Spatial and temporal variability of Paleocene-Miocene organofacies of the Kura Basin, eastern Azerbaijan, and implications for basin evolution and petroleum generation

摘要

Fine-grained Paleocene-Miocene strata of eastern Azerbaijan record the evolution of the Kura Basin from an open marine system connecting the South Caspian Basin to the Paratethys of eastern Europe to an isolated epicontinental sea. Tectonic uplift associated with the Greater Caucasus mountains in Azerbaijan resulted in exposure of these strata over much of the northeastern part of the basin, allowing detailed observation and sampling over a broad area. Four hundred Paleocene-Miocene samples collected in eastern Azerbaijan demonstrate spatial and temporal geochemical heterogeneity within the predominately mudstone succession, indicating a complex evolution of this elongate basin. Through detailed organic geochemical analysis of samples, trends can be seen in the distribution of total organic carbon (TOC), pyrolysis characteristics, and biomarker results from a subset of twenty-four samples. In addition to confirming the well-documented regional basin restriction during the Oligocene to early Miocene deposition of the Maikop Series, heterogeneity of these geochemical indicators across the study area shows spatial variability in oxicity and terrestrial organic input within the basin on a sub-regional scale.