Arcuate Thrust Systems in Sandbox Experiments:
A Comparison to the External Arcs of the
Ford, Mary1,
Henry
Lickorish2, Judith Buergisser3, Peter R. Cobbold4
(1) Nancy School of Geology, ENSG-CRPG, Nancy, France (2) Rock
Deformation Research, Calgery, Alberta (3) Dr. Henrich Jaeckli AG, Baden,
Switzerland (4) Rennes University, Rennes, France
In the external western
Sandbox
experiments investigate the role of the motion vector of a rigid rectangular indentor (orthogonal, diagonal, curved or rotational paths)
and the mechanical stratigraphy of the foreland in
the evolution of upper crustal arcuate
systems (e.g. presence of a basal easy-slip (silicone) horizon). Comparison of
experimental results with the external alpine arc suggest that the alpine indentor followed a slightly diagonal path with respect to
the European margin from the Eocene to the early Miocene and curved
anticlockwise by 10-15° in the mid-Miocene. Mechanical stratigraphy
experiments support the hypothesis that thick Triassic evaporites
played a primary role in the evolution of the Jura
arc. The influence of mechanical stratigraphy was
most prominent during weak deformation at the external boundaries of the Alpine
orogen (Jura fold belt, Digne Thrust).