strati.ch - Lessico lithostratigrafico della Svizzera

Rappresentazione e statuto

Varianti storiche: --- (Staub 1949 S.254), zone ophiolithique (Jaffé 1955), Nappe des Gets (Staub 1958), nappe du Col des Gêts (Trümpy 1976), nappe des Gets (Plancherel 1998), Gets nappe (Bill et al. 2001), Gets Nappe (TK500, Gouffon et al. 2024)

Descrizione: Nappe ophiolitique des Préalpes supérieures (la plus élevée des unités penniques), riche en ophiolites (cf. schistes lustrés piémontais ou Canavese ligure).

Limite inferiore: Les parties internes de la nappe chevauchent la nappe de la Brèche, tandis que les parties externes chevauchent la nappe de la Simme.

Geomorfologia

Età alla base

Paleogeografia

Bacino Piemontese

Termini generici

Tipo di origine

Metamorfismo

monociclico

Facies metamorfica

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

The Gets nappe is a decollement cover nappe situated in the front of the Alpine belt. This nappe was affected by very weak metamorphism, preliminary illite crystallinity data suggest anchizonal conditions (Caron and Weidmann, 1967). [...]

The Gets nappe is composed of two series (Caron, 1972): the base of the nappe (Perrieres series) essentially comprises a composite wildflysch containing ophiolitic material (serpentinite, gabbro, basalt and diabase). deep marine deposits (radiolarite, pelagic limestone, manganiferous shale), and Palaeozoic granite, all embedded in a shaly matrix (Fig. 2). The disrupted oceanic crust, the melange of ophiolitic rocks and the chaotic sedimentation are characteristic of an accretionary prism sequence (e.g. Mascle et al., 1988; Pickering et al., 1989). Isotopic dating, trace element data and Sm-Nd isotopes of the gabbros and basalts of the Gets nappe, together with structural and stratigraphic evolution of the northwest Shoulder of the Piedmont rift indicate that. at least in part, the ophiolitic material of the Gets nappe is a remnant of the onset of the Piedmont ocean spreading (Bill et al. 1997,2000,2001).The composite wildflysch is overlain by the Hundsrück series, composed mainly of turbiditic sandstones and polygenic conglomerates of Upper Cretaceous age.