Zircon U-Pb Dating and Lu-Hf Isotopic Composition of Some Granite Intrusions in Northern and Central Portugal: Constraints on the Emplacement Age and Nature of the Source Rocks

• Type: Article in International Scientific Journal
• Date: 2024

Authors

Gonçalves, A (Author) Other; Teixeira, R (Author) Other; Sant'Ovaia, H (Author) FCUP; Noronha, F (Author) FCUP

Journal

Title: Minerals

Vol. 14

Final page: 573

Publisher: MDPI

Indexing

ISI Web of Knowledge - 0 Citations

Scopus - 0 Citations

Other information

Authenticus ID: P-010-Q5B

DOI: 10.3390/min14060573

Abstract (EN): Freixo de Num & atilde;o (FNG) and Capinha (CG) granites are prominent intrusions in the Douro Group (northern Central Iberian Zone, CIZ) and Beiras Supergroup (southern CIZ) metasediments, respectively. U-Pb dating revealed crystallization ages of 306 +/- 2 Ma for FNG and 301 +/- 3 Ma for CG, whereas Lu-Hf systematics has shown epsilon Hft values ranging from -4.5 to +0.6 and from -5.5 to +0.3 in FNG and CG autocrysts, respectively, suggesting that they originate from heterogeneous crustal anatectic melts, but a direct mantle-derived material contribution can also be considered. The isotopic data of inherited zircon cores of both granites, with epsilon Hft values ranging from -16.8 to +8.4 in FNG, and from -19.4 to +10.1 in CG, are compatible with a derivation from heterogeneous Neoproterozoic metasedimentary sources, consisting of juvenile and recycled crustal materials, comparable to those of the wall rocks. However, the less evolved initial 176Hf/177Hf signature of magmatic zircons of both granites requires more immature metasediments/juvenile materials as main sources for the parental magmas. In fact, for FNG, the high Sr and Ba whole-rock content, and the upper Cambrian inheritance highlight the involvement of a metaigneous protolith in its genesis.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 26