Abstract: Folded Kiscellian turbidites - the evidence of dextral wrenching within ENE-WSW striking shear zone (Hrabnik, Male Karpaty Mts., Western Carpathians)
MARKO, FRANTISEK and MICHAL KOVAC*
Hrabnik formation (H. fm.) built up by sandstones intercalated with claystones was described in the Bukova furrow (B. fw.) in Male Karpaty Mts. The age of tectonicaly deformed H. fm. was determined as Uppermost Oligocene - Kiscellian (NP 22). The Paleogene shelf deposits of the Bukova furrow were regarded as unfolded post-orogenic basin fill Paleocene-Middle Eocene in age. Due to this concept neither so young, nor so deformed sediments as H. fm. represents had been expected there. That means H. fm. has anomalous character in respect to its age, facies and tectonics. There is a large time gap between the deposition of Middle Eocene sediments of B. fm. and H. fm. sediments. H. fm. is in contrast with unfolded Eocene sediments strongly folded. Folds are asymmetric and heterogeneous from the point of their scale, morphology, and distribution. Nevertheless, folds were described as tectonic ones. Strong argument supporting tectonic origin of folding is clear--preferred orientation of fold axes striking NNE-SSW (NE-SW), also evidences of flexural slip folding mechanism. Presence of folded H. fm. in B. fm. has great consequences for regional model of tectonic evolution. As we believe, these folds are wrench (en-echelon) ones produced during the Upper Paleogene-Lower Miocene dextral transpressional regime within ENE-WSW striking strike-slip zone. Strange character of H. fm. could be also explained by its allochthonous position as exotic tectonic slice incorporated to the shear zone.
AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria