Magmatic plumbing systems of the Tarim Large Igneous Province as revealed by 3D seismic images

Igneous sills are extensively developed in sedimentary basins and play a critical role in magma storage and transport during volcanic eruptions. Mounting evidence from Large Igneous Provinces (LIPs) highlights the significance of sill complexes in shaping eruption dynamics. However, existing models of shallow magmatic plumbing systems within LIPs are primarily based on field-based datasets, which often lack spatial continuity and subsurface resolution. We integrated high-resolution 3D seismic data with borehole observations to map the subsurface igneous rocks in the central Tarim Basin, a key region within the Tarim LIP. To better resolve the spatial architecture of residual flood basalts and underlying sill complexes in the Tarim LIP, we applied the Constrained Sparse Spike Inversion (CSSI) technique. Sixteen igneous sills are identified through combined seismic and well data analysis, alongside the mapped distribution of flood basalt sequences. Coherency attribute analysis reveals a network of magma conduits linking deep sill intrusions to overlying volcanic strata. These sills, emplaced along the Middle-Upper Ordovician disconformity in the Tarim Basin (the M disconformity), facilitated likely lateral magma transport. The associated dyke swarms formed by sill complexes can serve as conduits enabling magma ascent and subsequent surface eruption. Given the study area spans both central and marginal zones of the Tarim LIP, our results offer the 3D reconstruction of sill-to-conduit linkages of the shallow magmatic plumbing system and its role in feeding large-scale basaltic eruptions.