We process a 230-km-long MCS section and a coincident OBS refraction profile acquired across the Spratly Islands south of the SW SCS oceanic basin. By joint interpretation between MCS profile and OBS derived P-wave velocity field, we identify pre-rift units, two stages of syn-rift and post-rift sediments in the basins. Normal faults tilting pre-rift units root in a shallow decollement south of the profile. This shallow decollement is directly imaged by a thick band of reflectivity and also identified by a velocity contrast in the refraction derived P-wave velocity model. Deeper down (∼7s twt), significant reflectivity may be interpreted as the top of the lower crust with ∼7 km/s velocities. Even deeper reflectors around 10–11s may be related to the Moho or mantle. The images show moderate finite extension in the pre-rift sedimentary infill, although large faults penetrate the basement. Syn-rift units show that the tertiary rifting of the SW SCS may be characterized by rapid and short-lived activity of the faults or more subaerial conditions. Deeper, we infer that multiple heterogeneities present in the continental crust are used as decollement levels at different depths down to the ductile lower crust.


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  1. Ding, W., Schnabel, M., Franke, D., Aiguo, R., Zhenli, W.U.
    , [2012]. Crustal Structure across the Northwestern Margin of South China Sea: Evidence for Magma-poor Rifting from a Wide-angle Seismic Profile. Acta Geologica Sinica - English Edition 86, 854–866.
    [Google Scholar]
  2. Franke, D., Pubellier, M., Steuer, S, Meresse, F., Savva, D., Auxietre., J.L.
    [2014] The final rifting evolution in the South China Sea, In, Special Publication “Evolution, Structure, and Sedimentary Record of the South China Sea and Adjacent Basins”, Eds: Pubellier, M., McIntoshK., Franke, D, Li, C.F., Menier, D., Marine and Petroleum Geology, 58, 704–720 (2014)
    [Google Scholar]
  3. Kudrass et al
    . [1986] Mesozoic and Cenozoic rocks dredged from the South China Sea (Reed Bank area) and Sulu Sea and their significance for plate-tectonic reconstructions. Marine and Petroleum Geology, 3, 19–30
    [Google Scholar]
  4. Pichot, T et al
    . [2014] Deep crustal structure of the conjugate margins of the SW South China Sea from wide-angle refraction seismic data. Marine and Petroleum Geology, http://dx.doi.org/10.1016/j.marpetgeo.2013.10.008
    [Google Scholar]
  5. Zelt and Smith
    [1992] Seismic traveltime inversion for 2D crustal velocity structure. Geophysical Journal international, 108(1), 16–34
    [Google Scholar]

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