strati.ch - Lessico lithostratigrafico della Svizzera

Rappresentazione e statuto

Origine del nome: Frühkretazischer («Neokom»), flysch-artiger Mergelkalk mit Bioturbationsflecken.

Varianti storiche: Néocomien des Préalpes (Schardt 1899), Neokom (Trümpy 1916, Cadisch et al. 1919, Häfner 1926, Allemann & Blaser 1951, Gees 1954), Neokomschiefer (Ucik 1966, Thum 1966, Gruber et al. 2010), Neokom = tiefere Unterkreide (Dössegger 1987, Trümpy et al. 1997), Neokomflysch-Serie (Alleman 1957), Untere Kreide = Neokom (Cadisch et al. 1968), Shale Formation = Neokom (Florineth & Froitzheim 1994), "Neokom"-Serie (Gürler 1995 S.26), Fleckenkalk-Flysch, Neokomschiefer (Bertle 2002), Neocom schists (Bertle 2004), Neokom-Flysch (Friebe 2007), Tithon-Neokomflysche

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Geomorfologia

Età alla base

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Termini generici

Tipo di origine

Condizioni di formazione

Postrift Sedimente in «präflysch»-Fazies (Zoophycos).

Revisione: Florineth Duri, Froitzheim Nikolaus (1994) : Transition from continental to oceanic basement in the Tasna nappe (Engadine window, Graubünden, Switzerland): evidence for Early Cretaceous opening of the Valais ocean. Schweiz. min. petrogr. Mitt. 74/3, 437–448

p.441: The Cretaceous sequence of the study area begins with dark gre to olive green shale and siltstone, often strongly bioturbated, in which some limestone layers are intercalated.These rocks, of Early Cretaceous age ("Neokom") according to Kläy (1957) and Cadisch et al. (1968), have not yet been dated biostratigraphically and will therefore be informally referred to as "Shale Formation" in the following. We assume that the Lower Cretaceous age inferred by the above authors is correct, because we observed, particularly clearly on the southern slope of Piz Tasna, a gradational upward transition of the Shale Formation into the Tristel Formation, dated as Late Barremian to Early Aptian (Schwizer 1983). This interpretation is in contrast to Gürler (1982) who postulated a tectonic separation between the Shale Formation and the Tristel Formation. We found no evidence for such a tectonic contact, neither did Schwizer (1983) who studied the Tristel Formation of the Tasna nappe in great detail. Of special interest is the occurence of manganese nodules in the Shale Formation in the vicinity of the underlying Piz Nair serpentinite (Kläy 1957).

Pubblicazioni importanti: Allemann Franz (2002) : Erläuterungen zur geologischen Karte des Fürstentums Liechtenstein 1:25 000. Regierung des Fürstentums Liechtenstein (Vaduz), 129 S.