Upper Cretaceous of the Čerevićki Potok, Fruška Gora Mt., Serbia: state of art

The paper is dealing with three interpretations of well known section Čerevićki Potok (Fruška Gora Mt., Serbia): 1. According to KOCH, in: PETHÖ (1906), undisturbed succession of 23 lithologically different members, „Hipersenonian“; 2. According to PAŠIĆ (1974; unpublished text is used in monography of PETKOVIĆ et al. 1976), tectonically disturbed lithologically different Maastrichtian blocks; and 3. According to ČIČULIĆ-TRIFUNOVIĆ & RAKIĆ (1977), tectonically disturbed stratigraphic column, the Srem-Slavonian type of the Upper Cretaceous sediments, south of Srem dislocation, Maastrichtian.

In the fifties, studies of the Čerevićki Potok were recognized eight lithologically different blocks besides serpentinites and destroyed serpentinites (1-3, 5-9).Blocks 5 and 8 are not presented in Koch-Pethö's section.Some blocks are recurring: Coarse basal breccia and conglomerates thick 40 m and more (block 1), in tectonic contact with serpentinite, appear in few tectonically separated parts.These composed of very coarse basal crystalline schists, serpentinites and quartz gravels in carbonate-ferruginous cement, which pass upward into fine-grained conglomerates with sandstone intercalations.
RADOŠEVIĆ & MARKOVIĆ (1967) believed that the whole flysch series to be Upper Maastrichtian, and flysch sedimentation normally continued over fossiliferous sediments.They described three clearly different sedimentological parts (with Inoceramus in lower part).We would emphasize their opinion that the "upper part of the flysch, which really looks younger, resembles with the Ostružnica flysch in the Belgrade environment".The stratigraphic column, described and given on the geological map starts with the trasnsgressive deposits of shallow-water coastal facies which consist of breccias, conglomerates, sandstones, brecciated limestones, reefal and massive limestones and sandy reefal limestone.Upward, prevailing are claystone, siltstone and fine-grained clayey sandstone which gradually pass into marlstones and marly limestones that close the Upper Cretaceous lithostratigraphic column of this formational zone.The latter, distributed in western area in Debeli Cer, Čitluk Potok and Srednje Brdo are not mentioned in the Čerevićki Potok by PETHÖ.Although paleontological evidence was not discovered in sediment of PAŠIĆ'S block 5, they being litho-logically similar, were compared to sediments of the mentioned localities (PETKOVIĆ et al. 1976).
Authors considered that fauna of shallow-water sediments, without exception, and basinal marly limestones of Čitluk Potok and Srednje Brdo are Maastrichtian.DANILOVA (1960) described an association of planktonic foraminifers from Čitluk Potok with species prevailing the Maastrichtian.DANILOVA (acc. to mem. of R. RADOIČIĆ) corrected this stratigraphic conclusion in some of the internal reports and limestones of Čitluk Potok asigned to the Campanian. In

Comment
Sediments in some Čerevićki Potok blocks contain an abundance of mixed fauna not only of different fossil groups, but also different environments (including brackish and paralian, according PAŠIĆ 1951), of different preservation and different ages.Some specimens from the same block are very well preserved and undamaged (well preserved sculptures of gastropods, sculptures and hinge apparatus of bivalvia).Many specimens collected undamaged were washed away from soft sediments of stream slopes.Well preserved numerous rudists and other molluscs will be good material for Sr-isotope measurement.Sr-isotope stratigraphy has recently been used in the revision of stratigraphic range for some rudist species previously considered Maastrichtian.
The sediments older than Upper Senonian have not documented so far; the youngest known are Maastrichtian limestones with orbitoids, siderolites, loftusias and Pironea.An open question is whether sediments of the some blocks without paleontological evidence are younger than Cretaceous.
It should be mentioned that in the part of Fruška Gora flysch Oligocene sediments are documented on the base of nannofossils (CP19=NP25 biozone, DE CAPOA et al. 2002), what implies that the main tectonic events are not older than Chatian.
The observation of RADOŠEVIĆ & MARKOVIĆ (1967) on the similarity of the upper part of Fruška Gora and Ostružnica flysch is confirmed by the finding also Oligocene nannofоssils (CP19=NP25, DE CAPOA et al. 2002) in sediments of a part of Ostružnica Maastrichtian flysch.
Upper Cretaceous beds of the Čerevićki Potok were deposited in different shallow-water (and bathyal?) and different sedimentary environments.Some blocks of "pre-flysch Upper Cretaceous", i.e. "Srem-Slavonia structural-facial zone"of Fruška Gora indicate on a multiple preceding tectonic activity.Based on available data, Srednje Brdo block was also deformed by late Campanian tectonic events.

Fauna
described by PAŠIĆ (1951) is preserved partially in the Paleontological collection of the Faculty of Mining and Geology, Belgrade.Two structural-facial zones of the Upper Cretaceous on the Fruška Gora are identified: Bačka-Banat flysch development, north of Srem dislocation, and southern, Srem-Slavonia development, between Srem and Fruška Gora dislocations ("Čerević Upper Cretaceous s.l."; Fig. 3).The Cretaceous of the Srem-Slavonia zone is partially outcropping around 20 km east-west.Transgressive position of Upper Cretaceous deposits over Jurassic schists is visible only in the middle of the zone, in the Ugljarski and Čitluk Potok vallies.The authors mentioned the difficulty of giving the stratigraphic column for the Srem-Slavonia development due to tectonic disturbance in the section Čerevićki Potok.
the Srednje Brdo quarry very tectonically disturbed basinal sediments with planktonics are outcropped (see in: PETKOVIĆ et al. 1976).Marly reddisch limestones from a part of the quarry are Lower Campanian -Globotruncanita elevata zone (DE CAPOA et al.