A Vasasi Márga földtani, őslénytani és üledékföldtani jellegei a Zsibrik és Ofalu közötti területen

In the north-western segment of the research area chosen as the field for radioactive waste disposalin the Lower Jurassic Vasas Mari Formation, there also occur on the surface as smaller outcrops inconnection with the mass of the Moragy Granite Formation and the Ofalu Phyllite Formation. These liein a narrow beit between the villages Ofalu and Zsibrik. To the north-west of the Jurassic surfaceoutcrops underneath the Quaternary and Neogene sediments in a few boreholes (prospected for coal)penetrated not only the Vasas Mari but also its underlying formations as follows: Mecsek Coal Formationand Karolinavolgy Formation and some non-identifiable Upper Triassic carbonates. Thanks to themapping activity and the control of borehole successions new phenomena have been discovered such asdolomite fragment- and dolomite pebble-bearing beds containing also fragments of colonial corals andalso variegated young clays pressed into the tectonic zone bordering the Vasas Mari to the south-east.The issues that need to be solved during the activity mentioned above were answered by carrying outpalaeontological, mineralogical-petrological and sedimentological studies.The main conclusions are as follows:- angular fragments and pebbles of dolomite derive from an elevated area located to the south, southeast from the depocenter;- the highly weathered status of the dolomite is an indication of a secondary (Late Triassic)depositional environment from where the pebbles have been gravitationally transported (redeposited)to the recent place. Owing to the collision of the weathered pebbles, during the redeposition they wereoften broken into pieces and became angular again;- taking into consideration of the highly weathered condition of the dolomite pebbles it can be statedthat the distance the sediment was transported from the south to the north could not have exceeded 1or 2 km;- among extraformational pebbles there are only a few grains of quartz of metamorphite origin andthis may indicate a metamorphic source area in a more southerly position behind the Triassic platformduring the early Early Jurassic time;- only fragments of colonial corals and certain bivalves can be taken into account as intraformationalfossils; corals must have been living in a transparent, shallow water, coastal area where siliciclasts weresubordinate;- on the bases of the lithologic composition of the rock fragments it is suggeted that the Zsibrik studyarea is bordered by a dextral strike-slip fault (Ofalu Line) along which the Zsibrik Block was transportedat least 20 km in a north-east direction after the Early Jurassic (probably Neogene) (However a sinistralstrike-slip motionmight have taken place, given the evidence from recently acquired knowledge.