Dating deformation by the ⁴⁰Ar/³⁹Ar method: a review

Chiara Montemagni¹ & Igor M. Villa^2,3
1 Dipartimento di Scienze della Terra, Università di Firenze, Via La Pira 4, 50121 Firenze, Italy.
² Centro Universitario Datazioni e Archeometria, Università di Milano Bicocca, Piazza della Scienza 4, 20126 Milano, Italy.
³ Institut für Geologie, Universität Bern, Baltzerstrasse 3, 3012 Bern, Switzerland.
Corresponding author e-mail: chiara.montemagni@unifi.it

Shear zones contribute to the building of orogens by localizing displacements and element transfer between tectonic units, leading to both underthrusting and exhumation of large domains of the lithosphere. Constraining their activity over time is fundamental for understanding the tectonic processes and consequently producing realistic geological models. The ⁴⁰Ar/³⁹Ar dating method is an invaluable tool capable of extracting chronological information from a large variety of magmatic, metamorphic and metasomatic mineral chronometers. In particular, its ability to recognize and date sequential recrystallization event(s) by using compositional fingerprinting and/or in situ analyses provides constraints on the timescales of a wide range of geological processes.

⁴⁰Ar/³⁹Ar method, stepwise heating technique, in situ technique, shear zones, microstructures.