Submarine pockmarks: a case study from Belfast Bay, Maine

Measurements of fluid and gas properties associated with the sediments within and around the Belfast Bay, ME, pockmark field and in the overlying water column were conducted to determine whether fluid flow or methane gas venting is occurring through these pockmarks or has occurred recently. No clear geochemical, lithologic, or biological indications of methane and/or freshwater seepage, such as low salinity pore water, obvious authigenic carbonates, anomalously high water methane concentrations in pore water and the overlying water column, or unusual benthic fauna were observed. Thus, these pockmarks may be inactive or a process different from gas/and or freshwater seepage is responsible for creating and maintaining these features.