Linea di Lugano-Val Grande

Representation and status

Historical Variants: Luganer Hauptverwerfung = Linie Lugano-Mendrisio (Vonderschmitt 1941), linea di Lugano-Val Grande (Spalla et al. 1998), Lugano-Monte Grona-Val Grande fault system (TK500 / Gouffon et al. 2024)

Subordinate units

Tectonic unit (resp. main category)

Kind of protolith

Definition: Gouffon Yves (Editor) (2024) : Tectonic Map of Switzerland 1:500000, Explanatory notes. Federal Office of Topography swisstopo, Wabern

p.102: To the west, the thin-skinned Orobic thrust units of the Bergamasc Alps laterally give way to thick-skinned allochthonous units in the western South Alpine domain, including the Ivrea-Ceneri Complex. This fundamental change from thin- to thick-skinned deformation is likely associated with the greater depth of the basement east of the Lugano – Monte Grona – Val Grande fault system. This major Mesozoic normal fault is subdivided into three segments: 1) the N–S trending Lugano Fault extends at least from Mendrisio northwards to northeast of Lugano, 2) the W– E oriented Monte Grona Fault extends from northeast of Lugano to Lago di Como and was reactivated as an alpine backthrust (N-directed), 3) the SW–NE oriented Val Grande Fault extends from Lago di Como eastwards at least up to M. Legnone. Scaramuzzo et al. (2022) speculate that the change from thick-skinned to thin-skinned units might coincide with a change from N-directed thrusting in the northwest to S-directed thin-skinned thrusting in the east; however, the evidence for this is rather fragmentary.