On the "root zone" of the Alpine nappes in the Ticino area (Ivrea Zone, Insubric line and gneisses of the Southern Steep Belt): Geometry and kinematics Stefan M. Schmid 84th CONVENTION 2017 Ascona, Switzerland, Monte Verità, June 17–19, 2017 Livo gorge near Lake Como View from Losone towards Arcegno S N S N
23
Embed
S N S N - SASEG · Cima Lunga (Adula) Maggia (Vogorno ) Maggia (Cocco gneiss) Strona Ceneri Simano (490Ma granite gneiss) Lavertezzo Zerm .-Saas Fee southern part of the Lepontine
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
On the "root zone" of the Alpine nappes in the Ticino area (Ivrea Zone, Insubric line and gneisses of the Southern Steep
Belt): Geometry and kinematics
Stefan M. Schmid
84th CONVENTION 2017 Ascona, Switzerland, Monte Verità, June 17–19, 2017
Livo gorge near Lake Como View from Losone towards Arcegno
S N S N
OROGEN-SCALE
Austroalpine
Southern Alps
The Insubric line; part of the Periadriatic line
Main activity of the Insubric Line: 32-20 Ma. The eastern segments (Pustertal- Gailtal- and Balaton-lines) are also active after 20 Ma, when the
Periadriatic line became offset by the Giudiarie line the Eastern Alps became laterally extruded to the east.
200 km
140 km
103 km 45 Ma 35 Ma
25 Ma 0 Ma
reconstruction for the last 45 Ma after Schmid et al. (2017), Europe fixed
estimate of the amount of dextral strike slip, based on the reconstruction of the movement of the Ivrea mantle wedge (green) for the last 35 Ma: 140 km
Estimate of the amount of dextral strike slip
Schmid et al. 2017
Estimate of backthrusting along the Insubric Line
22 km
Schmid et al. 2004
Large amounts of exhumation by retro-thrusting and Subsequent erosion restricted to the Lepontine dome
Canavese Line (eastern branch of Insubric line) in Valle d’Ossola
NW SE
Ivrea Zone Sesia Zone
Zingg et al. 1990
SE NW
SE NW
SOUTHERN ALPS CENTRAL ALPS
CENTRAL ALPS SOUTHERN ALPS
Insubric line near Ascona
N S
Arcegno
Losone
Ivrea Zone Sesia-derived
mylonites
Canavese Mesozoic
Sesia Zone P.-L. Ocean Zerm.-Saas
Zone
Monte Rosa nappe
N S Ivrea-derived mylonites
2 km
Schmid et al. 1987 & 1989
The northern part of the mylonite belt records steep lineations, indicating back- thrusting. The southern part of the mylonite belt records sub- horizontal lineations, Indicating dextral strike slip