nappe

(redirected from nappes)
Also found in: Dictionary.

nappe

[nap]
(geology)
A sheetlike, allochthonous rock unit that is formed by thrust faulting or recumbent folding or both.
(mathematics)
One of the two parts of a conical surface defined by the vertex.
References in periodicals archive ?
This definition is generally accepted, even when it encounters some problems, mainly Kvetnice and Zavist nappes in the Svratka Dome, which close the same Devonian sediments as parautochtonous scales of Brunnia, but completely differing from the upper complex of "outer and inner phyllites" (Jiricek, 1991).
Jiricek (1991) considers keeping the existing range of Moravosilesian according to Suess (1912), but with the annex, that it represents the zone of detached folded nappes from the western side of Brunnia.
Other authors move this border even under the Kvetnice and Zavist nappes of Tisnov Brunnian and other ones describe Moravicum unit as an arch with its granite bedrock.
Higher nappes of Moravicum--include a metamorphosed complex of "the inner and outer phyllites", detached by the Bites gneiss (Batik, 1984).
It is shifted by Bites nappe from superincumbent bed and is overriding on the lower Moravian nappes of the Brunnian in the Svratka Dome or lies directly on crystalline cover of the Brunnia in the Dyje Dome.
Lower nappes of Moravicum--including the Devonian sediments and the basement crystalline complex, ruptured from the western Brunnia ridge into the Kvetnice and Zavist nappe.
However, in case of the Silesian nappe the covering partial nappes with different trajectory of movement became detached due to different rheologies of the body of the Godula nappe and the underlying and overlying units.
The mechanism of gravitational spreading may in specific instances generate gravitational nappes (Merle 1998) but, for the most part, it is effective on continental slopes of the present-day oceans.
1998, Emplacement Mechanisms of Nappes and Thrust Sheets, Kluwer Academic Publishers, Dordrecht, 1-159.
The Godula partial nappe is represented mainly by lithostratigraphic units of Upper Cretaceous age--the Godula and Istebna Formations.
This is caused by the fact that, due to the accumulation of light masses of Lower Miocene rocks of the Carpathian Foredeep in footwall of the Godula nappe and frontal parts of the Magura nappe, mountain peaks arrived to higher altitudes than one would expect from simple overthrusting of the Silesian and Subsilesian units over the underlying foreland (see cross-section in Fig.
Since sediments younger than the Istebna Formation are absent in the peak parts of mount Knehyne and mount Lysa hora, we believe this estimate to be correct, although tectonic erosion during the material displacement within duplex nappe slices might also have been partly involved (it can be assumed that this area has been partially overlapped by the frontal part of the Magura nappe.