UPb and 40Ar39Ar geochronology of Palaeozoic units in the northern Apennines: determining protolith age and alpine evolution using the Calamita Schist and Ortano Porphyroid
Article first published online: 20 OCT 2010
Copyright © 2010 John Wiley & Sons, Ltd.
Volume 46, Issue 4, pages 288–310, July/August 2011
How to Cite
Musumeci, G., Mazzarini, F., Tiepolo, M. and Di Vincenzo, G. (2011), UPb and 40Ar39Ar geochronology of Palaeozoic units in the northern Apennines: determining protolith age and alpine evolution using the Calamita Schist and Ortano Porphyroid. Geol. J., 46: 288–310. doi: 10.1002/gj.1266
- Issue published online: 16 JUN 2011
- Article first published online: 20 OCT 2010
- Manuscript Accepted: 6 JUL 2010
- Manuscript Received: 22 APR 2010
- PRIN. Grant Number: 2005-040-459
- northern Apennines;
- Palaeozoic basement;
- UPb zircon;
- 40Ar39Ar muscovite
In the northern Apennines, the Palaeozoic basement involved in the Late Oligocene–Middle Miocene nappe stack contains metamorphic units for which hypothetical ages have been assigned on the basis of lithological correlations with the Palaeozoic formations of the Variscan chain in Sardinia. This uncertainty concerning the age poses limitations to reconstructing the Palaeozoic stratigraphy, defining the Alpine and pre-Alpine histories and correlations with other domains of the Variscan chain. We present the UPb age of detrital zircon and the 40Ar39Ar age of metamorphic muscovite for the Calamita Schist and Ortano Porphyroid, two metamorphic units of undetermined Palaeozoic age cropping out in the eastern Elba Island. The radioisotopic data allows us to: (i) define the Early Carboniferous and Middle Ordovician ages for the Calamita Schist and Ortano Porphyroid, respectively, as well as their derivation (flysch deposit and magmatic rocks); (ii) pose some constraints concerning their alpine tectonic and metamorphic histories. These new data generate a more precise reconstruction of the Palaeozoic sequence in the northern Apennines, and they document that the Palaeozoic basement involved in the alpine deformation underwent internal stacking with an inversion of the original sequence. Copyright © 2010 John Wiley & Sons, Ltd.