Evolution of a plume-influenced source-to-sink system: An example from the coupled central Emeishan large igneous province and adjacent western Yangtze cratonic basin in the Late Permian, SW China

Abstract

Source-to-sink paleogeography in a time-constrained sequence stratigraphic framework has been reconstructed for the non-marine to marine transitional Lopingian strata (Late Permian) in the western Yangtze Cratonic Basin (WYCB) and the adjacent inner zone of the Emeishan large igneous province (ELIP) in order to reveal the evolution of a mantle plume influenced cratonic basin. The Lopingian coal-bearing strata can be subdivided into seventeen 4th-order sequences and three 3rd-order composite sequences representing 6.76 Myr. Paleogeographic reconstructions of the WYCB demonstrate the existence of N-S trending terrestrial, transitional and marine facies belts distributed west to east away from the central ELIP. Geomorphological analysis indicates that the western boundary of the source area coincided with the major axis of the uplifted central ELIP. Based on sediment flux estimates and modeling (BQART model), relief of the central ELIP increased from near sea-level in the earliest Late Permian and reached equilibrium at about 200 m in the latest Permian. Sediment volume backfilling analysis indicates that total tectonic uplift of the central ELIP in the Late Permian was more than 500 m. Evolution of the coupled central ELIP and WYCB can be subdivided into three stages, pre-eruptive uplift stage, pre- and syn-eruptive subsidence stage, and syn- and post-eruptive uplift stage. Post-eruptive basin filling was controlled by sediment supply that was related to tectonic uplift, drainage topography and climate change, and basin accommodation that was related to sea-level fluctuations and plume-induced syn-sedimentary tectonics.