Tristel Formation
Stratigraphic range: Late Barremian- Early Aptian ~127–123  Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Tristel Formation near its type locality, looking at Naafkopf from the southwest
Type	Geological formation
Unit of	Rhenodanubic Group, Bündnerschiefer
Thickness	150–250 m (490–820 ft) [1]
Lithology
Primary	Limestone, marl
Other	Shale
Location
Coordinates	47°03′39″N 9°36′25″E / 47.060767°N 9.607067°E / 47.060767; 9.607067
Region	Allgäu, Oberbayern, Tirol, Vorarlberg
Country	Austria   Germany   Liechtenstein   Switzerland
Type section
Named for	Tristel, a mountain next to the Naafkopf
Named by	Schwizer
Year defined	1984

The Tristel Formation is a stratigraphic formation of the northern-central Alps, deposited between the late Barremian and the early Aptian of the Early Cretaceous. It consists of thickly banked limestones, marls and shales. ^[1] It is the lowest formation of the Bündnerschiefer and belongs to the Rhenodanubic Group. ^[2]

Outcrops can be found in the Engadin window, the Tauern window, the Rechnitz window, and many localities of the Penninic realm of the eastern and western Alps. ^[3]

The type locality is the area around the Naafkopf ( 47°03′39″N 9°36′25″E / 47.060767°N 9.607067°E / 47.060767; 9.607067) in the border region of Austria, Liechtenstein and Switzerland. ^[1]

The Tristel Formation can be correlated with the Klus Formation in Graubünden and the Couches de l’Aroley Formation in Savoie ( France) and Valais ( Switzerland). ^{[4] [5]}

References