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The metamorphic basement, or granodiorites, and shear zone rocks of D'entrecasteaux Island in Papua New Guinea show a rapid cooling of the orogenic belt. Active extension at the western end of the propagating Woodlark Basin leads to the formation of metamorphic core complexes. A thermochronologic study reveals that the gneisses found in the core of the dome is cooling rapidly and that the retrogression of the metamorphic basement movement on the outer shear zone coincides with emplacement of granodiorites. This has resulted in the formation and the unroofing of the domes in the north-south directed extension of the region.