The Ontong Java Plateau is the largest oceanic plateau in the world. The P.I.s propose to carry out systematic field sampling and a detailed petrographic, chemical, Nd-Sr-Pb isotopic, and 40Ar-39Ar investigation of a >2000 m-thick tract of plateau basement exposed on the island of Malaita in the Solomon Islands. To complement this work, the P.I.s will also study a suite of lavas (collected previously by the Solomon Islands Geological Survey) from other basement exposures along a 300-km-long zone in southern Malaita and the neighboring islands of Small Malaita and Santa Isabel. The results will extend knowledge gained from drilling by providing a deep, stratigraphically controlled record of mantle source, age, and petrogenesis, and a wide spatial coverage of basement age and compositional variations over a much broader region.
