Architecture and Structure of a Fold-and-Thrust Belt During Initial
Inversion of a Salt-Bearing Passive Margin (Jurassic of the Eastern
Alps, Austria)
Abstract
Inversion of the Austroalpine Triassic salt-bearing passive margin,
represented by the Northern Calcareous Alps (Eastern Alps), started in
the Late Jurassic. Subsequent deformation during the Cretaceous and
Cenozoic mostly preserved the Late Jurassic deformation fabric in the
central Northern Calcareous Alps, making it an outstanding location to
understand the early history of inversion of salt-bearing margins.
Thrusting and folding in the central NCA during the Late Jurassic were
strongly conditioned by the distribution of Triassic salt structures,
the thickness of supra-salt stratigraphy, the lateral propagation of
deformation, and the possible influence of sub-salt basement faults.
Syn-orogenic sediments make it possible to reliably reconstruct the
timing of structural inversion. The description of Late Jurassic
structures presented here indicates that initial inversion of the
Northern Calcareous Alps led to the development of coherent deformation
systems that accumulated limited amounts of shortening, totaling few
tens of kilometers. This differs from previous interpretations of Late
Jurassic deformation of the area, that involve major amounts of
allochthony (many tens of kilometers). As a specific example of coherent
structural development, we present here an 80 km long linked system of
thrusts and folds (the Totengebirge–Trattberg contractional system),
whose outstanding continuity has gone previously unrecognized. The
anatomy of this system and its temporal evolution are described in
detail and discussed in the framework of the Jurassic to recent
evolution of the Eastern Alps.