Biostratigraphy of Sarmation Deposits of Kartli Molassic Subzone Based on Microfauna

The main distribution area of the Sarmatian sediments in Georgia is the Transcaucasian intermountain area. According to the tectonic zoning scheme of Georgia (Gamkrelidze, 2000), Kartli depression, which is the object of study, participates in the structural-facial composition of the eastern subsidence molassic zone of the Transcaucasian intermountain area. The Sarmatian sediments widespread in this area are distinguished in facies diversity and represent a prospective stratigraphic interval of natural hydrocarbons accumulation. Over the past years, quite rich factual material has accumulated on the Sarmatian sediments of the Kartli depression, including paleontological and biostratigraphical. The Sarmatian sediments are well studied makro- and micro-faunally and their detailed stratigraphic division has been accomplished as well (Buleishvili, 1960; Gruzinskaya, 1967; Koiava, 2006). In recent years, during oil exploration special attention is attracted to the identification of paleo-deltas. There was established certain regularity, according to which the largest oil fields are related just to the paleo-deltas. During the oil exploration works micro- paleontological investigations (foraminifers, ostracods) are of special importance. The Sarmatian deposits of the Kartli depression are well studied, in terms of foraminifers (Koiava, 2006). As for the Ostracods, this group is at the initial stage of the study, and studying them in complex with the foraminifera will make a significant contribution to the paleontological/biostratigraphic knowledge of the region and will help petroleum geologists in hydrocarbon exploration. That is why the Sarmatian sediments of Kartli Depression have been selected as the topic for the Master's thesis, and the research method is based on micropaleontology (Foraminifera, Otracoda). The aim of the research is establishment of the foraminifera and ostracod complexes of the Kartli depression Sarmatian sediments and according to them determination of biostratigraphic boundaries, stratigraphic division of the studied sediments, monographic study of the Sarmatian foraminifers and ostracods. For this purpose, in the limits of Kartli depression we have studied three sections of the Sarmatian sediments: 1 - in the Nadarbazevi ravine; 2 - in the environs of the Bebristsikhe (town of Mtskheta); 3 - in the gorge of river Noriostskali. As a result of the study, in the Kartli depression, complexes of foraminifers and ostracods characteristic of the Lower and Middle Sarmatian are distinguished. Their regular variability in time and space was established and due to that stratigraphic division of the studied sediments was carried out. 11 species of 3 foraminifer genera and 9 species of 4 ostracod genera are studied monographically. For the first time in the bounds of Kartli depression, a complex study of the Sarmatian sediments based on two groups of microfauna - foraminifers and ostracods was carried out.