Gas hydrate occurrence on the Antarctic Peninsula, Antarctica

Abstract

On the multi-channel seismic profiles, Bottom Simulating Reflectors (BSRs) are widespread on the South Shetland continental margin, northern Antarctic Peninsula, implying existence of large volumes of gas hydrates. In order to estimate the volume of gas hydrate in the area, interval velocities were determined using a 1-D velocity inversion method and porosities were deduced from their relationship with sub-bottom depth for terrigenous sediments. Two baseline models were proposed for the velocities and porosities of non-gas-hydrate-bearing sediments in the area, considering the velocity jump observed at the shallow sub-bottom depth due to joint contributions of gas hydrate and a shallow unconformity. Based on the models, an average volume gas hydrate concentration was determined as 6.3 %. Assuming that gas hydrates exist only where BSRs are observed on the seismic profiles, the total volume of gas hydrates along the seismic profiles in the area is about 4.8´10 10 m3 (7.7 ´10 12 m3 volume of methane at standard temperature and pressure).