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Abstract:
Lighting up the magma plumbing system beneath a large igneous province (LIP) is challenging because the complex magma migration paths are often covered by flood basalts and sediments. Here, we present a three-dimensional seismic image of the Permian Emeishan LIP in Southwest China, constructed by joint inversion of Rayleigh wave dispersions and receiver functions. The results outline a cylindrical, high-velocity anomaly extending to ~135 km depth below the inner zone of this continental LIP. The geometry and magnitude of the high-velocity anomaly suggest that it represents culminated crystallized materials of primary magmas, thereby mirroring a magma plumbing system fossilized in the lithosphere. Furthermore, our geodynamic models illustrate that the nearly vertical plumbing system was controlled by slow plate motion during the magma emplacement. The plume head beneath a nearly static plate has higher thermal buoyancy and thus promotes more intensive magma emplacement. This phenomenon may apply to other LIPs throughout Earth’s history
