The Northern Calcareous Alps consists of a nappe stack made up exclusively of sedimentary rocks, ranging from the Permian to the Late Cretaceous, occupying the entire northern part of the Austroalpine. These nappes were detached from their crystalline basement during the Late Cretaceous, as inferred from synorogenic Cretaceous deposits. They were affected by top-NW thrusting in the Cretaceous, followed by top-N thrusting in the Cenozoic. This led to a complicated internal structure.

The S-charl-Sesvenna Nappe (including the Tavrü Slice) in the southeastern compartment of the Engadine Fault occupies the same tectonic position as the Silvretta Nappe in the northwestern compartment of this fault.

The basement of the S-charl-Sesvenna Nappe is commonly referred to as the Sesvenna basement and its cover as “S-charl-Unterbau” (a series of NE–SW trending series of synclines and anticlines that affect both basement and cover without major detachments within the sedimentary sequence) and “S-charl-Oberbau” (nowadays referred to as Tavrü Slice, consisting entirely of a Norian to Cretaceous succession, volumetrically dominated by an over 2 km thick Hauptdolomit and completely detached from the Carnian Raibl Group).

Steilstehende tektonische Grenzfläche zwischen S-charl-Decke und Umbrail-Chavalatsch-Schuppen bzw. Quattervals-Decke.

The Quattervals Nappe consists of a series of NNE-dipping slices that overthrust the Ortler Nappe along the western part of the Trupchun-Braulio Thrust. It comprises almost exclusively Late Triassic sediments, mostly dolomitic and calcareous formations of the Norian Hauptdolomit Group of considerable thickness overlain by Rhaetian deposits, which became detached from their former substratum along the Carnian Raibl Group during the Cretaceous orogeny.

The Trupchun-Braulio Thrust formed during a later stage of the Cretaceous orogeny. It juxtaposed the Quattervals Nappe (in the west) and the Umbrail-Terza Slice Complex (in the east) over the Ortler Nappe. The thrust is marked by calcite mylonites derived from the footwall and exhibits numerous top-WNW sense-of-shear indicators (Conti 1997).

The Upper Austroalpine Ortler Nappe overthrusts the Campo Nappe along the WNW–ESE striking Zebrù Thrust, which follows the incompetent sediments of the Raibl Group over most of its strike as the dominant basal décollement horizon. Only small occurrences of basement and pre-Carnian sediments are preserved locally, the main Mesozoic sequence being dominated by massive Late Triassic sediments. The hangingwall of the Ortler Nappe is defined by the Trupchun-Braulio Thrust that formed during a later stage of the Cretaceous orogeny and juxtaposed the Quattervals Nappe (in the west) and the Umbrail-Terza Slice Complex (in the east) over the Ortler Nappe.