Seismic analysis and distribution of a bottom-simulating reflector (BSR) in the Chilean margin offshore of Valdivia (40° S)

Rodrigo, Cristián; Vera, E.; González‐Fernández, Antonio

doi:10.1016/j.jsames.2008.11.001

Cited by 10 publications

(1 citation statement)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Along South American continental margins, numerous accumulations of gas hydrates are known and have been described (Kvenvolden and Kastner, 1990;Brown et al, 1996;Pecher et al, 2001;Hubscher and Kukowski, 2003;Rodrigo et al, 2009). Off Peru, during Ocean Drilling Program (ODP) Leg 112, gas hydrates were identified in water depth greater than 3000 m, within core drillings, and on seismic profiles crossing the Yaquina and Lima forearc Basins (sites 682, 685, and 688) (von Huene et al, 1987) ( Figure 1A).…”

Section: Introductionmentioning

confidence: 96%

Seismic evidence of gas hydrates, multiple BSRs and fluid flow offshore Tumbes Basin, Peru

et al. 2017

View full text Add to dashboard Cite

International audienceIdentification of a previously undocumented hydrate system in the Tumbes Basin, localized off the north Peruvian margin at latitude of 3°20′—4°10′S, allows us to better understand gas hydrates of convergent margins, and complement the 36 hydrate sites already identified around the Pacific Ocean. Using a combined 2D–3D seismic dataset, we present a detailed analysis of seismic amplitude anomalies related to the presence of gas hydrates and/or free gas in sediments. Our observations identify the occurrence of a widespread bottom simulating reflector (BSR), under which we observed, at several sites, the succession of one or two BSR-type reflections of variable amplitude, and vertical acoustic discontinuities associated with fluid flow and gas chimneys. We conclude that the uppermost BSR marks the current base of the hydrate stability field, for a gas composition comprised between 96% methane and 4% of ethane, propane and pure methane. Three hypotheses are developed to explain the nature of the multiple BSRs. They may refer to the base of hydrates of different gas composition, a remnant of an older BSR in the process of dispersion/dissociation or a diagenetically induced permeability barrier formed when the active BSR existed stably at that level for an extended period. The multiple BSRs have been interpreted as three events of steady state in the pressure and temperature conditions. They might be produced by climatic episodes since the last glaciation associated with tectonic activity, essentially tectonic subsidence, one of the main parameters that control the evolution of the Tumbes Basin

show abstract