Abstract
Seismic profiling with 3.5-kHz and GeoPulse in the Amazon submarine delta indicates that gas-charged sediments cover an area greater than 31,000 km2. Gas appears on seismic profiles as gas-brightening reflectors near the river mouth, where mud and sand are well stratified. In fine sediments of the distal portion of the system, gas turbidity zones predominate. Biogenic gas is generated during degradation of terrestrial and marine organic matter by bacteria. The depth of gas in sediment below the seabed depends in part on anaerobic methane oxidation and the base of the sulfate reduction zone and on stratigraphic traps.
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Figueiredo, A.G., Nittrouer, C.A. & de Alencar Costa, E. Gas-charged sediments in the Amazon submarine delta. Geo-Marine Letters 16, 31–35 (1996). https://doi.org/10.1007/BF01218835
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DOI: https://doi.org/10.1007/BF01218835