Subduction-driven erosion enhances carbon sequestration and climate cooling during ocean-to-continent transformation

Abstract

Abstract How submerged oceanic domains trapped within growing continents become stable, subaerial continental interiors and what that conversion means for the long-term carbon cycle remain poorly understood. Traditional models of such ocean-to-continent conversion emphasize significant horizontal shortening or plume activity. Here we identify an alternative, surface-process-mediated pathway recorded in Central Asia, where formerly submerged cratonic blocks became intracontinental domains in the late Paleozoic. Geodynamic simulations of subduction, whose predicted uplift is used to drive landscape-evolution simulations of erosion and deposition, show that uplift of the surrounding orogenic belts can generate strong topographic gradients that drive intense erosion, sediment transport, and basin stabilization. This tectonic configuration leads to enclosed intracontinental basins with high-sedimentation rates, promoting efficient organic carbon burial and long-term sequestration. Although oxidative weathering of rock organic carbon and metamorphic degassing partly offset burial, thick Devonian–Carboniferous carbonate sequences indicate substantial net carbon sequestration. This coupling between deep Earth dynamics, surface erosion, and carbon burial amplified the late Paleozoic CO 2 decline and global cooling during Pangaea’s assembly. A similar process may have operated during the Cenozoic, when Tethys closure and Tibetan Plateau uplift enhanced erosion and carbon storage in the Mediterranean, Black, and Caspian basins, contributing to long-term cooling.