Siliciclastic sediment factories and the index of sediment generation

Siliciclastic sediment generation, a vital process connecting Earth’s spheres, is highly heterogeneous in space and time. A major obstacle to deciphering its patterns and mechanisms has been the absence of robust quantitative proxies for regional-scale comparison. Here, we overcome this limitation by proposing a dimensionless Index of Sediment Generation (ISG)—ratio of the sediment flux from a sub-catchment to the total sediment flux of the river—which controls for interannual variability and anthropogenic biases. Applying the ISG to data from 686 hydrological stations across Asia, we map regional sediment generation and define “sediment factories” as localized zones of disproportionately intense erosion that supply a major fraction of a river’s sediment load. Our analysis identifies Asian sediment factories clustered around the Himalaya and Tibetan Plateau margins. Covering only 8.9% (0.84 million km2) of the monitored basin area, these factories generate ~3240 Mt of suspended sediment per year, representing 75% of the monitored coastal flux. We classify them into three types: first-cycle (crystalline bedrock), recycled (soft sediments/rocks), and composite. The sediment factory concept not only quantifies generation but also pinpoints critical nodes in Earth surface dynamics, intrinsically linked to orogeny, weathering, carbon cycling, geohazards, and water resources management.