Sr and Nd isotopic compositions of 19 basalts from Hole 1179D, Leg 191 were analyzed to determine ridge and plume interaction. 87Sr/86Sr and 143Nd/144Nd ratios of the basalts ranged from 0.7029 to 0.7040 and from 0.5131 to 0.5132 (epsilon Nd0 = 9.3 ~ 10.8), respectively. Calculated initial isotopic compositions at 129 Ma, the age of magnetic Anomaly M8, are 87Sr/86Sri = 0.7026 ~ 0.7033 and epsilon NdT = 9.2 ~ 10.6. The initial Sr isotope ratio is higher than that of normal mid-ocean-ridge basalts (MORBs) from the East Pacific Rise and Mesozoic MORBs. They are similar to those of the Shatsky Rise, suggesting a plume component was involved in the formation.

Sediment depth is given in mbsf. K2O, Ba, Rb and Sr data are from Shipboard Scientific Party (2001, doi:10.2973/odp.proc.ir.191.104.2001) and Y. Hayasaka (unpubl. data). Epsilon Nd values at 129 Ma are estimated by 147Sm/144Nd = 0.2178, based on element data of average N-MORB (Sun and McDonough, 1989, doi:10.1144/GSL.SP.1989.042.01.19).

Supplement to: Sano, Sakae; Hayasaka, Yasutaka (2004): Sr and Nd geochemistry of Hole 1179D basalts. In: Sager, WW; Kanazawa, T; Escutia, C (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 191, 1-11