Gas hydrate BSR-derived heat flow variations on the South Shetland continental margin, Antarctic Peninsula

Abstract

Bottom simulating reflectors (BSR), representing the base of the gas hydrate stability field, are widespread on the South Shetland continental margin (SSM), Antarctic Peninsula. With the phase diagram for the gas hydrate stability field, heat flow can be derived from the 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, averaging to 65 mW/m2. Small deviation from the average heat flow values suggests that heat flow regime of the study area is relatively stable. The landward decrease of heat flow from the South Shetland Trench to the continental shelf 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 distinguished in the SSM, shows relatively large variation of heat flow possibly due to complex tectonic activities in the study area. The local high heat flow anomalies observed along the slope may be caused by heat transport mechanisms along a NW-SE trending large-scale fault.