The dominant lithologies are grayish green clay with quartz and nannofossils, olive gray and reddish brown clay with nannofossils, light grayish green clayey nannofossil ooze, brown nannofossil clay, and greenish gray nannofossil clay mixed sediment. Lower sections have the same composition but contain slumped and faulted intervals. This spliced interval from this site can be combined with the spliced record from nearby Site 1147 to construct an unambiguous, continuous splice from 0 to 155.34 mcd. At Site 1148, seven lithologic units are identified on the basis of compositional, facies and especially color variations. The sediment at Site 1148 is more variable than at the other sites drilled on Leg 184.
Dominant lithologies are clay with variable concentrations of nannofossils.
None of these units show any evidence of sediment redeposition and are representative of continuous hemipelagic sedimentation. Thus, these sediments were impacted by the opening of the South China Sea. Despite this, very little lithologic variation occurred since the Early Oligocene beyond a series of sharp color changes, and a general trend to decreasing carbonate content since Unit VI times. While the lithology does not change, the mineral variation in the post Unit VI sediments demonstrates a tendency towards a more strongly physically weathered mineral assemblage, based on the increasing quartz, plagioclase, and chlorite concentrations. Importantly, we found no lithological evidence for deepening or shallowing of the water depth, with the site remaining hemipelagic and probably bathyal throughout.