Falda del Simano
Representation and status
- Index
- Si
- Color CMYK
- N/A
- Color RGB
- R: 241 G: 239 B: 237
- Rank
- nappe
- Validity
- Unit is in Use
- Status
- valid
Nomenclature
- Deutsch
- Simano-Decke
- Français
- Nappe du Simano
- Italiano
- Falda del Simano
- English
- Simano Nappe
- Origin of the Name
- Historical Variants
-
Simanoteildecke = Simano-Decke (Heydweiller 1918), Simanodecke (Bosshard 1925, Kündig 1926a, Staub 1934), Ricoprimento Simano-Verzasca (Casasopra 1939b), Falda Simano (Godenzi 1963), Ricoprimento Simano = complesso Simano (Bianconi 1971), nappe du Simano (Mayerat Demarne 1994), Simano Nappe (Rütti et al. 2005), Simano nappe (Steck et al. 2013), unità del Simano (Schenker, Bl. Osogna)
Description
- Description
-
Steck et al. 2013, p.431: On their tectonic map of the Simano nappe, Keller et al. (1980) distinguished a northern Campo Tencia unit composed of staurolite–kyanite–garnet micaschist and biotite-plagioclase paragneiss (meta-graywacke), the latter intruded by the Ganna granite gneiss, from a southern zone, dominated by a granitic two mica augengneiss, the 300 Ma old Verzasca gneiss (Ko¨ppel et al. 1981). A discontinuous zone of amphibolites follows the contact of the two units. The contact of the Campo Tencia and Verzasca units resemble a shear zone (Keller 1968).
Hierarchy and sequence
- Subordinate units
- Upper boundary
-
Maggia-Decke
- Lower boundary
-
Lucomagno-Leventina-Decke > Leventina-Gneis (ursp. intrusives Kontakt ; Rütti et al. 2005) bzw. Maggia-Decke
Geography
- Geographical extent
- Lepontin zwischen Valle Maggia und Valle Mesolcina.
- Type locality
-
-
Cima del Simano (TI) - Acquarossa
Coordinates- (2717775 / 1146840)
-
Cima del Simano (TI) - Acquarossa
Palaenography and tectonic
- Paleogeography
-
Northern Tethyan Margin
:
Paleo-European Margin - Tectonic unit (resp. main category)
- Kind of protolith
-
- tectonic
- Metamorphism
- polycyclic
- Metamorphic facies
-
- amphibolite facies
- Note on metamorphism
-
Kaledonisch + Variszisch + Alpin
References
- Definition
-
(2024) :
Tectonic Map of Switzerland 1:500000, Explanatory notes. Federal Office of Topography swisstopo, Wabern
The Simano Nappe consists of a heterogenous metamorphosed magmatic complex intruded into pre-Variscan paragneisses, forming today the orthogneisses that dominate the southern and the western part of the Simano Nappe. The eastern part contains Ordovician orthogneisses within paragneisses and the northern part consists of semi- to metapelitic gneisses, micaschists, amphibolites and sporadic lenses of ultramafic rocks, locally covered by Permian and Triassic sedimentary rocks (e.g., Preiswerk et al. 1934). In its frontal part, the Simano Nappe forms a large-scale recumbent fold – characterized by a thinned and disrupted inverted limb – over the Leventina-Lucomagno Nappe. This contact is characterized by a shear zone that spreads out southwards, forming a multitude of shear bands in the Leventina orthogneisses. There, the boundary between the Simano and the Leventina-Lucomagno nappes consists of a sheared Variscan magmatic contact (Rütti et al. 2005, Schenker et al. in prep.; see Fig. 7). The upper limit of the eastern part of the Simano Nappe is defined by a prominent shear zone, the result of the overthrusting of the Adula Nappe (Tagliaferri et al. 2023). The frontal part of the Simano Nappe is bordered by metacarbonates, considered to be the Mesozoic sedimentary cover of the nappe. To the west, this nappe is capped by the Cima Lunga Nappe and to the northwest by the Maggia Nappe. This latter contact is intensely sheared.