(Table 2) Hf-Nd composition of DSDP site 18-174 sediments

Reported ratios are mass bias corrected and normalized based on 176Hf/177Hf=0.282160 for JMC 475 and 143Nd/144Nd=0.511860 LaJolla. Uncertainties for 176Lu/177Hf are 0.2%, for 147Sm/144Nd are 0.4%, and for concentrations of Lu, Hf, Sm, and Nd are <1%, based on isotopic reproducibility of USGS standard BCR-2. For calculation of epsilon values 143Nd/144Nd_CHUR(0)=0.512638 and 147Sm/144Nd_CHUR(0)=0.1966 were used. For calculation of epsilon Hf values 176Hf/177Hf_CHUR(0)=0.282772 and 176Lu/177Hf_CHUR(0)=0.0332 were used. For calculation of depleted mantle model ages 143Nd/144Nd_CHUR(0)=0.513150 and 147Sm/144Nd_CHUR(0)=0.2137 were used. Decay constant values used were: lambda_176Lu=1.867x10**-11 and lambda_147Sm=6.54x10**-12.