Comparisons of industrial emission signatures recorded by spheroidal carbonaceous particles and fossil fuel soot from maar lake sediments in Northeastern and Southeastern China

Spheroidal carbonaceous particles (SCPs) and fossil fuel-derived soot (FF soot) in sediments are valuable proxies for reconstructing industrial emissions and understanding the multi-scale impacts of anthropogenic forcing on Earth systems. However, a systematic comparison of their initial deposition timing, flux peaks, and temporal patterns across lacustrine sedimentary records remains poorly constrained, leading to significant gaps in the understanding of the underlying drivers of these sedimentary signals. This study compared sediment records of these proxies from two maar lakes, Sihailongwan in northeastern China and Huguangyan in southeastern China, revealing how their signals exhibit synchronous patterns on a global scale while demonstrating complex heterogeneity at the regional scale due to differences in geographical location, climate systems, and industrialization pathways. Results showed that both SCP and FF soot fluxes in Sihailongwan began to rise in the 1950s, reaching a peak during China's rapid industrialization. In contrast, Huguangyan exhibited increasing fluxes only after the 1980s, synchronous with accelerated economic development in southeastern coastal regions, and culminating around 2010 CE, thereby reflecting intensified industrial activity and urbanization in this area. Notably, in both sediment records, the SCP peak occurred systematically earlier than the FF soot peak. This temporal offset likely reflects their representation of different industrialization phases and emission sources: SCPs derive mainly from industrial coal combustion, which peaked earlier, whereas FF soot also incorporates emissions from transportation fuels that rose later. Thus, these differences highlight the spatiotemporal evolution of energy structures and pollutant types throughout China's industrialization, especially those associated with black carbon. These findings offer important insights for selecting appropriate indicators to define the onset of the mid-20th century Anthropocene at varying spatial scales, and enhance our understanding of anthropogenic impacts from a micro-particle perspective.