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DETRITAL ZIRCON GEOCHRONOLOGY OF THE CARBONIFEROUS BAIXO ALENTEJO FLYSCH GROUP, SOUTH PORTUGAL
Título: Detrital zircon geochronology of the Carboniferous Baixo Alentejo Flysch Group, South Portugal : constraints on the provenance and geodynamic evolution of the South Portuguese Zone / B. Rodrigues... [et al.]
In: Journal of the Geological Society. - ISSN 0016-7649. - Vol. 172, Part 3 (May 2015), p. 294-308
Sumário ou resumo: U–Pb detrital zircon data from the Baixo Alentejo Flysch Group in the South Portuguese Zone show significant age differences between formations. The Visean Mértola Formation and Serpukhovian to early Bashkirian Mira Formation are dominated by zircons in the 316–388?Ma age range, whereas the late Bashkirian to late Moscovian Brejeira Formation is dominated by zircons with an age range of 498–687?Ma. Detrital zircons spanning an age range of 0.9–1.1?Ga are present in the Brejeira Formation but are absent in the Mértola and Mira formations. Detrital zircon ages of the Mértola and Mira formations indicate provenance from an extra-basinal source (Ossa–Morena Zone) with a minor intra-basinal contribution (South Portuguese Zone). The abundant presence of detrital zircon with age ranges of 500–750 and 0.9–1.1?Ga in the Brejeira Formation suggests a sediment source from the Avalon–Meguma terranes with limited recycling from the SW Portugal Domain. The different inferred source areas for the Baixo Alentejo Flysch Group formations are attributed to the presence of a forebulge that was formed in Mid-Visean times during the foreland phase of the South Portuguese Zone. The forebulge acted as a physical barrier separating sub-basins that accumulated the Mértola–Mira and Brejeira sediments respectively.
Notas gerais: Contém 7 figuras e 1 tabela
Assuntos: Geocronologia / Evolução geodinâmica / Estratigrafia regional / Flysch / Carbónico / Baixo Alentejo (Portugal) / Zona Sul Portuguesa / Portugal (Sul)
URL: http://dx.doi.org./10.1144/jgs2013-084
URL: http://hdl.handle.net/10400.9/2841
Cota: E210-P5LGM-NBAH GB-117
Tipo de documento: Texto impresso
País de publicação: GB|London

Outro(s) autor(es) : Rodrigues, B. / Chew, D. M. / Jorge, Raul C. G. Santos / Fernandes, P. / Pires, Cristina Veiga / Oliveira, José Tomás

Detrital zircon geochronology of the Carboniferous Baixo Alentejo Flysch Group...

Detrital zircon geochronology of the Carboniferous Baixo Alentejo Flysch Group...



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DECIPHERING A MULTI-EVENT IN A NON-COMPLEX SET OF DETRITAL ZIRCON U-PB AGES FROM CARBONIFEROUS GRAYWACKES OF SW IBERIA
Título: Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia / A. Ferreira... [et al.]
Publicação: Amsterdam : Elsevier, 2014
Descrição física: [13] p. : il., 8 figuras e 7 tabelas ; 30 cm
Sumário ou resumo: The determination of U–Pb ages from detrital zircons of sedimentary rocks using LA-ICP-MS has been widely used for the purpose of provenance analysis. One problem that frequently arises is finding a population that appears to be non-complex despite several perceptible age peaks in its spectrum. These peaks are qualitatively defined by means of relative probability diagrams, or PDFs, but it is difficult to quantify their statistical significance relative to a zircon forming multi-event. Thus, can a multi-event in a non-complex set of detrital zircon U–Pb ages be deciphered and characterized?
The aim of this study is to attempt to provide an answer to this question by means of statistical analysis. Its objectives are: a) to determine the best minimum number of zircon age populations (peaks), BmPs, b) for the characterization of each peak in terms of age and event duration; c) to compare the results obtained from two datasets showing similar zircon ages; and d) to demonstrate the usefulness of deciphering these BmPs. First, cluster analysis is carried out, aimed at grouping zircon ages into a set of consistent clusters. A Gaussian Kernel function is then fitted to each cluster and summed to obtain a theoretical PDFm (modeled probability density function). Finally, the selected modeled PDFm (that built on the BmPs) is that which reports the lowest number of peaks for which the difference as compared with the original gPDF (global probability density function) is equal to or below 5%. Deciphered BmP peaks can be characterized and used for characterizing and providing an understanding of related event(s).
A geological interpretation, based on the results obtained, is attempted. This includes a robust measure for maximum age of deposition for both Cabrela and Mértola graywackes.
Notas ed.e hist.bibliográfica: Chemical Geology, Vol. 378-379 (15 June 2014), p. 62-74
ISSN: ISSN 0009-2541
Assuntos: Geocronologia / Grauvaques / Carbónico / Península Ibérica (Sudoeste)
URL: http://dx.doi.org/10.1016/j.chemgeo.2014.04.011
URL: http://hdl.handle.net/10400.9/2757
Cota: 3-s530LGM-NBAH 36743
Tipo de documento: Texto impresso
País de publicação: NL|Amsterdam

Outro(s) autor(es) : Ferreira, A. / Lopes, C. / Chichorro, Martím A. / Pereira, M. Francisco / Solá, Ana Rita

Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia

Deciphering a multi-event in a non-complex set of detrital zircon U-Pb ages from Carboniferous graywackes of SW Iberia



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Autor: HERBIG, Hans-Georg
Título: Crenistria Event and Asbian-Brigantian Transition in the South Portuguese Zone : Sea Level Control on a Hemipelagic Late Dinantian Platform / Hans-Georg Herbig, Dieter Korn, Bernd Mestermann
In: Facies. - ISSN 0172-9179. - Vol. 41 (1999), p. 183-195
Notas gerais: Contém 4 figuras e 2 estampas
Assuntos: Fácies / Estratigrafia sequencial / Goniatites / Viseano / Carbónico / Zona Sul Portuguesa / Portugal
Cota: E6-P1LGM-NBAH DE-39
Tipo de documento: Texto impresso
País de publicação: DE|Erlangen

Outro(s) autor(es) : Korn, Dieter / Mestermann, Bernd



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EVOLUÇÃO ESTRUTURAL DOS SECTORES SETENTRIONAIS DO AUTÓCTONE DA ZONA CENTRO-IBÉRICA
Título: Evolução estrutural dos sectores setentrionais do Autóctone da Zona Centro-Ibérica / R. Dias... [et al.]
In: Geologia de Portugal, Vol. I: Geologia Pré-mesozóica de Portugal / editores Rui Dias, Alexandre Araújo, Pedro Terrinha, José Carlos Kullberg. - Lisboa : Livraria Escolar Editora, 2013. - Cap. II.1.1., p. 73-147
Notas gerais: Contém 19 figuras
Assuntos: Geologia regional / Evolução estrutural / Litostratigrafia / Cadomiano / Grupo Dúrico-Beirão (Portugal) / Ordovícico / Silúrico / Devónico / Carbónico / Deformação / Fase sarda / Fase varisca / Zona Centro Ibérica (Portugal)
URL: http://www.escolareditora.com
URL: http://hdl.handle.net/10400.9/2240
Cota: 18-734LGM-NBAH 35556
Tipo de documento: Texto impresso
País de publicação: PT|Lisboa

Outro(s) autor(es) : Dias, Rui / Ribeiro, António / Coke, Carlos / Pereira, Eurico / Rodrigues, José Feliciano / Castro, Paulo Ferreira / Moreira, Noel / Rebelo, José Almeida

Evolução estrutural dos sectores setentrionais do Autóctone da Zona Centro-Ibérica

Evolução estrutural dos sectores setentrionais do Autóctone da Zona Centro-Ibérica



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THE SIGNIFICANCE OF REWORKED PALYNOMORPHS, MIDDLE CAMBRIAN TO TOURNAISIAN, IN THE VISEAN TOCA DA MOURA COMPLEX, SOUTH PORTUGAL
Título: The significance of reworked palynomorphs, middle Cambrian to Tournaisian, in the Visean Toca da Moura Complex, South Portugal : implications for the geodynamic evolution of Ossa Morena Zone / Gilda Lopes... [et al.]
Publicação: Amsterdam : Elsevier, 2014
Descrição física: 23 p. : il., 5 figuras, 3 tabelas e 9 estampas ; 30 cm
Sumário ou resumo: 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.
Notas ed.e hist.bibliográfica: Review of Palaeobotany and Palynology, Vol. 200 (January 2014), p. 1-23
ISSN: ISSN 0034-6667
Assuntos: Palinostratigrafia / Palinomorfos / Evolução geodinâmica / Orogenia Varisca / Carbónico / Paleozóico / Câmbrico médio / Tournaisiano / Complexo de Toca da Moura (Portugal) / Portugal (Sul) / Zona de Ossa-Morena
URL: http://dx.doi.org/10.1016/j.revpalbo.2013.07.003
URL: http://hdl.handle.net/10400.9/2204
Cota: 16-s2499LGM-NBAH 35986
Tipo de documento: Texto impresso
País de publicação: NL|Amsterdam

Outro(s) autor(es) : Lopes, Gilda / Pereira, Zélia / Fernandes, Paulo / Wicander, Reed / Matos, João Xavier / Rosa, Diogo R. N. / Oliveira, José Tomás

The significance of reworked palynomorphs (middle Cambrian to Tournaisian) in the Visean Toca da Moura Complex (South Portugal)...

The significance of reworked palynomorphs (middle Cambrian to Tournaisian) in the Visean Toca da Moura Complex (South Portugal)...



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