Based on the results of the studies, an insignificant difference in the geochemical characteristics of oil shales were established within the study area. The amount of OM in the samples taken from the outcrops and pits varies from 13,3 to 32,1 %. Based on the data of gravimetric studies and two-stage pyrolysis, the maturity of OM was assessed and the aliphatic type of OM was established. The Tmax obtained during the cracking process indicates the immaturity of the OM of shale rocks for the generation of hydrocarbons.

The paper presents a study on genesis and organic geochemical characteristics of oil shales, occurred in different tectonic zones of Eastern Azerbaijan. Lithostratigraphic properties of oil shale containing sediments, evolutionary dynamics and structural types of organic matter were studied. In terms of paleogeography, it was defined that the formation of oil shales in examined regions, are associated with an almost identical sedimentation conditions (in shallow freshwater and silty pools-lagoons). The organic matter of the oil shales is mainly consist of phytoplankton (algae) and zooplanktons (fish larvae etc.). Connected with orogenic phases, the formation of oil shale, coal and oil in southeastern slope of the Greater Caucasus links their similar genetic properties. Thermal analysis of oil shale revealed that when organic matter loses the most part of its weight at a higher temperature (≥400 °C) corresponds to aliphatic, but at lower temperatures (≥200 °C) aromatic structures. Pyrolysis of oil shale samples showed that in the initial stage (500-550 °C), excluding the amount of gas, bitumen and pyrolytic water were increased. Increasing the temperature up to 800-850 °C leads to the conversion of higher molecular hydrocarbons into lower, and formation of gases and coke residues. The gradual increase in temperature ends with carbonization of kerogen. An abrupt change in the yielding of bitumen is mainly observed at a temperature of 400 °C. Thermal analysis and pyrolysis of oil shale samples, taken from different studied regions allow making conclusion that some of their kerogens is fully matured.

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The Paleogene-Miocene oil shales studied in the paper were taken from the outcrops and ejecta of mud volcanoes in Shamakhi-Gobustan and Absheron regions. The geological age, mineralogy, and chemical composition of the samples were studied by analytical investigations. Minerals found oil shales were described in detail in the relevant categories. Some appropriate classifications were made in connection with the chemical composition of samples. The indices such as CIA, CIW, PIA, "RR = SiO2/Al2O3" - chemical weathering index, the diagrams like "(Al2O - K2O) – CaO – Na2O", "A-CN-K", and also reflecting mobility characteristics of elements, and estimates on large-ion lithophile elements were used to study the paleoweathering characteristics. Keywords: oil shale; geochemistry; mineral; paleoweathering.