Early Eocene magnetostratigraphy and tectonic evolution of the Xining Basin, NE Tibet
Dupont‐Nivet, Guillaume
Licht, Alexis
Roperch, Pierrick
Rohrmann, Alexander
Sun, Aijun
Lu, Shengcheng
Woutersen, Amber
Nowaczyk, Norbert
DOI: https://doi.org/10.1111/bre.12720
Persistent URL: http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/10651
Licht, Alexis; 3 CNRS, IRD, INRAE, CEREGE Aix Marseille University Aix‐en‐Provence France
Roperch, Pierrick; 2 Géosciences Rennes ‐ UMR CNRS 6118 Univ Rennes, CNRS Rennes France
Rohrmann, Alexander; 4 Institute of Geological Sciences Freie Universität Berlin Berlin Germany
Sun, Aijun; 5 Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences Lanzhou University Lanzhou China
Lu, Shengcheng; 8 School of Urban Construction and Environment Dongguan City College Dongguan China
Woutersen, Amber; 9 Department of Ecosystem and Landscape Dynamics (ELD), Institute for Biodiversity and Ecosystem Dynamics (IBED) University of Amsterdam Amsterdam the Netherlands
Nowaczyk, Norbert; 10 GFZ German Research Centre for Geosciences Potsdam Germany
Abstract
The Cenozoic strata of the Xining Basin, NE Tibet, have provided crucial records for understanding the tectonic and palaeo‐environmental evolution of the region. Yet, the age of the lower part of the sedimentary stratigraphy and, consequently, the early tectonic evolution of the basin remain debated. Here, we present the litho‐ and magnetostratigraphy of various early Eocene sections throughout the Xining Basin independently constrained by the U–Pb radiometric age of a carbonate bed. Our study extends the dated stratigraphy down to 53.0 Ma (C24n.1r) and reveals highly variable accumulation rates during the early Eocene ranging from 0.5 to 8 cm/ka. This is in stark contrast to the low but stable accumulation rates (2–3 cm/ka) observed throughout the overlying Palaeogene and Neogene strata. Such a pattern of basin infill is not characteristic of flexural subsidence as previously proposed, but rather supports an extensional origin of the Xining Basin with multiple depocentres, which subsequently coalesced into a more stable and slowly subsiding basin. Whether this extension was related to the far‐field effects of the subducting Pacific Plate or the India–Asia collision remains to be confirmed by future studies.