The global deep carbon cycle started in the Paleoproterozoic Era

Abstract

The deep carbon cycle plays a crucial role in Earth's evolution by regulating atmospheric composition and ensuring planetary habitability over geological timescales. However, the timing of when the global deep carbon cycle started remains debated. In this study, we synthesize data from basalt, carbonatite, kimberlite, and diamond samples to propose that significant global carbon deposits subducted into the deep mantle during the Paleoproterozoic era, where they were retained for an extended period. This major event of deep carbon subduction in the Paleoproterozoic may mark the beginning of the first global deep carbon cycle by which the surface materials can be subducted into upper mantle. Our findings suggest that the Earth's mantle, the primary reservoir for carbon, underwent its first substantial carbon infusion during Paleoproterozoic era. Acting as a vast carbon buffer, the mantle played a critical role in balancing carbon distribution between the atmosphere, oceans and crust, thus supporting Earth's transition towards a more habitable state.