Please use this identifier to cite or link to this item:
Title: Isotope geochemistry evidence for Laurussian-type sources of South Portuguese Zone Carboniferous turbidites (Variscan Orogeny)
Author: Pereira, Manuel Francisco
Gama, Cristina
Silva, Ícaro Dias da
Fuenlabrada, José Manuel
Silva, José Brandão
Medina, Jorge
Issue Date: 21-May-2020
Publisher: The Geological Society of London
Abstract: 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.
Peer review: yes
DOI: 10.1144/SP503-2019-163
ISSN: 0305-8719
Appears in Collections:DGeo - Artigos

Files in This Item:
File Description SizeFormat 
SP503-2019-163.full.pdf4.02 MBAdobe PDFView/Open

Formato BibTex MendeleyEndnote Degois 

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.