Estimates of heat flow derived from gas hydrate-BSRs on the northeastern South Shetland margin, Antarctic Peninsula

Abstract

Bottom simulating reflector (BSR), representing the base of gas hydrate stability field, is widespread on the northeastern South Shetland margin (SSM), Antarctic Peninsula. With phase diagram of gas hydrate stability field, heat flow can be derived from BSR depth beneath the seafloor determined on multichannel seismic profiles. The heat flow values in the study area range from 50 mW/m2 to 85 mW/m2 with an average value of 65 mW/m2. The landward heat flow decrease from the South Shetland Trench would be attributed to the landward thickening of the accretionary prism and the upward advection of heat associated with fluid expulsion. The continental slope 1500 m to 3000 m deep, where BSRs are most distinct in the SSM, shows high variation of heat flow possibly due to complex tectonic activities in the study area. The abrupt heat flow variation along the slope occurs near the NW-SE trending large-scale fault. The fault would be related to a fracture zone in the former Phoenix plate or a transfer fault across the Bransfield Basin between Antarctic Peninsula and the South Shetland Islands.