ELEMENT GEOCHEMICAL RECORD OF THE WESTERN PACIFIC OCEAN SITE ODP807A: IMPLICATION FOR THE MIDDLE PLEISTOCENE CLIMATE TRANSITION

The element geochemical analysis of the upper 60.77 m section of ODP Hole 807A reveals climatic variations since 3.2 Ma. Significant changes in element concentrations during the Middle Pleistocene Transition (MPT) are marked by decreases of elements related closely to terrigenous clasts and increases of biogenic elements. Because there was little change in the provenance of terrigenous elements, variations in the terrigenous clastic content were mainly affected by the reduction itself, indicating the weaker wind transportation. The obvious increase of biogenic elements was attributed to the marked enhancement of the ocean productivity during the MPT. Furthermore, the spectral analysis of the sum rare earth elements (∑REE) shows the orbital characteristics of tropical climate changes from 41 ka to 100 ka periods.