STRATIGRAPHY OF THE MIDDLE MIOCENE SALT DEPOSIT TETIMA NEAR TUZLA (THE CENTRAL PARATETHYS, NORTH BOSNIA).

During 2008. in the deposit of rock salt Tetima four exploratory boreholes: B-72, B-73, B-81 and B- 91 have been done. Sediments of the roof of salt formations have been drilled without coring and salt formation has been drilled with coring. Micropalaeontology sediments samples were taken from the sieve and the core drilling at the distance of 1-5 m. The main goal of the micropaleontologic research was to make biostratigraphic analysis of the salt roof and an attempt to define a new stratigraphic levels. On the basis of foraminifera it was defined the lower Badenian, which is divided into two local foraminiferal zones. The older part of the lower Badenian is presented by Ammonia viennensis and Nonion commune and the younger part of the lower Badenian makes the zone of Globigerinoides trilobus and Orbulina suturalis. These zones correspond to Lagenid zone of the Vienna basin. Within these zones the two new bench mark stratigraphic levels have been separated. The first is the immediate roof of salt formation and has a thickness of about 3 m, and the second level is 60-70 m above the salt formation and has a thickness of about 10 m. The first mark stratigraphic level is characterized by an extremely rare, dominantly planktonic foraminifera and lack of zoning type of Ammonia viennensis (d' ORBIGNY). The Second mark stratigraphic level is indicated by the presence of species Uvigerina macrocarinata PAPP & TURNOVSKY which is in the Central Paratethys related exclusively to the lower Badenian. This species on Tetima is represented in the boundary sediments of isolated foraminiferal zones. In laminated and thinly stratified dolomicrite of immediate substratum of rock salt some very rare foraminifera predominantly planktonic forms Globigerina praebulloides BLOW and Globigerina bulloides d ‘ORBIGNY have been found. Discovery of foraminifera in salt formation has confirmed the hypothesis about lagoon genesis and lower Badenian age of rock salt in Tuzla basin. The immediate roof of salt formation is presented with massive marls thickness of 65-80 m. About 3 m above the salt formation species Ammonia viennensis (d ‘ORBIGNY) emerges with the species Nonion commune (d ‘ORBIGNY) which together have the highest frequency and abundance in massive marls. It is interesting that shells of species Ammonia viennensis (d ‘ORBIGNY) are of orange colour and about three times larger than those in the upper Badenian. Above massive marls there are marls with interbeds of sandstones. These sediments with local foraminiferal zone Globigerinoides trilobus and Orbulina suturalis have a thickness of 220-242 m. Based on nannoplankton it was determined that the zone Ammonia viennensis and Nonion commune corresponds to zone NN5 (Sphenolithus heteromorphus zone by Martini, 1971), while zone Globigerinoides trilobus and Orbulina suturalis corresponds to upper part of zone NN5 and lower part of NN6 zone (Discoaster exilis zone by Martini, 1971). The results of these studies will be applied for the next investigations of salt formation. [ABSTRACT FROM AUTHOR]