Geophysical evidence of a large occurrence of mud volcanoes associated with gas plumbing system in the Ross Sea (Antarctica)

Abstract

Seafloor and buried reliefs occur along continental margin of the Ross Sea (Antarctica). These features are several kilometres wide and tens of metres high, exhibiting cone or flat-top dome shapes. Previous studies have proposed a volcanic or glacial origin for these formations, but these hypotheses do not account for all the available evidence.In this study, we use morpho-bathymetric data, intermediate resolution multichannel seismic and high resolution chirp profiles, as well as magnetic lines to investigate these clusters of mounds. By employing targeted processing techniques to enhance the geophysical characterization of the seafloor and buried reliefs, and to understand the underlying geological features, we propose that the reliefs are mud volcanoes. Some of these formations appear to be associated with a plumbing system, as indicated by acoustic anomalies linked to sediment containing gas. These formations are likely fed by clayey source rocks of Miocene age. Additionally, other reliefs might be the result of mud mobilisation caused by gravity instability and fluid overpressure.