What is a Thrust? What is a Nappe?

Abstract

Summary The definitions of thrusts and nappes are discussed and the criteria used to define these structures are analysed. A ‘thrust fault’ is defined as a map-scale contraction fault. A ‘thrust nappe’ is an allochthonous tectonic sheet which has moved along a thrust fault. Suggested definitions are also given for, a fold nappe; extension fault; contraction fault; listric normal fault; reverse listric fault; klippe; tectonic slide; ramps and flats; duplex structure; blind thrusts.