Limestone from Unit VI (857.1-859.15 meters below seafloor) collected at Site 1118 contains a planktonic foraminiferal fauna indicating a latest Miocene to early Pliocene age. Globorotalia tumida is recorded in Sample 180-1118A-68R-4, 46-48 cm, indicating an early Pliocene (N18) age at this level (J. Resig, pers. comm., 2000). Based on their known range in the western Papuan Basin, the presence of (rare) Lepidocyclina and common Amphistegina in some samples suggests that abundant shallow-water bioclastic debris present in these limestones may be reworked from older, possibly middle or early late Miocene sediments. Four samples were selected for whole-rock strontium isotopic analysis to further investigate this possibility. A petrographic examination of samples analyzed was also conducted.

Sediment depth is given in mbsf. 87Sr/86Sr ratios normalized to 87Sr/86Sr = 0.1194. 87Sr/86Sr ratios normalized to NBS-987 87Sr/86Sr = 0.710235. Measured NBS-987 87Sr/86Sr = 0.710244 ± 0.0024% (±0.000017) (95% confidence limits).

Supplement to: Allan, Tony; Robertson, Alastair H F; Sharp, Timothy R; Trotter, Julie (2001): Data report: Whole-rock 87Sr/86Sr composition and apparent strontium isotopic age of limestones from Site 1118, Woodlark rift basin, southwest Pacific (Ocean Drilling Program Leg 180). In: Huchon, P; Taylor, B; Klaus, A (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 180, 1-5