Structure and petrography of the Valle Mosso pluton, Sesia Magmatic System, Southern Alps

ABSTRACT

The Valle Mosso pluton (VMP) is a Permian granitic body intruded at intermediate to upper crustal levels in the rocks of the pre-Alpine basement of the Ivrea-Verbano Zone and Serie dei Laghi shortly after the end of Variscan orogeny. As a consequence of Triassic to Jurassic rifting and Alpine orogeny, the VMP and surrounding host rocks have been tilted more than 60° from their original Permian polarity. Thus at present day, the VMP offers the rare opportunity to study a roof-to-floor exposure of a granitic pluton, providing insights into pristine geometry of the magma chamber and its relations to the country rocks. This work presents a new drift and solid map of the VMP and its surrounding host rocks at 1:15.000 scale.

KEYWORDS:

• Ivrea-Verbano Zone
• Sesia Magmatic System
• granitic facies
• zoned pluton
• roof-to-floor exposure

Acknowledgments

Field discussions with Professor James Quick provided insightful suggestions on the relationship between the Valle Mosso intrusion and the overall Sesia Magmatic System. D. Nannini is also acknowledged for his helpful advices on Qgis software. L. Furlan is acknowledged for sample preparation at University of Trieste. The authors are grateful to Jennifer Carrel, Benoît Petri and Alfons Berger for their constructive and careful reviews and Monica Pondrelli for editorial handling.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Funding for this work was provided by the University of Trieste, FRA 2014 and Ministero dell'Istruzione, dell'Università e della Ricerca [PRIN2015EC9PJ5].