The fast increase of convergence rate between India and Eurasia around 65 million years ago (Ma)—from approximately 8 cm yr⁻¹ to a peak rate of approximately 18 cm yr⁻¹—remains a complex geological event to explain^{1,2,3,4,5,6,7,8}, given the inherent uncertainty surrounding the tectonic history and the intricate interplay of forces influencing plate speed^9,10,11. Here we use a combination of geochemical analysis and geodynamic modelling to propose that this rapid convergence can be explained by sediment subduction derived from the northern Indian passive margin. Through isotope and trace element analysis, we find an enhanced contribution of terrigenous sediment melt to the mantle source of the Gangdese magmatic rocks around 65 Ma, concurrent with the acceleration of India–Eurasia convergence. Numerical experiments suggest that subduction of sediments more than 1 km thick covering an approximately 1,000-km-wide ocean basin abutting the northern Indian passive margin starting from 65 Ma could have spurred the increased convergence rate and further led to significant crustal extension, consistent with empirical observations. Our study implies that the acceleration of India–Eurasia convergence marks the arrival of passive-margin-derived sediments, constraining the initial India–Eurasia collision to be around 60 Ma. It further suggests that temporary accelerations in subduction rates might be a common feature at the final stage of continental assembly.

大约 6500 万年前 （马） 印度和欧亚大陆之间的收敛速率迅速增加——从大约 8 cm ^yr-1 到大约 18 cm ^yr-1 的峰值速率——仍然是一个复杂的地质事件来解释^{1,2,3,4,5,6,7,8}，鉴于围绕构造历史的内在不确定性和影响板块速度的力量的错综复杂的相互作用^9,10,11.在这里，我们结合使用地球化学分析和地球动力学模型来提出，这种快速收敛可以用来自印度北部被动边缘的沉积物俯冲来解释。通过同位素和微量元素分析，我们发现陆源沉积物熔化对 65 马左右 Gangdese 岩浆岩的地幔源的贡献增加，同时印度-欧亚大陆趋同加速。数值实验表明，从 65 马开始，超过 1 公里厚的沉积物俯冲覆盖了毗邻印度北部被动边缘的约 1,000 公里宽的海洋盆地，这可能刺激了辐合速率的增加，并进一步导致显着的地壳扩展，这与经验观察一致。我们的研究表明，印度 - 欧亚大陆收敛的加速标志着被动边缘衍生沉积物的到来，将最初的印度 - 欧亚大陆碰撞限制在 60 马 左右。它进一步表明，俯冲速率的暂时加速可能是大陆组装最后阶段的一个常见特征。