APPLICATION OF CHEMOSTRATIGRAPHY AND RE-OS GEOCHRONOLOGY TO THE MAIKOP SERIES OF EASTERN AZERBAIJAN: CONSTRAINING KURA AND SOUTH CASPIAN BASIN EVOLUTION

The Oligocene-Miocene Maikop Series records a critical change in the regional paleogeography relating to the evolution of the Paratethys Sea. This strata is also a key source rock interval for the Kura and South Caspian basins of Eastern Azerbaijan. For these reasons, the Maikop Series has been a focus of many scientific studies. However, the Maikop Series is notoriously difficult to constrain geochronologically and stratigraphically because it is composed primarily of clay-rich rocks that are largely devoid of diagnostic microfaunal assemblages. In this study, thin, discreet intervals of organic-rich shale from Maikop outcrops within the Kura Basin, that represent periods of isolation of the Paratethys Sea, were sampled from three separate localities. In order to build upon our understanding of the paleogeographic evolution of the Paratethys Sea, the related preservation of organic matter, and the stratigraphic constraints on the Maikop, samples were analyzed using chemostratigraphic techniques (XRD, XRF, and ICP-OES) to quantify abundances of redox-sensitive trace elements.

In addition to geochemical analysis of samples, this study seeks to better constrain the geochronology of the Maikop Series strata. Re-Os geochronology, originally developed for the dating of ore bodies in metamorphic and igneous rocks, has recently been applied to organic-rich mudstones. Re and Os bind to preserved organic matter and remain stable in high temperatures and through the generation and migration of hydrocarbons. Re-Os abundances in sediments are controlled by the input of continental vs. marine sediments, and the relative abundances of Re-Os may vary from basin to basin depending on the degree of basin isolation and the influx of sediment. Therefore, in addition to providing geochronologic data, the abundances of Re-Os may be used to reconstruct depositional environments and further constrain stratigraphy of the Maikop Series.