31 documents found, page 1 of 4
Ediacaran and early-palaeozoic bimodal volcanism in the Ossa-Morena Zone, SW Ib...
Cachapuz, P.; Chichorro, Martim Afonso; Bento dos Santos, Telmo; Carvalho, D.; Linnemann, Ulf; Zieger-Hofmann, M.; Zieger, J.; Dantas, E.; Santos, R. V.ABSTRACT: This study focuses on bimodal meta-volcanic rocks present in the Iberian Massif, in the Evora-Aracena Metamorphic Belt of the Ossa-Morena Zone (OMZ), near the boundary with the South Portuguese Zone. New petrological, geochemical (whole-rock and Sr-Nd isotopes) and LA-ICP-MS U-Pb zircon geochronology data are presented to track the magmatic evolution of both felsic and mafic rocks and their respective...
The bimodal Fii-A2-type and calc-alkaline volcanic sequence of the Aljustrel br...
Lains Amaral, João; Solá, A. Rita; Santos, Telmo M. Bento Dos; Feitoza, L. M.; Tassinari, Colombo C. G.; Crispim, Lourenço; Chichorro, MartimABSTRACT: The Iberian Pyrite Belt (IPB) is a late Devonian- Early Carboniferous world-class polymetallic VMS province that includes significant Cu-(Sn)-Pb-Zn-(Ag) deposits of massive sulphides and feeder zones. The Aljustrel brownfield region contains one of the highest concentrations of ore in the IPB in 6 known deposits (Gaviao, Sao Joao, Moinho, Algares, Estacao and Feitais). To delve into the petrogenesis o...
Dados geocronológicos para o soco pré-Mesozoico localizado a Oeste da Falha Por...
Santos, Telmo M. Bento Dos; Chichorro, Martim; Carvalho, D.; Cachapuz, P.; Solá, A. Rita; Dantas, E.; Romão, José; Moreira, Noel; Silva, I. Dias daSUMMARY: Geochronological data from the pre-Mesozoic basement of the Lusitanian Basement (West of the Porto-Tomar Fault) was obtained. Results show a predominant Cadomian/Pan-African and Eburnean inheritance/source, placing this sector as a peri-Gondwanan domain. However, two major differences can be seen in the data: samples with a clear absence in Mesoproterozoic ages vs. samples with a clear presence of thes...
Dados geocronológicos para o soco pré-Mesozoico localizado a Oeste da Falha Por...
Santos, Telmo M. Bento Dos; Chichorro, Martim; Carvalho, D.; Cachapuz, P.; Solá, A. Rita; Dantas, E.; Romão, José; Moreira, Noel; Silva, I. Dias daSUMMARY: Geochronological data from the pre-Mesozoic basement of the Lusitanian Basement (West of the Porto-Tomar Fault) was obtained. Results show a predominant Cadomian/Pan-African and Eburnean inheritance/source, placing this sector as a peri-Gondwanan domain. However, two major differences can be seen in the data: samples with a clear absence in Mesoproterozoic ages vs. samples with a clear presence of thes...
Geochronological data for the Pre-Mesozoic basement located west of the Porto-T...
Bento dos Santos, Telmo; Chichorro, Martim; Carvalho, Diogo; Cachapuz, Pedro; Solá, Rita; Dantas, E.; Romão, José; Moreira, Noel; Dias da Silva, ÍcaroGeochronological data from the pre-Mesozoic basement of the Lusitanian Basement (West of the Porto-Tomar Fault) was obtained. Results show a predominant Cadomian/Pan-African and Eburnean inheritance/source, placing this sector as a peri-Gondwanan domain. However, two major differences can be seen in the data: samples with a clear absence in Mesoproterozoic ages vs. samples with a clear presence of these ages an...
A tectonic carpet of Variscan flysch at the base of a rootless accretionary pri...
Clavijo, Emilio; Silva, Ícaro; Martínez Catalán, José R.; Gómez Barreiro, Juan; Gutiérrez-Alonso, Gabriel; Díez Montes, Alejandro; Hofmann, MandyThe allochthonous complexes of Galicia–Trás-os-Montes Zone (NW Iberia) are part of a rootless tectonic stack which preserves part of a Variscan accretionary prism. They are formed by individual tectonic slices marked by specific tectonometamorphic evolutions, which were piled up in a piggy-back mode onto its relative autochthon, the Central Iberian Zone (CIZ). Allochthony decreases from the structurally upper t...
Evidence formulti-cycle sedimentation and provenance constraints from
Pereira, M. Francisco; Gama, Cristina; Chichorro, Martim; Silva, Jose B.; Gutierrez-Alonso, Gabriel; Hofmann, Mandy; Linnemann, Ulf; Gartner, AndyLaser ablation ICP-MS U–Pb analyses were conducted on detrital zircons of Triassic sandstone and conglomerate from the Lusitanian basin in order to: i) document the age spectra of detrital zircon; ii) compare U–Pb detrital zircon ages with previous published data obtained from Upper Carboniferous, Ordovician, Cambrian and Ediacaran sedimentary rocks of the pre-Mesozoic basement of western Iberia; iii) discuss p...
Provenance of Holocene beach sand in the Western Iberian
Pereira, M. Francisco; Albardeiro, Luis; Gama, Cristina; Chichorro, Martim; Hofman, Mandy; Linnemann, UlfDetrital zircons from Holocene beach sand and igneous zircons from the Cretaceous syenite forming Cape Sines (Western Iberian margin) were dated using laser ablation – inductively coupled plasma – mass spectrometry. The U–Pb ages obtained were used for comparison with previous radiometric data from Carboniferous greywacke, Pliocene–Pleistocene sand and Cretaceous syenite forming the sea cliff at Cape Sines and ...
Tracing the geodymamic evolution of the North Gondwana
Albardeiro, Luis; Pereira, M. Francisco; Gama, Cristina; Chichorro, Martim; Hofmann, Mandy; Linnemann, UlfPliocene–Pleistocene sand of the Alvalade basin was sampled from the sea-cliffs of SW Iberia close to Cape Sines for a provenance study using LA-ICPMS U-Pb dating of detrital zircons. The results are used to compare age distributions and to trace potential source areas based on existing knowledge of zircon-forming events in the pre-Cenozoic basement of SW Iberia. The 492 U-Pb ages obtained span a wide interval ...
New U-Pb zircon dating of Late Neoproterozoic magmatism in Western Meseta (Moro...
Pereira, M. Francisco; El Houicha, Mohamed; Aghzer, Moushine; Silva, Jose Brandao; Linnemann, Ulf; Jouhari, AbdhelWe present new U-Pb zircon ages from magmatic rocks of the Western Meseta, part of the Moroccan Variscan belt. The Neoproterozoic–Cambrian stratigraphy in the region of Goäida (Aguelmous massif, SE of Moroccan Central Massif) consists of limestones with conglomeratic and felsic volcaniclastic levels, pelites and mafic volcanic rocks assigned to the Cambrian which unconformably overlie rhyolites, andesites and r...