Analyses on distribution and origin of mud volcanoes and sill complexes in the VLB of the Ross Sea, Antarctica

Recent discoveries of abundant mud volcanoes in the Victoria Land Basin (VLB) of Ross Sea, Antarctica, highlight its significant hydrocarbon potential, yet their formation mechanisms and relationship to tectonic-magmatic processes remain poorly understood. This study integrates Chinese multi-channel seismic data with international geophysical datasets to reveal that mud volcanoes and domes exhibit distinct spatial distributions controlled by glacial erosion and tectonic activities. The western VLB tectonically active zone is characterised well-developed mud volcanoes along high-angle faults of the Terror Rift system, while the eastern basin with thick sediment hosts buried domes formed through magmatic sill-induced folding. Geophysical analyses demonstrate that these features correlate with high free-air gravity anomalies, shallow depths to the Curie, and distinct magnetic signatures of underlying saucer-shaped sill complexes. These igneous intrusions, linked to Cenozoic alkaline volcanism since ~ 4.6 Ma, drive mud volcano formation through sustained thermal fluid flowing upwards and local strata uplift. Based on these findings, a model is established for mud volcanoes and sill complexes that glacial unloading, rift-related faulting, and magmatic heating collectively control fluid migration pathways, providing new insights into fluid activities in magma-influenced rift basins. This research deepenes understanding of the neotectonic activities in VLB, while offering a reference for interpreting similar systems in glaciated continental margins around Antarctica.