Oberostalpin

Representation and status

Index

OOA / CAA

Color CMYK

N/A

Color RGB

R: 241 G: 239 B: 237

Rank

tectonic domain

Validity

Unit is in Use

Status

valid

Nomenclature

Deutsch

Oberostalpin

Français

Austroalpin supérieur

Italiano

Austroalpino superiore

English

Upper Austroalpine

Historical Variants

Oberostalpin = Tiroliden (Staub 1934), falde Austridi Superiori (Godenzi 1963), Zentralostalpine Decken (Trümpy 1974), Central Austroalpine = CAA (Furrer et al. 1985), Oberostalpin = OOA (Frank 1986), Zentralostalpin = ZOA (Naef 1987), Austroalpino superiore (Montrasio et al. 2012), Upper East Alpine, Upper Austroalpine (TK500 / Gouffon et al. 2024)

Description

Description

Höchste Einheit des ostalpinen Deckenbaus, die durch einer mächtigen triassischen Plattformsedimentation charakterisiert ist. Paläogeographisch betrachtet stellt das Oberostalpin den südlichen, proximalen adriatischen passiven Kontinentalrand dar.

Das Oberostalpin besteht aus heutzutage zentralalpin gelegenen variszisch metamorphen Grundgebirgseinheiten einerseits und den von ihrem Grundgebirge losgelösten und in Decken gestapelten mesozoischen Sedimenten der Nördlichen Kalkalpen andererseits (Ibele & Behrmann 2007). Kristallin- (Languard, Campo, Silvretta) und Sedimentdecken (Ela-Ortler, Engadiner Dolomiten).

Hierarchy and sequence

Subordinate units

• Nördliche Kalkalpen

Geography

Geographical extent

Zentralalpen, Nördliche Kalkalpen.

Palaenography and tectonic

Tectonic unit (resp. main category)

• Upper Austroalpine

Kind of protolith

• tectonic

References

Definition

Gouffon Yves (Editor) (2024) : Tectonic Map of Switzerland 1:500000, Explanatory notes. Federal Office of Topography swisstopo, Wabern

p.90: The Upper Austroalpine tectonically overlies the Lower Austroalpine. At the same time, it embraces those units originating from the Adriatic continental plate (Handy et al. 2010) that are interpreted to originally have been relatively more proximal in respect to the distal continental margin units preserved in the Lower Austroalpine. The Upper Austroalpine units underwent less deformation during the opening of the Piemonte-Liguria Ocean and generally appear less intensely deformed during the Alpine orogeny. Many of them are basement-cover nappes, except for the small Roggenstock-Mördergruebi Nappe, the nappes of the Northern Calcareous Alps (§ 8.2.2) and the Quattervals Nappe, which are made up entirely of sedimentary rocks.
The term “Middle Austroalpine” used by Tollm ann (1977), embracing many of these units, was abandoned by more recent studies and is not used here. In Austria, tectonic units are generally grouped into nappe systems; this is not the case in this map. This effects the following nappes: 1) The Silvretta-Seckau Nappe System comprises the Languard, S-charl - Sesvenna and Silvretta nappes as well as the Campo Nappe Complex, 2) the tectonically higher Ötztal-Bundschuh Nappe System is represented only by the Ötztal Nappe Complex, 3) although the Tonale Nappe lacks a Mesozoic cover, it is attributed to the still higher Drauzug-Gurktal Nappe System which is not affected by the Alpine metamorphic overprint (Schmid et al. 2004). Note that the Silvretta Nappe, the S-charl - Sesvenna Nappe and the Campo Nappe Complex, all being part of the Silvretta-Seckau Nappe System, essentially occupy the same position within the Upper Austroalpine nappe stack (Froitzheim et al. 1994). Other units, consisting predominantly of cover sequences detached from the S-charl - Sesvenna Nappe and the Campo Nappe Complex (Ortler and Quattervals nappes, Umbrail-Terza Slice Complex), are transported towards the WNW, below the advancing Ötztal Nappe Complex (Froitzheim et al. 1994, Conti 1997, Trümpy et al. 1997).