Document type
Journal articles
Document subtype
Full paper
Title
Isotope geochemistry evidence for Laurussian-type sources of South-Portuguese Zone Carboniferous turbidites (Variscan orogeny)
Participants in the publication
Manuel Francisco Pereira (Author)
Cristina Gama (Author)
Ícaro Dias da Silva (Author)
Dep. Geologia
IDL
IDL
José Manuel Fuenlabrada (Author)
José Brandão Silva (Author)
Dep. Geologia
IDL
Jorge Medina (Author)
Summary
New Rb–Sr isotopic data from South Portuguese Zone (SPZ) turbidites show that the 87Sr/86Sr(t) ratio increases from the basal Mértola Formation (Visean–Serpukhovian: 0.706–0.707), through the Mira Formation (Serpukhovian–Bashkirian: 0.706–0.712) to the uppermost Brejeira Formation (Bashkirian–Moscovian: 0.713–0.715). In addition, estimated Nd TDM model ages for the Mértola (1.29–1.09 Ga), Mira (1.58–1.1 Ga) and Brejeira (1.73–1.37 Ga) formations indicate inverted stratigraphy for their isotopic sources. The isotope geochemical data indicate significant changes in the sources from which the SPZ Carboniferous turbidites are derived, consistent with the progressive denudation of a continental magmatic arc built on the Laurussian margin. Mértola turbidites inherited their geochemical and isotopic characteristics from an adjacent dissected Middle–Late Devonian continental magmatic arc with an intermediate–felsic composition: that is a Laurussian (Rheic magmatic arc)-type source. The progressive erosion of its plutonic roots and older host continental basement rocks are indicated in the Mira and Brejeira formations by the increasing contribution of recycled ancient continental crust. The pronounced similarity between the Nd TDM model ages and the detrital zircon populations of the Mira and Brejeira formations (SW Iberia) suggest that they share a common Laurussian (West Avalonia/Meguma terrane)-type source but a contribution from Gondwanan (Ossa-Morena)-type sources cannot be discarded.
Date of Publication
2020-04-15
Where published
Geological Society, London, Special Publications
Publication Identifiers
ISSN - 0305-8719
eISSN - 2041-4927
Publisher
Geological Society of London
Number of pages
23
Starting page
619
Last page
642
Document Identifiers
DOI -
https://doi.org/10.1144/sp503-2019-163
URL -
http://dx.doi.org/10.1144/sp503-2019-163
Rankings
SCOPUS Q1 (2019) - 4.7 - Geology
SCOPUS Q1 (2019) - 4.7 - Water Science and Technology
SCOPUS Q1 (2019) - 4.7 - Ocean Engineering
SCIMAGO Q1 (2019) - 0.701 - Water Science and Technology (Q2)
SCIMAGO Q1 (2019) - 0.701 - Geology (Q2)
SCIMAGO Q1 (2019) - 0.701 - Ocean Engineering
SCIMAGO Q2 (2020) - 0.673 - Water Science and Technology
SCIMAGO Q2 (2020) - 0.673 - Geology
SCIMAGO Q1 (2020) - 0.673 - Ocean Engineering