Seismic Response and Sedimentary Evolution of a Deepwater Channel at a Passive Continental Margin:Case study of the Namibe Basin
[Objective]Deepwater turbidite sand bodies in passive continental margin basins are a new field of oil and gas exploration.[Methods]High-resolution 3D seismic data for a typical passive deepwater basin margin(in this case,the Namibe Basin margin)enabled the sedimentary characteristics of limited channel submarine Quaternary sedimentary strata to be finely depicted and analyzed.Because these have been relatively unaffected by tectonic activ-ity and sedimentary compaction,they have retained the original sedimentary configuration of the channel.[Results and Conclusions]It was found that the erosion of confined turbid channels generally exceeded deposition.The sedi-mentary mode of a single channel exhibits mainly concave bank erosion and convex bank'S'-type accretion,leading to'V'-type valley broadening into wide'U'-type channel deposition.Multiple-channel sedimentary systems are di-vided into either lateral or vertical erosive superposition.The submarine topography of a narrow continental shelf and a wide,gentle continental slope has determined both the direction and length of extension of limited channels.The frequency of paleoclimate events has affected the developmental times of turbidite sand bodies in the channel system.These results provide information for predicting the presence of reservoirs and for analyzing the sedimentary architec-ture of channel turbidite sand bodies in exploration for oil and gas in this type of deep formation.
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