Geologische Karte des Engadiner Fensters

The Engadin window or (Lower Engadin window) is a tectonic window that exposes

penninic The Penninic nappes or the Penninicum, commonly abbreviated as Penninic, are one of three nappe stacks and geological zones in which the Alps can be divided. In the western Alps the Penninic nappes are more obviously present than in the eastern ...

units lying below the

austroalpine The Austroalpine nappes are a geological nappe stack in the European Alps. The Alps contain three such stacks, of which the Austroalpine nappes are structurally on top of the other two (meaning they were thrust over the other two). The name Aus ...

units in the

alpine Alpine may refer to any mountainous region. It may also refer to: Places Europe * Alps, a European mountain range ** Alpine states, which overlap with the European range Australia * Alpine, New South Wales, a Northern Village * Alpine National P ...

nappe stack In geology, a nappe or thrust sheet is a large sheetlike body of rock that has been moved more than or above a thrust fault from its original position. Nappes form in compressional tectonic settings like continental collision zones or on the o ...

. It has a roughly elliptical shape with the long axis striking northwest-southeast and dimensions of 55 x 17 km. From a geographic perspective the window stretches from

Zernez Zernez is a village and a municipality in the Engiadina Bassa/Val Müstair Region in the Swiss canton of Graubünden. On 1 January 2015 the former municipalities of Lavin and Susch merged into the municipality of Zernez. Zernez is a major node ...

( Graubünden, Switzerland) to

Landeck Landeck () is a city in the Austrian state of Tyrol, the capital of the district of Landeck. Geography Landeck is located in the Tyrolean Oberland in the west of the state at an elevation of about . The town is situated in the valley of the Inn ...

(

Tirol Tyrol (; historically the Tyrole; de-AT, Tirol ; it, Tirolo) is a historical region in the Alps - in Northern Italy and western Austria. The area was historically the core of the County of Tyrol, part of the Holy Roman Empire, Austrian Emp ...

Austria Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...

), or the

Lower Engadin The Engadin or Engadine ( rm, ;This is the name in the two Romansh idioms that are spoken in the Engadin, Vallader and Puter, as well as in Sursilvan and Rumantsch Grischun. In Surmiran, the name is ''Nagiadegna'', and in Sutsilvan, it is ...

Overview

The rocks cropping out in the Engadin window are weakly metamorphosed sediments of middle

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...

age. Most of them are interpreted as deposits from

turbidite A turbidite is the geologic deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean. Sequencing Turbidites w ...

s. They are seen as part of the

units similar to the rocks that make up large portions of the Switzerland. Furthermore, the sediments are attributed to the

Valais ocean The Valais Ocean is a subducted oceanic basin which was situated between the continent Europe and the microcontinent Iberia or so called Briançonnais microcontinent. Remnants of the Valais ocean are found in the western Alps and in tectonic win ...

, the Briançonnais microcontinent, and the

Piemont-Liguria Ocean The Piemont-Liguria basin or the Piemont-Liguria Ocean (sometimes only one of the two names is used, for example: Piemonte Ocean) was a former piece of oceanic crust that is seen as part of the Tethys Ocean. Together with some other oceanic basi ...

. The metamorphic overprint was caused by the closure of the Valais and the Piemont-Liguria during the

Paleogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago (Mya) to the beginning of ...

part of the Alpine orogeny. The rocks experienced low-temperature-high-pressure overprint which reached the

blueschist facies Blueschist (), also called glaucophane schist, is a metavolcanic rock that forms by the metamorphism of basalt and rocks with similar composition at high pressures and low temperatures (), approximately corresponding to a depth of . The blue c ...

. On geologic maps the Engadine window has an onion shell appearance. From outside to inside, or from highest to lowest in the nappe stack, the following units are distinguished: * Fimber zone (including Arosa zone) * Tasna zone * Champatsch zone * Pfundser zone

Other tectonic windows

The Engadin window is not the only place where

units are exposed within the

. The

Tauern window The Hohe Tauern window is a geological structure in the Austrian Central Eastern Alps. It is a window (in German ''fenster'') in the Austroalpine nappes where high-grade metamorphic rocks of the underlying Penninic nappes crop out. The struct ...

is the largest one and lies east of the Engadin window. The Gargellen window in

Vorarlberg Vorarlberg ( , ; gsw, label= Vorarlbergisch, Vorarlbearg, , or ) is the westernmost state () of Austria. It has the second-smallest geographical area after Vienna and, although it also has the second-smallest population, it is the state with the ...

is the smallest one. The Rechnitzer window is the easternmost tectonic window.

References

{{coord, 46, 58, 15, N, 10, 23, 15, E, region:CH-GR_type:landmark_source:kolossus-dewiki, display=title Geology of the Alps Geology of Austria Geology of Switzerland