3D seismic characterization of magma plumbing components in the Tarim Large Igneous Province, north-central Tarim Basin, NW China

Linkages between upper-crustal intrusive and extrusive components of magma plumbing systems in Large Igneous Provinces (LIPs) are challenging to reconstruct. We used 3D seismic reflection and borehole data to characterize these components and their relationships in the Permian LIP of the north-central Tarim Basin in China. A connected network of areally extensive (from 10 to >115 km 2 ), saucer-shaped, gabbro and diabase sills cuts across 2 km of strata and fed extrusive basalt lava flows. These basalts cap a high-volume (>250 km 3 ) volcaniclastic mass transport complex and an underlying set of steeply dipping (5°) volcaniclastic clinoforms, indicating substantial remobilization and reworking of volcanic debris. The clinoform set records progradation of an arcuate shoreline composed of dacite tuff and tuffaceous sediment. The mass transport complex comprises dacite and basalt megaclasts (up to 4 km 3 ), basaltic tuff, and volcaniclastic sediment. Its base is marked by large polygonal ridges and depressions (up to 1000 m in lateral spacing and 40 m in relief), indicating water escape driven by loading and compaction. Older sills variably cut across and are cut by long-lived strike-slip faults, while the youngest sill intrudes the volcaniclastic clinoform set and is associated with forced folding and subsequent onlap of strata containing basalt lava flows.