Thrust

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The Glencoul Thrust Zone in the Irish-Scottish Caledonids . There is Proterozoic gneiss on Cambrian sandstone been postponed. In contrast to the Moine Thrust, which runs a few kilometers to the east, this one still runs within the Laurentian "foreland" of the Caledonids.

A thrust (engl .: thrust fault ) is in the geology a tectonic disorder , wherein the Hangendscholle performs an upward movement. There is little or no lateral offset (Ramsay & Huber, 1988; p. 521). In mining it is also referred to as a change . In contrast to a displacement , the fault surface of a thrust drops by less than 45 °. Möbus (1989) states that the overthrust amount is greater, the smaller the angle of fall. The mechanisms of formation of thrusts and thrusts are similar, but owing to the small angle of inclination, thrusts usually run within a rock body, while several rock packets break through with thrusts. Basically, both upheavals and thrusts are the result of constriction or compression tectonics. Orogenic thrusts and their foreland often bring older rock packets over younger ones. Ramsey & Huber (1988; p. 521) describe thrusts as tectonic nappes if they are offset by 10 km or more, whereby the nappes can be “torn off” from their area of ​​origin (“rootless nappes”).

Schematic representation of the formation of a so-called fault-bend fold with an offset along a partially completely flat, layer-parallel, partially shallow dipping, layer-penetrating thrust path (“ramp-flat path geometry”).

In folds and thrust belts of orrogens , it is not uncommon for step-like thrust geometries to form, which are associated with the formation of so-called fault bend folds (literally "fault bending folds"). The söhlig lying parallel to and extending between two multilayers portions of such a thrust can be flat web , the flat incident portions with vertical offset layer are ramp called.

Examples of thrusts

The thrusts in the Alps that are frequently listed in the literature include the Glarus Thrust and the Tauern Thrust . Thrusts are also common in the Rhenish Slate Mountains , such as the Aachen thrusts, which, along with other geological conditions, are responsible for the formation of the Aachen thermal springs . A prominent Caledonian thrust in Europe is the Moine Thrust in the Scottish Highlands .

literature

  • Dennis, JG; Murawski, H .; Weber, K .: International Tectonic Lexicon, a prodrome. (IUGS) . 1st edition. Schweizerbart, Stuttgart 1979, p. 153 .
  • Eisbacher, Gerhard H .: Introduction to tectonics . 1st edition. Ferdinand Enke Verlag, Stuttgart 1991, ISBN 3-432-99251-3 , pp. 57-69 .
  • Hobbs, BE; Means, WD; Williams, PF: An Outline of Structural Geology . Wiley & sons, New York 1976, pp. 511 .
  • Möbus, Günter: Tectonics . 1st edition. German publishing house for basic industry, Leipzig 1989, ISBN 3-342-00403-7 .
  • Ramsey, John, G. & Huber, Martin, I .: Modern Structural Geology Volume 1: Strain Analysis . 3. Edition. Academic Press Limited, London 1987, ISBN 0-12-576921-0 .
  • Ramsey, John, G. & Huber, Martin, I .: Modern Structural Geology Volume 2: Folds and Fractures . 2nd Edition. Academic Press Limited, London 1988, ISBN 0-12-576922-9 .

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