Appendix C - Description of poly phase tectonic regime of Getic Depression

Following a general tectonic scheme, the evolution of the Getic Depression was characterised by Paleogene to Lower Early Miocene extension/transtension followed by large scale Middle to late Miocene contractional to transpressional deformations, the entire system being buried by 1 -2 km of flat-lying Pliocene sediments, slightly deformed in the last, late Pliocene tectonic event (Dicea, 1996; Matenco, Bertotti, Dinu & Cloetingh, 1997; Rabagia & Fulop, 1994).

The Tertiary evolution of the Getic Depression is mainly characterised by major variations in sedimentary and structural patterns. A roughly S-ward thinning clastic wedge is observed, three main sedimentary cycles being defined in connection with the tectonic activity: the Uppermost Cretaceous -Paleogene cycle (characterised by molasses type sediments); the Miocene sedimentary cycle (mainly composed from clastic deposits, the basal coarse sediments being gradually replaced upward by finer sediments) and the Upper Sarmatian – Pliocene cycle (mainly characterised by up to 2,000 m clastic deposits covering the deformed part of the fore deep).

Rabagia and Matenco (1999) defined, after analysing an important number of seismic lines from the area, several deformations which control the development of different lithological and seismic sequences:

  • Pre-Middle Burdigalian deformations, created two major normal fault systems with NE–SW trending and WNE-ESE trending which defined several tilted blocks;
  • Late Burdigalian – Badenian deformations are represented by the reverse faults, which structurally define various uplifted areas along the fore deep. The deformation is mainly characterised by the formation of an imbricated thrust system with WNW – ESE strike;
  • Sarmatian – Early Pliocene deformations are the most important tectonic event in the foredeep characterised by the formations of transpressional strike – slip duplexes and flower structures associated with the frontal thrusting of the fore deep upon the Moesian platform.