Falda di Sesia

Representation and status

Color CMYK

N/A

Color RGB

R: 241 G: 239 B: 237

Rank

nappe

Validity

Unit is in Use

Status

valid

Nomenclature

Deutsch

Sesia-Decke

Français

Nappe de Sesia

Italiano

Falda di Sesia

English

Sesia Nappe

Origin of the Name

Alta Valsesia = Val di Sesia (Italia), S Monte Rosa

Historical Variants

Sesia-Gneissmasse (Gerlach 1869), gneiss Sesia (Argand 1906a), zone Sesia (Argand 1911b), zone Sesia-Lanzo (Henny 1918), Serie Sesia-Val di Lanzo (Bearth), Sesia-Lanzo zone (Dal Piaz et al. 1973), zona Sesia, massif de Lanzo (Debelmas 1976), Sesia Zone (Zingg et al. 1976, Berger & Mercolli 2007), Sesia-Lanzo continental unit (Pognante & Toscani 1985), Zona Sesia-Lanzo (Dal Piaz et al. 1992a), zone de Sesia (Carrupt & Schlup 1998), zona di Sesia + Lanzo Torinese (Piemonte) = Lans-l'Hermitage, Sesia nappe = Sesia-Decke = nappe de Sesia (TK500), Sesia Nappe (Gouffon et al. 2024)

Description

Description

characteristic jadeitic pyroxene-garnet-quartz assemblages in paraschists and metagranitoids (Dal Piaz et al. 1972 and 1973, Compagnoni & Maffeo 1973, Hunziker 1974, Compagnoni et al. 1977)

Hierarchy and sequence

Subordinate units

• unità di Bard
• unità di Bonze
• unità di Mombarone

Lower boundary

Canavese Line

Geography

Geographical extent

Stura di Lanzo (Torino) - Valle di Ossola - Locarno

Palaenography and tectonic

Paleogeography

Adriatic continental margin :

southern, passive continental margin / platform

Tectonic unit (resp. main category)

• Sesia

Kind of protolith

• tectonic

Metamorphism

polycyclic

Metamorphic facies

• greenschist facies (epizone)
• granulite facies
• eclogite facies

Note on facies

Spätvariszische Metamorphose: bis granulitfaziell (Unterkruste). Alpine Metamorphose: eklogitfazielle Metamorphose (bei 70-65 Ma), gefolgt von verbreiteter Überprägung in der Grünschieferfazies.

Note on metamorphism

métamorphisme éclogitique éo-alpin (Hunziker 1974, Compagnoni et al. 1977)

References

Definition

Gerlach Heinrich (1869) : Die penninischen Alpen, Beiträge zur Geologie der Schweiz. Neue Denkschriften allg. Ges. ges. Natf. 23

S.118

Definition

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

p.81: The Sesia Nappe is located between the Canavese Fault to the east and the Upper Penninic units to the west. It is composed of three units of crystalline basement characterized by different lithological associations. The Gneiss Minuti Unit consists mainly of orthogneisses, derived from granitoid of probable Permian age and interbedded with more mafic layers. High-pressure metamorphism of this unit was largely obliterated by the later greenschist-facies metamorphism. The Eclogitic Micaschist Unit comprises mostly paragneisses with minor mafic rocks, orthogneisses and calcitic marbles. Eclogitic mineral assemblages are well preserved, rarely overprinted by the subsequent greenschist-facies metamorphism. The unit referred to as Second Dioritic-Kinzigitic Zone (2DK) consists of kilometer-scale slices of micaschists, characterized by well-preserved pre-Alpine amphibolite to granulite-facies mineral assemblages as well as minor amphibolites and marbles, locally overprinted by the early Alpine high-pressure metamorphism.