Many rock types, including both aphyric basalt and plutonic rocks such as alkali granite, were recovered in a single dredge haul from Skiff Bank, quite close to Site 1139. The plutonic rocks were interpreted as ice-rafted debris. Hence, the age and composition of Skiff Bank's igneous crust and its relationship to the contiguous northern Kerguelen Plateau are not established. We chose this location as representative of the entire Skiff Bank on the basis of its relatively simple structural setting and thin sedimentary section. We recognize six lithologic units.
Trace fossils are very common.
Unit II records a substantial influx of terrigenous clay from an adjacent volcanic landmass. Sediments become semilithified by 100-110 mbsf. We observed very rare tephra layers and disseminated volcanic ash, locally concentrated in burrows. Within this depth interval, three volcanic ash layers have high P -wave velocities. The base of the pelagic section is earliest Oligocene in age.