Phanerozoic Onset of Massive Continental Weathering

Abstract Continental weathering acts as a nexus of global biogeochemical cycles yet its long‐term evolution remains unclear. Here we show that continental weathering may not have operated on a massive scale until the early Paleozoic based on a large‐number data compilation of mudstone geochemistry. We attribute the long‐term evolution of mudstone K/Al to the competing weathering inputs between continents and seafloor. Much of pre‐Phanerozoic mudstone is characterized by high K/Al relative to continents, indicating low weathering input of K and Al from continents relative to the hydrothermal input of K from seafloor alteration to the global sedimentary mud reservoir. A quantitative assessment indicates over one order of magnitude increase of weathering partition into continents during the Phanerozoic. The Phanerozoic onset of massive continental weathering reflects a fundamental evolution on the Earth's surface linked to an interactive feedback network consists of mountain building, atmospheric oxygenation, and land plant colonization.