| The record of terrigenous material in deep-sea sediment is a valuable archive providing information about past changes in continental aridity and wind systems, and also sheds light on carbon export to deepwater because terrigenous material is thought to be an important carrier of nutrients to oceanic biological systems. This dissertation examines over multiple timescales the inorganic chemistry of marine cores from the equatorial Pacific Ocean to determine the spatial and temporal variability of terrigenous composition, and evaluates the relationship between terrigenous input and biological export production.; Chemical analyses of bulk sediment, combined with multivariate statistics, from Ocean Drilling Program (ODP) Site 1215 in the central Pacific show that latitudinal positioning beneath different wind systems controls the distribution of terrigenous material. Locations south of 20-22°N are chemically distinct from locations to the north and receive material via northeast tradewinds, whereas northerly locations receive material via westerlies. The aluminosilicate component that is chemically isolated from biogenic sediment older than 22 Ma includes a significant authigenic contribution, hindering the characterization of terrigenous matter when export production was at its greatest (53-54 Ma) and suggesting that typical sedimentological measurements (e.g., grain size) used in paleoclimate interpretations may be compromised.; Aluminosilicate material extracted from biogenic sediment in the eastern Pacific (0-12 Ma; ODP Sites 850, 1256) does not contain an authigenic signature. These terrigenous records, in conjunction with export production estimates, indicate that terrigenous delivery did not influence biological production, which was instead driven by changes in ocean circulation associated with the uplift of the Panama Isthmus.; Over glacial-interglacial timescales in the Pleistocene and Holocene, the mechanism by which the limiting micronutrient Fe is delivered to surface waters for biological uptake remains unclear. While conventional hypotheses suggest Fe is delivered via eolian dust, Fe may also be delivered from mid-water depths via upwelling of the Equatorial Undercurrent. The chemical and isotopic signatures of terrigenous material delivered to the narrow equatorial band between 4°N and 5°S indicate that there is no relationship between changes in terrigenous source region and export production, suggesting that terrigenous variability is not the primary mediator of Fe limitation through the Pleistocene. |
