Observation of forearc seafloor deformation along the North d'Entrecasteaux Ridge - New-Hebrides Island Arc collision zone from Nautile submersible

• Published in: Proceedings of the Ocean Drilling Program. Initial reports 1992-03, Vol.134, p.43-53
• Main Authors: Greene, H. Gary, Collot, Jean-Yves, Pelletier, Bernard E, Lallemand, Serge
• Format: Article
• Language: English
• Subjects: Earth Sciences; Sciences of the Universe; Tectonics
• ISSN: 1096-2158
• DOI: 10.2973/odp.proc.ir.134.104.1992

Observations made from a dive (Dive 4) of the French submersible Nuririle along the deformation front associated with the North d'Entrecasteaux RidgeNew Hebrides Island Arc collision zone indicated strong compressional deformation and dewatering of an accretionary mass. Outcrops of highly tectonized nannofossil clay, chalk, and calcareous volcanic siltstone were examined and found to be smoothed and grooved from persistent downslope transport of sediment eroded from the upper forearc slope and islands of the arc. These sediments were directed from the nearshore and upper slope areas by a submarine canyon that is disrupted in mid-slope by the growing deformational front. From mid-slope, sediments are transported by sheet flow through many swales and gullies to the flat seafloor at the base of the slope, where the sediments are deposited as turbidites. Fluvial-like processes appear to be occurring along the deformation front as indicated by scour holes and depressions.