SHRIMP and LA-ICPMS U¿Pb zircon geochronology of post-tectonic granitoid intrusions in NW of central Iberian Zone [Geocronologia por SHRIMP e LA-ICPMS em granitóides póstectónicos no NW da Zona Centro-Ibérica]

• Type: Article in International Scientific Journal
• Date: 2014

Authors

Martins, HCB (Author) FCUP; Ribeiro, MA (Author) FCUP; Sant'Ovaia, H (Author) FCUP; Abreu, J (Author) Other; De Garcia Madinabeitia, S (Author) Other

Journal

Title: Comunicações Geológicas

Vol. 101

Pages: 147-150

ISSN: 0873-948X

Publisher: LNEG - Laboratório Nacional de Energia e Geologia

Indexing

ISI Web of Knowledge

Scopus - 2 Citations

Other information

Authenticus ID: P-00G-502

Abstract (EN): Resolving time differences between successive magmatic pulses in granitoid plutons is often a difficult task. High-precision ages, obtained by U-Pb SHRIMP in Lavadores granite, provide evidence that the crystallization of this granite happened at 294±3 Ma which is more precise that a previous age obtained by conventional U¿Pb method on multigrain zircon fractions by isotopic dilution (298±11 Ma). In Madalena and Castelo do Queijo granites a zircon geochronological study was performed using a LA-ICPMS. However, there are only a few concordant zircons due the presence of analysis with high amounts of common lead. The Concordia ages yield 307±8 Ma and 303±4.6 Ma for Castelo do Queijo and Madalena granites, respectively. Given the high discordance of zircons, weighted average diagrams were used for all analyses, obtaining a mean of 296±11 Ma for the Castelo do Queijo granite and 296±3 Ma for the Madalena granite. Although these means are not precise ages, they are more in agreement with geological and structural data than the Concordia ages. © 2014 LNEG ¿ Laboratório Nacional de Geologia e Energia IP

Language: English

Type (Professor's evaluation): Scientific