The sediments of the Pacific Ocean hold the key to unraveling past fluxes in biologic productivity, metalliferous inputs, terrigenous inputs, atmospheric wind patterns, position of the Intertropical Convergence Zone (ITCZ), and volcanically active regions and periods. Each of the three main components of marine sediment (terrigenous matter, biogenic matter, and volcanic ash) can be quantified by various analytical and statistical methods. Shipboard and shore-based analyses of complete major and selected trace elements by Inductively Coupled Plasma Emission Spectrometry (ICP-ES) and shore-based analyses of complete trace elements and rare-earth elements (REE) by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) were used to elucidate the composition of the sediment in both the northwest and eastern equatorial Pacific Ocean. Shipboard results provide first-order analyses that can be used to develop preliminary mass accumulation rates, sedimentation rates, and other key factors that help to guide sample selection and shore-based studies. The importance and usefulness of combined analytical and statistical approaches to estimate the chemical composition of sediment is explored at Site 1149 in the northwest Pacific. A baseline data set was developed to expand this method to other sites within the Pacific, including the sites of Leg 199 in the eastern equatorial Pacific. Normative calculations, elemental relationships, factor analysis, and linear regression procedure were used to estimate the total terrigenous inventory and the dispersed ash component at Site 1149. These values were then used to determine the sources of dispersed ash and the influence of these sources on the chemical composition of the sediment.