Organic matter in Oligocene Maikop Sequence of the North Caucasus

The results of the thorough study of organic matter (OM) in the Oligocene-Miocene Maikop sequence of the North Caucasus are considered. It is shown that its distribution within the Maikop sequence is characterized by irregular patterns. Despite that these rocks show the elevated TOC content, their hydrocarbon-generating potential is, as a rule, low. The low quality of OM is partly related to its intense anaerobic decomposition in anoxic environments with terrigenous sedimentation. The elevation of OM concentrations and hydrocarbon-generating potential could be connected with the reinforced phytoplankton influx into sediments. Sediments deposited in the second half of the Early Oligocene were synchronously enriched in OM. This enrichment chronologically corresponded to the restoration of connection with the World Ocean of the formerly partly isolated and freshened basin. Most probably, this event resulted from the sharp increase in biological productivity.