Falda Malenco-Forno-Lizun

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
Malenco-Forno-Lizun-Decke
Français
Nappe de Malenco-Forno-Lizun
Italiano
Falda Malenco-Forno-Lizun
English
Malenco-Forno-Lizun Nappe
Historical Variants

Ophiolithzug Val Maroz-Malenco (Staub 1921), Zone von Châtillon-Malenco (Staub 1942b), Malenker Ophiolith-Decken (Staub 1946), Zone Disgrazia-Val Malenco (Roesli 1946), Forno-Decke, Monte-del-Forno-Serie (Ferrario & Montrasio 1976), Monte-del-Forno-Komplex (Peretti 1985), Falda ofiolitica Malenco-Forno (Sciesa 1991), Malenco-Forno-Lizun-Einheit (Spillmann 1993), Malenco-Forno-Lizun units (Manatschal 1995), Malenco-Forno-Lizun-Decke (Spillmann & Trommsdorff 2007), Malenco-Forno-Lizun Nappe (TK500 / Gouffon et al. 2024), cf. Trommsdorff et al. 1993

Description

Description

Reliktischer exhumierter subkontinentaler Mantel, ozeanischer Basalt und Sedimente.

Hierarchy and sequence

Subordinate units
Upper boundary

Margna-Decke (Unterostalpin)

Geography

Geographical extent
Tiefste tektonische Einheit der Bernina-Gruppe.

Palaenography and tectonic

Tectonic unit (resp. main category)
Kind of protolith
  • tectonic

References

Definition
Staub R. (1921) : Geologische Karte der Val Bregaglia (Bergell ; 1:50'000). Geologische Spezialkarte 90
Definition
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).
Important Publications
Trommsdorff V., Piccardo G. B., Montrasio A. (1993) : From magmatism through metamorphism to sea floor emplacement of subcontinental Adria lithosphere during pre-Alpine rifting (Malenco, Italy). Schweiz. mineral. petrogr. Mitt. 73, 191-203

  • Lizun-Grünschiefer

    Name Origin

    Piz Lizun (GR)

    Rank
    lithostratigraphic unit
    Status
    informal term
    In short

    Metabasika der Malenco–Forno–Lizun-Decke nördlich der Engadiner-Linie. Metasedimente fehlen in dieser Region.

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  • Complesso del Monte del Forno

    Name Origin

    Monte del Forno (GR)/(Italia)

    Rank
    tectonically bounded lithostratigraphic unit
    Status
    informal term
    In short

    Within the Upper Penninic Malenco-Forno-Lizun Nappe, the Forno unit is situated southeast of the Engadine Fault and is sinistrally offset from the Lizun unit. It 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.

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    • Quarziti del Muretto

      Name Origin

      Val Muretto (GR), östlich des Malojapasses

      Rank
      lithostratigraphic Formation
      Status
      informal term
      In short
      Schistes quartzeux à diopside et plagioclase (bytownite). Le protolithe devait être une arkose à matrice argileuse et ciment carbonaté (Mützenberg 1986).
      Age
      Late Cretaceous
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    • Formazione dei Rossi

      Name Origin

      I Rossi (GR)

      Rank
      lithostratigraphic unit
      Status
      informal term
      In short
      Metasedimente (kalkhaltige Andalusit-Granat-Biotitschiefer) des Monte-del-Forno-Komplexes.
      Age
      Late Jurassic
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    • Quartziti di base

      Rank
      lithostratigraphic unit
      Status
      informal term
      In short
      Quarzit mit lokal zwischengeschaltete Amphibol-Pyroxen-Grünschiefer, Mn-Silikate und kalksilikat-führende Marmore.
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    • Anfibolite del Forno

      Name Origin

      Monte del Forno (GR)

      Rank
      lithostratigraphic unit
      Status
      informal term
      In short
      Getüpfelter (gefleckter) bis gebänderter Amphibolit (MORB-Metabasalt ; Gautschi 1980) mit Porphyroblasten aus metamorphem Plagioklas. Pillowstrukturen (mit Epidotschlieren und Kalksilikatlagen als «Interpillow-Sedimente») und Hyaloklastite sind lokal erhalten.
      Age
      Callovian
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    • Ofiolite del Forno

      Rank
      lithostratigraphic unit
      Status
      informal term
      In short
      Ophiolithsequenz des Monte-del-Forno-Komplexes.
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  • Corpo ultramafico della Val Malenco

    Name Origin

    Alta Val Malenco (Disgrazia, Italia)

    Rank
    tectonically bounded lithostratigraphic unit
    Status
    informal term
    In short

    Within the Upper Penninic Malenco-Forno-Lizun Nappe, the Malenco unit 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.

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    • Oficarbonati della Val Ventina

      Name Origin

      Val Ventina (Italia)

      Rank
      lithostratigraphic unit
      Status
      local name (informal)
      In short
      Ophikarbonat des Val-Malenco-Ultramafititkörpers, diskordant zu den alpinen Strukturen streichend.
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    • Ur-Brekzie

      Name Origin

      Pass d'Ur = Passo della Poschiavina (GR)

      Rank
      tectonically bounded lithostratigraphic unit
      Status
      informal term
      In short
      Ophikarbonate bzw. tektonische Brekzie am Kontakt zwischen der Margna-Decke und dem Malenco-Serpentinit.
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    • Oficarbonati di Scermendone

      Name Origin

      Valle Scermendone (Italia)

      Rank
      lithostratigraphic unit
      Status
      local name (informal)
      In short
      Ophikarbonate mit Sedimentstrukturen (Gradierung) des Val-Malenco-Ultramafititkörpers.
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    • Gabbro del Monte Braccia

      Name Origin

      Monte Braccia (Valmalenco, Italia)

      Rank
      lithostratigraphic Formation
      Status
      informal term
      In short
      Gabbroide Intrusion im Bereich der Krusten-Mantel-Grenze (d.h. zwischen Margna- und Malenco-Decke).
      Age
      Cisuralian (= Early Permian)
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    • Serpentinite della Val Malenco

      Name Origin

      Alta Val Malenco (Disgrazia, Italia)

      Rank
      lithostratigraphic unit
      Status
      informal term
      In short

      Grüner bis rostrotbraun anwitternder, Chlorit und/oder Brucit führender, magnetitreicher Antigoritschiefer mit wechselndem Gehalt an Diopsid und Olivin. Schwarze, gelängte Erzaggregate, die zur Hauptsache aus Magnetit bestehen, treten häufig vor.

      Age
      Bajocian
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