Geologija Kozjanskega

Abstract

The Kozjansko region covers the eastern part of Sava Folds between
Rudnica. Orlica, and Bohor mountains. The geologie mapping made in the
years 1957 til l 1963 have vielded a rather different pieture than showed
Dreger' s geologie map Rogatec — Kozje 1 : 75000. The Carboniferous and
Permian clay slates and quartz sandstones have a larger extension than tliis
has been known until now. The Permian Groden strata have now for the
first time been indicated in the geologie map. It is supposed that the Upper
Permian dolomite enriched with galena and sphalerite occurs in the eastern
Sava Folds.
The Mesozoic is represented by Triassic dolomite, limestone, clay slate
and calcarenite. Igneous roeks like diabases, tuffs, and tuffites have been
foiind in the Wengen strata of the Bohor and Orlica mountains.
Fossil remains of Daonella found in limestone and tuffites from the
eastern part of the Bohor mountain suggest the Ladinian age of the eruption.
While on the one hand ali Triassic sediments are preserved. on the other
hand the Jurassic and Lower Cretaceous strata are missing. The Flysch is
attributed to the Upper Cretaceous. Orbitolinae, Miliolidae, and Valvulinidae
have been established in breccias. The Tertiarv begins \vith the Oligocene conglomerate or marl and sand
In some localities the Oligocene strata are coal bearing.
In the periode from Oligocene to Tortonian this area was dry land,
and a considerable part of the Oligocene strata vas eroded. The Tortonian
consists of the Lithothamnian limestone and marl. The Lower and Middle
Tortonian sediments were determined through their marine microfauna.
The Sarmatian sho\vs brackish development. It consists of sand. marl,
clay, and conglomerate. North of the Bohor mountain the Sarmatian begins
almost always with a conglomerate, which proves at the same time the unconformity between the Tortonian and Sarmatian strata. The Sarmatian sediments are overlain by the Pannonian marl and sand containing Ostracoda.
The older geologic structure is obliterated by the younger one. The
folded Pannonian beds prove that the inain folding processes in PostPannonian age took plače. During the older Tertiary, hovvever, the epirogenetic movements were prevalent.
For the development of Tertiary depressions the main faults trending
east — west were important. Nevertheless, thev were also active after the
deposition of the Tortonian sediments. We are led to this conclusion because
the Lithothamnian limestone can be found high on the ridges of the Bohor
and Orlica mountains, but also low in the synclines in immediate neighbourhood.