Provenance and sedimentary characteristics of paleogene clastics from the Banovina area (Central Croatia)

S ciljem određivanja provenijencije klastičnog materijala (detritusa) koji ih izgrađuje, istraživani su paleogenski klastiti Banovine različitih granulometrijskih značajki (konglomerati, pješčenjaci, šejlovi). Pritom su korištene i različite metode istarživanja; od terenskoga rada, preko petrografske analize i određivanja udjela CaCO3 metodom otapanja, pa sve do analize teških minerala. U pokušaju pobliže odredbe starosti prikupljenih uzoraka, na uzorcima šejlova provedena je i preliminarna mikropaleontološka analiza. Detritus u najvećoj mjeri potječe od trošenja različitih magmatskih i metamorfnih stijena, a samo manjim dijelom i od trošenja starijih sedimentnih stijena; stoga izvorišno područje ovih klastita vjerojatno treba tražiti u stijenama Zapadnovardarskog ofiolitnog kompleksa i Sava zone, a možda i u onima Tisije. Jasno vidljiva razlika u sastavu klastita rubnog predgorskog bazena upućuje i na određene promjene u donosu detritusa, a do kojih vjerojatno dolazi tijekom kasnog paleocena, odnosno na premještanje glavnog izvorišnog područja sa Zapadnovardarskog ofiolitnog kompleksa prema Sava zoni i Tisiji.Aiming at determining provenance of clastic material (detritus) that composes them, research encompassed paleogene clastics of the Banovina area of different granulometric characteristics (conglomerates, sandstones, shales). At the same time different research methods were used; from field work, through petrographical analysis and determination of CaCO3 content (by means o dissolution), to heavy mineral analysis. In an effort of trying to determine the age of gathered samples more closely, preliminary micropaleontological analysis on shales was also carried out. The detritus mostly originates by weathering of different igneous and metamorphic rocks, and only by a small amount by weathering of older sedimentary rocks; therefore the source area of these clastics presumably should be sought in the rocks of the Western Vardar Ophiolitic Unit and the Sava zone, and possibly in those of the Tizsa Mega–Unit. Clearly seen differnce in the composition of these peripheral foreland basin clastics indicates certain changes in the detritus yield, which most probably occurs during late paleocene, that is the relocation of the main source area from the Western Vardar Ophiolitic Unit to the Sava zone and Tizsa Mega–Unit