Blattengrat-Sandstein

Rappresentazione e statuto

Colore CMYK

(0%,4%,51%,4%)

Colore RGB

R: 245 G: 235 B: 120

Rango

unità litostratigrafia

Uso

Unità in uso.

Status

termine formale valido

Discussione del statuto

Nomenclatura

Deutsch

Blattengrat-Sandstein

Français

Grès du Blattengrat

Italiano

Arenaria del Blattengrat

English

Blattengrat Sandstone

Origine del nome

Blattengrat (GL), nord-östlich von Elm (Sernftal)

Varianti storiche

Blattengratsandstein = priaboner Sandsteinflysch (Bisig 1957), Blattengratsandstein (Wegmann 1961), Südhelvetischer Flysch der Ostschweiz (Typus Blattengrat-Sandstein) (Bayer 1982), Blattengratflysch, Blattengrat-Serie, Blattengrat Sandstone (Menkveld et al. 2016), Blattengrat-Sandstein (Löpfe et al. 2018)

Nota sul nome

siehe auch Herb 1962

Descrizione

Potenza

Max. ein paar Zehnte Meter (Menkveld-Gfeller et al. 2016).

Gerarchia e successione

Unità sottostante

• Stad-Formation

Limite superiore

Tektonisches Kontakt.

Limite inferiore

Stad-Fm. bzw. Muot-da-Rubi-Fm.

Età

Geomorfologia

• Priaboniano

Età alla base

• Priaboniano

Metodo di datazione

Benthonische Grossforaminiferen: Heterostegina helvetica (Bisig 1957) ; Mittel- bis Späteozän (Bayer 1982).

Geografia

Estensione geografica

Ostschweiz (Sernftal, Glarus, St.Galler Oberland).

Regione-tipo

Südliches Glarnerland.

Località-tipo

• Blattengratt (GL), NE Elm
  Caratteristiche del sito
  • typische Fazies
  Agibilità del sito
  • Grat
  Coordinate
  • (2734540 / 1201260)
  Nota
  • Bisig 1957

Sezione-tipo

• Grat zwischen Fanenstock und Fanen (GL), NE Elm
  Caratteristiche del sito
  • typische Fazies
  Agibilità del sito
  • Grat
  Coordinate
  • (2734000 / 1200200)

Paleogeografia e tettonica

• Flysch sud-elvetico

Paleogeografia

Distal NHS (S-Helv.)

Termini generici

• Blattengrat

Tipo di origine

• sedimentaria

Metamorfismo

monociclico-monofase

Referenze

Definizione

Bisig Walter Karl (1957) : Blattengratflysch und Sardonaflysch im Sernftal nördlich der Linie Richetlipass - Elm - Ramintal - Grosse Scheibe Mitt. geol. Inst. ETHZ, Serie C, Nr.74

S.240: Die Globigerinenschichten gehen über in “einen Sandsteinflyschkomplex". Zuerst treten in den obersten Partien der Globigerinenkalke Feinsandschlieren auf, darauf setzt eine Wechsellagerung von Fleckenkalken mit feinkörnigen Glimmersandsteineinlagen ein, die schliesslich rasch übergeht in eine Floge von überwiegend Glimmersandkalkbänken.

Revisione

Menkveld-Gfeller Ursula, Kempf Oliver, Funk Hanspeter (2016) : Lithostratigraphic units of the Helvetic Palaeogene: review, new definition, new classification. Swiss J. Geosc. 109/2, 171-199

p.192: Bisig (1957) first described the Blattengrat Sandstone (Formation; Blattengrat-Sandstein) from its type locality at Blattengrat, northeast of Elm, Sernf valley (at P. 2248: 2734.540/1201.260). For further descriptions see Arn. Heim (1911) and Oberholzer (1933; ‘‘Blattengratschichten’’ pro parte); Leupold (1942); Lihou (1995).

The Blattengrat Sandstone, as true flysch deposit, is part of the so called ‘‘wrapped’’ flysch (‘‘eingewickelter Flysch’’, Arn. Heim 1911) representing the youngest and uppermost sediment succession of the Blattengrat nappe. There is a thin, basal unit of transitional sediments—sandstone beds in marlstone—that can be related to the Muot-da-Rubi Formation. However, since this unit is not mapable at 1:25’000 scale, we consider it as part of the above following Blattengrat Sandstone.

Lithology: The Stad Formation, comprising here a patchy marlstone (‘‘Fleckenmergel’’), terminates with the first occurrence of sand lenses in the marlstone (i.e., representing the Muot-da-Rubi Formation). It is succeeded by mica-sandstone beds, the proper Blattengrat Sandstone, which alternates with thin beds of patchy, more or less siliceous limestone (‘‘Fleckenkalk’’). The Blattengrat Sandstone consists of coarse-grained quartz sand and mica; a Fe-bearing variety of the latter appears reddish on a weathered surface. Black slate fragments and siliceous and calcareous pebbles may additionally be present, as well as fragments of Cretaceous and Palaeogene reworked foraminifera. Priabonian foraminifera (Heterostegina helvetica), known from the Subalpine Flysch zone, can also occur. The thickness is a few tens of meters at most. Overlying strata: tectonic boundary; underlying strata: Stad Formation (‘‘Fleckenmergel’’), Muot-da-Rubi Formation. Biostratigraphy: Priabonian, foraminfera. Current geographical extent: Eastern Switzerland: Sernf valley. Tectonic units: Eastern Switzerland: Blattengrat nappe, Bad-Ragaz nappe.