Possible causes for structural variation where the New Hebrides island arc and the d' Entrecasteaux zone collide.

Abstract:

A major submarine mountain chain called the d'Entrecasteaux zone (DEZ) collides with the central part of the New Hebrides arc. Three migrated multichannel seismic sections obtained across this collision zone show considerable structural variability within slope rocks. The subducted top of the north ridge of the DEZ can be traced beneath the accretionary wedge. Strata forming this wedge could be uplifted remnants of a wedge that predated collision, or they could have been accreted from rocks that form the ridge crest. Large slope anticlines and major vertical-offset faults are absent from the vicinity of this ridge; therefore, such structures do not necesssarily form in collision zones. Between the two ridges of the DEZ, rocks forming the accretionary wedge dip towards the trend and terminate obliquely downward at the decollement between arc and subducted rocks. This attitude is unique to the collision zone and probably records the progradation of a flood of sediment eroded from nearby islands that underwent rapid uplift during the late Quaternary.-from Authors

Año de publicación:

1986

Keywords:

Fuente:

scopus