NOTICIAS DE GEOFÍSICA

 

21 de julio de 2018

Geólogos revelan que en Chile se esconde la mayor reserva de hielo combustible del mundo
Fuente: El Mostrador

El estudio, publicado por la revista “Marine and Petroleum Geology”, titulado “A first estimation of gas hydrates offshore Patagonia (Chile)”, advierte que, pese a ser el gas metano una posible fuente de energía en el futuro, tras un terremoto, la liberación de este gas desde los fondos marinos podría magnificar los efectos de un tsunami.

Enormes reserva de hidratos de metano en la Patagonia

Paper: A first estimation of gas hydrates offshore Patagonia (Chile)
Authors: Lucía Villar-Muñoz, Joaquim P. Bento, Dirk Klaeschen, UmbertaTinivella, Iván de la Cruz Vargas-Cordero, Jan H. Behrmann.

Abstract
In many places along the central and southern Chilean active continental margin sedimentary successions covering the forearc contain methane hydrate, resulting from a mixture of biogenic and thermogenic processes. Here, we report the spatial distribution of gas hydrate in the accretionary prism and forearc sediments offshore western Patagonia (50°S and 57°S), landward of the Antarctica-South America plate boundary. Knowledge of the forearc structure here is limited, owing to the small number of reflection seismic profiles available, lack of high-resolution bathymetry data and the absence of scientific drillholes. However bottom-simulating reflectors (BSR) indicative of gas hydrate occur regionally extensive below about one third of the forearc slope, between about 280 and 630 m below sea floor. BSR-derived heat flow was calculated at about 30 and 70 mWm-2. These are typical values above subduction zones of oceanic crust older than 10 Ma, where vigorous fluid flow above young and hot subducting oceanic crust has leveled off. To move towards an estimate of gas hydrate present in the sediments, the velocity model was converted into a gas-phase concentration model using data from one of the seismic sections. Average thickness of gas hydrate is about 290?m, and average concentrations estimated are in a range of 3.4%–10%. If we use the minimum value of 3.4%, the amount of methane present in the region is about 3.0×1013 m3 at standard pressure-temperature conditions. We conclude that the Pacific forearc of Patagonia area is an important reservoir of methane hydrates and we propose this area be considered as a potential methane hydrate concentrated zone and a key area to be investigated in the future.



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