Minerals are fundamental regulators of biogeochemical cycling, controlling the retention, transformation, and release of keystone elements that regulate ocean chemistry, climate, and oxygenation. Marine sediment minerals, particularly highly reactive iron and manganese phases, help control organic carbon preservation and burial, the abundance and distribution of micronutrient trace metals, and play a pivotal role in the cycling of other elements—such as the rare earth elements—that are widely used to proxy Earth-system processes. Connecting these smallscale sedimentary reactions to large-scale Earth-system feedbacks provides critical constraints on, and levers within, the Earth system that can be used to explore planetary change over both geological and modern timescales. Here, we will see how marine sediment minerals control the preservation and burial of organic carbon through both sorptive protection and sorptive transformation, within a framework referred to as the Mineral Carbon Pump. Work indicates that interactions between organic carbon and iron and manganese minerals enhance carbon preservation efficiency, such that variations in iron and manganese fluxes to the ocean influence long-term carbon burial, climate, and oxygenation. We will also examine how marine sediment minerals regulate the concentrations and isotopic compositions of micronutrient trace metals and rare earth elements in sediments and seawater. Work shows that as manganese minerals age and transform during early diagenesis, they exert strong controls on metal retention and release, supporting a bottom-up perspective on ocean chemistry. Together, these studies exemplify the central role of sedimentary minerals in regulating elemental cycling and demonstrate the importance of experimentally constrained mineralogical processes for understanding the ancient and modern Earth system.

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