Ofiolite della falda di Antrona

Back to Antrona nappe

Representation and status

Color CMYK
(38%,0%,25%,37%)
Color RGB
R: 100 G: 160 B: 120
Rank
tectonically bounded lithostratigraphic unit
Validity
Unit is in Use
Status
informal term

Nomenclature

Deutsch
Ophiolith der Antrona-Decke
Français
Ophiolite de la nappe d'Antrona
Italiano
Ofiolite della falda di Antrona
English
Ophiolite of the Antrona nappe
Origin of the Name

Antronapiana (Italia)

Historical Variants

Ophiolite der Antrona-Anzasca-Mulde (Bearth 1939), Ophiolithe von Antrona-Bognanco = Ophiolithe der Zone von Antrona = Antronamulde (Bearth 1956), Antrona ophiolitic unit, Antrona ophiolite complex, Antrona mafic-ultrmafic complex (Colombi & Pfeifer 1986), unità ofiolitica di Antrona = ofioliti della Zona di Antrona = ofioliti mesozoiche di Antrona (Dal Piaz et al. 1992a), Antrona ophiolites (Keller 2004, Steck et al. 2015)

Description

Description

Serpentinite, Metabasalte und Metagabbros (mit Eklogitrelikten), sowie Kalkschiefern (ehemalige Sedimentbedeckung)

Hierarchy and sequence

Upper boundary

Portjengrat-Einheit

Lower boundary

Monte-Rosa-Decke

Age

Age at top
  • Kimmeridgian
Age at base
  • Callovian
Dating Method

163.1 +/- 2.4 Ma, 158 +/-17 Ma and 155.6 +/- 2.1 Ma (U/Pb SHRIMP zircon ; Liati et al. 2005)

Palaenography and tectonic

Paleogeography
Piemont Basin
Tectonic unit (resp. main category)
Kind of protolith
  • ophiolitic
Metamorphic facies
  • greenschist facies (epizone)
  • amphibolite facies
  • eclogite facies
Note on metamorphism

HP-mtm (eclogite) + greenschist/amphibolite

References

Definition
Bill Markus, Masson Henri, Thélin Philippe (2001) : Low-grade metamorphism of the Gets nappe (Western Alps). Schweiz. Mineral. Petrogr. Mitt. 81, 229-237

The Antrona and Zermatt-Saas ophiolitic nappes are found in a structurally low position. They are affected by high-P metamorphism (eclogite facies) followed by greenschist to amphibolite grade metamorphism (Bearth, 1974; Dal Piaz, 1974b; Hunziker, 1974; Dal Piaz and Ernst, 1978; Colombi, 1989; Steck, 1989; Vannay and Allemann, 1990; Reinecke, 1991; Amato et al., 1999).

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