| Summary: | XI Congreso Geológico de España, 2-6 de julio 2024, Ávila.-- 1 page [EN] Gas hydrates (GHs) stability is highly sensitive to climate-induced perturbations (e.g., changes in sea level and temperature) and may provide feedback to global climate change. The occurrence of GHs in the Pacific margin of the Antarctic Peninsula (PAP) is manifested as a negative polarity Bottom Simulating Reflector (BSR) in seismic reflection data. The BSR indicates the contact between the top GH-bearing sediment and the bottom free gas-rich sediment. This study uses legacy seismic, bathymetric, oceanographic and heat flow data to investigate trends and spatial variations in BSR depth that could point to transient processes in the GH system. In the PAP, a BSR level is widespread between Elephant and King George Is. between 500 and 4000 m water depth and is 200-400 m deeper than expected given the average geothermal gradient (100 ± 30 ºC/km) taken from the scarce data available in the Global heat flow database. Due to difficulties in precise geothermal gradient determination in the first few meters of the subsurface (eg. porosity and bottom temperature changes, hydrate dissociation processes, etc), temperature and pressure have been inferred from the BSR burial depth for different gas compositions. Results indicate that any potential overpressure resulting from rapid sedimentation or tectonic stresses cannot account for the observed depth of the BSR, as it cannot balance the thermal conditions at such depths. On the contrary, the geothermal gradient calculated under hydrostatic conditions, 34 ± 6,5 ºC/km (100% CH4), is considered a plausible scenario given available heat flux models for the PAP. Finally, we identify higher geothermal gradients near the trench where seismic chaotic facies occur. This could indicate a more vigorous and focused fluid flow systems near the trench as well as around antiformal structures and faults [ES] La estabilidad de los hidratos de gas (HG) es sensible al cambio climático (eg. cambios del nivel del mar ...
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