India-Eurasia convergence speed-up by passive-margin sediment subduction

This dataset provides data and visualization code of the numerical experiments on India-Eurasia convergence speed-up by passive-margin sediment subduction. The repository contains six main subfolders, one for each model with different sediment thickness and pore pressure. Each subfolder contains hdf5 output files. Each hdf5 file has three main groups: Group 1-ModelGroup, which includes two datasets and an additional group with 5 model parameters; Group 2-NodeGroup, which contains velocity, stress, strain rate, and temperature datasets, as well as datasets of physical and rheological properties on the nodes; Group 3-VisMarkerGroup, which contains one dataset. The dataset, named Mtype, includes the rock type number of each marker (see details of the README file). Numerical experiments suggest that subduction of >1 km-thick sediments covering a ~1000 km-wide ocean basin abutting the northern Indian passive margin could have spurred the increased convergence rate and further led to significant crustal extension, consistent with empirical observations. This dataset also provides compiled major and trace elements and Sr-Nd isotope compositions of the Late Cretaceous-Early Cenozoic magmatic rocks from the Gangdese arc (Supplementary Table 1). 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. The fast increase of convergence rate between India and Eurasia around 65 million years ago — from ~8 cm/year to a peak rate of ~18 cm/year — remains a complex geological event to explain, given the inherent uncertainty surrounding the tectonic history and the intricate interplay of forces influencing plate speed. Here, we use a combination of geochemical analysis and geodynamic modeling to propose that this rapid convergence can be explained by sediment subduction derived from the northern Indian passive margin. 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.