Early Eocene magnetostratigraphy and tectonic evolution of the Xining Basin, <scp>NE</scp> Tibet

The Cenozoic strata of the Xining Basin, NE Tibet, have provided crucial records for understanding tectonic and palaeo-environmental evolution region. Yet, age lower part sedimentary stratigraphy and, consequently, early basin remain debated. Here, we present litho- magnetostratigraphy various Eocene sections throughout Basin independently constrained by U–Pb radiometric a carbonate bed. Our study extends dated down to 53.0 Ma (C24n.1r) reveals highly variable accumulation rates during ranging from 0.5 8 cm/ka. This is in stark contrast low but stable (2–3 cm/ka) observed overlying Palaeogene Neogene strata. Such pattern infill not characteristic flexural subsidence as previously proposed, rather supports an extensional origin with multiple depocentres, which subsequently coalesced into more slowly subsiding basin. Whether this extension was related far-field effects subducting Pacific Plate or India–Asia collision remains be confirmed future studies.