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Critical taper behaviour and out‐of‐sequence thrusting on orogenic wedges – an example of the Eastern Alpine Molasse Basin
Author(s) -
Schuller Volker,
Frisch Wolfgang,
Herzog Ulrich
Publication year - 2015
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/ter.12152
Subject(s) - molasse , geology , foreland basin , wedge (geometry) , structural basin , thrust , sequence (biology) , chronosequence , paleontology , geomorphology , seismology , geometry , physics , mathematics , genetics , biology , soil water , soil science , thermodynamics
We demonstrate that increasing erosion during the kinematic evolution of a thrust wedge will lead to out‐of‐sequence thrusting as a result of backwards critical taper movement. In‐sequence thrusting in the Subalpine German Molasse Basin built a critical‐tapered foreland Coulomb thrust wedge. Later, out‐of‐sequence thrusts dissected all but the frontal duplex stacks. The footwall/hangingwall relation visible on seismic data proves the out‐of‐sequence nature of the latest thrusting stage. Establishing a stable drainage system leads to increased erosion in elevated areas of the thrust wedge, resulting in flattening of the critical wedge. In order to keep its predefined angle, the critical wedge repositions and the tip of the taper moves towards the hinterland. Thus, thrusting will also reposition and move towards the hinterland.