Abstract: Multiple Thrust Events at the Carpathian Orogen/Foreland Contact in Romania

Mihai O. Stefanescu, Oprea Dicea

The outermost nappes (Outer Moldavids) of the Carpathian Orogen were emplaced during Middle Sarmatian. Their outer contact is cropping out between the northern Romanian boundary and Trotus Valley. Southwards of it the contact is covered by a Late Sarmatian-Pleistocene post over thrusting cover that is common both for the orogen and its foreland. This latter situation is very well expressed on some of the seismic lines recorded across the Orogen/Foreland contact between Trotus Valley and Danube.

On the analyzed seismic lines the following aspects can be distinguished: on the upper part of the sections there is a Late Sarmatian-Pleistocene sequence that is common both to the Carpathian Orogen and to its Foreland and which seals the intra-Sarmatian tectonic contact between them; behind the frontal line of the orogen there are other reverse faults that are obviously younger than the intra-Sarmatian one; generally, the more you advance towards the interior of the orogen the younger the faults are, thus displaying an "against the grain" polarity with respect to the general polarity of the Carpathian Orogen which is from inside to outside; the younger thrust faults are connected to the depth to the older sole over thrust, situation that is very important because it proves that part of Outer Moldavids still remain tectonically active after the Middle Sarmatian nappes emplacement and the sealing of their frontal contact. Some of these younger thrust faults are important enough as they trapped hydrocarbons.

The facts enumerated above lead to a model on the basis of which the genesis of the post-over thrusting faults occurring on the territories of the Inner Moldavids and Outer Dacids can be explained.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France