Structural Correlation Between the Northern Calcareous Alps (Austria) and the Transdanubian Central Range (Hungary) and Its Hydrocarbon Potential

Hans-Gert Linzer¹ and Gabor Tari^2
1Rohoel-Aufsuchungs AG, Vienna, Austria
²OMV, Vienna, Austria

In the East Alpine-Pannonian transitional area significant amount of syn-rift extension occurred during the Middle Miocene. In the Rába River extensional corridor a metamorphic core complex-style extensional period was shortly followed by and partly overlapped with a wide rift-style one. Based on the correlation of Eoalpine (Cretaceous) structural markers, about 80 km of ENE-WSW-directed extension can be documented for metamorphic core complex-style extension. The magnitude of later wide-rift-style extension in a NW-SE direction is less constrained, but it is on the order of tens of kilometers (>40 km) based on cross-sectional balancing efforts. These findings have an important corollary for the relative, pre-extensional position of the Northern Calcareous Alps (NCA) and the Transdanubian Central Range (TCR). Taking also into account the displacement on Miocene strike-slip faults in the NCA, e.g. the Salzach-Ennstal-Mariazell-Puchberg fault with a sinistral displacement of about 60 km, the restoration of Neoalpine deformation brings the NCA and the TCR unexpectedly close. In fact, some WNW-trending right-lateral strike-slip faults in the TCR are interpreted to be analogous to those described from the NCA. These Cretaceous tear faults were reactivated during the Late Miocene as it can be documented by reflection seismic data in the subsurface of the Danube Basin. The structural correlation between the NCA and TCR based on the characteristic fault pattern provides evidence for contiguous Triassic to Cretaeous carbonate platform which is in its recent separated position hydrocarbon productive in its eastern part, that is covered by Neogene sediments (Vienna basin, Pannonian Basin). The western NCA mountain chain remains a frontier area for hydrocarbon exploration.

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas