Aliyeva E.H.¹, Mustafayev K.F.²

¹ Ministry of Science and Education of the Republic of Azerbaijan, Azerbaijan Institute of Geology and Geophysics, 119, H. Javid Ave., Baku, AZ1073: e_aliyeva@yahoo.com

² "AZLAB"LLC, Azerbaijan 4B, Yaver Aliyev str., Sabunchu distr. Bakikhanov settl. Baku, AZ1040: kamal@azlab.az

DOI: 10.35714/ggistrat20250100013

Summary. To study the sediment sources of Miocene reservoir rocks, samples were collected from the Upper Maykop (Lower Miocene), Chokrak (Middle Miocene), and Diatom (Middle and Upper Miocene) oil-bearing formations recorded in different tectonic zones of Gobustan. Based on the results of mineralogical and geochemical analyses of the Cheildere, Gyrgyslag, and Gyurdag sections – covering various stratigraphic intervals – a comparative mineralogical and geochemical characterization of the Maykop, Chokrak, and Diatom sediments was obtained. The geochemical ranking results and the constructed diagrams of the tectonic discriminant function led to conclusions about the protoliths, mineralogical maturity, tectonic environment of sedimentation, and other characteristics of the Miocene deposits.

The Chokrak rocks attract more attention regarding the total thickness (up to 40 meters) of oil-bearing layers in Miocene surface exposures studied in the Cheildag, Gyrgyslag, and Gyurdag structures. The highest content of quartz is characteristic of the Chokrak deposits (>70%). Oil-bearing rocks of this age contain fewer clay minerals and, as a rule, do not contain carbonate minerals. For the Upper Maykop sediments, calcite is typical, while for Diatom rocks, dolomite predominates. The highest quantities of clay minerals are observed in samples of Diatom age (average value equals 19.75%).

The tectonic setting of the accumulation of Miocene-Maykop rocks can be characterized as passive tectonic margin.

Keywords: Miocene, sedimentation, mineralogy, geochemistry, drift source and oil bearing capacity

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