Strontium, neodymium and lead isotopic signatures were measured on sediment samples from silt mantles that drape the bedrock of Anacapa and San Clemente Islands offshore California. These silt mantles are interpreted to be aeolian in origin and were deposited in the Late Quaternary (Muhs et al. 2007). All sediment samples had carbonates, organic material, biogenic silica and Fe-Mn oxides removed before full chemical digestion prior to analysis. Size fractions analysed were <63 μm and <10 μm.