Zircon U-Pb Dating of a Lower Crustal Shear Zone
PUBLICATIONS Tectonics RESEARCH ARTICLE Zircon U-Pb Dating of a Lower Crustal Shear Zone: A Case 10.1002/2017TC004638 Study From the Northern Sector of the Ivrea-Verbano Special Section: Zone (Val Cannobina, Italy) Orogenic cycles: from field observations to global A. Langone1 , A. Zanetti1, N. R. Daczko2 , S. Piazolo3, M. Tiepolo1,4, and M. Mazzucchelli1,5 geodynamics 1Istituto di Geoscienze e Georisorse-C.N.R. U.O.S. of Pavia, Pavia, Italy, 2Australian Research Council Centre of Excellence for Core to Crust Fluid Systems (CCFS)/GEMOC, Department of Earth and Planetary Sciences, Macquarie University, Sydney, Key Points: 3 4 • Lower crustal high-temperature New South Wales, Australia, School of Earth and Environment, University of Leeds, Leeds, UK, Dipartimento di Scienze 5 deformation is Late Triassic to Early della Terra “A. Desio”, Università degli Studi di Milano, Milan, Italy, Dipartimento di Scienze Chimiche e Geologiche, Jurassic Università degli Studi di Modena e Reggio Emilia, Modena, Italy • Large-scale shear zones at different crustal levels were coeval • Zircon U-Pb dating of mylonitic mafic Abstract A geochronological study was performed on zircon grains from a middle-lower crustal shear rocks provides the first evidence of fi lower crustal deformation associated zone exposed in the northern sector of the Ivrea-Verbano Zone (Southern Alps, Italy) for the rst time. The with Mesozoic rifting shear zone developed at the boundary between mafic rocks of the External Gabbro unit and ultramafic rocks of the Amphibole Peridotite unit. It is ~10–20 m wide, can be followed along a NE strike for several Supporting Information: kilometers, and consists of an anastomosing network of mylonites and ultramylonites.
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