Seismic data show at least 1000 m of sediment accumulation with a prominent BSR, which occurs at the base of the gas hydrate stability zone. In addition, the sedimentary record recovered at Site 1055, together with that at Sites 1054 and 1056, may prove useful for testing models of continental slope sedimentation during glacial lowering of sea level. Biogenic carbonate and opal are present throughout the succession. There is evidence of downslope transport with as many as 20 thin carbonate turbidites and debris-flow deposits observed at Hole 1054A, but their thickness and occurrence among Site 1054 holes suggests spatial variability. The succession contains abundant and well preserved calcareous nannofossils and planktonic and benthic foraminifers.
Diatoms are common to abundant and exhibit moderate to good preservation.
Pteropods are well represented and become abundant in several discrete layers. The abundance of diatoms suggests that conditions of high productivity might have characterized the area of Site 1054 in the past 2.5 m.y. Reworking and displacement of shallow-water forms is surprisingly low, in spite of the sedimentological evidence of downslope transport and current activity. Below 75 mbsf in Hole 1054A, the magnetization signature is weak and difficult to interpret owing to drilling overprints. Low sedimentation rates between 0.5 and 1.0 Ma are associated with an interval where there is evidence of removal and redeposition of sediments by bottom currents.