First results of dives during the SUBPSO 1 cruise in the collision zone between the d'Entrecasteaux Ridges and the New Hebrides island arc

Abstract:

Geological cross-sections, constructed from observations and samples collected during seven dives of the French submersible Nautile, reveal that the inner wall of the New Hebrides trench, in front of the North d'Entrecasteaux ridge and the Bougainville guyot, is primarily composed of volcanic and volcaniclastic rocks, most likely shed from the arc. Observations indicate that the bedding of the arc-slope rocks, which generally slopes trenchward in this collision zone, dips steeply (40-80°) arcward near the contact of the colliding features. In this particular area, arc-slope rocks are generally highly fractured and sheared, an exception being rocks forming the ridge east of the Bougainville guyot. Arc-slope rocks are deeply incised by erosional channels and show numerous fresh slump scars. These scars confirm the importance of mass wasting along the deformation front. No evidence for fluid venting, such as mud volcanoes, was observed during the dives. -English summary

Año de publicación:

1989

Keywords:

Fuente:

scopus