Presentamos dos capiteles tardorromanos inéditos elaborados en mármol blanco de Almadén de la Pla... more Presentamos dos capiteles tardorromanos inéditos elaborados en mármol blanco de Almadén de la Plata (Sevilla), según demuestran los análisis arqueométricos realizados (petrografía, microscopía óptica, catodoluminiscencia óptica, difracción de rayos X y geoquímica isotópica (87Sr/86Sr). Las piezas están reutilizadas como benditeras en la iglesia de Santa María Magdalena en la localidad toledana de El Viso de San Juan. La revisión de la documentación de archivo referente a la propia iglesia desde inicios del siglo XVI (expedientes de Reparación de Templos y Visitas Pastorales), nos permite situar la primera mención a las mismas en un inventario de inicios del siglo XX y proponer para los capiteles un origen en el cercano yacimiento de Santa María de Abajo (Carranque, Toledo) donde pudieron haber formado parte de la decoración arquitectónica de su edificio palacial, a partir de paralelos documentados en este enclave. / We present two unpublished Late Roman capitals made of white marble from Almadén de la Plata (Seville), as demonstrated by the archaeometric analyses carried out (petrography, optical microscopy and cathodoluminescence, XRD, isotopic geochemistry (87Sr/86Sr). The pieces are reused as holy water fonts in the church of Santa María Magdalena in the town of El Viso de San Juan, Toledo. A review of the archival documentation referring to the church itself from the beginning of the 16th century onwards (Temples Repairs and Pastoral Visits), situates the first mention of the holy water fonts in an inventory from the beginning of the 20th century. We propose that originally the capitals were at the nearby Late Roman site of Santa María de Abajo (Carranque, Toledo) where they may have formed part of the architectural decoration of its palatial building, based on parallels documented in this site.
No âmbito do já habitual Curso de Primavera realizado pelo projeto ZOM3D: Modelos Metalogénicos 3... more No âmbito do já habitual Curso de Primavera realizado pelo projeto ZOM3D: Modelos Metalogénicos 3D da Zona de Ossa-Morena, em parceria com o Núcleo de Estudantes de Geociências da Universidade de Évora (GeoUE) e o Centro de Ciência Viva de Estremoz realiza-se nos dias 27, 28 e 29 a edição 2018 do Curso de Primavera, este ano sob o mote “A Febre do Ouro”. Neste sentido, e indo ao encontro dos objetivos e áreas de estudo do projeto ZOM3D vamos fazer um passeio geológico por um dos importantes setores tectono-estratigráficos da Zona de Ossa-Morena, o sector Montemor-Ficalho (Oliveira et al., 1991), mostrando algumas das principais características estruturais, metalogénicas e paisagísticas deste setor em plena paisagem alentejana de montado. Tendo em conta as suas características metalogénicas, este sector foi em 1971 definido por Goinhas como a faixa Magnetítico-Zincífera da ZOM, uma vez que nela se localizam importantes jazigos minerais de ferro, zinco e chumbo, tais como as minas de ...
The record of Lower and Middle Devonian sedimentation in the SW border of the Iberian Massif is s... more The record of Lower and Middle Devonian sedimentation in the SW border of the Iberian Massif is scarce. The scattered presence of uppermost Lower Devonian to Middle Devonian limestones in the SW margin of the Ossa-Morena Zone sheds light on the local and regional paleogeography and allows to clarify geodynamic models for the northern Gondwana realm during the Devonian. The several studied localities show the presence of isolated reef structures and spatially associated calciturbidites, interpreted as a result of the erosion of the reef buildings. Coeval volcanic rocks suggest reef development was supported by volcanic edifices, but in other instances basement highs may have supported the reef structures. Two global events, the basal Choteč and the Kačák, are recorded in these limestones, providing a better understanding of the paleogeographical extent of these events and their lithological, stratigraphical and paleoecological expression
Several metabasites were sampled for major and trace element ICP-OES analysis (prepared with alka... more Several metabasites were sampled for major and trace element ICP-OES analysis (prepared with alkaline fusion, acid digestion and cation-exchange chromatography), in order to characterize their geochemical variability and attempt to correlate with other autochthonous volcanic rocks, thus inferring their geodynamic setting
This work presents, in a non-exhaustive way, the main geological features of the Estremoz Anticli... more This work presents, in a non-exhaustive way, the main geological features of the Estremoz Anticline marbles (historically known as Estremoz Marbles). This geological characterization comprises the description of the main features of these marbles from their origin and geodynamic evolution, but whenever possible it will seek to make a connection with the archaeological sciences. The Estremoz Marbles have been exploited at least since Classical Antiquity. It is known that they had widespread use in many places of the Roman Empire, for their petrographic characteristics (both textural and mineralogical), their chemical composition and isotopic signature, which are intrinsic to their nature and geodynamic evolution, allowing a very reliable identification of their geographical origin. However, this approach of their origin must also be a comparative view with other marbles used in the same time period and also located in the same tectono-stratigraphic zone (Ossa-Morena Zone). All the ma...
In the Iberian Peninsula the fossil record of artiodactyls spans over 53 million years. During th... more In the Iberian Peninsula the fossil record of artiodactyls spans over 53 million years. During the Pleistocene, wild cattle species such as Bison and especially Bos became common. In Late Pleistocene, the aurochs (Bos primigenius) was widespread and the only bovine living along the large river valleys of southern Iberia. Although commonly found in fossil sites and especially in cave bone assemblages, the trace fossil record of aurochs was known worldwide only from the Holocene. Large bovine and roe deer/caprine tracks were found in at least five horizons of the early Late Pleistocene (MIS 5) beach and eolian deposits of Cape Trafalgar (Cadiz Province, South of Spain). The large bovine tracks are formally described as Bovinichnus uripeda igen. et isp. nov. and compared with the record of aurochs tracks, large red deer tracks and steppe bison biogeographical distribution in Iberia. Aurochs were the most likely producers of the newly described Trafalgar Trampled Surface (TTS) and some ...
This paper is a contribution to IGCP 652 “Reading geological time in paleozoic sedimentary rocks”... more This paper is a contribution to IGCP 652 “Reading geological time in paleozoic sedimentary rocks” project.Abstract: The Devonian sedimentary record of the Ossa-Morena Zone is scarce. In its southwestern domains, the Odivelas Limestone and correlatable units represent the single evidence of latest Early Devonian to Middle Devonian (possibly into Frasnian)sedimentation in this area. Reefal and perireefal sediments are frequently, but not always, associated to coeval volcanic rocksthat probably supported atoll-like systems on the top of volcanic edifices. The northernmost occurrences are spatially associated with mississippian volcanic-sedimentary complexes. Their geometrical relation is still unclear, the limestones are possibly embedded as olitoliths, but can also be tectonically imbricated or simply reflecting draping of younger sediments around and above older (Devonian) sea-bed topography.Resumo: O registo sedimentar Devónico da Zona de Ossa-Morena é escasso. Durante o Devónico In...
É bem conhecida a existência de uma actividade sísmica fraca, difusa e persistente na região a No... more É bem conhecida a existência de uma actividade sísmica fraca, difusa e persistente na região a Norte de Évora, particularmente concentrada entre Arraiolos, Pavia e Vimieiro. No dia 15 de Janeiro de 2018, pelas 11 horas e 51 minutos ocorreu um sismo de magnitude consideravelmente superior ao habitual, de 4.9 segundo os dados do Instituto Português do Mar e da Atmosfera (IPMA). Este evento ocorreu a uma profundidade de 11 km e o seu epicentro localizou-se entre as povoações de Aldeia da Serra e São Gregório. O seu efeito foi sentido numa região bastante vasta, inclusivamente até na cidade do Porto, de acordo com o que foi noticiado nos órgãos de comunicação social. Tendo em conta a magnitude deste evento, realizámos um estudo de macrossismicidade a nível regional, com vista à construção de um mapa de intensidades sísmicas. Os trabalhos de campo decorreram entre os dias 17 e 24 do mesmo mês, tendo-se usado o inquérito que o IPMA tem disponível em https://www.ipma.pt/pt/geofisica/inform...
A Mina de Maciços é uma das diversas antigas explorações de Cobre da Faixa Metalogénica de Sousel... more A Mina de Maciços é uma das diversas antigas explorações de Cobre da Faixa Metalogénica de Sousel-Barrancos (Zona de Ossa-Morena). O levantamento estrutural desta mineralização, de carácter filoniano, é essencial para a conceptualização do modelo metalogenético associado a esta tipologia de mineralizações na Zona de Ossa-Morena. O presente trabalho apresenta os primeiros resultados do levantamento estrutural em curso, mostrando a presença de uma cinemática direita associada às estruturas mineralizadas principais (NlSºW), bem como a presença de diversas estruturas filonianas menores (N4SºE-N60ºE), com geometria e cinemática distinta s da mineralização principal, embora cogenéticas
No Varisco da Ibéria têm sido identificadas diversas macroestruturas arqueadas cuja caracterizaçã... more No Varisco da Ibéria têm sido identificadas diversas macroestruturas arqueadas cuja caracterização e génese é objecto de controvérsia. Neste trabalho discutem-se os argumentos associados a cada uma destas estruturas, bem como os processos de formação dos arcos Ibero-Armoricano e Cantábrico. Os elementos existentes sugerem uma génese polifásica, onde a indentação de um promontório principal da Gondwana aparece como um elemento fundamental
The physical and chemical properties of mineralising fluids may provide important input for the m... more The physical and chemical properties of mineralising fluids may provide important input for the metallogenic modelling of a particular deposit. The purpose of this study is to characterise the fluids involved with Cu mineralisation in the Miguel Vacas and Mociços ancient mines, as well as the Ferrarias occurrence, located in the Portuguese Ossa-Morena Zone (OMZ), in the denominated Sousel-Barrancos metallogenic belt (SBMB). These deposits are characterised by quartz + carbonate veins with main sulphide mineral assemblages of chalcopyrite + pyrite and bornite ± digenite in the supergene enrichment zone. In Ferrarias, sphalerite and galena were also identified, whereas arsenopyrite was found in the Miguel Vacas deposit. The evaluation of relative ages and spatial distribution of fluid inclusions is essential for establishing a metallogenic model for these Cu-rich deposits. Twenty bipolished thick sections were prepared from borehole and surface samples, and over 400 fluid inclusions (...
O Maciço Ibérico foi subdividido num conjunto de terrenos tectonoestra tigráficos com característ... more O Maciço Ibérico foi subdividido num conjunto de terrenos tectonoestra tigráficos com características próprias, entre os quais os Terrenos Finisterra (TF) e Ibérico (TI). O TF contacta com TI, nomeadamente com a Zonas Centro Ibérica e Ossa-Morena, através de uma zona de cisalhamento, a Zona de Cisalhamento Porto-Tomar-Ferreira do Alentejo. O TF apresenta características que contrastam com as que especializam o TI, destacando-se: (1) um evento tectono-metamórfico de alta temperatura Varisco, acompanhado de magmatismo granítico, de idade ante-mississipia na; (2) a presença de unidades de baixo grau metamórfico discordantes, sendo que a Unidade de Albergaria (Devónico superior), apresenta uma natureza marinha, que contrasta com o gap na sedimentação da mesma idade no TI; e (3) a existência de zircões detríticos de idade mesoproterozóica em alguns litótipos, o que não é característico dos terrenos Peri-Gondwânicos. As característica s do TF permitem a sua correlação com o Bloco de León ...
Chemical features regarding the different detrital lithostratigraphic Palaeozoic (Cambrian – Devo... more Chemical features regarding the different detrital lithostratigraphic Palaeozoic (Cambrian – Devonian) units from the Portuguese sector of the Ossa-Morena Zone regist geochemical aspects typical of their depositional environment, which allow inferences on the geodynamic evolution of the Iberian Authoctonous Terrain during the Variscan Cycle. Trace elements relationships (essentialy Nb/Ta, Zr/Hf, Th/U, La/Th-Sc and REE chondrite-normalized patterns) of the detrital succession reveal that the different formations derive mostly from an acid continental source, though with features that suggest mixed sedimentary components. Cambrian, Ordovician and Silurian representative samples show significative influences typical of passive margin sediments, while Devonian samples appear to have an oceanic arc contribution, with an increase in basic components, which may indicate a transition on the tectonic environment, during their deposition. Ante-Devonian Variscan formations are therefore interp...
The Finisterra Terrane is located in the western sector of the Iberian Variscides and its eastern... more The Finisterra Terrane is located in the western sector of the Iberian Variscides and its eastern boundary is a N-S to NNW-SSE lithospheric structure, the Porto-Tomar-Ferreira do Alentejo Shear Zone (PTFSZ). The PTFSZ makes the contact between the Finisterra Terrane and two distinct paleogeographic zones of the Iberian Terrane: Central Iberian and Ossa-Morena Zones. The Finisterra Terrane is characterized by three low to high-grade tectono-metamorphic units: - A lower gneiss-migmatite unit, mainly composed by para-derived gneisses, highly deformed migmatites and mylonites, with lenses of micaschists and ortho-derived gneisses and amphibolites (Lourosa, S. Pedro de Tomar and Foz do Douro gneisse-migmatite complexes); - An upper micaschist unit, mainly composed by garnet-staurotide-biotite micaschists with some metaquartzwackes, quartzites, mylonites and ortho-derived mafic rocks, presenting high-strain patterns (Junceira-Tramagal and Espinho Units); - A low-grade tectono-metamorphic ...
ABSTRACT: The Mociços mine is one of the ancient explorations of copper in the Sousel Barrancos M... more ABSTRACT: The Mociços mine is one of the ancient explorations of copper in the Sousel Barrancos Metallogenic Belt (Ossa-Morena Zone). The structural mapping of this copper mineralization is an essential contribution to the Metallogenic Model of this type of copper-rich veins. This work presents a first structural approach, showing dextral kinematics associated with the main N15ºW mineralized veins, as well as the occurrence of another family of minor veins (N45ºE-N60ºE), with distinct geometry and kinematic, but cogenetic of the main mineralization. RESUMO:A Mina de Mociços é uma das diversas antigas explorações de Cobre da Faixa Metalogénica de Sousel-Barrancos (Zona de Ossa-Morena). O levantamento estrutural desta mineralização, de carácter filoniano, é essencial para a conceptualização do modelo metalogenético associado a esta tipologia de mineralizações na Zona de Ossa-Morena. O presente trabalho apresenta os primeiros resultados do levantamento estrutural em curso, mostrando a ...
New lithogeochemical data of Lower-Middle Palaeozoic metasedimentary rocks of the Ossa-Morena Zon... more New lithogeochemical data of Lower-Middle Palaeozoic metasedimentary rocks of the Ossa-Morena Zone are here presented and integrated with previously published data, as well as a discussion on their provenance and geotectonic settings. In the Cambrian – Lower Ordovician rift stages, metasediments mostly derived from an acid continental source with passive margin geochemical affinities, showing a significant recycled sediment component, as well as an oxidizing depositional environment. Metasediments related with the drift stage, during Ordovician and Silurian ages, display general geochemical features similar to those that characterize the Cambrian units, inferring the prevailing acid source and passive margin geotectonic settings, and slightly anoxic depositional conditions in the end of this stage. In turn, geochemistry of samples representative of the Devonian debris deposition contrast with the passive continental margin geochemical data; notwithstanding the dominant acid source, ...
Kink bands are usually related to the late deformation stages in polydeformed areas. In Portugal,... more Kink bands are usually related to the late deformation stages in polydeformed areas. In Portugal, the Late Variscan deformation generates in Almograve and Abrantes regions (SW Iberian Massif), brittle to brittle-ductile NNE-SSW sinistral kink bands, which deflects the NNW-SSE regional trend. This deflection induces the counterclockwise rotation of primary layering/foliation in the kink band inner domains, generating a complex and heterogeneous structural pattern. In Almograve, within metric to decametric kink bands, a wide spectrum of structures (mainly folds and brittle to brittle-ductile shear zones) are developed, while in the internal domains of the Abrantes metric kink band, a high strain pattern composed by 2nd order conjugate kink bands were generated. Previous structures allows to calculate internal and external stress fields, showing a variation from the outer to inner domains of kink band. During the development of the type III fixed hinge kink bands, the formation of the ...
The 87Sr/86Sr ratio is usually used in stratigraphy to correlate and even date marine carbonate s... more The 87Sr/86Sr ratio is usually used in stratigraphy to correlate and even date marine carbonate sedimentation events. The variation of the 87Sr/86Sr isotopic ratio along the geological time scale combined with the fact of this isotopic ratio could be considered uniform in all ocean at a given geological moment, opens a thematic for the investigation and characterization of carbonate sedimentation and as well it sedimentation environment. Therefore, it is important to understand the inherent limitations to the use of this isotope ratio as a method of correlation. For the present work, the Cambrian (or Cambrian attributed) carbonates from the Ossa-Morena Zone were sampled in several sectors. These samples present distinct metamorphic features and their litho-facies were been characterized, as well as the presence of late dolomitization processes (i.e. post-metamorphic). The data show that the late dolomitization processes induce a significant increase of the 87Sr/86Sr ratio, when comp...
<p>Since the 1990s, detailed studies on the relief units of the central and upper A... more <p>Since the 1990s, detailed studies on the relief units of the central and upper Alentejo region have been lacking. Previously, tectonics were used to explain most of the relief units, even those in which lithological differentiation is remarkable, such as the dolomitic plateaus of Elvas and Estremoz. The morphotectonic reliefs like Serra d’Ossa and Serra de S. Mamede were previously explained by vertical tectonics, in a horst-graben system, difficult to understand under the Cenozoic compressive tectonic regime affecting the Western Iberian margin.</p><p>The superposition of geological maps with digital terrain models suggests a more complex genesis in the formation of the morphotectonic regional reliefs. The Serra d’Ossa (652 m) develops in a WNW-ESE general trend (N80ºW), slightly asymmetrical with a 200 m high north-facing escarpment, much steeper than the south-facing slope. The north-facing escarpment (Ossa Fault – OF) is transversal to the NW-SE variscan structures (N40ºW). Thus, this escarpment cannot be explained by differential erosion. Indeed, Feio (1983) already hypothesized a tectonic origin to the Serra d'Ossa, although without presenting a tectonic model.</p><p>The western termination of the Serra d‘Ossa small scarps, with NE-SW orientation, coincide with the horse tail terminations of the NNE-SSW left strike-slip Graça do Divor fault (GDF). If both GDF and OF are connected, the Serra d’Ossa can be interpreted as a <em>push up</em> deformation of the South Portuguese Planation Surface (SPPS).</p><p>In this work, a greater relevance of differential erosion is highlighted in the individualisation of Elvas and Estremoz plateaus, as well as the Serra de Monfurado.</p><p>Towards the north of the town of Évora, the landscape is formed by broad-bottomed valleys at 240 m, with gentle slope and flat uplands at ca. 320-340 m. Looked in Davisian terms, the valleys looks like a mid-cycle maturity landscape. The flat upland level corresponds to the SPPS, well developed in the upper Alentejo (Nisa and Alpalhão), while the bottom of the valleys correspond to a younger level, embedded ca. 80–100 m in the SPPS. The valley bottoms widens to downstream forming a flattening surface (named N1 fluvial surface) related with the beginning of the incision of the drainage network in the SPPS and with the first (older) terraces of the Tejo and Guadiana rivers.</p><p>The prominence in the landscape of the Serra de Monfurado should be understood as a resistant ridge, whose summits were not completely flattened due to the lithological diversity and to the geographic location in the watershed limit of the Tejo, Guadiana and Sado rivers, where the flattening of the SPPS was difficult to achieve. Differential erosion during the formation of the N1 fluvial surface is thought to be the main responsible for the prominence of this ridge in the central Alentejo landscape, as well as other resistant reliefs as the Monsaraz <em>inselberg</em>.</p><p> </p><p>Acknowledgments: The authors acknowledge the funding provided by the Institute of Earth Sciences (ICT), under contract with Science and Technology Foundation (UID/GEO/04683/2019).</p><p>References:</p><p>Feio, M., 1983. O Relevo da Serra de Ossa: uma interpretação tectónica. Finisterra, XVIII, 35, 5-26.</p><p> </p>
O Departamento de Geociências da Escola de Ciências e Tecnologia da Universidade de Évora, em con... more O Departamento de Geociências da Escola de Ciências e Tecnologia da Universidade de Évora, em conjunto com o Instituto de Ciências da Terra e o Laboratório HERCULES, têm a honra e o prazer de organizar este evento que reúne a comunidade científica ibérica ligada à geoquímica e às suas múltiplas fronteiras. O Congresso Ibérico de Geoquímica é tutelado conjuntamente pela Sociedade Geológica de Portugal e o seu Grupo de Geoquímica, o Colegio Oficial de Químicos Madrid, a Asociación de Químicos y Ingenieros Químicos, o Consejo Superior de Colegios de Ingenieros de Minas de España e o Colegio Oficial de Geólogos de España, sendo realizado desde 1997, de dois em dois anos e sem interrupções, em Portugal e Espanha, de forma alternada. Quando o Congresso se realiza em Portugal, associa-se a Semana de Geoquímica, que perfaz a sua vigésima edição neste encontro, também ela ininterrupta ao longo de todos estes anos. Esta é a primeira vez que estes encontros se realizam em Évora, o que muito nos apraz e responsabiliza. A adesão a esta edição do congresso foi muito positiva, estando inscritos cerca de 150 participantes, que submeteram mais de 120 trabalhos, repartidos entre apresentações orais e em formato poster. Como é hábito, dividimos o congresso num conjunto de sessões temáticas abrangentes que vão desde os processos geológicos geodinâmicos até às fronteiras da geoquímica; queremos também salientar as sessões ligadas aos diversos tipos de recursos hídricos, energéticos, metálicos e não metálicos. Refletindo as preocupações atuais da sociedade, as sessões ligadas ao ambiente apresentam, como habitualmente, a mais elevada participação. O facto deste congresso decorrer no Ano Internacional da Tabela Periódica vem dar ainda mais significado e importância à sua realização, tendo mesmo a honra de contar com uma palestra do comissário nacional para este evento, o Professor José Ferreira Gomes. Contamos ainda com uma elite de palestrantes convidados, que nos apresentam um conjunto de temáticas inovadoras e de fronteira ligadas à geoquímica. Agregámos ao programa de trabalhos atividades técnico-científicas que complementam as sessões temáticas, nomeadamente dois breves workshops relacionados com obtenção e tratamento de dados geoquímicos e duas saídas de campo, que esperamos que sejam do agrado dos participantes. Procurando valorizar o papel dos jovens investigadores, iremos atribuir um prémio para a melhor apresentação oral e para o melhor poster: prémio PARALAB e prémio BERALT, respetivamente.Reservámos ainda espaço para que os participantes se possam conhecer melhor, fora do ambiente mais formal do congresso, de forma a possibilitar a criação de redes de colaboração durante os momentos de socialização. Esperamos ainda que durante a estadia tomem contacto com o forte carácter da paisagem, da cultura e das gentes deste sudoeste ibérico. Queremos agradecer a todas as empresas e instituições que apoiaram a realização deste evento, sem as quais ele não seria possível. Por fim, deixamos umas palavras de profundo reconhecimento aos moderadores; aos membros da comissão científica e organizadora que, através da sua disponibilidade, asseguraram a qualidade científica dos trabalhos apresentados e da dinâmica do congresso; assim como a todos os participantes que tornaram este encontro de pessoas e ideais uma realidade
Presentamos dos capiteles tardorromanos inéditos elaborados en mármol blanco de Almadén de la Pla... more Presentamos dos capiteles tardorromanos inéditos elaborados en mármol blanco de Almadén de la Plata (Sevilla), según demuestran los análisis arqueométricos realizados (petrografía, microscopía óptica, catodoluminiscencia óptica, difracción de rayos X y geoquímica isotópica (87Sr/86Sr). Las piezas están reutilizadas como benditeras en la iglesia de Santa María Magdalena en la localidad toledana de El Viso de San Juan. La revisión de la documentación de archivo referente a la propia iglesia desde inicios del siglo XVI (expedientes de Reparación de Templos y Visitas Pastorales), nos permite situar la primera mención a las mismas en un inventario de inicios del siglo XX y proponer para los capiteles un origen en el cercano yacimiento de Santa María de Abajo (Carranque, Toledo) donde pudieron haber formado parte de la decoración arquitectónica de su edificio palacial, a partir de paralelos documentados en este enclave. / We present two unpublished Late Roman capitals made of white marble from Almadén de la Plata (Seville), as demonstrated by the archaeometric analyses carried out (petrography, optical microscopy and cathodoluminescence, XRD, isotopic geochemistry (87Sr/86Sr). The pieces are reused as holy water fonts in the church of Santa María Magdalena in the town of El Viso de San Juan, Toledo. A review of the archival documentation referring to the church itself from the beginning of the 16th century onwards (Temples Repairs and Pastoral Visits), situates the first mention of the holy water fonts in an inventory from the beginning of the 20th century. We propose that originally the capitals were at the nearby Late Roman site of Santa María de Abajo (Carranque, Toledo) where they may have formed part of the architectural decoration of its palatial building, based on parallels documented in this site.
No âmbito do já habitual Curso de Primavera realizado pelo projeto ZOM3D: Modelos Metalogénicos 3... more No âmbito do já habitual Curso de Primavera realizado pelo projeto ZOM3D: Modelos Metalogénicos 3D da Zona de Ossa-Morena, em parceria com o Núcleo de Estudantes de Geociências da Universidade de Évora (GeoUE) e o Centro de Ciência Viva de Estremoz realiza-se nos dias 27, 28 e 29 a edição 2018 do Curso de Primavera, este ano sob o mote “A Febre do Ouro”. Neste sentido, e indo ao encontro dos objetivos e áreas de estudo do projeto ZOM3D vamos fazer um passeio geológico por um dos importantes setores tectono-estratigráficos da Zona de Ossa-Morena, o sector Montemor-Ficalho (Oliveira et al., 1991), mostrando algumas das principais características estruturais, metalogénicas e paisagísticas deste setor em plena paisagem alentejana de montado. Tendo em conta as suas características metalogénicas, este sector foi em 1971 definido por Goinhas como a faixa Magnetítico-Zincífera da ZOM, uma vez que nela se localizam importantes jazigos minerais de ferro, zinco e chumbo, tais como as minas de ...
The record of Lower and Middle Devonian sedimentation in the SW border of the Iberian Massif is s... more The record of Lower and Middle Devonian sedimentation in the SW border of the Iberian Massif is scarce. The scattered presence of uppermost Lower Devonian to Middle Devonian limestones in the SW margin of the Ossa-Morena Zone sheds light on the local and regional paleogeography and allows to clarify geodynamic models for the northern Gondwana realm during the Devonian. The several studied localities show the presence of isolated reef structures and spatially associated calciturbidites, interpreted as a result of the erosion of the reef buildings. Coeval volcanic rocks suggest reef development was supported by volcanic edifices, but in other instances basement highs may have supported the reef structures. Two global events, the basal Choteč and the Kačák, are recorded in these limestones, providing a better understanding of the paleogeographical extent of these events and their lithological, stratigraphical and paleoecological expression
Several metabasites were sampled for major and trace element ICP-OES analysis (prepared with alka... more Several metabasites were sampled for major and trace element ICP-OES analysis (prepared with alkaline fusion, acid digestion and cation-exchange chromatography), in order to characterize their geochemical variability and attempt to correlate with other autochthonous volcanic rocks, thus inferring their geodynamic setting
This work presents, in a non-exhaustive way, the main geological features of the Estremoz Anticli... more This work presents, in a non-exhaustive way, the main geological features of the Estremoz Anticline marbles (historically known as Estremoz Marbles). This geological characterization comprises the description of the main features of these marbles from their origin and geodynamic evolution, but whenever possible it will seek to make a connection with the archaeological sciences. The Estremoz Marbles have been exploited at least since Classical Antiquity. It is known that they had widespread use in many places of the Roman Empire, for their petrographic characteristics (both textural and mineralogical), their chemical composition and isotopic signature, which are intrinsic to their nature and geodynamic evolution, allowing a very reliable identification of their geographical origin. However, this approach of their origin must also be a comparative view with other marbles used in the same time period and also located in the same tectono-stratigraphic zone (Ossa-Morena Zone). All the ma...
In the Iberian Peninsula the fossil record of artiodactyls spans over 53 million years. During th... more In the Iberian Peninsula the fossil record of artiodactyls spans over 53 million years. During the Pleistocene, wild cattle species such as Bison and especially Bos became common. In Late Pleistocene, the aurochs (Bos primigenius) was widespread and the only bovine living along the large river valleys of southern Iberia. Although commonly found in fossil sites and especially in cave bone assemblages, the trace fossil record of aurochs was known worldwide only from the Holocene. Large bovine and roe deer/caprine tracks were found in at least five horizons of the early Late Pleistocene (MIS 5) beach and eolian deposits of Cape Trafalgar (Cadiz Province, South of Spain). The large bovine tracks are formally described as Bovinichnus uripeda igen. et isp. nov. and compared with the record of aurochs tracks, large red deer tracks and steppe bison biogeographical distribution in Iberia. Aurochs were the most likely producers of the newly described Trafalgar Trampled Surface (TTS) and some ...
This paper is a contribution to IGCP 652 “Reading geological time in paleozoic sedimentary rocks”... more This paper is a contribution to IGCP 652 “Reading geological time in paleozoic sedimentary rocks” project.Abstract: The Devonian sedimentary record of the Ossa-Morena Zone is scarce. In its southwestern domains, the Odivelas Limestone and correlatable units represent the single evidence of latest Early Devonian to Middle Devonian (possibly into Frasnian)sedimentation in this area. Reefal and perireefal sediments are frequently, but not always, associated to coeval volcanic rocksthat probably supported atoll-like systems on the top of volcanic edifices. The northernmost occurrences are spatially associated with mississippian volcanic-sedimentary complexes. Their geometrical relation is still unclear, the limestones are possibly embedded as olitoliths, but can also be tectonically imbricated or simply reflecting draping of younger sediments around and above older (Devonian) sea-bed topography.Resumo: O registo sedimentar Devónico da Zona de Ossa-Morena é escasso. Durante o Devónico In...
É bem conhecida a existência de uma actividade sísmica fraca, difusa e persistente na região a No... more É bem conhecida a existência de uma actividade sísmica fraca, difusa e persistente na região a Norte de Évora, particularmente concentrada entre Arraiolos, Pavia e Vimieiro. No dia 15 de Janeiro de 2018, pelas 11 horas e 51 minutos ocorreu um sismo de magnitude consideravelmente superior ao habitual, de 4.9 segundo os dados do Instituto Português do Mar e da Atmosfera (IPMA). Este evento ocorreu a uma profundidade de 11 km e o seu epicentro localizou-se entre as povoações de Aldeia da Serra e São Gregório. O seu efeito foi sentido numa região bastante vasta, inclusivamente até na cidade do Porto, de acordo com o que foi noticiado nos órgãos de comunicação social. Tendo em conta a magnitude deste evento, realizámos um estudo de macrossismicidade a nível regional, com vista à construção de um mapa de intensidades sísmicas. Os trabalhos de campo decorreram entre os dias 17 e 24 do mesmo mês, tendo-se usado o inquérito que o IPMA tem disponível em https://www.ipma.pt/pt/geofisica/inform...
A Mina de Maciços é uma das diversas antigas explorações de Cobre da Faixa Metalogénica de Sousel... more A Mina de Maciços é uma das diversas antigas explorações de Cobre da Faixa Metalogénica de Sousel-Barrancos (Zona de Ossa-Morena). O levantamento estrutural desta mineralização, de carácter filoniano, é essencial para a conceptualização do modelo metalogenético associado a esta tipologia de mineralizações na Zona de Ossa-Morena. O presente trabalho apresenta os primeiros resultados do levantamento estrutural em curso, mostrando a presença de uma cinemática direita associada às estruturas mineralizadas principais (NlSºW), bem como a presença de diversas estruturas filonianas menores (N4SºE-N60ºE), com geometria e cinemática distinta s da mineralização principal, embora cogenéticas
No Varisco da Ibéria têm sido identificadas diversas macroestruturas arqueadas cuja caracterizaçã... more No Varisco da Ibéria têm sido identificadas diversas macroestruturas arqueadas cuja caracterização e génese é objecto de controvérsia. Neste trabalho discutem-se os argumentos associados a cada uma destas estruturas, bem como os processos de formação dos arcos Ibero-Armoricano e Cantábrico. Os elementos existentes sugerem uma génese polifásica, onde a indentação de um promontório principal da Gondwana aparece como um elemento fundamental
The physical and chemical properties of mineralising fluids may provide important input for the m... more The physical and chemical properties of mineralising fluids may provide important input for the metallogenic modelling of a particular deposit. The purpose of this study is to characterise the fluids involved with Cu mineralisation in the Miguel Vacas and Mociços ancient mines, as well as the Ferrarias occurrence, located in the Portuguese Ossa-Morena Zone (OMZ), in the denominated Sousel-Barrancos metallogenic belt (SBMB). These deposits are characterised by quartz + carbonate veins with main sulphide mineral assemblages of chalcopyrite + pyrite and bornite ± digenite in the supergene enrichment zone. In Ferrarias, sphalerite and galena were also identified, whereas arsenopyrite was found in the Miguel Vacas deposit. The evaluation of relative ages and spatial distribution of fluid inclusions is essential for establishing a metallogenic model for these Cu-rich deposits. Twenty bipolished thick sections were prepared from borehole and surface samples, and over 400 fluid inclusions (...
O Maciço Ibérico foi subdividido num conjunto de terrenos tectonoestra tigráficos com característ... more O Maciço Ibérico foi subdividido num conjunto de terrenos tectonoestra tigráficos com características próprias, entre os quais os Terrenos Finisterra (TF) e Ibérico (TI). O TF contacta com TI, nomeadamente com a Zonas Centro Ibérica e Ossa-Morena, através de uma zona de cisalhamento, a Zona de Cisalhamento Porto-Tomar-Ferreira do Alentejo. O TF apresenta características que contrastam com as que especializam o TI, destacando-se: (1) um evento tectono-metamórfico de alta temperatura Varisco, acompanhado de magmatismo granítico, de idade ante-mississipia na; (2) a presença de unidades de baixo grau metamórfico discordantes, sendo que a Unidade de Albergaria (Devónico superior), apresenta uma natureza marinha, que contrasta com o gap na sedimentação da mesma idade no TI; e (3) a existência de zircões detríticos de idade mesoproterozóica em alguns litótipos, o que não é característico dos terrenos Peri-Gondwânicos. As característica s do TF permitem a sua correlação com o Bloco de León ...
Chemical features regarding the different detrital lithostratigraphic Palaeozoic (Cambrian – Devo... more Chemical features regarding the different detrital lithostratigraphic Palaeozoic (Cambrian – Devonian) units from the Portuguese sector of the Ossa-Morena Zone regist geochemical aspects typical of their depositional environment, which allow inferences on the geodynamic evolution of the Iberian Authoctonous Terrain during the Variscan Cycle. Trace elements relationships (essentialy Nb/Ta, Zr/Hf, Th/U, La/Th-Sc and REE chondrite-normalized patterns) of the detrital succession reveal that the different formations derive mostly from an acid continental source, though with features that suggest mixed sedimentary components. Cambrian, Ordovician and Silurian representative samples show significative influences typical of passive margin sediments, while Devonian samples appear to have an oceanic arc contribution, with an increase in basic components, which may indicate a transition on the tectonic environment, during their deposition. Ante-Devonian Variscan formations are therefore interp...
The Finisterra Terrane is located in the western sector of the Iberian Variscides and its eastern... more The Finisterra Terrane is located in the western sector of the Iberian Variscides and its eastern boundary is a N-S to NNW-SSE lithospheric structure, the Porto-Tomar-Ferreira do Alentejo Shear Zone (PTFSZ). The PTFSZ makes the contact between the Finisterra Terrane and two distinct paleogeographic zones of the Iberian Terrane: Central Iberian and Ossa-Morena Zones. The Finisterra Terrane is characterized by three low to high-grade tectono-metamorphic units: - A lower gneiss-migmatite unit, mainly composed by para-derived gneisses, highly deformed migmatites and mylonites, with lenses of micaschists and ortho-derived gneisses and amphibolites (Lourosa, S. Pedro de Tomar and Foz do Douro gneisse-migmatite complexes); - An upper micaschist unit, mainly composed by garnet-staurotide-biotite micaschists with some metaquartzwackes, quartzites, mylonites and ortho-derived mafic rocks, presenting high-strain patterns (Junceira-Tramagal and Espinho Units); - A low-grade tectono-metamorphic ...
ABSTRACT: The Mociços mine is one of the ancient explorations of copper in the Sousel Barrancos M... more ABSTRACT: The Mociços mine is one of the ancient explorations of copper in the Sousel Barrancos Metallogenic Belt (Ossa-Morena Zone). The structural mapping of this copper mineralization is an essential contribution to the Metallogenic Model of this type of copper-rich veins. This work presents a first structural approach, showing dextral kinematics associated with the main N15ºW mineralized veins, as well as the occurrence of another family of minor veins (N45ºE-N60ºE), with distinct geometry and kinematic, but cogenetic of the main mineralization. RESUMO:A Mina de Mociços é uma das diversas antigas explorações de Cobre da Faixa Metalogénica de Sousel-Barrancos (Zona de Ossa-Morena). O levantamento estrutural desta mineralização, de carácter filoniano, é essencial para a conceptualização do modelo metalogenético associado a esta tipologia de mineralizações na Zona de Ossa-Morena. O presente trabalho apresenta os primeiros resultados do levantamento estrutural em curso, mostrando a ...
New lithogeochemical data of Lower-Middle Palaeozoic metasedimentary rocks of the Ossa-Morena Zon... more New lithogeochemical data of Lower-Middle Palaeozoic metasedimentary rocks of the Ossa-Morena Zone are here presented and integrated with previously published data, as well as a discussion on their provenance and geotectonic settings. In the Cambrian – Lower Ordovician rift stages, metasediments mostly derived from an acid continental source with passive margin geochemical affinities, showing a significant recycled sediment component, as well as an oxidizing depositional environment. Metasediments related with the drift stage, during Ordovician and Silurian ages, display general geochemical features similar to those that characterize the Cambrian units, inferring the prevailing acid source and passive margin geotectonic settings, and slightly anoxic depositional conditions in the end of this stage. In turn, geochemistry of samples representative of the Devonian debris deposition contrast with the passive continental margin geochemical data; notwithstanding the dominant acid source, ...
Kink bands are usually related to the late deformation stages in polydeformed areas. In Portugal,... more Kink bands are usually related to the late deformation stages in polydeformed areas. In Portugal, the Late Variscan deformation generates in Almograve and Abrantes regions (SW Iberian Massif), brittle to brittle-ductile NNE-SSW sinistral kink bands, which deflects the NNW-SSE regional trend. This deflection induces the counterclockwise rotation of primary layering/foliation in the kink band inner domains, generating a complex and heterogeneous structural pattern. In Almograve, within metric to decametric kink bands, a wide spectrum of structures (mainly folds and brittle to brittle-ductile shear zones) are developed, while in the internal domains of the Abrantes metric kink band, a high strain pattern composed by 2nd order conjugate kink bands were generated. Previous structures allows to calculate internal and external stress fields, showing a variation from the outer to inner domains of kink band. During the development of the type III fixed hinge kink bands, the formation of the ...
The 87Sr/86Sr ratio is usually used in stratigraphy to correlate and even date marine carbonate s... more The 87Sr/86Sr ratio is usually used in stratigraphy to correlate and even date marine carbonate sedimentation events. The variation of the 87Sr/86Sr isotopic ratio along the geological time scale combined with the fact of this isotopic ratio could be considered uniform in all ocean at a given geological moment, opens a thematic for the investigation and characterization of carbonate sedimentation and as well it sedimentation environment. Therefore, it is important to understand the inherent limitations to the use of this isotope ratio as a method of correlation. For the present work, the Cambrian (or Cambrian attributed) carbonates from the Ossa-Morena Zone were sampled in several sectors. These samples present distinct metamorphic features and their litho-facies were been characterized, as well as the presence of late dolomitization processes (i.e. post-metamorphic). The data show that the late dolomitization processes induce a significant increase of the 87Sr/86Sr ratio, when comp...
<p>Since the 1990s, detailed studies on the relief units of the central and upper A... more <p>Since the 1990s, detailed studies on the relief units of the central and upper Alentejo region have been lacking. Previously, tectonics were used to explain most of the relief units, even those in which lithological differentiation is remarkable, such as the dolomitic plateaus of Elvas and Estremoz. The morphotectonic reliefs like Serra d’Ossa and Serra de S. Mamede were previously explained by vertical tectonics, in a horst-graben system, difficult to understand under the Cenozoic compressive tectonic regime affecting the Western Iberian margin.</p><p>The superposition of geological maps with digital terrain models suggests a more complex genesis in the formation of the morphotectonic regional reliefs. The Serra d’Ossa (652 m) develops in a WNW-ESE general trend (N80ºW), slightly asymmetrical with a 200 m high north-facing escarpment, much steeper than the south-facing slope. The north-facing escarpment (Ossa Fault – OF) is transversal to the NW-SE variscan structures (N40ºW). Thus, this escarpment cannot be explained by differential erosion. Indeed, Feio (1983) already hypothesized a tectonic origin to the Serra d'Ossa, although without presenting a tectonic model.</p><p>The western termination of the Serra d‘Ossa small scarps, with NE-SW orientation, coincide with the horse tail terminations of the NNE-SSW left strike-slip Graça do Divor fault (GDF). If both GDF and OF are connected, the Serra d’Ossa can be interpreted as a <em>push up</em> deformation of the South Portuguese Planation Surface (SPPS).</p><p>In this work, a greater relevance of differential erosion is highlighted in the individualisation of Elvas and Estremoz plateaus, as well as the Serra de Monfurado.</p><p>Towards the north of the town of Évora, the landscape is formed by broad-bottomed valleys at 240 m, with gentle slope and flat uplands at ca. 320-340 m. Looked in Davisian terms, the valleys looks like a mid-cycle maturity landscape. The flat upland level corresponds to the SPPS, well developed in the upper Alentejo (Nisa and Alpalhão), while the bottom of the valleys correspond to a younger level, embedded ca. 80–100 m in the SPPS. The valley bottoms widens to downstream forming a flattening surface (named N1 fluvial surface) related with the beginning of the incision of the drainage network in the SPPS and with the first (older) terraces of the Tejo and Guadiana rivers.</p><p>The prominence in the landscape of the Serra de Monfurado should be understood as a resistant ridge, whose summits were not completely flattened due to the lithological diversity and to the geographic location in the watershed limit of the Tejo, Guadiana and Sado rivers, where the flattening of the SPPS was difficult to achieve. Differential erosion during the formation of the N1 fluvial surface is thought to be the main responsible for the prominence of this ridge in the central Alentejo landscape, as well as other resistant reliefs as the Monsaraz <em>inselberg</em>.</p><p> </p><p>Acknowledgments: The authors acknowledge the funding provided by the Institute of Earth Sciences (ICT), under contract with Science and Technology Foundation (UID/GEO/04683/2019).</p><p>References:</p><p>Feio, M., 1983. O Relevo da Serra de Ossa: uma interpretação tectónica. Finisterra, XVIII, 35, 5-26.</p><p> </p>
O Departamento de Geociências da Escola de Ciências e Tecnologia da Universidade de Évora, em con... more O Departamento de Geociências da Escola de Ciências e Tecnologia da Universidade de Évora, em conjunto com o Instituto de Ciências da Terra e o Laboratório HERCULES, têm a honra e o prazer de organizar este evento que reúne a comunidade científica ibérica ligada à geoquímica e às suas múltiplas fronteiras. O Congresso Ibérico de Geoquímica é tutelado conjuntamente pela Sociedade Geológica de Portugal e o seu Grupo de Geoquímica, o Colegio Oficial de Químicos Madrid, a Asociación de Químicos y Ingenieros Químicos, o Consejo Superior de Colegios de Ingenieros de Minas de España e o Colegio Oficial de Geólogos de España, sendo realizado desde 1997, de dois em dois anos e sem interrupções, em Portugal e Espanha, de forma alternada. Quando o Congresso se realiza em Portugal, associa-se a Semana de Geoquímica, que perfaz a sua vigésima edição neste encontro, também ela ininterrupta ao longo de todos estes anos. Esta é a primeira vez que estes encontros se realizam em Évora, o que muito nos apraz e responsabiliza. A adesão a esta edição do congresso foi muito positiva, estando inscritos cerca de 150 participantes, que submeteram mais de 120 trabalhos, repartidos entre apresentações orais e em formato poster. Como é hábito, dividimos o congresso num conjunto de sessões temáticas abrangentes que vão desde os processos geológicos geodinâmicos até às fronteiras da geoquímica; queremos também salientar as sessões ligadas aos diversos tipos de recursos hídricos, energéticos, metálicos e não metálicos. Refletindo as preocupações atuais da sociedade, as sessões ligadas ao ambiente apresentam, como habitualmente, a mais elevada participação. O facto deste congresso decorrer no Ano Internacional da Tabela Periódica vem dar ainda mais significado e importância à sua realização, tendo mesmo a honra de contar com uma palestra do comissário nacional para este evento, o Professor José Ferreira Gomes. Contamos ainda com uma elite de palestrantes convidados, que nos apresentam um conjunto de temáticas inovadoras e de fronteira ligadas à geoquímica. Agregámos ao programa de trabalhos atividades técnico-científicas que complementam as sessões temáticas, nomeadamente dois breves workshops relacionados com obtenção e tratamento de dados geoquímicos e duas saídas de campo, que esperamos que sejam do agrado dos participantes. Procurando valorizar o papel dos jovens investigadores, iremos atribuir um prémio para a melhor apresentação oral e para o melhor poster: prémio PARALAB e prémio BERALT, respetivamente.Reservámos ainda espaço para que os participantes se possam conhecer melhor, fora do ambiente mais formal do congresso, de forma a possibilitar a criação de redes de colaboração durante os momentos de socialização. Esperamos ainda que durante a estadia tomem contacto com o forte carácter da paisagem, da cultura e das gentes deste sudoeste ibérico. Queremos agradecer a todas as empresas e instituições que apoiaram a realização deste evento, sem as quais ele não seria possível. Por fim, deixamos umas palavras de profundo reconhecimento aos moderadores; aos membros da comissão científica e organizadora que, através da sua disponibilidade, asseguraram a qualidade científica dos trabalhos apresentados e da dinâmica do congresso; assim como a todos os participantes que tornaram este encontro de pessoas e ideais uma realidade
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and cathodoluminescence, XRD, isotopic geochemistry (87Sr/86Sr). The pieces are reused as holy water fonts in the church of Santa María Magdalena in the town of El Viso de San Juan, Toledo. A review of the archival documentation referring to the church itself from the beginning of the 16th century onwards (Temples Repairs and Pastoral Visits), situates the first mention of the holy water fonts in an inventory from the beginning of the 20th century. We propose that originally the capitals were at the nearby Late Roman site of Santa María de Abajo (Carranque, Toledo) where they may have formed part of the architectural decoration of its palatial building, based on parallels documented in this site.
and cathodoluminescence, XRD, isotopic geochemistry (87Sr/86Sr). The pieces are reused as holy water fonts in the church of Santa María Magdalena in the town of El Viso de San Juan, Toledo. A review of the archival documentation referring to the church itself from the beginning of the 16th century onwards (Temples Repairs and Pastoral Visits), situates the first mention of the holy water fonts in an inventory from the beginning of the 20th century. We propose that originally the capitals were at the nearby Late Roman site of Santa María de Abajo (Carranque, Toledo) where they may have formed part of the architectural decoration of its palatial building, based on parallels documented in this site.