Advances in Reverse Weathering and Its Role in Clay Mineral Formation and the Carbon Dioxide Cycle

Reverse weathering plays a significant role in the cycle of atmospheric carbon dioxide (CO2) and elements between oceanic and continental environments during the Earth's evolution. Through summarizing various previous research on reverse weathering, this review found much evidence that suggested that reverse weathering commonly occurs in dynamic areas of element exchange and abundant material sources, such as river mouths, deltas, sedimentary basins, and deep-sea sediments, accompanied by the formation of authigenic clay minerals. These clay minerals, by incorporating elements including Si, K, Li, and Mg, are reburied and contribute to a crucial reverse weathering sink, resulting in maintaining an elemental balance between the ocean and land. Concurrently, the process of reverse weathering releases CO2, which holds great significance in studying CO2 anomalies in the paleoenvironment. The extensive formation of authigenic clay minerals during pre-Cambrian glaciations and the δ7Li shifts around the Permian–Triassic boundary and within the Cenozoic provide compelling evidence of the occurrence of reverse weathering. This evidence sheds light on explaining the prolonged high CO2 concentrations during pre-Cambrian glaciations, dramatic CO2 concentration changes near the Permian–Triassic boundary, and cooling of the Cenozoic climate. It also offers new perspectives for paleoenvironmental reconstructions and the study of carbon cycling. This review can help to deeply understand the significant role of reverse weathering concerning clay mineral formation and the CO2 cycle during Earth's evolution, providing a theoretical foundation for future research endeavors.