Controls on Physical and Chemical Denudation in a Mixed Carbonate‐Siliciclastic Orogen

Mixed siliciclastic-carbonate active orogens are common on Earth's surface, yet most studies have focused erosion and weathering in silicate-rich landscapes. Relative to purely siliciclastic landscapes, the response of uplift may differ mixed-lithology regions. However, our knowledge mixed carbonate-silicate lithologies is limited and, thus, so understanding mechanistic coupling between uplift, weathering, carbon cycle. Here, we partition denudation fluxes into carbonates silicates Northern Apennines—a carbonate-siliciclastic orogen—using dissolved solutes, carbonate sand fraction, existing 10Be rates. Erosion generally dominates total relative by an order magnitude. Carbonate silicate contributions vary lithologic units, but systematically dominated carbonates. Silicate be kinetically limited, whereas acid supply. re-precipitation estimated comparing ion ratios (Sr, Ca, Na) from rivers bedrock suggests that up 90% Ca2+ lost carbonate-rich catchments. Corresponding [Ca2+] estimates for zone high, likely driven high soil CO2 partial pressures (pCO2); however, re-equilibration with atmospheric pCO2 converts solutes back grains become part physical flux. Weathering limits this landscape therefore subsurface riverine exports, findings suggest cycle models overestimate sensitivity solute exports (Ca2+ HCO3−) derived weathering.