Petrological investigations indicate that the diabases at Sites 1109 and 1118 show a typical intersertal texture between plagioclase and augite and chilled margin expressed by grain size reduction at the contact with a second sill/dyke injection. Gabbro at Site 1117 shows a typical gabbroic texture with the following order of crystallization: plagioclase, pyroxene, and quartz. The secondary mineralogy developed in the gabbro and diabases are typical of greenschist to subgreenschist facies conditions. This evolution is synchronous with the deformation (brittle to ductile) developed in the rocks at Site 1117 that is considered to be caused by present-day extension. In agreement with geochronological data, our results show that over the last 8 m.y. the upper crust in the Woodlark Basin was not thermally reset by subsequent heat supply.