Ortler-Decke
Back to Ortler NappeRepresentation and status
- Color CMYK
- N/A
- Color RGB
- R: 241 G: 239 B: 237
- Rank
- nappe
- Validity
- Unit is in Use
- Status
- valid
Nomenclature
- Deutsch
- Ortler-Decke
- Français
- Nappe de l'Ortler
- Italiano
- Falda dell'Ortler
- English
- Ortler Nappe
- Origin of the Name
- Historical Variants
-
Ortlerdecke (Roesli 1927, Staub 1934), Ortler-Einheit (Dössegger 1987), Ortler Zone = Ortler-Sedimente (Spillmann 1993), Ortler Nappe (TK500 / Gouffon et al. 2024)
Description
- Description
-
Substituierte oberostalpine Sedimentbedeckung, die entlang der Zebrù-Linie auf dem Campo-Kristallin überschoben wurde.
Couverture sédimentaire (de substitution) du socle cristallin du Campo.
Furrer et al. 1985: "Permian to Turonian (especially Triassic to Lower Jurassic) sediments affected by internal thrusts and flat-lying normal faults (lags). The Ortler sediments are often considered as cover of the Campo crystallines; however, the contact between the two is usually tectonic ("substitution de couverture")."
Hierarchy and sequence
- Upper boundary
-
Quattervals-Decke (via Trupchun-Braulio-Linie)
- Lower boundary
-
Campo-Decke (via Zebrù-Linie)
Age
- Age at top
-
- Turonian
- Age at base
-
- Permian
Geography
- Geographical extent
- Engadiner Dolomiten (SE der Engadin-Störung).
References
- Definition
-
(2024) :
Tectonic Map of Switzerland 1:500000, Explanatory notes. Federal Office of Topography swisstopo, Wabern
p.96: The Ortler Nappe overthrusts the Campo Nappe along the WNW– ESE striking Zebrù Thrust, which curves eastward to a NNW– SSE orientation. This thrust formed during an early stage of Late Cretaceous WNW- directed thrusting (Conti et al. 1994). Over most of its strike, the Zebrù Thrust follows the incompetent sediments of the Raibl Group, which serve as the dominant basal decollement horizon for the Mesozoic sequence of the Ortler Nappe dominated by massive Late Triassic sediments. The youngest sediments are of Turonian age (Caron et al. 1982), thus providing an important constraint regarding the timing of Cretaceous orogeny in eastern Switzerland. Only small occurrences of basement and pre-Carnian sediments are preserved locally, where the decollement horizon in the Carnian sediments encountered a syn-rift normal fault of Jurassic age (Conti et al. 1994). According to a paleogeographic reconstruction by Conti (1997), the former basement of the predominantly Mesozoic sequence of the Ortler Nappe most probably occurred east of the present Campo Nappe Complex outcrops and west of the future Ötztal Nappe Complex that nowadays occupies a higher structural position. The transport distance during top-WNW thrusting amounts to well over 100 km.
The hangingwall of the Ortler Nappe is defined by the Trupchun-Braulio Thrust that formed during a later stage of the Cretaceous orogeny. This thrust juxtaposes 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).