Structural features of the quarry at the Patkó Cliffs, Bükkzsérc and its surroundings

Abstract

The rock body of the 'Patkó Cliffs' at Bükkzsérc (Bükk Mts, NE Hungary) comprises limestone
containing oolites and redeposited carbonate grains. It is a stratigraphically important occurrence as the
quarry and the Bzs-5 borehole in the quarry together form the type locality of the Bükkzsérc Limestone
Formation with a cca 70 m thick succession, this is the most complete known section of this formation.
The shape of the body on the southern slope of the Hódos Hill is NE-SW elongated while the bedding
generally dips toward the SW with 23° on average, but it is folded on the NW edge. The zigzag style open
folds were formed by slip along the bedding planes and fracturing of the limestone beds. The folding
seems to be connected with ENE-vergent thrusts along the bedding planes and dextral strike-slip faults
dipping towards the NW with 65-70°. Thus the body forms a SW-dipping lens. As the more significant
movements were subparallel with the dip of the bedding or occurred on bedding planes, they had no
important influence on the continuity of the succession: the beds remained traceable in the quarry, in the
borehole and on the SE edge of the rock body. Deformations were mainly brittle. The markers indicate
at least 4 phases as shown their orientations, extensional or shortening character and overprinting
relations. These phases can be correlated with Neogene phases described from the E part of the Bükk
Mts and from the Bükkalja.