Complesso del Monte del Forno

Darstellung und Status

Historische Varianten: Monte del Forno Series (Ferrario & Montrasio 1976), Fornoserie (Kubli 1983, Peretti 1983), Monte-del-Forno-Komplex (Peretti 1985), Mte del Forno-Komplex (Spillmann 1993), Forno mafics = Forno suite (Puschnig et al. 1996), ozeanische Fornoserie (Hansmann et al. 1996), Monte-del-Forno-Komplex = Forno-Ophiolithe (Spillmann & Trommsdorff 2007), Forno unit (TK500 / Gouffon et al. 2024)

Beschreibung: Ophiolitische Abfolge (Metavulkanite/Amphibolite und Metasedimente) der Malenco-Forno-Lizun-Decke. Wurde von der Bergeller Intrusion durchschlagen und kontaktmetamorph überprägt (Ferrario & Montrasio 1976, Peretti 1985).

Untergeordnete Einheiten

Herkunftstyp

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

p.78: Three units with distinct lithological assemblages of oceanic origin, situated in adjacent areas, form the Malenco-Forno-Lizun Nappe. The Malenco unit (Montrasio et al. 2005) consists of large volumes of serpentinite that represent exhumed subcontinental mantle formerly exposed at the ocean floor, and, in a small area adjacent to the Margna Nappe, a transition into continental lower crust in Permian granulite facies, associated with a Permian gabbroic intrusion (Müntener & Hermann 1996). Further north, the Forno unit consists of metabasalts and metagabbros of oceanic origin covered by metasedimentary rocks of Jurassic to Early Cretaceous age, which are in direct contact with the roof of the Bregaglia Intrusion (Puschnig 1998, Froitzheim et al. 1996 a). The Lizun unit, located around the Piz Lizun, northwest of the Engadine Fault and sinistrally offset from the Forno unit (Schmid & Froitzheim 1993), exposes same rocks of oceanic origin as in this latter unit (Liniger & Nievergelt 1990). The Malenco-Forno-Lizun Nappe, together with the Platta Nappe, is located in the hangingwall of the Turba Normal Fault (Nievergelt et al. 1996).