strati.ch - Lithostratigraphisches Lexikon der Schweiz

Darstellung und Status

Historische Varianten: Gruf migmatite complex (Gulson 1973), Gruf-Masse (Schmutz 1976), Bodengo-Gruf Unit (Berger & Mercolli 2007), Gruf complex (Galli et al. 2013)

Geographische Verbreitung: Östliches Lepontin [kommt auf den GA25-Blättern 070_Sciora, XXX_Grono und XXX_Val-Bregaglia vor].

Tektonische Einheit (bzw. Überbegriff)

Herkunftstyp

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

p.54: The Gruf Complex is a migmatitic body that directly underlies the Tambo Nappe and the ophiolitic Chiavenna Nappe to the north along a steeply N-dipping fault and follows the base of the Bregaglia Intrusion to the south. This complex consists of granulites, charnockites and migmatites representing polymetamorphic lower crust that was dragged up by the rise of the Bregaglia Intrusion (Galli et al. 2013). This complex is therefore lithologically distinct from other migmatitic Lepontic units, in particular the Adula Nappe. The Gruf Complex is either regarded as a singular lower crustal unit that has nothing in common with all the other units of the Lepontic nappe stack nor any other tectonic domain (Galli et al. 2013), or alternatively, due to its tectonic position below the Tambo and the Chiavenna nappes, is interpreted as the southernmost part of the Adula Nappe that became differentially exhumed during the rise of the Bregaglia Intrusion (Schmid et al. 1996 a, b).