The pre-Alpine history of the Venaco-Ghisoni Unit, a continental unit belonging to the Alpine Corsica (France), was reconstructed on the basis of U–Pb dating of zircon and allanite. Zircon was separated from a metagranitoid and an epidote-bearing metagabbro and analyzed by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Magmatic ages ranging from 291 to 265 Ma were obtained for the metagranitoid samples and 276.9 ± 1.1 Ma for the epidote-bearing metagabbro. This geochronological dataset, combined with field observations, microstructural and cathodoluminescence analysis demonstrate that in the Early Permian, the Variscan basement of the Venaco-Ghisoni Unit was intruded first by the granitoid and then by the gabbro. Allanite was identified in the metagranitoid and exhibit an U–Pb age of 225 ± 8 Ma. We interpret this age as reflecting metamorphism associated to the Late Triassic rifting predating the opening of the Piemonte-Liguria Ocean. The absence of middle Eocene—Oligocene zircon and allanite overgrowths is compatible with the low metamorphic conditions (< 350–400 °C) recorded by the Venaco-Ghisoni Unit during Alpine metamorphism.
Pre-Alpine thermal history recorded in the continental crust from Alpine Corsica (France): evidence from zircon and allanite LA-ICP-MS dating / M. Di Rosa, F. Farina, P. Lanari, M. Marroni. - In: SWISS JOURNAL OF GEOSCIENCES. - ISSN 1661-8726. - 113:1(2020 Dec).
|Titolo:||Pre-Alpine thermal history recorded in the continental crust from Alpine Corsica (France): evidence from zircon and allanite LA-ICP-MS dating|
FARINA, FEDERICO (Secondo) [Methodology]
|Parole Chiave:||Allanite; Alpine Corsica; Early Permian magmatism; Late Triassic rifting; Pre-Alpine thermal event; U–pb dating; Venaco-Ghisoni Unit; Zircon|
|Settore Scientifico Disciplinare:||Settore GEO/03 - Geologia Strutturale|
Settore GEO/08 - Geochimica e Vulcanologia
|Data di pubblicazione:||dic-2020|
|Data ahead of print / Data di stampa:||nov-2020|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1186/s00015-020-00374-2|
|Appare nelle tipologie:||01 - Articolo su periodico|