350px, Schematic overview of a thrust system. The hanging wall block is (when it has reasonable proportions) called a
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A tectonics, tectonic window, or fenster (lit. "window" in German language, German), is a geology, geologic structure formed by erosion or normal faulting on a thrust fault, thrust system. In such a system the rock mass (
fault (geology), hanging wall block) that has been transported by movement along the thrust is called a
nappe
In geology, a nappe or thrust sheet is a large sheetlike body of rock (geology), 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 z ...
. When erosion or normal faulting produces a hole in the nappe where the underlying autochthonous (i.e. un-transported) rocks
crop out this is called a window.
Klippen are also a feature near windows.
The klippe is the remnant portion of a nappe after erosion has removed connecting portions of the nappe. This process results in an outlier of exotic, often nearly horizontally translated strata overlying autochthonous strata.
Windows can be almost any size, from a couple of
metre
The metre (British spelling) or meter (American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure"), symbol m, is the primary unit of length in the International System of Units (SI), though its pref ...
s to hundreds of
kilometre
The kilometre ( SI symbol: km; or ), spelt kilometer in American English, is a unit of length in the International System of Units (SI), equal to one thousand metres (kilo- being the SI prefix for ). It is now the measurement unit used for ex ...
s. Well known examples of tectonic windows are
Hohe 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 ...
in
Eastern Alps
Eastern Alps is the name given to the eastern half of the Alps, usually defined as the area east of a line from Lake Constance and the Alpine Rhine valley up to the Splügen Pass at the Alpine divide and down the Liro River to Lake Como in the ...
or
Hrzdavá dolina tectonic window in
Western Carpathians
The Western Carpathians are a mountain range and geomorphological province that forms the western part of the Carpathian Mountains.
The mountain belt stretches from the Low Beskids range of the Eastern Carpathians along the border of Poland wi ...
.
[Vojtko, R., Králiková, S., Jeřábek, P., Schuster, P., Danišík, M., Fügenschuh, B., Minár, J., Madarás, J., 2016, Geochronological evidence for the Alpine tectono-thermal evolution of the Veporic Unit (Western Carpathians, Slovakia). Tectonophysics, 666, 48-65, https://doi.org/10.1016/j.tecto.2015.10.014.]
References
Structural geology
German words and phrases
{{Geology-stub
