From Carbon Micro-Heterogeneity to Macro-Evolutionary Pattern: Insight from the Plate Tectonic Pump

In geociences, as in other branch of science, there is a gap between microscopic heterogeneity and macroscopic patterns. The heterogeneity of reduced carbon materials on and within Earth is staggering; probably unique in the solar system. Every year, hundreds of megatons of fresh biomolecules, kerogens and graphitic materials of biological and abiotic origins are injected in the solid Earth and exhumed from it back to the surface environment by the plate tectonic cycle. We highlight key pathways that shape the heterogeneity of the lithospheric carbon reservoir. This heterogeneity results in a remarkably broad spectrum of organic carbon reactivity in the environment. Implications of this reactive complexity for long-term patterns of ocean and atmosphere evolution will be discussed.