1,000 surface drill-holes, 7,000 underground drill-holes, as well as updated geological cross-sections and surface geology data. Gravity and magnetic data were also used qualitatively to assess the model. The result is an explicit 3D model with a considerable level of detail honouring all available data which may be used for further mineral exploration.

The Iberian Pyrite Belt (IPB) hosts world-class massive sulphide deposits, such as Neves-Corvo in Portugal and Rio Tinto in Spain. In Portugal, the Palaeozoic Volcanic-Sedimentary Complex (VSC) hosts these ore deposits, extending from the Grândola-Alcacer region to the Spanish border with a NW–SE to WNW–ESE trend. In the study area, between the Neves-Corvo mine region and Alcoutim (close to the Spanish border), the VSC outcrops only in a small horst near Alcoutim. Sparse exploration drill-hole data indicate that the depth to the top of the VSC varies from several 100 m to about 1 km beneath the Mertola Formation Flysch cover. Mapping of the VSC to the SE of Neves-Corvo mine is an important exploration goal and motivated the acquisition of six 2D seismic reflection profiles with a total length of approximately 82 km in order to map the hidden extension of the VSC. The data, providing information deeper than 10 km at some locations, were integrated in a 3D software environment along with potential-field, geological and drill-hole data to form a 3D structural framework model. Seismic data show strong reflections that represent several long Variscan thrust planes that smoothly dip to the NNE. Outcropping and previously unknown Late Variscan near-vertical faults were also mapped. Our data strongly suggest that the structural framework of Neves-Corvo extends south-eastwards to Alcoutim. Furthermore, the VSC top is located at depths that show the existence within the IPB of new areas with good potential to develop exploration projects envisaging the discovery of massive sulphide deposits of the Neves-Corvo type.

Heavy-metal contamination of Pinus pinaster, P. sylvestris, Quercus robur, and Q. rotundifolium was studied in four abandoned historic Cu deposits from Italy (Libiola, Caporciano), Portugal (São Domingos), and Slovakia (L'ubietová). The highest Cu and Mn contents in anthropogenic soil were described in Libiola and Caporciano whereas the highest Pb, Zn, As, and Sb contents in São Domingos. The anthropogenic soil in L'ubietová shows the highest Co contents. The area of São Domingos is the most acidified. There are important differences between the bioaccumulation of plants from individual deposits. Bioavailability of the heavy metals is generally independent of the pH values. The high Ca and Mg contents in soil are able to block the transport of heavy metals to the plant tissues. The bioconcentration factor values of all plant taxa, in all deposits, indicate a predominant strategy of excluders. Only Ag shows excellent bioconcentration ability. In L'ubietová, Pinus sylvestris has a strategy as an accumulator of Pb (2.43) and Zn (2.49); Pinus pinaster of Mn (4.97), Cd (1.85), and Co (5.62) and Quercus rotundifolium of Mn (3.54) in São Domingos. The predominantly low translocation factor values indicate that in most cases the heavy metals are accumulated in roots; only in a few rare cases do they migrate to shoots (e.g. Zn in Pinus sp. from all localities, Co in P. pinaster in São Domingos).

The geology of SW Iberia records a sequence of geologic events from the Cambrian-Early Ordovician rifting and subsequent passive margin development along the southern flank of the Rheic Ocean, to onset of oblique (sinistral) subduction in the Devonian, followed by oblique terrane accretion, ocean closure/continental collision and orogenic collapse. As a result, SW Iberia contains the southernmost exposure of the Pangean suture in the European Variscides. This suture zone is characterized by a belt of dismembered oceanic-related rocks and HP metamorphic complexes which are tectonically juxtaposed with the Gondwanan passive margin to the north (OMZ) and with the exotic South Portuguese Terrane to the south, which is thought to be either a remnant of Avalonia or Meguma.

The South Portuguese Terrane encompasses three major pre-orogenic mega-sequences: the Phyllite-Quartzite Group and the Tercenas Fm., the Volcanic-sedimentary Complex, and the Carrapateira Group, all three overlain by the syn-orogenic Baixo Alentejo Flysch Group, dealt with in Chap. 11. During the Mid-Late Devonian all the three mega-sequences belonged to an epicontinental sea. From the late Devonian to late Visean major changes took place: the region that became the IPB Domain was the locus of important lithospheric extension that led to the emplacement of important volumes of igneous rocks associated to a Volcanic-Sedimentary Complex, to which the VHMS ore deposits are associated; in Southwest Portugal the Tercenas Fm. shallow water sediments changed to a mixed-siliciclastic-carbonate shelf succession (Carrapateira Group); during the late Visean the extensional regime changed to crustal compression that caused the onset of huge deposits of flysch sediments (Baixo Alentejo Flysch Group) in successive depocenters migrating southward until the late Moscovian.

Energy and metals are essential resources in the 21st century and with the economic and technical development are more and more required. The fulfilling of these requirements leads to the need to p...

Extensive Cu- and Zn-soil geochemical data in the Albernoa/Entradas–S. Domingos region (NE border of the Iberian Pyrite Belt, South Portuguese Zone) were examined to separate anomalies from background using the concentration–area fractal model. Distribution patterns of Cu and Zn concentrations in soil are primarily influenced by bedrock. The regional threshold values of Cu- and Zn-soil contents over metasedimentary sequences are 20–25 and 20–60 ppm, respectively, becoming 30–50 and 20–90 ppm, respectively, when metavolcanic rocks are present. The first-order threshold values for Cu are 80–90 ppm in soils over metasediments and 70–80 ppm in soils over sequences bearing metavolcanics. For Zn, the first-order threshold values are 40–80 and 90–100 ppm in soils over metasediments and metavolcanic rocks, respectively. Metasediments and metavolcanics comprising significant sulphide disseminations are outlined by Cu- and Zn-soil values above 100 and 300 ppm in soil, respectively. On the basis of these results, Alvares and Albernoa/Entradas areas emerge as the first priority targets for exploration. The observed non-coincidence of Cu- and Zn-soil anomalies in soil in the area could reflect difference in element dispersion during weathering, they mostly indicate distinct metal sources related to the original composition of different rock types or to chemical changes developed during Variscan deformation/re-crystallization path. The established regional baseline data can be used as reference for environmental studies.

The lithostratigraphic sequence in the Rosário–Neves Corvo antiform comprises the Phyllite–Quartzite Group, whose top is of Famennian age, the Volcanic Sedimentary Complex, of Strunian to upper Visean age, and the Mértola Formation (the lower unit of the Baixo Alentejo Flysch Group) of upper Visean age. The volcanic sedimentary complex comprises a lower sequence of Strunian (Late Famennian) age and an upper sequence of lower to upper Visean age. Detailed mapping of the antiform towards NW of the Neves Corvo mine, supported by palynological dating, identified two new lithostratigraphic units: the Barrancão member (upper Famennian) ascribed to the Phyllite–Quartzite Group and made up of laminated dark shales with siliceous lenses and nodules, and the Ribeira de Cobres Formation of the Volcanic Sedimentary Complex, containing shales, siltstones and fine volcaniclastic rocks. Based on zircon U–Pb isotope dating, five discrete felsic magmatic events were identified at approximately 354, 359, 365, 373 and 384 Ma. This suggests that the volcanic activity in the area has extended for about 30 Ma, in a context of high regional heat flow as indicated by the geochemical signatures of the felsic volcanic rocks. The characteristics of magmatism and the depositional environment indicated by the sedimentary record should therefore have been highly favourable for massive sulphide formation. However, evidence of massive sulphide mineralization in the study area is still to be found. Moreover, reconstruction of the volcanic facies architecture demonstrated that the volcanic units in the Rosário area are strongly dominated by coherent facies typical of the inner part of thick lavas/domes. In fact, most of their external part, the more favourable location for possible massive sulphide mineralization, is missing. Palynological dating indicates a significant hiatus, recognised between the lower and upper sequences of the volcanic sedimentary complex, which implies erosion of the top of the volcanic centre, where VHMS deposits could possibly have formed. However, lateral areas of this volcanic centre, eventually preserved at depth, have good potential to host massive sulphide mineralization.

Lousal mine is a typical “abandoned mine” with all sorts of problems as consequence of the cessation of the mining activity and lack of infrastructure maintenance. The mine is closed at present, but the heavy metal enriched tailings remain at the surface in oxidizing conditions. Surface water and stream sediments revealed much higher concentrations than the local geochemical background values, which the “Contaminated Sediment Standing Team” classifies as very toxic. High concentrations of Cu, Pb, Zn, As, Cd and Hg occurred within the stream sediments downstream of the tailings sites (up to: 817 mg kg −1 As, 6.7 mg kg −1 Cd, 1568 mg kg −1 Cu, 1059 mg kg −1 Pb, 82.4 mg kg −1 Sb, 4373 mg kg −1 Zn). The AMD waters showed values of pH ranging from 1.9 to 2.9 and concentrations of 9249 to 20,700 mg L −1 SO 4 −2 , 959 to 4830 mg L −1 Fe and 136 to 624 mg L −1 Al. Meanwhile, the acid effluents and mixed stream waters also carried high contents of SO 4 2−, Fe, Al, Cu, Pb, Zn, Cd, and As, generally exceeding the Fresh Water Aquatic Life Acute Criteria. Negative impacts in the diatom communities growing at different sites along a strong metal pollution gradient were shown through Canonical Correspondence Analysis: in the sites influenced by Acid Mine Drainage (AMD), the dominant taxon was Achnanthidium minutissimum . However, Pinnularia acoricola was the dominant species when the environmental conditions were extremely adverse: very low pH and high metal concentrations (sites 2 and 3). Teratological forms of Achnanthidium minutissimum (Kutzing) Czarnecki, Brachysira vitrea (Grunow) Ross in Hartley, Fragilaria rumpens (Kutzing) G. W. F. Carlson and Nitzschia hantzschiana Rabenhorst were found. A morphometric study of B. vitrea showed that a decrease in size was evident at the most contaminated sites. These results are evidence of metal and acidic pollution.

Ore prospecting using gravimetric and magnetic data has become one of the traditional approaches used in past decades, often complemented with electric and electromagnetic methods. However, due to the problem of non-uniqueness inherent to potential-field modelling, constraints provided by structural methods such as seismic reflection are often used. During the exploration of polymetallic massive sulfide minerals in the Iberian Pyrite Belt, Figueira de Cavaleiros sector, located in the Sado Tertiary Basin, several gravimetric and magnetic anomalies were considered to be interesting targets. In order to reduce any ambiguity in the gravimetric modelling and to confirm the geological model of the area, two seismic reflection profiles were acquired. The interpretation of these profiles was assisted by three mechanical boreholes, two of which were located in the research area to make a seismostratigraphic interpretation. Unfortunately, the gravimetric modelling suggests that the anomaly has a lithological and structural origin and is not related to massive sulfides. Nevertheless, a good agreement between the seismic and potential-field data was achieved and new insights into the geological model for the region were obtained from this work, with accurate data about the Tertiary cover and Palaeozoic basement.

Land pollution due to past mining activities is a major environmental issue in many European countries. The Aljustrel mine (SW Portugal), located in the western sector of the Iberian Pyrite Belt (IBP) presents a negative visual and environmental impact as a consequence of the mining activity that has developed since the Roman era. Its impacts are also a restraint on the life quality of the population. The exposure of pyrite and other sulphides to air are responsible for the pollution observed in soils, surface water and stream sediments. This paper investigates the pollution load of potential toxic elements in soil samples collected around the Aljustrel mining area. The aim is to assess the levels of soil contamination with respect to average concentrations of toxic elements in the region and to understand the partitioning and availability of pollutants in the area. The results showed severe soil contamination (mainly As, Cd, Cu, Pb and Zn). The concentrations of As (up to 3936 mg kg−1) and certain heavy metals (up to 5414 mg kg−1 Cu, 61·6 mg kg−1 Cd, 20 000 mg kg−1 Pb and 20 000 mg kg−1 Zn) are two orders of magnitude above the regional South Portuguese Zone (SPZ) background values. The median concentrations of As, Cd, Cu, Pb and Zn exceed the values established for world soils, the European Union, Portugal and Andalusia. The results suggest that the distribution patterns of Co, Cr and Ni element concentrations in the Aljustrel area are primarily influenced by the lithology and geochemistry nature of bedrock. The soil background of this geological domain is characterized by relatively high heavy metal contents, essentially derived from the parent rocks. Copyright © 2010 John Wiley & Sons, Ltd.

Aljustrel mine is located in SW Portugal, in the western sector of the Iberian Pyrite Belt. The Aljustrel village was developed around the exploitations of massive polymetallic sulphides that occur in the area (4 orebodies mined, 2 in exploration phase). The pyrite ore was extensively exploited from 1850 to 1993, when production was discontinued. A mining restart occurred in 2008, only during a few months. The objectives of the study were to assess the levels of soil contamination, to determine associations between the different chemical elements and their spatial distribution, as well as to identify possible sources of contamination that can explain the spatial patterns of soil pollution in the area. Principal component analysis combined with spatial interpretation successfully grouped the elements according to their sources and provided evidence about their geogenic or anthropogenic origin. From this study, it is possible to conclude that soils around Algares/Feitais tailing deposits, Estereis and Aguas Claras mine dams and S. Joao mine show severe contamination. The highest concentrations of As (up to 3,936 mg kg−1) and certain heavy metals (up to 321.7 mg kg−1 for Bi, 5,414 mg kg−1 for Cu, 20,000 mg kg−1 for Pb, 980.6 mg kg−1 for Sb, and 22 mg kg−1 Cd) were obtained near Algares area while the highest concentration of Cd (up to 61.6 mg kg−1) and Zn (up to 20,000 mg kg−1) were registered in samples collected in the S. Joao area. The highest pollution load index (>4.0) was recorded at the Algares area where the metal concentrations exceed typical soil background levels by as much as two orders of magnitude.

The Barrigao re-mobilized copper vein deposit, Iberian Pyrite Belt, southern Portugal, is located about 60 km south of Beja and 10 km southeast of the Neves Corvo ore deposit, in Alentejo Province. The deposit is structurally associated with a NE–SW striking fault zone inferred to have developed during late Variscan deformation. The copper ore itself is a breccia-type ore, characterized by up to four ore-forming stages, with the late stages showing evidence of fluid-driven element re-mobilization. The ore is dominated by chalcopyrite + tennantite-tetrahedrite, with minor arsenopyrite, pyrite, and lollingite. The supergene paragenesis is composed mainly of bornite, covellite, and digenite. Whole-rock analyses show anomalous tin and germanium contents, with averages of 320 and 61 ppm, respectively. Electron microprobe analysis of Barrigao ores revealed the germanium and tin to be restricted to chalcopyrite, which underwent late-stage hydrothermal fluid overprint along distinct vein-like zones. The measured ...

The aim of this study was to validate lichens as biomonitors of PAH atmospheric deposition; for that, an inter-comparison between the PAH profile and concentrations intercepted in lichens with those of air, soil and pine needles was performed. The study was conducted in a petro-industrial area and the results showed that PAH profiles in lichens were similar to those of the air and pine needles, but completely different from those of soils. Lichens accumulated higher PAH concentrations when compared to the other environmental compartments and its concentrations were significantly and linearly correlated with concentrations of PAHs in soil; we showed that a translation of the lichen PAHs concentrations into regulatory standards is possible, fulfilling one of the most important requirements of using lichens as biomonitors. With lichens we were then able to characterize the air PAHs profile of urban, petro-industrial and background areas.

Aljustrel mining area is located in the Iberian Pyrite Belt, one of the greatest concentrations of massive sulphide deposits that extends from Lousal (Portugal) to Aznalcollar (Spain). The surrounding streams, Roxo, Agua Azeda and Agua Forte, are influenced by the erosion of the tailing deposits and the input of acid mine drainage (AMD) from the abandoned Aljustrel pyrite mines, recently reopened in 2007. The purpose of this study was to understand how these adverse conditions influenced the stream sediments, water quality and periphytic diatom communities and establish the pre-restoration local conditions to judge the success of rehabilitation program now under way. For stream sediments, the highest metal concentration samples were found at sites F, G and H. Arsenic, Cu, Fe, Pb and Sb detected concentrations, generally exceeded the probable effect concentration values reaching level 4: the highest toxicity level. In surficial water samples of AMD affected sites (F, G and H), low pH values (1.5 to 3.5) and high metal concentrations of As (6,837 μg L−1), Cd (455 μg L−1), Cu (68,795 μg L−1), Fe (1,262,000 μg L−1), Mn (19,451 μg L−1), Pb (136 μg L−1), and Zn (264,377 μg L−1) were found. In these sites, the diversity index (H′) for diatoms was low (0.6 to 2.8) and the dominant taxa were Eunotia exigua (site F, 33.5%) and Pinnularia acoricola (abundances in sites: F, 86.8%; G, 88.5%; and H, 91.1%). In opposition, in less AMD impacted, H′ was high (1.5 to 4.6) and low metal concentrations and high pH were found. Achnanthidium minutissimum was the dominant taxon in (abundances in sites: A, 76.1% and B, 24.39%). Canonical correspondence analysis showed that spatial variation due to mine influence was more important than seasonal variation, which did not show any pattern.

This study investigates the geochemical characteristics of the acid mine drainage discharged from the abandoned mine adits and tailing piles in the vicinity of the Lousal mine and evaluates the extent of pollution on water and on the stream sediments of the Corona stream. Atmospheric precipitation interacting with sulphide minerals in exposed tailings produces runoff water with pH values as low as 1.9–2.9 and high concentrations of \( {\text{SO}}^{{{\text{2}} - }}_{{\text{4}}}\)(9,249–20,700 mg l−1), Fe (959–4,830 mg l−1) and Al (136–624 mg l−1). The acidic effluents and mixed stream water carry elevated Cu, Pb, Zn, Cd and As concentrations that exceed the water quality standards. However, the severity of contamination generally decreases 4 km downstream of the source due to mixing with fresh waters, which causes the dilution of dissolved toxic metals and neutralization of acidity. Some natural attenuation of the contaminants also occurs due to the general reduced solubility of most trace metals, which may be removed from solution, by either co-precipitation or adsorption to the iron and aluminium precipitates.

The Enfermarias Zn-Pb(Ag, Sb, Au) prospect, located in the Moura-Ficalho region (Alentejo, Portugal), was intensively explored during 1980s. A drilling programme was successful, intersecting massive and disseminated sulphide mineralizations. The geological and geophysical data set available for Enfermarias is quite vast and comprises 13 borehole geological logs, as well as gravity, magnetic and resistivity data. In this paper, the dipole-dipole resistivity surveys are re-examined and interpreted using both 2D and 3D inversion to provide an interesting comparison of the two different approaches. Results from gravity data modelling and data from borehole logs are used as independent validity tests on the quality of the results. The 2D and 3D models indicate a conductive overburden covering more resistive bedrock, which appears at a depth of 70–100 m in the western part of the profiles. Results obtained from 3D inversion, however, show a very clear separation of the most resistive domains in the two different bodies, whereas this separation does not appear in the 2D models. The 3D model also shows a higher degree of spatial continuity than the partial 2D models, which are, in general, richer in shortwavelength anomalies, and show a higher variation from profile to profile. Comparison of the resistivity results with gravity in two coincident profiles reveals an excellent agreement between the main shallow features of both 2D and 3D models. This suggests that the resistivity model does indeed satisfy the main features of the available geological and geophysical data.

The 250 × 20–70 km Iberian Pyrite Belt (IPB) is a Variscan metallogenic province in SW Portugal and Spain hosting the largest concentration of massive sulphide deposits worldwide. The lowermost stratigraphic unit is the early Givetian to late Famennian-Strunian (base unknown) Phyllite-Quartzite Group (PQG), with shales, quartz-sandstones, quartzwacke siltstones, minor conglomerate and limestones at the top. The PQG is overlain by the Volcanic Sedimentary Complex (VSC), of late Famennian to mid-late Visean age, with a lower part of mafic volcanic rocks, rhyolites, dacites and dark shales, hosting VHMS deposits on top (many times capped by a jasper/chert layer), and an upper part, with dark, purple and other shales and volcanogenic/volcaniclastic rocks, carrying Mn oxide deposits. The VSC is covered by the thousands of meters thick Baixo Alentejo Flysch Group of late Visean to Moscovian age. The VSC comprises a bimodal submarine volcanic succession, with VHMS deposits spatially associated to dacites and rhyolites corresponding to effusive/explosive lava-cryptodome-pumice cone volcanoes. The lava/domes consist of coherent lithofacies surrounded by clast-rotated hyaloclastite breccia and minor autobreccia, with massive VHMS ore at the top of the felsic effusive units and stockworks in the autoclastic and pyroclastic breccias. The eastern IPB rocks are intruded by the voluminous Sierra Norte Batholith (tonalite-trondhjemite-granodiorite, TTG series). Felsic volcanic rocks (dacite to high-silica rhyolite) predominating over basalts and dolerites, belong to the calc-alkaline series and plot mostly in the within-plate field in tectonic discriminative diagrams. Several periods of volcanism, from 384 to 359 Ma are recognized. Dacites and rhyolites exhibit Nd and Sr enrichment, typical of a crustal signature, and their overall geochemistry suggests generation by fractionation/partial melting of amphibolites at low pressure. Trace elemental modelling of the basic rocks, involving tholeiitic lavas and alkaline basaltic lavas and dolerites, points to mixing between E- and N-MORB and assimilation of crustal material. Variscan NW-SE/W-E-trending and SW- or S-verging folds (with NE- or N-dipping planar cleavage) and thrusts, occur in west-central and eastern IPB, respectively. In late to post-Variscan time strike-slip oblique faults formed, either N-S to NNW-SSE or NE-SW to ENE-WSW, dextral or sinistral (both extensional), respectively. The first set hosts late Variscan Cu-Pb-Ba veins and Mesozoic(?) dolerite dykes. IPB contains over 90 VHMS deposits, estimated before erosion at >1700 Million tonnes (Mt), with 14.6 Mt Cu, 34.9 Mt Zn, 13.0 Mt Pb, 46,100 t Ag, 880 t Au and many other metals, particularly Sn. Eight of these are giant (≥100 Mt) VHMS deposits, namely Rio Tinto, Tharsis, Aznalcollar-Los Frailes, Masa Valverde, Sotiel-Migollas and La Zarza (Spain) and Neves Corvo and Aljustrel (Portugal). The VHMS deposits are of the felsic-siliclastic type and mostly of the Zn–Pb–Cu and Zn–Cu–Pb metal content types. The deposits range in thickness from 1 m to tens of meters (plus increase from tectonic stacking) and up to a few kilometers in extension, and many are underlain by large stockwork zones. Their age is either Strunian (palynological age) in the southern IPB or mostly Tournaisian in the northern IPB. The major massive ore minerals are pyrite, sphalerite, chalcopyrite, galena (and cassiterite at Neves Corvo), also present with dominant quartz-chlorite-sericite-carbonate in the stockwork ore. Sericite and chlorite were also formed from additional alteration in the hanging wall rocks. Metal zonation in most VHMS deposits consists of a Cu-rich stockwork and base of the massive ore, with Zn–Pb massive ore above and extending laterally. S-, O-, H- and C-isotope data indicate that ore-forming fluids contain predominant or exclusive modified seawater. A magmatic fluid contribution to the dominant seawater has been proposed for some deposits. The deposits are exhalative or formed by shallow subsurface replacement of either muds/shales or coherent felsic volcanic rocks.

3D, 4D and predictive geological modelling, including all known geoscientific data, were applied to the 100 × 25 km large Neves Corvo project area located in the Portuguese part of the Iberian Pyrite Belt. The lowermost unit in the area is the Givetian to Famennian-Strunian Phyllite-Quartzite Group (PQG), which is overlain by three SE-plunging volcanic axes with the Strunian to Visean Volcanic Sedimentary Complex (VSC), hosting in its lower sequence the Neves Corvo VHMS giant deposit. The VSC is covered with mid late Visean and Serpukhovian to Bashkirian flysch rocks [Mertola and Mira formations of the Baixo Alentejo Flysch Group (BAFG), respectively]. Six NE-SW deep 2D reflection seismic profiles acquired by LNEG between Neves Corvo mine and the Spanish border (60 km to the SE) during the ProMine project, allowed to extend a 3D-model of the Neves Corvo main thrust (that brings VSC rocks onto Mertola Fm. very close to VHMS ores) throughout the eastern part of the area. NE-SW to ENE-WSW (sinistral) and N-S to NNW-SSE (dextral) late Variscan strike-slip oblique faults (a few >5 km deep) displaced all former geological units and structures, as shown by the 3D models. In late Variscan time, small vein-type Cu (and other metals) deposits were emplaced along them.

To evaluate the accumulation of trace elements (TE) by vegetables produced in the vicinity of abandoned pyrite mines, eighteen different small farms were selected near three mines from the Portuguese sector of the Iberian Pyrite Belt (Sao Domingos, Aljustrel and Lousal). Total and bioavailable As, Cu, Pb, and Zn concentrations were analyzed in the soils, and the same TE were analyzed in three different vegetables, lettuce (Lactuca sativa), coriander (Coriandrum sativum), and cabbage (Brassica oleracea), collected at the same locations. The soils were contaminated with As, Cu, Pb, and Zn, since their total concentrations exceeded the considered soil quality guideline values for plant production in the majority of the sampling sites. The maximum total concentrations for those TE were extremely high in some of the sampling sites (e.g. 1851 mg As kg(-1) in Sao Domingos, 1126 mg Cu kg(-1) in Aljustrel, 4946 mg Pb kg(-1) in Sao Domingos, and 1224 mg Zn kg(-1) in Aljustrel). However, the soils were mainly circumneutral, a factor that contributes to their low bioavailable fractions. As a result, generally, the plants contained levels of these elements characteristic of uncontaminated plants, and accumulation factors for all elements

Available online 15 August 2013 The 404.5 m deep SDJ1 borehole is located in the Jongeis mining sector of the Santa Susana Basin (SSB), and has been palynostratigraphically studied. The SSB is a Carboniferous coal-bearing basin developed along the suture contact between the Ossa Morena Zone (OMZ) and the South Portuguese Zone (SPZ). The recovered palynologic assemblages are assigned to the NM Miospore Biozone of mid Visean age, with the lowermost 6.8 m of the borehole yielding an in situ miospore assemblage assigned to the SL Miospore Biozone of mid Moscovian age. All of the studied samples contained more than 90% of reworked palynomorphs ranging in age from the middle Cambrian to the early Tournaisian (0–397.7 m depth), with the first 6.8 m (397.7–404.5 m depth) yielding reworked palynomorphs from the middle Cambrian to the mid Moscovian. This particular palynologic signature provides further evidence for the interpretation of the reworked palynomorphs in the Toca da Moura Complex (TMC) and its importance in the geodynamic evolution of the OMZ, regarding the probable provenance areas of the reworked palynomorphs within the OMZ and SPZ. Six reworked sub-assemblages were discriminated: i. middle to (?)upper Cambrian; ii. Lower to Middle Ordovician; iii. middle to upper Silurian; iv. Lower Devonian; v. Upper Devonian and vi. lower Carboniferous. From the study of the palynomorph assemblages (both in situ and reworked) recovered from the SDJ1 borehole samples, new inferences are made regarding the recognition of the subsurface extension of the Toca da Moura Complex and its structural relationship to the Pennsylvanian continental coal-bearing SSB. These new data, together with the palynologic study of a control sample (STS15) from the Jongeis old coal mine, housed in the LNEG Geological Museum, in Lisbon, makes possible new interpretations concerning the evolution of the SSB.

Relatório final de um estudo efectuado no âmbito de um contrato de pesquisa celebrado entre o LNEG e a MAEPA/AVRUPA Submitted by Paula Serrano (paula.serrano@ineti.pt) on 2013-04-13T16:27:03Z No. of bitstreams: 1 35507.pdf: 1925364 bytes, checksum: 67b08ddfa4d9ab3e3251d04aadd2c97b (MD5) Approved for entry into archive by Paula Serrano (paula.serrano@ineti.pt) on 2013-04-13T16:27:17Z (GMT) No. of bitstreams: 1 35507.pdf: 1925364 bytes, checksum: 67b08ddfa4d9ab3e3251d04aadd2c97b (MD5) Made available in DSpace on 2013-04-13T16:27:17Z (GMT). No. of bitstreams: 1 35507.pdf: 1925364 bytes, checksum: 67b08ddfa4d9ab3e3251d04aadd2c97b (MD5) Previous issue date: 2012-10

Stream sediment samples were collected in the Trindade–Chanca region at 1034 sites for mineral exploration purposes during 1996–97. Concentrations of Cu, Zn, Pb, Co, Cr and Ni are high enough in most sample sites to allow data assessment by multi-element anomaly definition and threshold computation using the area concentration multifractal model technique. The regional threshold values are 20, 45, 30 and 15 ppm for Cu, Zn, Pb and Co respectively. Anomalies for Cu, Zn, Pb, Co, Cr and Ni are delimited by first order local threshold values at 40, 94, 70, 21, 37 and 42 ppm. The main anomalies are clustered to the east-southeast of the surveyed region and reflect mixed contributions from a variety of sources, namely different volcanic units with local contributions from pelite rocks, contamination from old (abandoned) mining activities and hydrothermal mineralisation controlled by different fault zones.

An environmental study was conducted in 193 stream sediments and 355 soil samples collected in the lower section of Guadiana River Basin to evaluate the trace elements transfer from one compartment into another. The objective was to evaluate the dispersion of Pb, Cu, Zn and other chemical elements resulting from upstream mines into the lower N-S sector of the Guadiana River Basin to the Atlantic Ocean. The area partly includes the Iberian Pyrite Belt, a known volcanogenic massive sulphide (VMS) province with important mining activity history. Median concentrations of the elements Cu, Pb, Zn, Al, As, Ba, Br, Ca, Mg, Mn and Na are generally higher in the studied sediments than in soils. Soils are normally acidic and mobility of elements is in these conditions higher. When the relations between upstream soils and downstream sediments were established, median values were higher in the upstream soils only for elements such as Co, Ni, K, Pb, Mn and Ti, probably the less mobile, and the Cu, Zn, Al, As, Ba, Br, Ca, Cr, Fe, Mg and Na have highest concentrations in the downstream sediments. Lead was considered the less mobile element and Zn the highly mobile of the base metals in the mining area of the lower Guadiana River. Dispersion of the metals, considering the studied soil and sediment samples is partially restricted to the mining areas or downstream sediments but close to the mine sources, where ore tailings and acid waters occur. Near the mouth, concentrations of As, Cu, Pb and Zn increase in relation with mining and other pollution sources. Interaction with salt water forces chemical elements precipitation from water and subsequent increase of their concentration in sediments. This may be the reason for the increase of those chemical elements concentrations in the sediments, Unidade de Recursos Minerais e Geofísica, Laboratório Nacional de Energia e Geologia, Portugal, Unidade de Investigação de Química Ambiental, Instituto Superior de Agronomia, Portugal, Instituto Geológico y Minero de España, España, Direcção Geral de Energia e Geologia, Portugal, Centro de Recursos Minerais, Mineralogia e Cristalografia, Universidade de Lisboa, Portugal

Submitted by Paula Serrano (paula.serrano@ineti.pt) on 2011-03-16T17:54:43Z No. of bitstreams: 1 33759.pdf: 1597675 bytes, checksum: e49c240aa37826e60a5e8e25a9d47459 (MD5) Approved for entry into archive by Paula Serrano(paula.serrano@ineti.pt) on 2011-03-16T17:54:58Z (GMT) No. of bitstreams: 1 33759.pdf: 1597675 bytes, checksum: e49c240aa37826e60a5e8e25a9d47459 (MD5) Made available in DSpace on 2011-03-16T17:54:58Z (GMT). No. of bitstreams: 1 33759.pdf: 1597675 bytes, checksum: e49c240aa37826e60a5e8e25a9d47459 (MD5) Previous issue date: 2010

O valioso património geológico e mineiro da Faixa Piritosa Ibérica (FPI) tem vindo a ser valorizado através da consolidação da Rota da Pirite, inserida no projecto ibero-americano Rumys. Esta rede reune os principais sítios mineiros da FPI localizados no Alentejo e Algarve e pretende assumir-se como uma referência no mercado de turismo temático português. A Rota da Pirite definida na FPI portuguesa interliga-se com a sua congénere espanhola da província de Huelva (Andaluzia), partilhando em comum o espaço transfronteiriço. Ao trabalho já desenvolvido pelo LNEG/INETI, expresso através dos percursos geo-eco-mineiros de São Domingos, Aljustrel e Cova dos Mouros, acrescentam-se novas propostas e conceitos inovadores como os jardins geológicos de Algares (Aljustrel) e da corta da mina do Lousal. Enquanto que o primeiro se insere numa fase de reabertura e reabilitação ambiental da mina de Aljustrel, o segundo pretende apoiar o Centro de Ciência Viva do Lousal, em fase de conclusão, contribuindo para a sustentabilidade desta importante infra-estrutura técnico-científica. A Rota da Pirite afirma-se assim cada vez mais como um espaço próprio, perfeitamente adaptado ao ciclo de vida mineiro, da fase de prospecção à de mineração, da fase de abandono à de reabilitação e de valorização.

Anomalously high germanium contents have been detected by means of whole-rock trace element analysis in remobilised vein type copper ores from the abandoned Barrigão mine, located in the Iberian Pyrite Belt, southern Portugal. The late-Variscan brecciated copper ores consist manly of chalcopyrite, with minor tennantite, rare pyrite and arsenopyrite. The ores, investigated for elements increasingly used in several thin-film and other semiconductor high-technology applications (e.g. indium, selenium, tellurium and germanium), show germanium contents up to 280 ppm, with an average of 61 ppm from 10 samples. Electron Probe Microanalysis of Barrigão ore samples revealed that germanium is contained in chalcopyrite, with a range of 0.1 to 0.4 wt% (0.23 wt% average). High germanium contents seem to be linked to "dirty" chalcopyrite phases, showing irregular patchy zoning under the microscope and on back-scattered electron images.

No sector de Barranco das Lages-Abegoaria (Faixa Magnetítico-Zincífera, Zona de Ossa Morena), as anomalias de Cu, Zn e Pb em solos apresentam anisotropia espacial NW-SE / NNW-SSE e posicionam-se acima de 17.5, 97 e 24 ppm, respectivamente; o fundo local para o Cu cifra-se em 363 ppm. As principais anomalias coincidem com os chapéus de ferro de Barranco das Lages e Vale de Rebolo, circunscritos a unidades predominantemente metassedimentares do Neoproterozóico e Câmbrico Inferior. A NE destas anomalias geoquímicas, e sobre o contacto entre unidades de natureza xistenta e anfibolítica (Ordovícico-Silúrico?), desenvolve-se uma importante anomalia gravimétrica, a qual foi investigada por sondagem, revelando conter mineralização sulfuretada disseminada; a sua génese é correlativa da retrogradação metamórfica Varisca, cujos estádios tardios são marcados por razões a/r elevadas e maior focalização dos fluídos ao longo de fracturas diversas.

A Mina da Caveira (NW da FPI) foi intermitentemente explorada desde a época Romana até aos anos 60 do séc. XX. Os resíduos mineiros aí existentes documentam esta longa actividade e incluem materiais diversos com conteúdos elevados em vários metais. O essencial destas acumulações concentra.se numa escombreira de gandes dimensões, que é uma fonte potencial de metais para as águas de escorrência. A caracterização química dos sedimentos de corrente, complementada pela análise das distribuições espaciais de concentração em Cu, Zn e Pb, revela, porém, que a dispersão sedimentar é bastante reduzida. Tal deve-se a circunstâncias de natureza geomorfológica/sedimentar e à possibilidade de estabilizar fases minerais secundárias que incorporam aqueles metais.

Submitted by Paula Serrano (paula.serrano@ineti.pt) on 2014-04-12T14:43:16Z No. of bitstreams: 1 33841_p1.pdf: 1080415 bytes, checksum: d4230e2a2cdd0af0fb8469693a719d37 (MD5) Approved for entry into archive by Paula Serrano (paula.serrano@ineti.pt) on 2014-04-12T14:43:26Z (GMT) No. of bitstreams: 1 33841_p1.pdf: 1080415 bytes, checksum: d4230e2a2cdd0af0fb8469693a719d37 (MD5) Made available in DSpace on 2014-04-12T14:43:26Z (GMT). No. of bitstreams: 1 33841_p1.pdf: 1080415 bytes, checksum: d4230e2a2cdd0af0fb8469693a719d37 (MD5) Previous issue date: 2005-04

S. Domingos ores have been exploited for Cu and S from antiquity to 1966. Slag is composed of Fe-, Ca-, Zn- and Pb-rich silicate glass, fayalite, hedenbergite, Fe-spinel, and blebs of Fe-, Cu-, Zn- (and Pb-)sulphides, minor sulphosalts and Cu-Zn-Pb-iss with evidence for low-T exsolution and reactions. Silicates and oxides often crystallised far from equilibrium out of undercooled melts. Weathering leads to Fe-(hydro)oxide + digenite ±Fe-, Cu- and Pb-sulphate, Ca, Zn and Pb loss from glass and acid drainage. The slag is an excellent aggregate raw material but its chemical instability calls for preliminary processing, which might lead to economic metal recovery.