Open AccessMap view retrodeformation of an arcuate fold‐and‐thrust belt: The Jura case
Author(s) -
Affolter Thomas,
Gratier JeanPierre
Publication year - 2004
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2002jb002270
Subject(s) - molasse , geology , clockwise , fold and thrust belt , paleomagnetism , flattening , fold (higher order function) , geodesy , foreland basin , geomorphology , paleontology , geometry , rotation (mathematics) , structural basin , physics , mechanical engineering , mathematics , astronomy , engineering
The mechanism of arcuate mountain range formation is a matter of debate. Here we perform a map view restoration of a detailed three‐dimensional model of the Jura arc, a typical arcuate mountain range in the foothills of the Swiss and French Alps. This retrodeformation is performed using the UNFOLD surface‐balanced program, based on a “block mosaic” method. It results in a displacement field divergent toward the deformation front. This displacement field suggests counterclockwise rigid rotations in the horizontal plane up to 30° in the southern Internal Jura and a corresponding vertical axis rotation or shear strain of the Savoie molasse basin hinterlandward. We also predict a 10° clockwise, vertical axis rotation of the molasse basin in Switzerland. All these rotations agree with those documented by paleomagnetic data. The former are taken to result from a substantial decrease in shortening at the southern Jura end, while the divergence of displacements is interpreted to result from variations in the detachment level distribution.