Unresolved Complex Mixture of Hydrocarbons as a Potential Stratigraphic Anthropogenic Marker for the Great Acceleration

The unresolved complex mixture (UCM) consists of chromatographically unresolvable branched, cyclic, and aromatic hydrocarbons, which are intermediate- to semivolatile organic compounds primarily derived from anthropogenic fossil fuel usage, including industrial emissions and gasoline and diesel exhaust. The UCM in natural archives, expressed as its ratio to resolved compounds (UCM/R), may thus provide an indication of fossil fuel-derived contamination in the environment over time. To test this hypothesis, accurately dated sediment records from the Black Sea, the Baltic Sea, and the northeastern Germany Tiefer See lake were analyzed for hydrocarbons. Each record presents a similar temporal pattern with a synchronous main increase of UCM/R in the early 1950s and a decrease in the 1990s. This UCM/R pattern most likely reflects the pronounced increase in the use of petroleum-derived products during the Great Acceleration of the mid-20th century and, subsequently, the application of filters and catalytic converters to reduce volatile organic compound emissions in the 1980s–1990s. Therefore, UCM/R in recent sediments represents a stratigraphic anthropogenic marker for the Great Acceleration in European midlatitudes and, if replicated globally, could be a further marker for the beginning of the Anthropocene as a potential geological epoch.