Journal Article

Mantle Plume‐Lithosphere Interactions Beneath the Emeishan Large Igneous Province

Zhang, Anqi, Afonso, Juan Carlos, Yang, Yingjie, Shellnutt, J. Gregory, Guo, Zhen

2024

Overview

The formation of large igneous provinces (LIPs) has been widely believed to be linked to mantle plume activity. However, how the plume modifies the overlying lithosphere, particularly its compositional structure, remains uncertain. Here, we characterize the deep thermochemical structure beneath the Emeishan LIP (ELIP), which is a well‐known Permian plume‐related LIP in China, by taking a multi‐observable probabilistic inversion. Our results find a clear correlation between the lithospheric composition with the ELIP's concentric zones. We infer that the fertile feature of the lithospheric mantle in the ELIP's inner zone was caused by the plume‐derived fertile magmas which infiltrated into and chemically refertilized the ambient depleted lithosphere. This plume‐modified lithospheric compositional structure is likely to be preserved after the plume event, while the present lithospheric thermal structure has been mainly influenced by the subsequent thermal‐tectonic activity. Our results improve our understanding of the physicochemical interactions between the lithosphere and ancient plume. Plain Language Summary Gaining insights into the nature of large igneous provinces (LIPs) helps understand mass extinction and climate change in the past, since the outpouring of large accumulations of igneous rocks associated with LIPs could alter ancient climates and environments. Here, we focus on a well‐known plume‐related LIP during the Permian in China, Emeishan LIP (ELIP), to construct its deep thermochemical structure based on a multi‐observable probabilistic inversion method. Our results suggest that the bulk fertile feature (not depleted by melt extraction) of the lithospheric mantle in the vicinity of the ELIP's inner zone was caused by the plume‐derived fertile magmas which infiltrated into the ambient depleted (deficient in minerals extracted by partial melting of the rock) lithospheric mantle and chemically refertilized it by melt‐rock interaction. However, the imaged thermal structure shows a large ongoing asthenospheric upwelling and small‐scale thermal convection, implying that the present‐day lithospheric thickness has been mainly influenced by the subsequent tectonic events. Our results improve the understanding of the physicochemical interactions between the lithosphere and ancient plume and contribute to the knowledge of the nature of LIPs. Key Points Image the thermochemical structure beneath the Emeishan Large Igneous Province via novel joint inversions Reveal plume refertilization of the lithosphere beneath the Emeishan Large Igneous Province's inner zone Image complex mantle circulation patterns beneath the Emeishan Large Igneous Province region

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Asthenosphere / Cellular convection / Climate change / Convection / Depletion / Emeishan large igneous province / Fertility / Free convection / Igneous rocks / Lithosphere / Mantle plumes / mantle plume‐modified lithosphere / Mass extinctions / multi‐observable probabilistic inversion / Ocean circulation / Permian / Tectonics / Thermal convection / Thermal structure / thermochemical structure / Upwelling