15 documents found, page 1 of 2
Ediacaran and early-palaeozoic bimodal volcanism in the Ossa-Morena Zone, SW Ib...
Cachapuz, P.; Chichorro, M.; Bento dos Santos, T.; Carvalho, D.; Linnemann, U.; Zieger-Hofmann, M; Zieger, J.; Dantas, E.; Santos, R.V.; Moita, P.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 geodynam...
Chronostratigraphic framework and provenance of the Ossa-Morena Zone Carbonifer...
Pereira, M.F.; Gama, C.; Dias da Silva, I.; Silva, J.B.; Hofmann, M.; Linnemann, U.; Gartner, A.Carboniferous siliciclastic and silicic magmatic rocks from the Santa Susana–São Cristovão and Cabrela regions contain valuable information regarding the timing of synorogenic processes in SW Iberia. In this region of the Ossa-Morena Zone (OMZ), late Carboniferous terrigenous strata (i.e., the Santa Susana Formation) unconformably overlie early Carboniferous marine siliciclastic deposits alternating with volcan...
S-type granite generation and emplacement during a regional switch from extensi...
Pereira, M.F.; Díez Fernández, R.; Gama, C.; Hofmann, M.; Gartner, A.; Linnemann, U.Zircon grains extracted from S-type granites of the Mêda-Escalhão-Penedono Massif (Central Iberian Zone, Variscan Orogen) constrain the timing of emplacement and provide information about potential magma sources. Simple and composite zircon grains from three samples of S-type granite were analyzed by LA-ICP-MS. New U–Pb data indicate that granites crystallized in the Bashkirian (318.7 ± 4.8 Ma) overlapping the ...
Provenance of upper Triassic sandstone, southwest Iberia (Alentejo and Algarve ...
Pereira, M. F.; Ribeiro, C.; Gama, C.; Drost, K.; Chichorro, M.; Vilallonga, F.; Hofmann, M.; Linnemann, U.Laser ablation ICP-MS U–Pb analyses have been conducted on detrital zircon of Upper Triassic sandstone from the Alentejo and Algarve basins in southwest Iberia. The predominance of Neoproterozoic, Devonian, Paleoproterozoic and Carboniferous detrital zircon ages confirms previous studies that indicate the locus of the sediment source of the late Triassic Alentejo Basin in the pre-Mesozoic basement of the South ...
Sedimentary record of the amalgamation and break-up of Pangea: U-Pb detrital zi...
Pereira, M. F.; Chichorro, M.; Gutiérrez-Alonso, G.; Gama, C.; Drost, K.; Ribeiro, C.; Albardeiro, L.; Hofmann, M.; Linnemann, U.In SW Iberia there is a basal unconformity where Triassic sandstones overlie previously deformed Carboniferous turbidites. This important stratigraphic boundary records the transition from the final stages of Pangaea’s amalgamation to the initial stages of break-up. U-Pb dating of detrital zircon from Carboniferous greywackes of the South Portuguese Zone and Triassic sandstones of the Algarve and Alentejo basin...
Provenance of Late Triassic Basins during the First Stages of Rifting in Pangea...
Vilallonga, Filipa; Pereira, Manuel Francisco; Ribeiro, Carlos; Chichorro, Martim; Hofmann, M.; Linnemann, U.; Drost, K.The Late Triassic basins of SW Portugal were filled with continental detrital deposits dominated by sandstones and some interbedded conglomerates and mudstones. In this study, detrital zircons were separated from samples of the Upper Triassic sandstones of the Silves Formation collected in the Alentejo and Algarve basins. Conventional methods of separation of heavy minerals by sizing, magnetism, and gravity wer...
The Significance of Changes of Source Areas During Carboniferous Turbiditic Dep...
Pereira, Manuel Francisco; Chichorro, Martim; Gutierrez-Alonso, G.; Vilallonga, Filipa; Drost, K.; Ribeiro, Carlos; Silva, J.B.; Albardeiro, LuisU–Pb dating of detrital zircons from the Carboniferous turbidites of southwestern Iberia (the Cabrela, Mértola, Mira, and Brejeira formations) shows that synorogenic sedimentation during the Carboniferous was marked by significant variations in the source areas, involving the denudation of different crustal blocks and a break in synorogenic volcanism. The Visean is characterized by the accumulation of immature ...
Provenance Analysis of the Late Ediacaran Basins from Southwestern Iberia (Séri...
Lopes, Luís; Pereira, M. F.; Chichorro, M.; Solá, A. R.; Hofmann, M.; Linnemann, U.; Silva, J. B.; Gerdes, A.; Medina, J.This study makes a comparison of detrital-zircon age populations from upper Ediacaran greywackes of the Ossa–Morena Zone (OMZ) with those from the southern domains of the Central Iberian Zone (S-CIZ). The results reveal that the main difference between the age spectra of both populations of detrital zircon is the Neoproterozoic, in particular the Cryogenian grains. Our new data suggest that deposition in the CI...
Provenance of Cambrian–Ordovician Siliciclastic Rocks of Southwestern Iberia: I...
Lopes, Luís; Pereira, M. F.; Solá, A. R.; Chichorro, M.; Medina, J.; Silva, J.B.; Gerdes, A.; Linnemann, U.; Hofmann, M.This study makes a comparison between the populations of detrital zircons of the Cambrian sandstones from the Ossa–Morena Zone (OMZ) and the Ordovician quartzites from the southern domains of the Central Iberian Zone (S-CIZ) to identify the sediment sources during the development of North Gondwana basins (southwestern Iberia). The U–Pb results obtained for the lower Cambrian sandstones of the OMZ show a remarka...
Provenance Analysis of the Late Ediacaran Basins from Southwestern Iberia (Séri...
Lopes, Luís; Pereira, M. F.; Solá, A. R.; Chichorro, M.; Medina, J.; Silva, J. B.; Gerdes, A.; Hofmann, M.; Linnemann, U.This study makes a comparison of detrital-zircon age populations from upper Ediacaran greywackes of the Ossa–Morena Zone (OMZ) with those from the southern domains of the Central Iberian Zone (S-CIZ). The results reveal that the main difference between the age spectra of both populations of detrital zircon is the Neoproterozoic, in particular the Cryogenian grains. Our new data suggest that deposition in the CI...