Carbon export and burial pathways driven by a low-latitude arc-continent collision

Abstract. Chemical weathering of silicate rocks of low-latitude arc–continent collisions has been hypothesized as a driver of global cooling since the Neogene. In mid- to low-latitude regions, monsoon and tropical cyclone precipitation also drive intense physical erosion that contribute to terrestrial carbon export and nutrient-stimulated marine productivity. Despite this, the role of physical erosion on carbon sequestration has largely been overlooked. To address this gap, we analyse late Miocene–early Pleistocene sedimentary and geochemical records from the Taiwan Western Foreland Basin and time-equivalent records from the northern South China Sea. Along the continental slope, organic carbon accumulation is largely controlled by long-term sea-level fall and shoreline progradation. In contrast, on the continental rise, organic carbon burial is controlled by high sedimentation rates related to Taiwan's uplift and erosion (since ∼ 5.4 Ma). Despite increased terrestrial erosion of Taiwan, the organic material remains mainly marine in origin, suggesting that primary production was enhanced along the coast by nutrient exported from Taiwan. Marine organic matter along Taiwan's shore was subsequently remobilized by turbidity currents through submarine canyon systems and accumulating on the continental rise of Eurasia. The onset of Northern Hemisphere Glaciation (∼ 3 Ma) and subsequent intensification of the East Asian Summer Monsoon during interglacial periods, and persistent tropical cyclone activity all further amplified nutrient export across the basin, further stimulating marine primary production. Our findings demonstrate that arc–continent collision influences carbon sequestration through two pathways: (1) direct burial of terrestrial organic matter and (2) nutrient-fuelled marine productivity and burial. This work establishes a direct link between the erosion of an arc-continent collision and long-term carbon burial in adjacent ocean basins.