Nature Of The Provenance And Tectonic Setting Of Oil Shale (Middle Eocene) In The Greater Caucasus Southeastern Plunge

Objective. The protolith and tectonic settings of the Middle Eocene oil shale sampled from the outcrops and ejected products of mud volcanoes in the Greater Caucasus southeastern plunge were determined using bulk rock geochemistry data. The obtained results were adapted to the palaeogeodynamic conditions of the study areas. Method. The concentrations of element content in the samples were measured by "S8 TIGER Series 2 WDXRF" and "Agilent 7700 Series ICP-MS" mass spectrometers. The microscopes "Loupe Zoom Paralux XTL 745" and "MC-10" and a digital camera "OptixCam" were used to define the age of samples. The distribution of element contents of samples was normalized to Post-Archaean Australian shale (PAAS), Upper Continental Crust (UCC) and Continental Crust (CC). The source terrains of the parent rocks and tectonic settings of oil shale were determined using various ratios and diagrams. Results. The samples show a nature of basaltic and basalt andesitic protolith, which supports an idea that the original composition was derived from mafic and intermediate source terrains. The tectonic setting of oil shale correlates well with the active continental margin and the rift-to-collision transition or paleogeodynamic conditions of the initial collision. Thus, in the shallow sea basin and the initial collision conditions, the process of sedimentation in the middle Eocene was probably associated with the final Paleocene-Eocene basin, which was the northern branch of Meso-Tethys in the Crimea-Greater Caucasus-Kopetdag system. The Jurassic and Cretaceous volcanism associated with subductions, which occurred on the southern slope of the Greater Caucasus (in the Tufan and Vandam uplifts), played an important role as a source of transported materials. Scientific novelty. In the published literature, numerous geological and organic-geochemical features of oil shale in Azerbaijan have been studied. The literature on the study of the provenance and tectonic setting is nonexistent, and this study is the first attempt. Practical significance. The obtained results and the used methodology can be applied to study the genesis of the Middle Eocene deposits and as well as sedimentary rocks in Azerbaijan.