Recursos Minerais - RM
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Browsing Recursos Minerais - RM by Author "Albardeiro, Luís"
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- Biostratigraphic and structural research in the Guedelhinha–Lançadoiras–Algaré sector in the context of the geology of the Neves–Corvo mine region, Iberian Pyrite BeltPublication . Pereira, Zélia; Matos, João Xavier; Mendes, Márcia; Solá, A. Rita; Albardeiro, Luís; Araújo, Vítor; Pacheco, Nelson; Oliveira, José TomásABSTRACT: Based on drill hole sampling and sedimentary rock dating by palynology, the present research focuses on the palynostratigraphic events established in the key geological section of Guedelhinha–Lançadoiras–Algaré located in the Portuguese Neves–Corvo mine region, Iberian Pyrite Belt. The age data allow detailing the lithostratigraphic sequence and further understanding the complex structural setting, representing an important contribution to the geological knowledge of this sector located to the immediate WNW of the Neves–Corvo VMS deposit. The combination of the studied events allows the reconstruction of the Devonian-Carboniferous sedimentation and paleoenvironments along the Iberian Pyrite Belt. Several stratigraphic hiatuses identified in the Neves–Corvo region by the palynological record are confirmed, mainly occurring from the mid Frasnian to mid Famennian, from the early and mid Strunian, and from the early to late Tournaisian, which were mainly coincident with the worldwide extinction events, in particular during Frasnian–Famennian and Late Devonian times. Extensional tectonics and related gravitational faults, local uplift mechanisms and intense volcanic activity could also explain the lack of palynological data and sedimentary hiatus. In this research, the importance of the late Strunian times in the Iberian Pyrite Belt (Miospore Biozone LN of the Neves Formation) is highlighted, confirming the contemporaneity of felsic volcanism, hydrothermalism, sulphide mineralization precipitation and black shale anoxic sedimentation.
- Critical raw materials deposits map of mainland Portugal: new mineral intelligence in cartographic formPublication . de Oliveira, Daniel Pipa Soares; Filipe, Augusto; Gonçalves, Pedro; Santos, Sara; Albardeiro, LuísABSTRACT: Reliable and unhindered access to raw materials is a growing concern within the EU and across the globe and the demand for Critical Raw Materials (CRM) plays a crucial economic role in most developed countries around the world. These are of extreme importance for supply chains regarding new technologies, sustainability issues and carbon footprint reduction. The definition of a continuously updated list of CRM by the European Commission led to the first CRM Map of Europe in 2016. Following this, several countries have been surveying, preparing, and evaluating their mineral occurrences to create a resources/deposits database and, therefore, to create a CRM map of their own. With this purpose in mind, we present and explain the first Critical Raw Materials Deposits Map of mainland Portugal, at 1:700,000 scale. This paper describes the scientific, technical, and graphical methodologies involved in its design.
- Detrital zircon geochronology of the Lower Karoo Group in the N’Condédzi Basin, MozambiquePublication . Fernandes, Paulo; Jorge, Raul CG Santos; Albardeiro, Luís; Chew, David; Drakou, Foteini; Pereira, Zélia; Marques, JoãoSUMÁRIO: A Bacia de N’Condédzi, pertence ao conjunto de bacias sedimentares moçambicanas do Ciclo Karoo. O preenchimento sedimentar consiste numa sequência detrítica, com ca. 2000 m de espessura, depositada em ambientes lacustres e aluvionares. Com a finalidade de conhecer a proveniência dos terrenos fonte das rochas detríticas, foram estudadas para geocronologia U-Pb, as populações de zircões detríticos de arenitos interceptados em três sondagens. Independentement, da idade dos arenitos (Lopingiano – Triásico Superior), a população dominante de zircões detríticos está no intervalo 1140 – 920 Ma com pico aos ca. 1035 Ma, sugerindo uma constância temporal das áreas fonte, restritas a terrenos formados durante a consolidação do Supercontinente Rodínia (1400 – 1000 Ma). Todavia, e apenas nos arenitos do Triásico Inferior, ocorre uma segunda população de zircões com idades U-Pb entre os 670 – 490 Ma, com picos aos 618 e 525 Ma., sugerindo o envolvimento transitório de terrenos associados ao Ciclo Pan-Africano.
- Detrital zircon U-Pb geochronology of the Moatize and N’Cond´edzi coalfields, Zambezi Karoo Basin of Mozambique: Implications for provenance, sediment dispersal and basin evolutionPublication . Fernandes, Paulo; Jorge, Raul CG Santos; Albardeiro, Luís; Chew, David; Drakou, Foteini; Pereira, Zélia; Marques, JoãoABSTRACT: Detrital zircon U-Pb geochronology of the Moatize and N'Condedzi coalfields in the Zambezi Karoo Basin of Mozambique provides key insights into the regional provenance, sediment dispersal pathways and basin evolution. Borehole cores from the two coalfields reveal a stratigraphy spanning the early Roadian (middle Permian) to the Carnian (Upper Triassic). The Permian sandstones of the Moatize Coalfield (MC) yield three detrital zircon populations, with ages ranging from 1150 to 950 Ma, 900-780 Ma and 650-490 Ma. In contrast, the Permian sandstones of the N'Condedzi Coalfield (NC) have only one population, which ranges from 1150 to 950 Ma. During the Permian, the provenance area for the NC was the Tete-Chipata Terrane and Malawi Complex (1150-950 Ma) to the north-northeast. In the MC, the detrital zircon populations of the early lake delta depositional setting (Roadian to Wordian) indicate a main provenance in the Zambezi Belt (900-780 Ma) located to the south of the MC, with minor sourcing from the Nampula Block (1150-950 Ma and 650-490 Ma) to the east. The transition from a lake delta to an alluvial depositional setting is attributed to a major tectonic event in the MC, which involved the formation of a braided channel belt. Sandstones from this braided channel belt yield three detrital zircons populations (650-490 Ma, 900-780 Ma and 1150-950 Ma), indicating provenance from both the Zambezi Belt and the Nampula Block. The overlying sandstones in the MC show only a minor population from the Zambezi Belt (900-780 Ma), implying a shift in provenance to the Nampula Block that was likely induced by tectonics. The absence of detrital zircon populations of 900-780 Ma and 650-490 in the Permian sandstones of NC implies that the two coalfields were not connected during the mid to late Permian. It is likely that an intra-rift horst (the Mesoproterozoic Gabbro-Anorthosite Tete Suite) separated the two coalfields. The Lower Triassic sandstones of the NC yield a main detrital zircon population indicating provenance from the TeteChipata Terrane and Malawi Complex (1150-950 Ma). A minor population at 650-490 Ma is linked to increased aridity at the Permian - Triassic boundary, which caused expansion of the watershed across the Tete-Chipata Terrane and the Malawi Complex. The Upper Triassic sandstones in the NC yield a 1150-950 Ma detrital zircon population, indicating provenance from the Tete-Chipata Terrane and Malawi Complex and a return to the source-to-sink conditions seen in the mid to late Permian.
- Geocronologia U-Pb dos zircões detríticos das regiões de Moatiz e N'Condedzi, Bacia Karoo do Zambeze de Moçambique: implicações para a proveniência, dispersão de sedimentos e evolução da baciaPublication . Fernandes, Paulo; Jorge, Raul CG Santos; Albardeiro, Luís; Chew, David; Drakou, Foteini; Pereira, Zélia; Marques, João
- Geophysical characterization of the Cercal Paleozoic structure, Iberian Pyrite Belt, from a mineral exploration perspectivePublication . Feitoza, L. M.; Carvalho, João; Represas, Patricia; Ramalho, Elsa; Sousa, Pedro; Matos, João Xavier; Albardeiro, Luís; Morais, Igor; Santos, Telmo M. Bento DosABSTRACT: The Cercal Volcano-Sedimentary Complex (Cercal VSC) structure is the westernmost sector of the Iberian Pyrite Belt (IPB) giant metallogenic province and was explored since Roman times for volcanogenic massive sulphides (VMS) and Fe–Mn (Ba) deposits. However, presently only a single deposit is known, the Salgadinho Cu-Ag-Au stockwork/disseminated deposit. Nevertheless, according to several mining companies that operated in the area during the last two decades, the Cercal area keeps a high potential for the discovery of new massive and stockwork mineralization deposits hosted in VSC felsic volcanic rocks. The lack of seismic data and deep drill holes (> 800 m), has been limiting the discovery of possible deep seated massive/stockwork deposits. The goal of this work is to provide new insights into the Cercal deep and near surface structure through the integrated interpretation of geophysical and geological data and contribute to the discovery of new stockwork or massive sulphide deposits. For this purpose, we reprocessed ground gravity, airborne magnetic/radiometric and electrical resistivity/induced polarization data which was interpreted and integrated with geological data. Data interpretation included 2.5D forward gravimetric modeling constrained by i) a new rock density database (from outcrops and drill-holes) built under the scope of this work, ii) the scarce available drill-holes and iii) geological information. A small magnetic susceptibility/conductivity database based on drill-hole core samples was also built to assist the magnetic and electrical/chargeability data interpretation. The integrated interpretation agrees with some of the expected geological scenarios predicted by surface mapping and exploration drill-hole logs in the IPB and provides further details on the deep structure of the Cercal Anticline, a NNW-SSE oriented VSC unrooted structure, controlled by variscan SW verging thrust faults and discordant strike-slip Late-Variscan faults. This geological scenario favors the possibility of new findings at relatively shallow depths (200–900 m), and a few sites for further exploration are indicated based on the integrated interpretation. Therefore, this work contributes to the understanding of the Cercal deep structure from a mineral exploration perspective and confirms the proposed structural models for the IPB’s westernmost region.
- Idade e ambientes deposicionais da sucessão do Karoo Inferior da Bacia Carbonífera de Moatize em Moçambique: compreenções sobre a história pós-glacial do Gondwana centralPublication . Fernandes, Paulo; Hancox, J.; Mendes, Márcia; Pereira, Zélia; Lopes, Gilda; Marques, João; Jorge, Raul CG Santos; Albardeiro, Luís
- Inventariação do património geológico e mineiro de Aljustrel : Proposta para o aproveitamento geoturístico da regiãoPublication . Morais, Igor; Santos, Sara; Matos, João Xavier; Albardeiro, Luís; de Oliveira, Daniel Pipa Soares; Aguiar, M.; Guerreiro, M.SUMMARY: The Aljustrel mining district, in the SW Iberian Pyrite Belt, hosts the oldest mining activity known to date in the Iberian Peninsula. The unique geological record of the region with a good exposure of the host rocks and ores and the vast mining heritage makes this territory an outdoor laboratory for natural sciences learning, in particular for the ore generating processes. Inaugurated in 2018, the National Laboratory of Energy and Geology in Aljustrel has been developing, in collaboration with the Aljustrel Municipality, a set of activities for geological and mining heritage assessment.
- O magmatismo mais antigo da Faixa Piritosa Ibérica: dados geocronológicos UPb da Jazida do Salgadinho, CercalPublication . Feitoza, L. M.; Santos, Telmo M. Bento Dos; Amaral, Joao Lains; Solá, A. Rita; Tassinari, Colombo C. G.; Basei, M.A.S.; Matos, João Xavier; Albardeiro, Luís; Morais, IgorSUMMARY: New U-Pb geochronological data (SHRIMP/LA-ICP-MS) is presented for zircons of volcanic rocks and dark shales of the Salgadinho deposit, located in Cercal, Iberian Pyrite Belt. Results show that the main magmatic event was placed between 387-392 Ma, indicating the oldest volcanism in the Iberian Pyrite Belt so far. Inherited and detrital zircon ages suggest affinity to Laurussian and Avalonia (s.l.) peri-Gondwanan sources, which provides additional constraints on the paleogeographic positioning of the Iberian Pyrite Belt during the Variscan Cycle.
- Metallogenetic potencial of the Paleoproterozoic mafic-ultramafic Hamutenha intrusion (SW Angola). New data from PLANAGEO project [Abstract]Publication . Morais, Igor; Batista, Maria Joao; Represas, Patricia; Albardeiro, Luís; Prazeres, Cátia; Plastov, José Manuel; Sousa, João Carlo; Bravo, Paulo; Sousa, Pedro; Carvalho, João; Rodrigues, José Feliciano; de Oliveira, Daniel Pipa Soares; Cordeiro, DomingosABSTRACT: In the SW sector of the Angolan shield occur the Kunene Anorthositic Complex (KAC), one of the most remarkable magmatic anorthositic suites worldwide. The KAC is considered a long-lived magmatic system that operated in the area intermittently during the Mesoproterozoic (1450 ± 2 Ma to 1371 ± 2.5 Ma). Smaller mafic-ultramafic intrusive bodies ranging in composition from dunite to harzbugite, pyroxenite, troctolite and gabbro are located in the KAC periphery (e.g. Epupa, Ombuku, Hamutenha, Oncócua). The Hamutenha body is a 3 km long oriented NW-SE, banded intrusion with internal zonation hosted in the Paleoproterozoic granitic rocks (1970 ± 2 Ma). The internal zone is composed by rocks with ultramafic nature, mostly harzburgites and dunites with diorites in the external zone.