Acoustic evidences of gas in the continental slope sediments of the Gulf of Cadiz (E Atlantic)

• Published in: Geo-marine letters Vol. 23; no. 3-4; pp. 300 - 310
• Main Authors: Casas, D, Ercilla, G, Baraza, J
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer Nature B.V 01-12-2003
• Subjects: Acoustics; Continental slope; Diapirs; Gas hydrates; Gases; Hydrates; Marine; Pore pressure; Sediments; Slope stability; Turbidity; Volcanoes; Water column; Gulf of Cadiz; ANE, Atlantic, Cadiz Gulf
• ISSN: 0276-0460; 1432-1157
• DOI: 10.1007/s00367-003-0160-z

Detailed reviews of high-resolution acoustic studies in the continental slope of the Gulf of Cadiz has revealed the following gas-related features: acoustic turbidity and blanking, bright spots, ancient and modern pockmarks, high-amplitude diffractions, acoustic plumes and turbidity in the water column, and BSRs. The origin of the gas is believed to be biogenic and thermogenic. The BSR-like acoustic anomalies occur intermittently in some areas of the upper slope and tend to occur in the volcanoes/diapirs. The pressure-temperature conditions deduced for the location of those acoustic anomalies do not correspond to the conditions of stability of gas hydrates. It is suggested that these volcanoes/diapirs intrusions may locally induce anomalously higher pore pressure conditions on the immediately surrounding sediments, affecting the stability field of the gas hydrates.